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Risk Assessment of Short-Chain Chlorinated Paraffins in Japan

  • Kiyotaka TsunemiEmail author
Chapter
Part of the The Handbook of Environmental Chemistry book series (HEC, volume 10)

Abstract

The objective of this chapter is to assess the ecological and human health risk of short-chain chlorinated paraffins (SCCPs) via the environment in Japan. First, release sources of SCCPs are identified based on the substance flow analysis, and the volume of their releases is estimated. Next, the behavior of SCCPs in the environment is estimated using a multimedia model, and the estimated SCCPs concentrations in the environment and food are validated with measured concentrations. Then, the endpoints and doses of SCCPs as the criteria for ecological and human health risk assessment are derived through the review of the existing toxicological data. Finally, risk characterization is performed based on the results of exposure assessment and dose-response assessment. As a result, it is determined that there is little need to be concerned about potential ecological risk to aquatic, sediment-dwelling, and soil-dwelling organisms in local areas and the regions in Japan. As far as human health risk is concerned, the Margins of exposure are 1.5 × 105 and 2.2 × 106, which are larger than uncertainty factors. Thus, it is determined that there is no significant human health risk via the environment.

Keywords

Ecological risk Exposure assessment Human health risk Multimedia model Risk assessment Short-chain chlorinated paraffins 

Abbreviations

BCF

Bioconcentration factor

CPs

Chlorinated paraffins

EA

Environment agency

EUSES

European union system for the evaluation of substances

FRCJ

Flame retardant chemicals association of Japan

HC5

Hazard concentration 5

LCCPs

Long-chain chlorinated paraffins

LOD

Limit of detection

MCCPs

Medium-chain chlorinated paraffins

MHLW

Ministry of health, labor and welfare

MLIT

Ministry of land, infrastructure and transport

MOE

Margin of exposure

NOAEL

No observed adverse effect level

NOEC

No observed effect concentration

NOEL

No observed effect level

NTP

National toxicology program

PNEC

Predicted no effect concentration

PRTR

Pollutant release and transfer register

SCCPs

Short-chain chlorinated paraffins

SRTI

Statistical research and training institute

SS

Suspended solid

SSD

Species sensitivity distribution

TGD

Technical guidance document

TRI

Toxics release inventory

1 Introduction

In Japan, no regulation for short-chain chlorinated paraffins (SCCPs) had been implemented and SCCPs are not included in the list of designated chemical substances for the Pollutant Release and Transfer Register (PRTR). Risk assessment of SCCPs, which was performed in Europe, the U.S, Canada, and Australia, was not conducted in Japan, and the releases of SCCPs into the environment, which can be obtained from the Toxics Release Inventory (TRI) in the U.S., are not available.

In 2003, the Law Concerning the Evaluation of Chemical Substances and Regulation of Their Manufacture, etc. was amended in Japan. The main aims of the amendment are the implementation of the system to assess and regulate chemical substances from the viewpoint of the effects on plants and animals in the environment, the introduction of regulations for existing chemical substances with persistence and high bioconcentration, and a screening system based on the probabilities of releases into the environment. In February 2005, SCCPs were classified into Class I Chemical Substances Monitored, which include substances with persistence and high bioconcentration. Therefore, public attention on the risk of SCCPs has been increased.

With this background, National Institute of Advanced Industrial Science and Technology (AIST) conducted a risk assessment for SCCPs with regard to the domestic industrial structures related to SCCPs including production, use, and waste management processes [1].

2 Releases into the Environment

With the current regulatory situation in Japan, where no regulation of SCCPs has been implemented and SCCPs are not designated as PRTR-list substances, almost no information is available on their production and use to identify release resources, and also very little data of environmental monitoring have been obtained. Under such difficult conditions with limited data on SCCPs, the demand and use of SCCPs are estimated in this assessment not only using statistics and reported data but also by obtaining information via interviews with companies and industrial organizations; further releases into the environment are estimated using release factors established overseas as required.

2.1 Substance Flow Analysis

SCCPs are used as extreme-pressure additive to metal working fluids, flame retardant, and plasticiser of plastics, rubber, and paints, and the products including these additives are used for various purposes. As shown in Fig. 1, the usage and releases into the environment of SCCPs are estimated on each life cycle stage of SCCP production, formulation, processing, use, waste treatment, disposal, and recycling. This study estimated the substance flow at each of these stages in Japan in 2001.
Fig. 1

Main life cycle stages of SCCPs

Interannual changes in production of total chlorinated paraffins (CPs) reported by the Flame Retardant Chemicals Association of Japan (FRCJ) [2] are shown in Fig. 2. FRCJ also reported the production and shipment of SCCPs, medium-chain chlorinated paraffins (MCCPs), and long-chain chlorinated paraffins (LCCPs) in 2001 [2] as shown in Table 1. It indicates that ≈500 tons per year of SCCPs were shipped, suggesting that SCCPs were not used for polyvinyl chloride. In the Kanto region, 500 tons per year of SCCPs were mainly used in oil fluids. In contrast, nearly 200 tons of SCCPs were shipped to the Kansai region for other uses including flame retardant additives and lipid additives for rubber, paint, and adhesives. As shown in Table 1, approximately half of SCCPs were used in oil fluids and the other half for other products.
Fig. 2

Interannual changes in production of total CPs [2]

Table 1

Domestic shipment of CPs in 2001 by region [2]

Product

Region

Use for oil fluid (tons per year)

Use for polyvinyl chloride (tons per year)

Other use (tons per year)

Total (tons per year)

SCCPs

Kanto

175

32

207

Kansai

31

190

221

Overall Japan

240

262

502

MCCPs

Kanto

2,279

1,516

348

4,143

Kansai

710

1,951

173

2,834

Overall Japan

3,199

3,619

799

7,617

LCCPs

Kanto

190

592

1,347

2,129

Kansai

145

243

618

1,006

Overall Japan

390

966

2,365

3,721

Total CPs

Kanto

2,644

2,108

1,727

6,479

Kansai

886

2,194

981

4,061

Overall Japan

3,829

4,585

3,426

11,840

The amount of MCCPs was the largest among total CPs and 7,600 tons of MCCPs were shipped all over Japan, mainly for use as plasticizers for polyvinyl chloride. Also, 3,700 tons of LCCPs were shipped mainly for other uses. Based on these data, the production percentage of SCCPs to total CPs is estimated to be 4.15% in 2001.

The above data are the only available data on SCCP production and no specific data before 2000 are obtained. Therefore, interannual changes of SCCP production are estimated, based on the assumption that the percentage of 4.15% for SCCPs was constant from the beginning of production in 1950. Specifically, it is assumed that SCCP production was increased in proportion to the enhanced production of total CPs along with the industrial development in Japan, and the promotion of substitution with non-chlorine-based products had similar effects, both on SCCPs and total CPs. Also, it is assumed that SCCP production was increased linearly during the period from 1950 to 1975 and 1975 to 1979 because of the lack of data. Further, it is assumed that 50% of SCCPs were used in metal working fluids and another 50% for other products including flame retardant additives and lipid additives. As a result, the estimated consumptions of SCCPs from 1950 to 2002 in Japan are obtained and presented in Fig. 3, which indicate a profile with a peak of 1,200–1,400 tons per year from 1980 to 1990, and a decrease to 500 tons per year by 2000.
Fig. 3

Estimated consumption of SCCPs from 1950 to 2002 in Japan

The substance flow of SCCPs in 2001 is estimated as shown in Table 2. As of 2002, there are three domestic companies (four plants) producing CPs; Tosoh (Shin-nanyo and Sakata, total production capacity: 18,000 tons per year), Ajinomoto Fine-Techno (Kawasaki, production capacity: 12,000 tons per year), and ADEKA (Kajima, production capacity: 12,000 tons per year) [3]. Two plants with similar production capacity are located in the Kanto region and their production capacity was ≈50–60% of all plants in Japan as of 2000. When the domestic distribution of production is almost equal to the production capacity, it is assumed that 50% of nationwide production is in the Kanto region, of which 50% is produced in one plant, and used as the basis for exposure analysis.
Table 2

Volumes of production and use of SCCPs in 2001. Figures in parenthesis indicate the range from half to twice of the median

Life cycle stage

Whole Japan (tons per year)

Kanto region (tons per year)

Plant as a local area (tons per year)

SCCP production

502

250

125

Metal working fluid formulation

240

175

35

Metal working fluid use

240

72

7.2 (3.6–14.4)

Manufacturing of SCCP- containing products

262

32

3.2 (1.6–6.4)

Based on the reliable data provided by FRCJ as shown in Fig. 4 [2], the SCCPs in metal working fluids in the stages of production and the use of metal working fluids is determined to be 240, of which 175 tons were used in the Kanto region. In the Kanto region, more than five formulation plants for metal working fluids are located, and therefore, it is assumed that 20% of the usage of the Kanto region is used in each plant.
Fig. 4

Amount of SCCPs demanded by regions in 2001 [2]

The usage of metal working fluids containg SCCPs in the Kanto region is estimated from the values of shipment related to metal working in nationwide industrial statistics. As the shipment of Kanto region was ≈30% of the total values in Japan from the industrial statistics in 2001, it is assumed that the volumes of fluid usage are in proportion to the shipment values of 240 tons of SCCPs used in fluids across the country, ≈30%; 72 tons is estimated to have been used in the Kanto region. There are, however, no data available on the number of companies using metal working fluids containing SCCPs. Although many small companies are located, assuming that ten large and middle companies are located in the Kanto region, the scenario is set for 10% of usage of the Kanto region being used in each plant.

The total volume of SCCPs in plastics, gum, paint, and adhesive is determined to be 262 tons without classifying the volume of each use of SCCPs.

The SCCP use for manufacturing SCCP-containing products in the Kanto region is estimated to be 32 tons [2], and ≈10% of usage of the Kanto region is used in each plant, similar to the use of metal working fluids.

To estimate the environmental concentration in a local area near the release site, the usage of SCCPs in one plant in the Kanto region is estimated. Firstly, it is required to estimate the number of plants that are located in the Kanto region. SCCPs are used only for specific purposes including additives to metal working fluids for difficult metal processes and flame-retardant additives, and thus, plants using SCCPs are expected to be limited. It is assumed that one plant using SCCPs is located around a sewage treatment plant with the average capacity in Japan and releases SCCPs into water through the sewage treatment plant. In the stages of SCCP production and metal working fluid formulation, the approximate number of plants in the Kanto region is estimated. However, in the stages of using metal working fluids and manufacturing SCCP-containing products, the number of plants is estimated based on insufficient data. Therefore, a sensitivity analysis is to be conducted using the estimated usage as a median and with the range from half to twice the median.

The amount of end-use products containing SCCPs was estimated using the following equation that represents Weibull distribution that is a continuous probability distribution and is often used in the field of life data analysis due to its flexibility.
$$ f(x) = \left( {\frac{u}{{{v^u}}}} \right){x^{u - 1}}\exp \left[ { - {{\left( {\frac{x}{v}} \right)}^u}} \right] $$
(1)
where f (x) is the function of lifetime, u and v are the parameters of the Weibull distribution. Because the ratio of SCCP-containing products is unclear, the uses of CPs are combined. Assuming that 90% of final products are disposed of in 5–30 years, parameters are estimated as u = 3 and v = 17.5. The interannual changes in SCCP production that are shown in Fig. 3 are applied to this function; the cumulative volumes of SCCP production are estimated. As a result, the cumulative disposal from 1950 to 2001 is estimated to be ≈15,800 tons and the volume of stock of SCCPs in 2001, as contained in products, is estimated to be 5,300 tons. Assuming that the disposal of SCCP-containing products depends on population distribution, the cumulative disposal of SCCPs in the Kanto region is estimated to be 30% of the total volume in Japan, i.e., 4,740 tons.

2.2 Estimation of Releases into the Environment

Although there are no release data for SCCPs in Japan, relevant guidance documents and risk assessment reports were referred to derive appropriate release factors [4] as shown in Table 3.
Table 3

Release factors of SCCPs by life cycle stage

Life cycle stage

Air release factor (%)

Water release factor (%)

Soil release factor (%)

Source

Production of SCCPs

0

0.01

0

[37]

Formulation of metal working fluids

0.005

0.2

0.001

[40]

Use of metal working fluids

8

5

0

[1]

Waste treatment of scraps after use of metal working fluids

0

0.82

0

[1]

Disposal of waste oil after use of metal working fluids

0

0.039

0

[1]

Manufacturing of SCCP-containing products

0

0.001

0

[37]

Use of SCCP-containing products (outdoor)

0.0029

0.16

0

[42]

Use of SCCP-containing products (indoor)

0.0029

0.0029

0

[42]

Waste treatment of SCCPs

0

0.0029

0

[42]

Multiplying the estimated volumes of SCCP use by each of the SCCP release factors by life cycle stage, the SCCP releases into the environment are estimated as shown in Table 4. Regarding the volumes of local releases, a 10% release factor from a sewage treatment plant into river water is applied to the releases from a single plant in the Kanto region to estimate the release after waste treatment.
Table 4

Estimated SCCP releases in 2001. Figures in parenthesis indicate the range from a half to twice of the median

Life cycle stage

Releases in the whole of Japan (kg per year)

Releases in the Kanto region (kg per year)

Releases in a local area (kg per year)

Medium to which release occurs

Production of SCCPs

50

25

13

Water

Formulation of metal working fluids

12

8.75

1.75

Air

480

350

70

Water

2.4

1.75

0.35

Soil

Use of metal working fluids

19,200

5,760

576 (288–1,152)

Air

12,000

3,600

360 (180–720)

Water

Waste treatment of scraps after use of metal working fluids

1,968

590

 

Water

Disposal of waste oil after use of metal working fluids

93.6

28.1

 

Water

Manufacturing of SCCP-containing products

2.6

0.32

0.03 (0.02– 0.06)

Water

Use of SCCP-containing products

154

46

 

Air

4,317

1,295

 

Water

Waste treatment of SCCP-containing products

183

55

 

Water

Total

19,366

5,815

 

Air

19,095

5,944

 

Water

2.4

1.75

 

Soil

Of the total volume of SCCPs released into water, it is assumed that 63.5%, which is the ratio of sewage system coverage in 2001, flows into sewage treatment plants. Total SCCP releases from life cycle processes into water (whole Japan: 19,095 kg per year, Kanto region: 5,944 kg per year) are multiplied by the treatment percentage in domestic sewage treatment plants (63.5%) [5], and as a result, the volumes of SCCPs in influent into sewage treatment plants are estimated to be 12,125 kg per year (whole Japan) and 3,774 kg per year (Kanto region). Subsequently, the direct releases of SCCPs in surface water are estimated to be 6,970 kg per year (whole Japan) and 2,170 kg per year (Kanto region). These values are multiplied by the release factor into water (10%) and transfer factor into sludge (90%) at sewage treatment plants and the SCCP releases from sewage treatment plants are estimated as shown in Table 5.
Table 5

Estimated SCCP releases from sewage treatment plants in 2001

 

Japan

Kanto region

Release into surface water (kg per year)

1,213

377

Release into sludge (kg per year)

10,913

3,397

The flow of SCCPs through sewage treatment plants is summarized as shown in Fig. 5. It is estimated that the volumes of SCCPs released in agricultural land are 218 kg per year in the whole of Japan and 3.40 kg per year in the Kanto region, respectively from the values in Table 5.
Fig. 5

Estimated flow of SCCPs through sewage treatment plant. The figures in italics indicate the percentages of the volume of SCCPs by each recycling stage to that of SCCPs in sewage sludge

In this section, the release sources of SCCPs into the various environmental compartments in 2001 are identified and shown in Fig. 6. The material flow of SCCPs consists of two major routes of metal working fluids and other products containing SCCPs, and each route has life cycle stages of production, use, and disposal. SCCPs are released mainly at the use stage of metal working fluids into the air (19,200 kg per year) and water (12,000 kg per year), which is expected to have local effects in the areas around metal working plants. The second largest is the release into water from the use stage of SCCP-containing products (4,317 kg per year), which is estimated from the accumulated volume of SCCPs in the products shipped up to 2001. As these products were dispersed and had little local effect, it is relevant to assess their effects only with spatial levels of the Kanto region and the whole of Japan.
Fig. 6

Flow and emission of SCCPs in 2001 in Japan and Kanto region. The figures in parenthesis indicate the flow and emission in Kanto region

3 Exposure Assessment

SCCPs released into the environment reach humans and organisms through various pathways. It is necessary to identify the main exposure routes from release sources to humans and organisms in the environment in order to assess exposures to SCCPs. In this section, the existing data about equilibrium partition and degradation of SCCPs are summarized. Also, the behavior of SCCPs in environmental media including air and soil and the biokinetics in plants and fish is estimated using a multimedia model, and the main exposure routes are identified. The concentrations of SCCPs in the environment and food that were obtained in domestic monitoring are reviewed, and the observed data, mainly in the Kanto region where high volumes of SCCPs are used, are summarized. Based on these results, the concentrations of SCCPs in the environment and food are identified for risk assessment.

3.1 Behavior in Environment

In this section, selecting C12H20Cl6 (chlorine: 56.5%) with C12 (mean of C10–13) and Cl6 (mean of Cl1–12) as the representative SCCP, the parameters used for estimating the behavior of SCCPs in the environment are described briefly.

3.1.1 Physical Properties and Partition Coefficients

The data of physical property used for model application are as follows: molecular weight of C12H20Cl6 is 377 g mol−1, melting point is –30°C [6], vapor pressure is 0.000227 Pa (25°C) [7], and solubility in water is 0.0625 mg L−1 (25°C) [8]. The data of partition coefficients used for model application are as follows: log octanol-water partition coefficient (log K OW) is 6.4 [9] and log organic carbon-water partition coefficient (log K OC) is 5.3 [10].

3.1.2 Degradation

Abiotic degradation of SCCPs in the air has been reported. [11, 12] estimated that the second reaction rate constant of SCCPs with C10–13 and 49–71% chlorine with OH radical was 2.2–8.2 × 10−12 cm3 molecule−1 s−1. The author reported that the half-life in air was estimated to be 1.9–7.2 days, based on the assumption that the OH radical concentration in the air was 5 × 105 molecule cm−3. In this assessment, the half-life as a parameter for modeling is set to be 3.1 days, which is estimated by multiplying the median of the second reaction rate of 5.2 × 10−12 cm3 molecule−1 s−1 by the OH radical concentration of 5 × 105 molecule cm−3.

Abiotic degradation in other media has not been reported and most available publications are on biodegradation in aerobic conditions. In all of the biodegradation studies, however, the concentrations of SCCPs exceeded the maximum water solubility of SCCPs (0.975 mg L−1). Therefore, it is assumed as a worst case scenario that SCCPs are not degraded in water, soil, sediments, or sewage sludge.

3.1.3 Bioconcentration

Because log K OW of SCCPs is estimated to be 6.4, it is necessary to discuss the bioconcentration of SCCPs, not just for the effects on the survival and reproduction of aquatic organisms but also for those on birds and mammals, the predictors of fish. Furthermore, SCCPs were classified as chemicals with high bioconcentration under the Law Concerning the Examination of Chemical Substances and Regulation of Manufacture, etc.

At the meeting of the Chemical Substances Council held by the Japanese government in 2004, it was reported that a bioconcentration study was conducted in 2003 with SCCPs with C11 and Cl7, 8, 9, 10 (chlorine: 62.5, 65.7, 68.5 and 70.9%) containing 1% of stabilizer and the quantitative data on each individual substance were obtained [13]. The study was conducted with flow-through system at concentrations of 1 and 0.1 μg L−1 of SCCPs, and 20 mg L−1 of 2-metoxyethanol was used as dispersant. Liquid chromatography/mass spectrometry (LC/MS) was used for the analysis of the test species, carp (Cyprinus carpio). After 62-day exposure, a 14-day excretion study was also conducted. The result is shown in Table 6.
Table 6

Summary of the study on bioconcentration of carp, Cyprinus carpio [13]

CPs

Concentration

BCF, whole body

BCF, skin

BCF, head

BCF, viscera

BCF, edible part

C11H17Cl7

0.1 μg L−1

1,900–5,900

<720

3,900

7,000

<720

1,900

2,300

C11H17Cl7

1.0 μg L−1

5,400

2,400

7,800

5,300

11,000

7,400

20,000

1,500

2,900

C11H16Cl8

0.1 μg L−1

2,500–7,000

4,800

5,300

6,200

11,000

<640 28,000

1,600

4,100

C11H16Cl8

1.0 μg L−1

6,700

2,900

14,000

8,700

15,000

11,000,

26,000

1,800

3,800

C11H15Cl9

0.1 μg L−1

2,700–9,500

<680

<680

5,500

12,000

<680

21,000

<680

4,600

C11H15Cl9

1.0 μg L−1

8,100

3,600,

17,000

9,500

18,000

15,000

34,000

2,200

4,500

C11H14Cl10

0.1 μg L−1

2,600–6,700

<620

<620

3,100

11,000

<620

13,000

<620

<620

Exposure 62 days and depuration 14 days, flow-through test system, dispersant: 2-metoxyethanol, 20 mg L−1

The results indicated that the Bioconcentration factor (BCF) of the whole body at a concentration of 0.1 μg L−1 peaked at 38 days of exposure and the BCFs of CPs with C11 and Cl7, 8, 9, 10 were 5,900, 7,000, 9,500, and 6,700, respectively. BCFs at a concentration of 1 μg L−1 of BCFs of CPs with C11 and Cl7, 8, 9, 10 were 8,100, 9,200, 11,000, and 9,200, respectively. With the local analyses of two carps at a concentration of 0.1 μg L−1, BCF ranged from 620 to 720 or less in the skin, 3,100–12,000 in the head, 3,100–28,000 in the viscera, and 1,100–4,700 in the edible part, respectively. The excretion half-life was longer with CPs of higher chlorine, i.e., half-lives of CPs with C11 and Cl7, 8, 9, 10 at a concentration of 0.1 μg L−1 were 2.6, 6.2, 8.6, and 14 days, respectively, and those at a concentration of 1 μg L−1, 6.7, 10, 9.7, and 13 days, respectively.

The EU risk assessment adopted 7,816, the maximum BCF, which was estimated in a study of SCCPs with C10–12 and 58% chlorine in rainbow trout by [14, 15]. In this assessment, considering the high applicability of the data obtained in the bioaccumulation study through the gill of SCCPs conducted in Japan for domestic risk assessment, the BCF through gill in fish is established to be 5,900, BCF of CP with Cl7, which is most similar to the representative SCCP, C12H20Cl6.

3.2 Estimation of the Main Exposure Routes by Environmental Fate Modeling

The concentrations of SCCPs in the environment are estimated in the local areas around release sources, in Kanto region, and the whole of Japan using the EUSES [16]. The quantities used as inputs in the model are the total amount released in the Kanto region and across Japan. Details of the parameters for land use are shown in Table 7. The average temperature and the amount of rainfall are identified as 15°C and 1,500 mm per year, respectively [17].
Table 7

Parameters for land use as used in the model

Scale

Parameter

 

Value

Year of data

Japan

Area

 

372,837 km2

2000

 

Number of inhabitants

 

126,926,000

2000

 

Area fraction

Agricultural soil

13.00%

2000

  

Natural soil

67.10%

2000

  

Water

3.60%

2000

  

Industrial and urban soil

16.30%

2000

Kanto region

Area

 

32,423 km2

2000

 

Number of inhabitants

 

40,434,000

2000

 

Area fraction

Agricultural soil

20.40%

1998–2002

  

Natural soil

44.10%

1998–2002

  

Water

5.00%

1998–2002

  

Industrial and urban soil

30.30%

1998–2002

The concentrations of SCCPs in the environment estimated by the multimedia model are shown in Tables 7 and 8. The environmental concentrations in Kanto region are higher than the average concentrations in Japan. Further, as shown in Table 3, SCCP concentrations in water and sediments around release sources are higher than those in Kanto region, suggesting that SCCPs remain locally and affect the ecosystem. Of these concentrations, the highest concentrations are those in water and sediment from the use stage of metalworking fluids, and the main route is the release into water from metal working plants through sewage facilities (Table 9).
Table 8

Estimated SCCP concentrations in the environment in Kanto region and Japan

Item

Unit

Kanto region

Japan

Concentration in air

ng m−3

0.430

0.180

Concentration in water

µg L−1

0.0375

0.0125

Concentration in sediment

mg kg−1 ww

0.286

0.0959

Concentration in soil

mg kg−1 ww

0.150

0.0627

Concentration in agricultural soil

mg kg−1 ww

0.151

0.0790

Table 9

Estimated SCCP concentrations in the environment around release sources

Item

Unit

Production of SCCPs

Production of metal working fluids

Use of metal working fluids

Manufacturing of SCCP-containing products

Concentration in water

µg L−1

0.0567

0.126

0.492

(0.265–0.947)

0.0375

(0.0375–0.0375)

Concentration in sediment

mg kg−1 ww

0.246

0.629

2.56

(1.36–4.96)

0.163

(0.163–0.163)

Values in parenthesis are the range of concentrations when SCCP use volumes are set in the range of half to twice of the median

The concentrations of SCCPs in the environment estimated by the multimedia model are shown in Table 10. Concentrations in the root tissue of plants are relatively high. The SCCP concentrations in fish are also high, which, on the other hand, is due to high bioaccumulation of SCCPs.
Table 10

Estimated SCCP concentrations in food

Food

Concentration

Leaves of plant

2.06 μg kg−1

Root tissue of plant

738 μg kg−1

Meat

13.4 μg kg−1

Milk

4.23 μg kg−1

Fish

221 μg kg−1 ww

3.3 Monitoring Data in Japan

While monitoring data of total CPs and LCCPs are available, no data of SCCPs alone are available in Japan. In order to supplement the information on concentrations of SCCPs in the domestic environment by obtaining the measured concentrations of SCCPs in Japan, AIST conducted its own monitoring in the Kanto and Kansai regions, which have many industrial plants and large populations.

3.3.1 Water

In 1980 and 1981, the first monitoring of CPs in the domestic environment was performed by Environment Agency (EA). The environment monitoring for water and sediment was conducted in 1980 [18] and the comprehensive environmental monitoring for water, sediment, and fish (edible part) in 1981 [19]. In these monitorings, the total CPs including SCCPs, MCCPs, and LCCPs were analyzed.

Water samples were collected from 17 sites (three samples/site) in the environment monitoring and 40 sites (three samples/site) in the comprehensive environmental monitoring. CP concentrations were analyzed using GC/ECD and the detection limit in water was 0.01 μg mL−1. In the environment monitoring in 1980, no CPs were detected in all 51 water samples. In the comprehensive environmental monitoring in 1981, no CPs were detected in all 120 water samples.

The results of the Environmental Investigation on the Status of Pollution by Chemical Substances by the Ministry of the Environment have been reported in Chemicals in the Environment published annually in Japan, and LCCPs were selected as the substances analyzed in 2001 [20]. The analysis was conducted according to the analytical method for LCCPs that was reviewed by [21]. CPs analyzed were LCCPs with 40 and 70% chlorine whose standards were available from Wako Pure Chemical Industries, and eight congeners each shown in Table 11 were selected and analyzed. Test samples were collected from water and sediment.
Table 11

Measured congeners of LCCPs [21]

LCCPs with 40% chlorine

C22H40Cl6, C23H42Cl6, C23H41Cl7, C24H43Cl7, C24H42Cl8, C25H44Cl8, C25H43Cl9, C26H45Cl9

LCCPs with 70% chlorine

C24H31Cl19, C25H33Cl19, C25H32Cl20, C26H34Cl20, C26H33Cl21, C27H35Cl21, C27H34Cl22, C28H36Cl22

LCCPs were determined by APCI negative ion chemical ionization analysis (APCI-negative) using LC/MS. The detection limits of this method were based on the experimental values obtained in six recovery tests as shown in Table 12.
Table 12

Results from the environmental investigation on the status of pollution by chemical substances in Japan (water), monitored in 2001 [20], n.d. means not detected

District

LCCPs, chlorine: 40%

(Standard detection limit: 0.28 μg L−1)

LCCPs, chlorine: 70%

(Standard detection limit: 0.14 μg L−1)

Ishikari River estuary

0.77, 0.49, n.d.

0.46, 0.83, n.d.

Nagoya port

n.d., n.d., n.d.

n.d., n.d., n.d.

Yokkaichi port

n.d., n.d., n.d.

n.d., n.d., n.d.

Toba port

n.d., n.d., n.d.

n.d., n.d., n.d.

Mizushima offshore (Tamashima)

n.d., n.d., n.d.

n.d., n.d., n.d.

Takamatsu port

n.d., n.d., n.d.

n.d., n.d., n.d.

Kanmon channel

n.d., n.d., n.d.

n.d., n.d., n.d.

The environmental survey was conducted at seven sampling sites (three samples/site) and there was no sampling site in which LCCPs were detected in all three samples. LCCPs were detected in only two samples from the Ishikari River estuary and these samples showed different physical appearance in the pretreatment stage. Considering a better sensitivity in later years has led to detection of CPs, it is possible to conclude that almost no LCCP was detected in the water.

AIST measured CPs in river water. Samples were collected in Tokyo and Osaka in June 2002. The analytical results are shown in Table 13 and the mean concentrations of SCCPs in the river water samples in the Kanto region was 25.5 ng L−1 (Table 14).
Table 13

Analytical results of SCCPs in domestic river water samples (ng L−1) [22]

CPs

Sumidagawa River, Iwabuchi-suimon, Tokyo

Arakawa River, Kasaibashi, Tokyo,

Yodogawa River, Hirakataohashi, Osaka

Yodogawa, Ozeki, Osaka

C10H18Cl4

<5

<5

<5

<5

C10H17Cl5

<5

<5

<5

<5

C10H16Cl6

7.7

8.1

9.5

7.6

C 10 total

7.7

8.1

9.5

7.6

C11H20Cl4

<5

<5

<5

<5

C11H19Cl5

<5 (1.6)

<5 (1.9)

<5 (2.3)

<5 (2.2)

C11H18Cl6

<5 (2.1)

<5 (2.5)

<5 (2.6)

<5 (2.6)

C11H17Cl7

5.6

11

<5 (3.9)

<5 (4.2)

C11H16Cl8

6.5

12

<5 (2.3)

<5 (2.4)

C 11 total

12.1 (15.8)

23 (27.4)

0 (11.1)

0 (11.4)

C12H22Cl4

<5

<5

<5

<5

C12H2Cl5

<5

<5

<5

<5

C12H20Cl6

<5

<5

<5

<5

C12H19Cl7

<5 (2.2)

<5 (2.1)

<5 (2.0)

<5 (2.1)

C12H18Cl8

<5 (1.0)

<5 (0.9)

<5 (0.7)

<5 (0.7)

C 12 total

0 (3.2)

0 (3.0)

0 (2.7)

0 (2.8)

C13H24Cl4

<5

<5

<5

<5

C13H23Cl5

<5

<5

<5

<5

C13H22Cl6

<5 (0.5)

<5 (0.3)

<5

<5

C13H21Cl7

<5 (0.6)

<5 (0.4)

<5 (0.3)

<5 (0.2)

C13H20Cl8

<5 (0.8)

<5 (0.4)

<5 (0.2)

<5 (0.2)

C 13 total

0 (1.9)

0 (1.1)

0 (0.5)

0 (0.4)

C 10–13 total

20 (29)

31 (40)

9.5 (24)

7.6 (22)

Detection limit is 5 ng L−1. Results in parentheses are data when distinguishable peaks lower than the detection limit are counted

Table 14

Results from environmental investigation on the status of pollution by chemical substances in Japan (sediment) monitored in 2001 [20], n.d. means not detected

District

LCCPs, chlorine: 40% (Standard detection limit: 0.038 mg kg−1 dw)

LCCPs, chlorine: 70% (Standard detection limit: 0.011 mg kg−1 dw)

Ishikari River estuary

n.d., n.d., n.d.

n.d., n.d., 0.013

Nagoya port

0.074, 0.071, 0.057

n.d., n.d., n.d.

Yokkaichi port

0.096, 0.097, 0.34

0.024, 0.076, 0.3

Toba port

2, 0.28, 0.28

0.39, 0.06, 0.064

Mizushima offshore (Tamashima)

n.d., 0.042, 0.045

0.011, 0.033, 0.061

Takamatsu port

0.5, 0.28, 0.47

0.057, 0.041, 0.076

Kanmon channel

0.15, 0.16, 0.83

0.023, 0.049, 0.073

3.3.2 Sediment

EA conducted the environmental monitoring of chemical substances, including all CPs in sediments similar to those conducted in water at 17 sampling sites (three samples/site) in 1980 and the environmental survey at 40 sampling sites (three samples/site) in 1981. CP concentrations were analyzed using GC/ECD with the detection limit of 0.5 mg kg−1.

In 1980, while monitoring the chemical substances in the environment [18], CPs were detected in all three samples from 6 of 17 sampling sites, i.e., Yokohama port (2.7–7.4 mg kg−1 dw), Tsurumi River estuary (1.7–3.7 mg kg−1 dw), Lake Suwa (1.6–4.8 mg kg−1 dw), Osaka port (1.3–4.1 mg kg−1 dw), Kobe port (0.9–4.1 mg kg−1 dw), and Kure bay (2.0–6.2 mg kg−1 dw). The highest concentration of six sampling sites was 7.4 mg kg−1 dw in Yokohama port and the highest in all samples was 9.4–10 mg kg−1 dw in Himeji offshore (Ichi River estuary).

In the 1981 comprehensive monitoring of chemical substances in the environment [19], CPs were detected in all three samples from 8 of 40 sampling sites, i.e., Niigata-Higashi port, Arakawa River estuary, Tama River estuary, Kawasaki port, Yokohama port, Tsurumi River estuary, Kobe port, and Himeji offshore. The highest concentration of eight sampling sites was 8.5 mg kg−1 dw in Yokohama port and this concentration was the highest in all samples and was far higher than the other measured values. In the analyses of CPs in fish (edible part) conducted at the same time, no CPs were detected in all 108 samples (28 sampling sites). It should be noted, however, that the detection limit in fish was 0.5 mg kg−1 at that time.

In the environmental investigation on the status of pollution [20], LCCPs with 40 and 70% chlorine in sediments were determined by APCI-negative using LC/MS. The detection limits of this method were based on the experimental values obtained in six recovery tests. The results indicated that LCCPs were accumulated in sediments of all sampling sites except the Ishikari River estuary. In the Ishikari River estuary, however, LCCPs were detected in river water but not in sediments, which was the reverse of the result of others.

In the analyses in 1980 [18], all CPs were analyzed although the analytical sensitivity was low. In contrast, in the analyses in 2003 [20], only LCCPs were analyzed. Therefore, it is not possible to directly compare these results. Although the production of CPs reduced by half from 1990 to 2000, considering the high K OC of SCCPs, the low degradation of highly CPs, and a remarkable improvement in analytical sensitivity, it is estimated that SCCP concentrations in sediments have not been reduced significantly, but they possibly gradually decreased over 20 years after 1980.

In the analysis of total CPs (including SCCPs, MCCPs, and LCCPs) conducted by the production plants of CPs in 1978 in sediments around the outlets of wastewater from the plants, it was reported that the concentrations detected ranged from 2.2 to 9.4 mg kg−1 ww [2], which were similar to the concentrations in sediments of the Japanese coast that were determined by EA in the same period. It was also reported that the analytical results of total CPs in sediments around the same sampling sites in 2002 (by the same analytical method as used in 1978) were 1.0–3.3 mg kg−1 ww [2].

AIST conducted sampling of sediments in two rivers in Tokyo in Kanto region and one river in Osaka in Kansai region in July 2003. The sampling sites were Arakawa River, Tamagawa River in Tokyo, and Yodogawa River in Osaka. The analytical results are shown in Table 15 [22]. The results indicated that the concentrations of SCCP with C11 was very high, and the concentrations of SCCPs with high chlorine were high in sediments.
Table 15

Analytical results of SCCPs in domestic sediment samples (µg kg−1 ww) [22]

CPs

Arakawa River, Horikiribashi

Arakawa River, Kasaibashi

Tamagawa River, Oshibashi

Tamagawa River, Den-en Chofu Zeki

Yodogawa River, Hirakata Ohashi

Yodogawa River, Dempo Ohashi

C10H18Cl4

<1

<1

<1

<1

<1

<1

C10H17Cl5

<1

<1

1.1

1.5

<1

12

C10H16Cl6

1.5

4.3

6.8

14

<1

19

C10H15Cl7

2.8

9.4

9.3

21

<1 (0.46)

22

C10H14Cl8

4.1

15

9.4

22

<1 (0.39)

19

C10H14Cl9

3.6

16

5

17

<1

7.1

C10H14Cl10

2.1

9.3

2.1

8.1

<1

2.4

C10H14Cl11

<1 (0.40)

2.7

<1 (0.79)

1.8

<1

1.3

C 10 total

14.1

56.3

33.7

86

0

82.7

C11H20Cl4

<1

<1

<1

<1

<1

<1

C11H19Cl5

<1 (0.38)

<1 (0.74)

1.1

1.4

<1

6.8

C11H18Cl6

2.9

5.8

3.7

6.2

<1

11

C11H17Cl7

39

65

13

23

1.3

45

C11H16Cl8

62

106

16

30

2.1

58

C11H15Cl9

47

92

18

43

1.6

41

C11H14Cl10

19

49

20

46

<1 (0.48)

11

C11H13Cl11

5

9

11

22

<1

<1 (0.75)

C 11 total

175

326

83

171

5

172

C12H22Cl4

<1

<1

<1

<1

<1

<1

C12H21Cl5

<1

<1

<1 (0.30)

<1 (0.40)

<1

3.0

C12H20Cl6

<1

<1 (0.70)

1.9

3

<1

8.0

C12H19Cl7

<1 (0.80)

3

5.1

8

<1

12

C12H18Cl8

1.3

5

5.2

7

<1

11

C12H17Cl9

1.6

6.3

2.8

4.7

<1

5.5

C12H16Cl10

2.3

9.7

2

4.1

<1

2.3

C12H15Cl11

1.9

8.6

1.3

2.7

<1

1.0

C 12 total

7.1

32.6

18.3

29.5

0

42.8

C13H24Cl4

<1

<1

<1

<1

<1

<1

C13H23Cl5

<1

<1 (0.38)

<1 (0.88)

1.2

<1

3.7

C13H22Cl6

1.2

3.5

7.4

13

<1

20

C13H21Cl7

2.9

11

19

30

<1

40

C13H20Cl8

3.4

15

18

27

<1

33

C13H19Cl9

2.4

13

9.1

15

<1

17

C13H18Cl10

2.7

14

5.1

7.9

<1

8.7

C13H17Cl11

2.8

14

2.8

5.1

<1

2.9

C 13 total

15.3

69.2

61.3

98.2

0

126.4

C 10–13 total

211.1

484.4

196.6

384.7

4.9

424.0

Water content

30.2%

52.8%

48.9%

35.3%

19.2%

62.0%

TOC

0.5%

2.5%

2.1%

1.7%

0.05%

4.0%

Detection limit is 1.0 μg kg−1 ww. Results in parentheses are data when distinguishable peaks lower than the detection limit are counted

3.3.3 Sewage Treatment Plant

AIST measured SCCPs in influents and effluents at three sewage treatment plants (A, B and C) in Tokyo in Kanto region. The processing capacity (average operating rate to processing capacity) of sewage treatment plants A, B, and C in 2001 was 2.71 × 105 m3 per day (80%), 3.78 × 105 m3 per day (41%), and 2.02 × 105 m3 per day (43%), respectively [23]. The analytical results are shown in Table 16 [22].
Table 16

Analytical results of SCCPs in domestic sewage treatment plant samples (ng L−1) [22]

CPs

STP A influent

STP A effluent

STP B influent

STP B effluent

STP C influent

STP C effluent

C10H18Cl4

<5

<5

<5

<5

<5

<5

C10H17Cl5

6.5

<5

6.5

2.5

11

<5

C10H16Cl6

23

11

34

18

29

9.9

C 10 total

29.5

11

40.5

20.5

40

9.9

C11H20Cl4

<5

<5

<5

<5

<5

<5

C11H19Cl5

6.2

<5 (2.6)

10

<5 (3.0)

14

<5 (4.1)

C11H18Cl6

15

<5 (3.4)

23

5.3

26

<5 (4.4)

C11H17Cl7

32

7.2

31

9.1

62

5.9

C11H16Cl8

20

7.7

13

<5 (4.3)

47

<5 (3.3)

C 11 total

73.2

14.9 (20.9)

77

14.4 (21.7)

149

5.9 (17.7)

C12H22Cl4

<5

<5

<5

<5

<5

<5

C12H2Cl5

<5(2.5)

<5

6.6

<5

8.4

<5

C12H20Cl6

12

<5

26

<5

29

<5

C12H19Cl7

25

<5

31

<5 (2.9)

34

<5 (2.5)

C12H18Cl8

13

<5

13

<5 (1.3)

12

<5 (0.96)

C 12 total

50 (52.5)

0

76.6

0 (4.2)

83.4

0 (3.5)

C13H24Cl4

<5

<5

<5

<5

<5

<5

C13H23Cl5

<5 (4.5)

<5

5.6

<5

7.1

<5

C13H22Cl6

25

<5 (0.85)

26

<5

33

<5 (0.60)

C13H21Cl7

29

<5 (0.90)

25

<5 (0.19)

31

<5 (0.89)

C13H20Cl8

13

<5 (1.3)

11

<5 (0.79)

12

<5 (0.82)

C 13 total

67 (71.5)

0 (3.1)

67.6

0 (0.98)

83.1

0 (2.3)

C 10–13 total

220 (230)

26 (35)

260

35 (47)

360

16 (33)

Detection limit is 5 ng L−1. Results in parentheses are data when distinguishable peaks lower than the detection limit are counted

SCCPs with high chlorine were frequently detected in influents of sewage treatment plants and little difference by the carbon chain length was found. SCCPs with short carbon chain length and low chlorine were released in effluents, as the degradation capacity was low for these congeners. In total, 4.4–13.5% of SCCPs were released into effluents. Effluents from sewage treatment plans are usually diluted with river water approximately tenfold. However, the mean SCCP concentration in effluents from sewage treatment plans in Tokyo was 26 ng L−1, which was close to the SCCP concentrations in the water samples of the Arakawa and Sumidagawa Rivers, 31 and 20 ng L−1, respectively. Therefore, the SCCP concentrations in river water in Tokyo are considered extremely high, and it is possible to assume that these concentrations are of worse cases.

3.3.4 Food

Regarding the SCCP concentrations in food, no monitoring data are available in Japan. To supplement the information on SCCP concentrations in food by obtaining the data of food in Japan, a market basket survey was conducted by AIST to measure the SCCP concentrations in food. Based on the results of this survey, the relevance of the estimated concentrations in food is confirmed, and the daily intake of SCCPs in humans is estimated.

Market-basket samples are samples consisting of food items that are purchased in the market representing a typical diet for a certain population. As shown in Table 17, 11 food categories were listed based on 18 food categories used for the National Health and Nutrition Survey conducted by Ministry of Health, Labour and Welfare (MHLW), [22]. Specifically, nuts and seeds with extremely small consumptions were combined with potatoes as one group. Assuming that the SCCP concentrations in sugar and sweets and snacks were similar, these were grouped together, and seasoning and beverages with ND in the analyses by [24] was added to this group. Green and yellow vegetables and other vegetables were grouped together; mushroom and seaweed, of which the consumptions were small, and beans, of which the concentrations of CPs were close to the detection limit in the analyses [24], were added into this group. Seafood, on the other hand was divided into two food categories, as high concentrations of SCCPs were expected in both fish and shellfish.
Table 17

List of food analyzed by the market basket survey

Food categories

Sub groups

 

Food analyzed

Origin

Mixed amount (g)

1. Grain crops

Rice

Rice

White rice

Japan

1,445

 

Processed rice

Rice threads

Thailand

11.3

Wheat

Flour

Flour

Japan

28

 

Bread

Bread

 

134

 

Pastry

Bean jam bread

 

34

 

Noodles

Raw Udon

 

34

  

Boiled Udon

 

34

  

Raw Soba

 

34

  

Chinese noodles

 

34

 

Dried noodles

Dried Soba

Japan

11

  

Macaroni

 

11

 

Instant noodles

Instant noodles

 

14

Other crops

 

Corn starch

 

8

2. Seeds and potatoes

Seeds

 

Mixed nuts (peanuts, almonds, walnuts, giant corn, cashew nuts)

China, USA, Peru, India

28

Potatoes

Sweet potato

Sweet potato

Japan

140

 

Potato

Potato

Japan

458

 

Other potatoes

Satoimo (taro)

Japan

174

 

Potato processed

Konnyaku

Japan

170

3. Sugar, sweets and snacks, seasoning and beverages

Sugar and honey

Sugar

Brown sugar

 

30

  

Honey

 

7

 

Jam

Jam

 

7

Snacks

Rice cracker

Rice cracker

 

9

 

Cakes

Baumkuchen

 

15

 

Biscuit

Biscuit

 

17

 

Other snacks

Chocolate

 

30

  

Bean jam rice cake

 

30

Seasoning and beverages

Soy sauce

Soy sauce

 

91

Sauces

Worcester sauce

 

23

Salt

Salt

 

6

 

Other seasoning

Mirin (a sweet sake)

 

53

 

Japanese sake

Japanese sake

 

66

 

Beer

Beer

 

302

 

Other liquors

Liquor

Germany

48

 

Other beverages

Cider

 

263

4. Fats

Butter

 

Butter

Japan

61

Margarine

 

Margarine

 

15

Salad oil

 

Salad oil

 

543

Animal fat

 

Animal fat

 

12

Mayonnaise

 

Mayonnaise

 

293

5. Beans, green vegetables, other vegetables, mushrooms, seaweeds

Beans

Miso

Miso

Japan

36

 

Tofu (bean curd)

Tofu (bean curd)

Japan

106

 

Tofu processed

Fried bean curd

 

20

Carrots

 

Carrots

Japan

60

Spinach

 

Spinach

Japan

48

Green pepper

 

Green pepper

Japan

12

Tomatoes

 

Tomatoes

Japan

55

Green vegetables

 

Leek

Japan

88

  

Garland chrysanthemum

Japan

88

  

Broccoli

Japan

88

  

Parsley

Japan

88

Daikon (Japanese radish)

 

Daikon (Japanese radish)

Japan

100

Onions

 

Onions

Japan

76

Cabbages

 

Cabbages

Japan

65

Cucumbers

 

Cucumbers

Japan

31

Chinese cabbage

 

Chinese cabbage

Japan

62

Other vegetables

 

Long onion

Japan

27

  

Myoga (Japanese ginger)

Japan

27

  

Ginger

Japan

27

  

Gobo (Burdock)

Japan

27

Pickles

 

Nozawana (pickled Brassica campestris var. hakabura)

Japan

18

Mushrooms

 

Shiitake mushrooms

Japan

39

  

Shiitake mushrooms

China

39

Seaweeds

Wakame seaweed

Japan

13

 

Hijiki (Hizikia fusiforme)

Japan

2

6. Fruit

Citrus fruit

Amanatsu (an orange)

Japan

245

Apples

SunFuji (an apple)

Japan

104

 

Ourin (an apple)

Japan

104

Banana

Banana

Philippines

89

Other fruit

Grapes

Japan

284

 

Cherry

Japan

83

Fruit juice

Tomato juice

Turkey, China

91

7. Fish

Salmon and trout

Rainbow trout

Japan

14

  

Silver salmon

Japan (culture)

40

 

Tuna

Tuna lean meat (bluefish)

Italy

21

  

Tuna

Spain

21

  

Katsuo (Bonito)

Japan

21

  

Mekajiki (swordfish)

Japan

21

 

Tai (sea bream) and flat fish

Black flat fish

Japan

50

  

Kinnmedai (Alfonsin)

Japan

50

 

Aji (horse mackerel or saurel) and Sardines

Maaji (Saurel)

Japan

48

 

Gomasaba (Mackerel)

Japan

48

  

Samma (Saury)

Japan

48

 

Other fish

Koi (Carp)

Japan

60

  

Ayu (sweetfish)

Japan

60

 

Squid, octopus, crabs

Octopus

Japan

85

  

Fire fly squid

Japan

85

 

Salted fish

Salted salmon

USA

55

  

Salted mackerel

Norway

55

 

Dried fish

Shishamo (Smelt)

Canada

31

  

Shirasu (young sardine)

Japan

31

  

Dried squid

Japan

31

 

Canned fish

Tuna

 

17

 

Tsukudani (fish boiled in soy)

Shrimp Tsukudani

Japan

2

 

Fish processed

Fried fish (sardine) balls

 

50

  

Chikuwa (fish paste)

 

50

  

Hanpen (fish cake)

 

50

 

Fish sausage

Fish sausage

 

6

8. Shellfish

Shellfish

Asari (short-necked clam)

Japan

156

  

Asari (short-necked clam)

Japan

156

  

Scallop

Japan

187

  

Hamaguri (Clam)

Japan

26

  

Hamaguri (Clam)

China

26

  

Shijimi (Corbicula leana)

Japan

145

  

Tsubugai (Buccinidae)

Japan

26

  

Akagai (Ark shell)

China

26

 

Canned fish

Canned scallop

 

228

 

Tsukudani (fish boiled in soy)

Scallop Tsukudani (fish boiled in soy)

China

24

9. Meat

Pork

Pork

 

175

  

Pork rib

 

175

 

Beef

Beef

USA

131

  

Beef

Japan

131

 

Chicken

Chicken

Japan

129

  

Chicken

Japan

129

 

Ham and sausage

Ham

 

122

 

Other meat

Lamb

New Zealand

8

10. Eggs

 

Quail eggs

Japan

65

  

Eggs

Japan

480

  

Eggs

Japan

455

11. Milk

Milk

Milk

Japan

832

 

cheese

Camembert cheese

Japan

16

 

Other dairy products

Cream

Japan

76

 

Yogurt

Japan

76

The intake fractions of food items in each group were estimated from the average intake of whole-generation data of the MHLW’s National Health and Nutrition Survey. According to the estimated percentages, foods were purchased in Ibaraki Prefecture and they were mixed to prepare mixed samples. One sample for each food group was prepared. The mixed samples were analyzed using high-resolution gas chromatography and mass spectrometry with electron capture negative ionization (HRGC/ECNI-HRMS). The usage of internal standard of total PCBs was acceptable due to the good recovery percentage; therefore the analytical conditions were found to be ideal. The analytical results of SCCP concentrations in food are shown in Table 18 [22].
Table 18

Analytical results of SCCPs in food categories by market basket survey (unit: μg kg−1)

SCCPs

Blank

1. Grain crops

2. Seeds and potatoes

3. Sugar, etc.

4. Fats

5. Beans, etc.

6. Fruit

7. Fish

8. Shellfish

9. Meats

10. Eggs

11. Milk

Quantitation limit

0.1

0.1

0.2

0.2

2

0.2

0.2

0.2

0.2

0.5

0.2

0.3

LOD

0.03

0.03

0.06

0.06

0.5

0.06

0.06

0.06

0.06

0.2

0.06

0.1

Lipid content (%)

 

0.54

0.9

1.86

94.2

0.92

0.04

9.4

0.72

24.7

11.4

6.96

C10H18Cl4

<0.1

<0.1

<0.2

<0.2

<2

<0.2

<0.2

<0.2

<0.2

<0.5

<0.2

<0.3

C10H17Cl5

<0.1

0.14

<0.2 (0.095)

<0.2 (0.12)

<2 (1.1)

<0.2 (0.084)

<0.2

0.28

0.46

0.22

<2 (0.17)

<0.3

C10H16Cl6

<0.1

0.57

0.47

0.42

8.6

0.5

0.39

0.87

2

1.5

0.49

<0.3 (0.25)

C10H15Cl7

<0.1

0.64

0.61

0.75

18

0.47

0.53

2.4

3.9

2

0.45

0.38

C10H14Cl8

<0.1

0.44

0.34

0.5

18

0.31

0.28

4.3

3.6

1.3

0.36

0.37

C10H14Cl9

<0.1

0.13

<0.2 (0.075)

<0.2 (0.17)

9.3

<0.2 (0.082)

<0.2

2.6

1.1

<0.5 (0.35)

<0.2 (0.082)

<0.3 (0.10)

C10H14Cl10

<0.1

<0.1 (0.033)

<0.2

<0.2

4.9

<0.2

<0.2

0.88

<0.2 (0.14)

<0.5

<0.2

<0.3

C10H14Cl11

<0.1

<0.1

<0.2

<0.2

<2 (0395)

<0.2

<0.2

<0.2 (0.10)

<0.2

<0.5

<0.2

<0.3

C10 total

0

1.9 (2.0)

1.4 (1.6)

1.7 (2.0)

59 (61)

1.3 (1.4)

1.2

11 (11)

11 (11)

5.1 (5.4)

1.3 (1.5)

0.75 (1.1)

C11H20Cl4

<0.1

<0.1

<0.2

<0.2

<2

<0.2

<0.2

<0.2

<0.2

<0.5

<0.2

<0.3

C11H19Cl5

<0.1

0.17

<0.2 (0.18)

0.26

<2 (1.8)

0.24

0.28

0.34

0.28

0.65

0.28

<0.3 (0.20)

C11H18Cl6

<0.1

0.16

<0.2 (0.11)

0.22

3.5

<2 (0.18)

<0.2 (0.16)

0.32

0.63

0.53

0.2

<0.3 (0.14)

C11H17Cl7

<0.1

0.24

<0.2 (0.12)

0.21

14

0.21

<0.2 (0.19)

0.94

1.7

0.75

0.2

<0.3 (0.15)

C11H16Cl8

<0.1

<0.1 (0.077)

<0.2

<0.2 (0.094)

8.3

<0.2 (0.10)

<0.2 (0.069)

1.1

1.1

<0.5 (0.30)

<0.2 (0.082)

<0.3

C11H15Cl9

<0.1

<0.1 (0.035)

<0.2

<0.2

4.6

<0.2

<0.2

0.83

0.65

<0.5 (0.30)

<0.2 (0.063)

<0.3

C11H14Cl10

<0.1

<0.1

<0.2

<0.2

<2 (0.2)

<0.2

<0.2

0.36

<0.2 (0.15)

<0.5

<0.2

<0.3

C11H13Cl11

<0.1

<0.1

<0.2

<0.2

<2

<0.2

<0.2

<0.2

<0.2

<0.5

<0.2

<0.3

C11 total

0

0.57 (0.68)

0 (0.41)

0.69 (0.79)

30 (40)

0.45 (0.73)

0.28 (0.70)

3.8

4.3 (4.5)

1.9 (2.4)

0.69 (0.84)

0 (0.49)

C12H22Cl4

<0.1

<0.1

<0.2

<0.2

<2

<0.2

<0.2

<0.2

<0.2

<0.5

<0.2

<0.3

C12H21Cl5

<0.1

<0.1

<0.2

<0.2

<2

<0.2

<0.2

<0.2

<0.2

<0.5

<0.2

<0.3

C12H20Cl6

<0.1

<0.1 (0.054)

<0.2

<0.2

<2 (1.9)

<0.2

<0.2

<0.2 (0.078)

0.23

<0.5

<0.2

<0.3

C12H19Cl7

<0.1

<0.1 (0.074)

<0.2

<0.2 (0.072)

12

<0.2 (0.060)

<0.2

0.3

0.65

<0.5 (0.25)

<0.2 (0.079)

<0.3

C12H18Cl8

<0.1

<0.1 (0.061)

<0.2

<0.2

16

<0.2 (0.086)

<0.2

0.34

0.53

<0.5 (0.32)

<0.2 (0.12)

<0.3

C12H17Cl9

<0.1

<0.1

<0.2

<0.2

8.1

<0.2

<0.2

0.25

0.23

<0.5

<0.2 (0.091)

<0.3

C12H16Cl10

<0.1

<0.1

<0.2

<0.2

5

<0.2

<0.2

<0.2 (0.16)

<0.2 (0.11)

<0.5

<0.2

<0.3

C12H15Cl11

<0.1

<0.1

<0.2

<0.2

3.8

<0.2

<0.2

<0.2 (0.083)

<0.2

<0.5

<0.2

<0.3

C12 total

0

0 (0.19)

0

0 (0.072)

45 (46)

0 (0.15)

0

0.89 (1.2)

1.6 (1.8)

0 (0.57)

0 (0.29)

0

C13H24Cl4

<0.1

<0.1

<0.2

<0.2

<2

<0.2

<0.2

<0.2

<0.2

<0.5

<0.2

<0.3

C13H23Cl5

<0.1

<0.1

<0.2

<0.2

<2

<0.2

<0.2

<0.2

<0.2

<0.5

<0.2

<0.3

C13H22Cl6

<0.1

<0.1 (0.059)

<0.2

<0.2

<2 (0.59)

<0.2

<0.2

<0.2 (0.088)

0.29

<0.5

<0.2

<0.3

C13H21Cl7

<0.1

<0.1 (0.084)

<0.2

<0.2 (0.082)

2.8

<0.2

<0.2

<0.2 (0.16)

0.55

<0.5 (0.22)

<0.2

<0.3

C13H20Cl8

<0.1

<0.1 (0.057)

<0.2

<0.2 (0.068)

4.4

<0.2

<0.2

<0.2 (0.17)

0.36

<0.5

<0.2 (0.064)

<0.3

C13H19Cl9

<0.1

<0.1

<0.2

<0.2

2.9

<0.2

<0.2

<0.2 (0.10)

<0.2 (0.12)

<0.5

<0.2

<0.3

C13H18Cl10

<0.1

<0.1

<0.2

<0.2

<2 (1.5)

<0.2

<0.2

<0.2 (0.79)

<0.2

<0.5

<0.2

<0.3

C13H17Cl11

<0.1

<0.1

<0.2

<0.2

<2 (1.2)

<0.2

<0.2

<0.2

<0.2

<0.5

<0.2

<0.3

C13 total

0

0 (0.20)

0

0 (0.15)

10 (13)

0

0

0 (0.60)

1.2 (1.3)

0 (0.22)

0 (0.064)

0

C10–13 total

0

2.5 (3.1)

1.4 (2.0)

2.4 (3.0)

140 (150)

1.7 (2.3)

1.5 (1.9)

16 (17)

18 (19)

7.0 (19)

2.0 (2.7)

0.75 (1.6)

SCCPs concentration in lipid

 

460 (570)

160 (220)

130 (160)

150 (160)

180 (250)

3800 (4800)

170 (180)

2500 (2600)

2.8 (3.4)

1.8 (2.5)

1.1 (2.3)

(μg/kg-lipid)

3.3.5 Validation of Model Estimation

Analyses of environemntal concentrations of SCCPs were conducted for this assessment in river water and sediment of typical rivers, and the influents and effluents of sewage treatment plants. The scope of monitoring, however, was limited in terms of sampling time and site. As water concentration data usually has lognormal distribution, it is assumed that the measured concentrations of SCCPs also have a lognormal distribution. Further, it is assumed that SCCP concentrations in the Tamagawa and Arakawa Rivers, sampling sites in the Kanto region, are distributed according to the distribution of suspended solid (SS) concentrations. The reason for this assumption is that SCCPs easily adsorb on SS. Using a logarithmic mean of the measured concentrations and the logarithmic standard deviation of SS concentrations in the Tamagawa and Arakawa Rivers, a 90% confidence interval is estimated as shown in Table 19.
Table 19

Comparison of measured and estimated values of SCCPs in the environment. Estimated values in river water and sediment are referred from Table 8

Item

Measured value

Estimated value

Concentration in river water

0.020, 0.031 (mean: 0.0255) µg L−1

90% confidence interval: 0.0051– 0.12 µg L−1

0.0375 μg L−1

Concentration in river sediment

0.197, 0.211, 0.385, 0.484 (mean: 0.319) µg kg−1 ww

90% confidence interval: 0.060–1.48 µg kg−1 ww

0.286 μg kg−1 ww

Regarding the SCCP concentrations in river water and sediment, the estimated values are within the 90% confidence interval, suggesting the relevance of the estimated values. Regarding the SCCP concentrations in the influents and effluents of sewage treatment plants and the release factors to water, the estimated values are close to the means of the measured values, suggesting the relevance of the estimated values.

For risk characterization, the upper limit of 90% confidence interval of the measured concentrations, i.e., 95th percentile are to be used as a worst case. The reasons for this assumption include first the fact that the rivers where samples were collected are located in the Kanto region with many industrial plants. Secondly, the SCCP concentrations in river water were approximately half of those in effluents from sewage treatment plants, which indicates that the measured concentrations of river water were extremely high, considering that usual concentrations are about 10% of those in effluents. Thirdly, based on the assumption that the measured concentrations have distribution with the mean of measured concentrations and the standard deviation of SS, the 95th percentile is calculated extremely high. Therefore, it is considered relevant to assume this as a worst case scenario for risk assessment.

Total SCCP concentrations in food obtained through the market basket survey and the estimated concentrations are compared in Table 20. First, the SCCP concentration in the food group including green and yellow vegetables, beans, and others was 1.7 μg kg−1, which is comparable to the estimated concentration in leaf vegetables of 2.06 μg kg−1. Secondly, the SCCP concentration in nuts and seeds and potatoes was 1.4 μg kg−1, which is more than two orders lower than the estimated concentration in root tissue of plants of 738 μg kg−1. The root tissue of plants applied for in the model shoud be fine roots and different from tubers such as potatoes and thick roots like carrots. It was indicated that this difference in the definitions of the root tissue of plants was reflected in the difference in concentrations [25], because the structural characteristics of the model had some effect on the high concentration in root tissue of plants. Therefore, it is concluded that actual concentrations would not be as high as the estimated concentrations.
Table 20

Comparison of measured and estimated concentrations of SCCPs in food

Item

Measured value

Estimated value

Green and yellow vegetables and beans

1.7 μg kg−1

2.06 μg kg−1

Seeds and potatoes

1.4 μg kg−1

738 μg kg−1

Meat

7.0 μg kg−1

13.4 μg kg−1

Milk and dairy product

0.75 μg kg−1

4.23 μg kg−1

Fish

16 μg kg−1 ww

221 μg kg−1 ww

Estimated values are referred from Table 10

The SCCP concentration in fish was 16 μg kg−1, which is more than one order lower than the European Union System for the Evaluation of Substances (EUSES) estimated concentration in fish of 221 μg kg−1. The reason for this difference might be that while the subject fish in the model were freshwater species, fish purchased according to the market basket method were primarily marine species, i.e., salmon, tuna, sea bream ,and flounder, and SCCP concentrations in fish living in marine water would be lower than those in river water. Consequently, it is considered that the actual human exposures of SCCPs from fish consumed daily are not so high as estimated.

In contrast, the SCCP concentration in meat was 7.0 μg kg−1, which is comparable to the estimated concentration in meat of 13.4 μg kg−1. The SCCP concentration in milk and dairy products was 0.75 μg kg−1, which is one order lower than the estimated concentration in milk and dairy products of 4.23 μg kg−1.

It was found, however, that SCCP concentrations in fat and oil, which cannot be estimated by the model, were extremely high (140 μg kg−1). The major food items of fat and oil are vegetable oil, mayonnaise, and rapeseed, and the main raw material of these products, was imported from Australia and Canada, so it is indicated that exposure sources may not be domestic.

In summary, the estimated concentrations are not necessarily consistent with the measured concentrations, and therefore, it is not reliable to estimate human intakes of SCCPs via food based on the results of the model estimation. Also, it is assumed that the high concentrations in fat are probably from exposure sources overseas; however, it is not possible to estimate those concentrations by the model. Therefore, for risk characterization in this assessment, it is considered relevant to estimate human intakes directly using the analytical results by the market basket survey as actual intakes of the Japanese.

3.4 Estimation of Indirect Exposure of Humans from the Environment

Inhalation of SCCPs from the atmosphere by humans is small based on the estimation by mathematical modeling, and there are little data about the inhalation toxicity of SCCPs. Thus, SCCP inhalation from the atmosphere is not considered. Based on estimation by mathematical modeling, oral intake of SCCPs via food is large, and therefore, oral intake is estimated using the analytical results of the market basket survey.

The SCCP intake via food is estimated by multiplying the analytical results obtained in the market basket survey with the food consumptions of the Japanese population and dividing by body weight. Food consumption and body weight data are obtained from “amounts of food intake by food group” and “mean body weight and standard deviation” described in the report of the 2000 National Nutrition Survey [26], and probability density function was applied to each parameter in the assumption of lognormal distribution by Monte Carlo simulation. In the market basket survey, fish and shellfish were divided into two groups and analyzed; however, in order to make it consistent with the food categories of the “amounts of food intake by food group”, a SCCP concentration in seafood (16.2 μg kg−1) is calculated considering the consumption ratios of fish and shellfish. The estimation results are shown in Tables 20 and 21.
Table 21

Total SCCP intake in Japanese male by age (unit: μg kg−1 per day)

Age (year)

Geometric mean

5th percentile

50th percentile

95th percentile

1

0.371

0.2094

0.3422

0.6741

5

0.2142

0.1171

0.1951

0.3728

10

0.1867

0.1021

0.1804

0.3413

15

0.1374

0.0757

0.1285

0.2429

20

0.1137

0.0594

0.1072

0.2152

25

0.1105

0.0584

0.1049

0.2076

30–39

0.117

0.0629

0.1103

0.2134

40–49

0.1182

0.0648

0.1128

0.2081

50–59

0.1259

0.0676

0.1157

0.214

60–69

0.1159

0.0507

0.0886

0.1821

70<

0.1075

0.0549

0.0972

0.1938

Based on the estimated results, the intake in females aged one year is the highest, with a mean of 0.391 μg kg−1 per day and 95th percentile of 0.680 μg kg−1 per day. The market basket method, however, established the percentages of food consumption based on the average intake of whole-generation data of the National Nutrition Survey. For this reason, the possibility cannot be ruled out that the percentages of items in food group are different in one-year old infants from the composition of composite samples in the market basket survey. In the comparison of the food consumption in one-year old infants with the mean in whole-generation, there is little difference in the intake ratios of food items in fat – the food group with the highest contribution. These indicate that the composition of composite samples has little effect on food consumption and it is relevant to estimate the SCCP intake of a one-year old infant by the above method (Table 22).
Table 22

Total SCCP intake in Japanese female by age (unit: μg kg−1 per day)

Age (year)

Geometric mean

5th percentile

50th percentile

95th percentile

1

0.3911

0.2169

0.3696

0.6795

5

0.2135

0.1187

0.2046

0.3753

10

0.1747

0.0939

0.1664

0.3272

15

0.1284

0.0706

0.1208

0.2233

20

0.1185

0.0638

0.1109

0.212

25

0.1267

0.0697

0.1191

0.2234

30–39

0.1155

0.0605

0.1088

0.2097

40–49

0.1176

0.0641

0.1091

0.2171

50–59

0.1226

0.0676

0.1157

0.2147

60–69

0.0955

0.0507

0.0886

0.1827

70<

0.1039

0.0549

0.0972

0.1952

3.5 Exposure Data Used for Risk Assessment

95-percentile of the measured concentrations is used as a worst case scenario for ecological risk assessment. Estimated values are used for SCCP concentrations in soil, and in water and sediment around release sources, for which measured data are not available. Human daily intake of SCCPs is estimated using results of market basket survey, and 95-percentile of intake of one-year old female is applied to repeated dose toxicity, and the 95-percentile of intake of 25-year old female in childbearing age is applied to developmental toxicity. The exposure data used for risk assessment are shown in Table 23.
Table 23

Exposure data used for risk characterization

Risk

Medium

Exposure concentration or intake

Note

Ecological risk

(Kanto region)

Water

0.12 μg L−1

Measured value

Sediment

1.48 mg kg−1 ww

Measured value

Soil

0.150 mg kg−1 ww

Estimated value

Ecological risk

(local area)

Water

0.0567 µg L−1

SCCP production, estimated value

0.126 µg L−1

Production of metal working fluids, estimated value

0.492 (0.265–0.947) µg L−1

Use of metal working fluids, estimated value

0.0375 (0.0375 –0.0375) µg L−1

Manufacturing of SCCP-containing products, estimated value

Sediment

0.246 mg kg−1 ww

SCCP production, estimated value

0.629 mg kg−1 ww

Production of metal working fluids, estimated value

2.56 (1.36– 4.96) mg kg−1 ww

Use of metal working fluids, estimated value

0.163 (0.163– 0.163) mg kg−1 ww

Manufacturing of SCCP-containing products, estimated value

Human health risk (repeated dose toxicity)

Intake via food

0.68 μg kg−1 per day

Measured value multiplied by the 95th percentile of intake of 1-year old female

Human health risk (developmental toxicity)

Intake via food

0.223 μg kg−1 per day

Measured value multiplied by the 95th percentile of intake of 25-year old female in child-bearing age

4 Dose-Response Assessment

Toxicity of SCCPs to ecosystem and human health is summarized in dose-response assessment. The toxicity and bioaccumulation of SCCPs to organisms in the environment are summarized from the existing data of studies in aquatic organisms including fish, and in birds. The percentages of species affected by SCCPs in biotic community in water and sediment are estimated, and the SCCP concentrations as the criteria for screening SCCP effects on ecosystems are established. On the other hand, after reviewing the controversial issues in human health risk assessment of SCCPs in the existing assessments, human health effects of SCCPs are summarized from the existing data of studies in experimental animals including rats and mice, and in vitro studies. The endpoint and no observed adverse effect level (NOAEL) of SCCPs to human health are identified for risk assessment.

4.1 Ecological Toxicity

Through the review of the existing data, it is clarified that for biokinetics of SCCPs in organisms, high CPs are hard to be metabolized and are excreted slowly from the lipid-rich organs. SCCPs are highly bioaccumulative and the main route is identified as uptake of fish from river water through gills, and the BCF is established as 5,900 based on the results of an existing study in Japan.

The ecological toxicity of SCCPs is reviewed in the existing publications of studies on aquatic organisms including fish and in birds, based on highly reliable data as shown in Table 24 where the percentages of species affected by SCCPs in biotic community are estimated. As a result, 5% Hazard Concentration (HC5), a concentration with which 5% of aquatic species are affected, is estimated from the species sensitivity distribution (SSD) shown in Fig. 7 to be 2.9 μg L−1. This is used as the criteria for the screening assessment for aquatic organisms.
Table 24

The lowest NOECs in aquatic species of toxicity studies used for generation of sensitivity distribution of species

Species

CPs

Test method

Concentration, temperature

Solubilizing agent

Endpoint

Test period

NOEC (μg L−1)

Reference

Water flea, Daphnia magna

C10–12, chlorine 58%

Flow-through

3.2, 5.6, 10, 18, 32, 56 µg L−1, 20°C, salinity: 30.5‰

Acetone 67.1 mg L−1

Reproduction inhibition

21 days

5.6

[43]

Mysid shrimp, Mysidopsis bahia

C10–12, chlorine 58%

Flow-through

0.6, 1.2, 2.4, 3.8, 7.3 µg L−1, 25°C, salinity: 20‰

Acetone (unstabilized)

Death

28 days

>7.3

[44]

Skeletonema costatum

C10–12, chlorine 58%

NA

4.5, 6.7, 12.1, 19.6, 43.1, 69.8 µg L−1, 20°C

Acetone 100 μL L−1 (79.2 mg L−1)

Growth inhibition

96 h

12.1

[45]

Rainbow trout, Oncorhynchus mykiss

C10–12, chlorine 58%

Flow-through

10°C

Unknown

Sublethal effect

15–20 days

<40

[46]

Bloodworm, Chironomus tentans

C10–12, chlorine 58%

61–394 µg L−1, 21–23°C

Acetone (unstabilized)

Halt of adult emergence

49 days

61

[47]

Sheapshead minnow, Cyprinodon variegatus

C10–12, chlorine 58%

Flow-through

36.2, 71.0, 161.8, 279.7, 620.5 µg L−1, 25°C, salinity: 25‰

Acetone

Growth inhibition

32 days

279.7

[48]

Selenastrum capriconutum

C10–12, chlorine 58%

NA

0.11, 0.22, 0.39, 0.57, 0.90, 1.2* mg L−1, 24°C

Acetone 100 μL L−1 (79.2 mg L−1)

Growth inhibition

10 days

390

 

Values with * are test concentrations exceeding the maximum water solubility of SCCP (0.975 mg L−1)

Fig. 7

Species sensitivity distribution (SSD) of aquatic organisms – lognormal distribution

Using equilibrium partitioning, the HC5 values for sediment- and soil-dwelling organisms are determined to be 11 and 10 mg kg−1 ww, respectively. For risk assessment for birds as higher predators, the NOAEL is established as 166 mg kg−1-feed with the endpoint of embryo viability.

4.2 Human Toxicity

4.2.1 Biokinetics

The oral absorption rate of SCCPs is 100-fold higher than that of percutaneous absorption and the rate of gastrointestinal absorption is high. SCCPs are distributed mainly in the organs with high metabolic activity including the liver, kidney, thyroid gland, and adipose and excreted in respiration, urine, and feces. SCCPs with high chlorine content are poorly absorbed, and once absorbed, poorly excreted. With these available data and information without any study having attemped to identify metabolites, it is difficult to identify the specific metabolic pathway of SCCPs. Considering the above, risks are assessed by comparing average human daily intake with NOAELs in this assessment.

4.2.2 Toxicity to Human Health

Acute toxicity and irritation of SCCPs are low and SCCPs have no potential of sensitization or mutagenicity. Regarding repeated dose toxicity of SCCPs, the results of oral studies in rats and mice indicated that the liver, thyroid gland, and kidney are target organs [27, 28, 29].

Marked increases in liver weight and hepatocyte hypertrophy have been shown to be a reflection of peroxisome proliferation [30, 31, 32, 33]. Hepatocyte hypertrophy and increased liver weight induced by peroxisome proliferation are known to be specific in rodents [34], and humans are not susceptible to peroxisome proliferation [30, 31]. Therefore, the effects on the liver are considered unlikely to be relevant to human health.

The decrease of T4 concentration with the increased thyroid weight and enhanced thyroid follicular cell hypertrophy [28, 29] was induced by an increased activity of a liver enzyme (UDPG-transferase) involved in peroxisome proliferation [33, 35, 36]. This mechanism is also specific to rodents. Therefore, thyroidal effects that were observed in the studies in rats and mice are considered unlikely to be relevant to human health.

Regarding the increase in kidney weight, the presence of male rat-specific α2u globulin has not yet been confirmed [37]. This change, however, was observed only in males not in females, and further only in rats. For this reason, it is considered relevant to determine this change to be α2u globulin nephropathy.

Tubular pigmentation was observed in female rats [29]. However, there are no data that rule out the possibility of this effect on humans. Therefore, it is considered reasonable to assume the possible effects on humans. It is assumed that SCCPs accumulated in the tubules have some effects on the kidney due to this toxicity; however, no further information is available at present. Consequently, the NOAEL is established as 100 mg kg−1 per day with the endpoint of tubular pigmentation in female rats.

Regarding carcinogenicity, it is relevant that the renal tubular adenoma that was observed in male rats is related to α2u globulin nephropathy, which is specific to male rats, and the possibility that SCCPs are carcinogenic to humans is extremely low.

Regarding reproductive toxicity, the teratogenic effects in fetuses were observed in [38] and the study in rats by [29]; however, it is reasonable to consider that the observed effects are not the direct effects of test substance but the secondary effects derived from the maternal toxicity. In general, a threshold exists for teratogenicity and when some maternal toxicity occurs, fetal anomaly is observed. Therefore, a dose without any maternal toxicity can be used for risk assessment as the no observed effect level (NOEL) for teratogenicity. Consequently, the NOAEL for developmental effect is established as 500 mg kg−1 per day.

5 Risk Assessment

In this section, the screening-level assessment of ecological risk to aquatic, sediment- and soil-dwelling organisms are conducted. Human health risk assessment is also conducted. CPs are usually mixtures of different carbon chain length and different degrees of chlorination; therefore, this assessment is concerned with the short-chain length ***(C 10–13) CPs as mixtures.

5.1 Ecological Risk Assessment

The methodology of SSD has been used for derivation of environmental quality criteria and for ecological risk assessment. In this chapter, the ecosystem was assumed to be preserved when 95% of species are protected [39], and in this screening-level risk assessment, if the actual or estimated environmental concentration of SCCPs is larger than the HC5 which will protect 95% of species based on the SSD, it is interpreted that it should be assessed further. Risk characterization for birds, the higher predators is also performed because of the high bioconcentration of SCCPs in fish.

5.1.1 Risk Characterization for Aquatic, Sediment-Dwelling, and Soil-Dwelling Organisms

In the screening-level assessment of SCCPs to aquatic, sediment-, and soil-dwelling organisms, risk characterization is conducted to find whether SCCP concentrations are larger than the HC5 estimated from SSD. The data obtained from the SCCP monitoring in domestic rivers or the estimated values are used as the environmental concentrations of SCCPs. The result is shown in Table 25.
Table 25

Screening-level ecological risk assessment at regional level

Medium

HC5

Environmental concentration

Risk characterization

Water

2.9 μg L−1

0.12 μg L−1 (the upper limit of 90% confidence interval of measured values)

Concentrations are lower than the HC5 values, which indicate there are low potential risks

Sediment

11 mg kg−1 ww

1.48 mg kg−1 ww (the upper limit of 90% confidence interval of measured values)

Soil

10 mg kg−1 ww

0.15 mg kg−1 ww (estimated value)

Because the domestic rivers where monitoring was conducted are typical rivers in Japan running through heavily populated areas where many facilities are also located, the measured SCCP concentrations are relatively high. In addition, the SCCP concentrations measured in the effluents from sewage treatment plant were on the same level as the detected concentrations in river water. Therefore, it is relevant to assume an upper limit of 90% confidence interval of the river water data as a worst case scenario in Japan. Screening-level assessment using these upper limits of 90% confidence interval of the monitoring data indicates that the upper limits are lower than the HC5. As a result, there is alow potential risk to aquatic and sediment-dwelling organisms in the regions.

As there is no monitoring data for soils, the screening-level assessment is conducted using the regional SCCP concentration in soil estimated at 0.150 mg kg−1 ww, which is two orders lower than the HC5. When the distribution of SCCP concentrations in soil is estimated, the possibility is extremely low that the estimated value will exceed the HC5. This result indicates that there is a low potential risk to soil-dwelling organisms in the regions.

Ecological risks in local areas around plants are also assessed according to the same procedure. There are, however, uncertainties in estimating the SCCP concentrations around release sources in the use of metal working fluids and in the manufacturing process of products containing SCCPs because the number of plants cannot be identified. For this reason, in addition to the estimation of risks based on the estimated release volumes, sensitivity analysis is conducted with the range from half to twice of the estimated release volumes. As a result, in all life stages, environmental concentrations in local areas are lower than the HC5 and the results of sensitivity analysis do not exceed the HC5 as shown in Table 26. It is clarified that there is a low potential risk to organisms in local areas around industrial plants.
Table 26

Screening ecological risk assessment at local level. All environmental concentrations are estimated values

Medium

HC5

Life cycle stage

Environmental concentration

Risk characterization

Water

2.9 μg L−1

SCCP production

0.0567 μg L−1

Concentrations are lower than HC5 value, which indicates there are low potential risks

Metal working fluid formulation

0.126 μg L−1

Metal working fluid use

0.492 (0.265– 0.947) µg L−1

Manufacturing of SCCP-containing products

0.0375 (0.0375– 0.0375) µg L−1

Sediment

11 mg kg−1 ww

SCCP production

0.246 mg kg−1 ww

Metal working fluid formulation

0.629 mg kg−1 ww

Metal working fluid use

2.56 (1.36–4.96) mg kg−1 ww

Manufacturing of SCCP-containing products

0.163 (0.163– 0.163) mg kg−1 ww

Values in parenthesis are the range of concentrations when the amounts of SCCP use are estimated as half to twice the median

5.1.2 Risk Characterization for Birds as Higher Predators

Ecological risk to higher predators is a concern because SCCPs are highly bioaccumulative in fish. Risk to birds as higher predators is estimated as the margin of exposure (MOEoral, fish), and MOE is compared with uncertainty factors. MOEoral, fish is defined by the following equation:
$$ {\hbox{MO}}{{\hbox{E}}_{{\rm{oral,}}\;{\rm{fish}}}} = \frac{\text{NOAEL}}{{{C_{\rm{fish}}}}} $$
(2)
where, the NOAEL has no observed adverse effect concentration in birds of 166 mg kg−1-feed. C fish is a concentration in fish in a local area, i.e., a predator exposure concentration (mg kg−1 ww), and C fish, j is a concentration in fish for fish-eating predators calculated as the local and regional concentration in river water [16]
$$ {C_{{\rm{fish}},\, j}} = {\hbox{BC}}{{\hbox{F}}_{\rm{fish}}} \times ({C_{{\rm{local}},\,j}} + {C_{\rm{reg}}})/2 $$
(3)
where BCFfish is the BCF in fish as 5,900. C local, j is a concentration in river water in a local area j and C reg is a concentration in river water in the Kanto region. EU-TGD [40] proposed to apply an uncertainty factor of 10 for the NOAEL in a reproductive toxicity study, and [41] similarly proposed an uncertainty factor of 10. Therefore, this risk assessment is performed using an uncertainty factor of 10. Using the estimated SCCP concentrations in local environment, risk characterization for birds is performed as shown in Table 27.
Table 27

Risk characterization for birds as higher predators

Life cycle stage

C local, j

C reg

C fish

MOE

SCCP production

0.0567 μg L−1

0.0375 μg L−1

278 mg kg−1 ww

597

Metal working fluid formulation

0.126 μg L−1

0.0375 μg L

482 mg kg−1 ww

344

Metal working fluid use

0.492 (0.265–0.947) µg L−1

0.0375 μg L−1

1,562 (892– 2,904) mg kg−1 ww

106 (57–186)

Manufacturing of SCCP-containing products

0.0375 (0.0375–0.0375) µg L−1

0.0375 μg L−1

221 (221–221) mg kg−1 ww

750 (750–750)

Values in parenthesis are the range of concentrations when the amounts of SCCP use are estimated as half to twice the median

As a result, the margins in all life stages are substantially larger than the uncertainty factor of 10, and in the sensitivity analysis also the margins are not lower than the uncertainty factor of 10. In conclusion, there is no significant risk to birds.

5.2 Risk Characterization for Human Health

Because the major human exposure pathway is food, human exposures to SCCPs as indirect exposures via food are evaluated. The risk of SCCPs to human health is estimated as MOE and MOE is compared with uncertainty factors. The MOE is defined by the following equation:
$$ {\hbox{MOE}} = \frac{\text{NOAEL}}{{\hbox{DOSE}}} $$
(4)
where the NOAEL is no observed adverse effect level for human health, and the DOSE is the daily intake for humans. The NOAEL for tubular pigmentation is 100 mg kg−1 per day, and a total uncertainty factor of 1,000 is applied; which includes 10 for a study period of less than 1 year; 10 for interspecies differences; and 10 for individual differences. The NOAEL for developmental effects is 500 mg kg−1 per day, and a total uncertainty factor of 100 is applied; which includes 10 for interspecies differences and 10 for individual differences.
Based on the food intake estimated with the market basket survey in Japan, the 95-percentile of the intake of a one-year old female of 0.68 μg kg−1 per day is applied to the endpoint of tubular pigmentation, and the 95-percentile of the intake of a 25-year old female of child-bearing age of 0.223 μg kg−1 per day is applied to the endpoint of developmental toxicity. The result of risk characterization is shown in Table 28.
Table 28

Risk characterization for human health

Endpoint

Tubular pigmentation

Developmental effect

NOAEL

100 mg kg per day

(NOAEL in female rats)

500 mg kg per day

(NOAEL in female rats)

Uncertainty factor

1,000 (Short-term study × interspecies difference × individual difference)

100 (Interspecies difference × individual difference)

Human intake

0.68 μg kg−1per day (95th percentile of one-year old female)

0.223 μg kg−1 per day (95th percentile of 25-year old female in child-bearing age)

MOE

1.5 × 105

2.2 × 106

As a result, although a worst case scenario is considered in this assessment, the MOEs for both toxicity endpoints are larger than the uncertainty factors. In conclusion, there is no significant risk to human health via the environment, and there is no need for further risk assessment based on more detailed exposure assessment.

6 Conclusion

This assessment is developed with the objective of assessing the current situations of ecological and human health risk of SCCPs in Japan based on the exposure and hazard assessments.

Based on the results of exposure and hazard assessments, risk characterization is performed. Screening ecological risk assessment is performed using the HC5 estimated from SSD. As a result, the 95th percentile of the measured concentrations of SCCPs in water and sediments of general environment is lower than the HC5, and it is therefore determined that there is low potential ecological risk to aquatic and sediment-dwelling organisms at the regional level. In local areas around plants using metal working fluids, the estimated local concentrations in all stages of life cycle of SCCPs do not exceed the HC5, and therefore, it is determined that there is a low potential ecological risk. Further, in the risk characterization of birds as the predators of fish with high bioaccumulation of SCCPs, the MOEs in all stages of the life cycle are larger than the uncertainty factor of 10, and therefore, it is determined that there is no significant risk to birds.

Human health risk assessment is performed using the endpoints of tubular pigmentation and the developmental effect. As a result, the MOEs are 1.5 × 105 and 2.2 × 106, respectively, which are larger than the uncertainty factor of 1,000 (short-term study × interspecies difference × individual difference) in tubular pigmentation and that of 100 (interspecies difference × individual difference) in developmental effect. Consequently, it is determined that there is no significant human health risk of SCCPs.

After the result of this risk assessment, all domestic companies in Japan stopped producing SCCPs in 2006, since SCCPs were classified as Class I Chemical Substances Monitored in 2005. In 2009, the import volume of SCCPs is said to be decreasing, but some companies still use SCCPs as metal working fluids, flame retardant, and for other purposes.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  1. 1.National Institute of Advanced Industrial Science and Technology, Research Institute of Science for Safety and SustainabilityTsukubaJapan

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