Summary of Initial Risk Assessment Report

Transcription

1 Summary of Initial Risk Assessment Report Cresol CAS No : PRTR No of Japan: 67 This substance is assessed based on Guideline for Initial Risk Assessment Version General Information 1.1 Physico-chemical properties Appearance Melting point Boiling point Water solubility Henry's constant Octanol/water partition coefficient ( log Kow) Soil adsorption coefficient Colorless, light yellow liquid (isomeric mixture) 30degC (o-cresol), 11-12degC (m- cresol), 35.5degC (p- cresol) degC (o- cresol), 202degC (m- cresol), 201.8degC (p- cresol) 25 g/l (o- cresol, 5degC), 24 g/l (m- cresol, 20degC), 19 g/l (p- cresol, 25degC) Pa*m 3 /mol (1.20*10-6 atm*m 3 /mol) (o- cresol, 25degC, measured) 8.67 Pa*m 3 /mol (8.56*10-7 atm*m 3 /mol) (m- cresol, 25degC, measured) Pa*m 3 /mol (1.00*10-6 atm*m 3 /mol) (p- cresol, 25degC, measured) 1.95 (o- cresol, measured), 2.06 (o- cresol, estimated) 1.96(m- cresol, measured), 2.06 (m- cresol, estimated) 1.94 (p- cresol, measured), 2.06 (p- cresol, estimated) Koc = 443 (o- cresol, estimated), 434 (m- cresol, p- cresol, estimated) 1.2 Environmental fate Low bioaccumulative Bioaccumulation Bioconcentration factor (BCF): 18 (calculated using logkow of ), 20(m-, carp) measured Biodegradation Readily biodegradable - 1 -

2 Stability in the environment Environmental fate (In air) Reaction with OH radical: Reaction rate constant is 4.2*10-11 cm 3 /molecule-sec. (o-group, 25degC, measured), 6.4*10-11 cm 3 /molecule-sec. (m-group, 25degC, measured), 4.7*10-12 cm 3 /molecule-sec. (p-group, 25degC, measured) The half-life is 5-9 hours (o-group), 3-6 hours (m-group), 4-8 hours (p-group), given OH radical concentration of 5*10 5-1*10 6 molecule/cm 3. Reaction with ozone: Reaction rate constant is 2.55*10-19 cm 3 /molecule-sec. (o-group, 25degC, estimated), 6.0*10-19 cm 3 /molecule-sec. (m-group, 25degC, estimated) and 4.71*10-19 cm 3 /molecule-sec. (p-group, 25degC, estimated). The half - life is 1 month (o-group), 0.6 month (m-group), 0.8 month (p-group), given ozone concentration of 7*10 11 molecule/cm 3. Reaction with nitrate radical: Reaction rate constant is 2.0*10-11 cm 3 /molecule-sec. (o-group, p-group, 25degC, measured), and 1.2*10-11 cm 3 /molecule-sec. (m-group, 25degC, measured) The half life is minutes (o-group, p-group), minutes (m-group), given nitrate radical concentration of 2.4* *10 9 molecule/cm 3 (10-100ppt). (In water) Not expected to hydrolyze in water. If released to water, cresol is expected to be removed by biodegradation easily under aerobic conditions. It is also known to biodegrade under specific anaerobic conditions using activated sludge. Volatilization from water surfaces is not expected to be an important fate process. 2. Sources of release to the environment 2.1 Annual production, import, export and domestic supply in 2002 (ton/year) Production Import Export Domestic supply Remarks 47,000 3,000 23,000 27, Uses Epoxy resin raw materials (30%), electric wire varnish solvents (20%), agricultural chemicals raw materials and antioxidant raw materials (20%), plasticizer (tricresyl phosphate and others) raw materials(10%), phenol resin raw materials (10%), antiseptic solution and other (10%) - 2 -

3 Listed industries 2.3 Release from the industries within the scope of PRTR system (in 2001) Release sources Air (ton) Waters (ton) Soil (ton) Remarks Reported release Release outside notification Release outside notification from non listed industry 2 <0.5 0 Release to river: ton Households Mobile sources Total Releases from other sources Phenolic resin containers may be another source of cresol. 2.5 Main release route Cresol is expected to be released mainly during use of the substance or the products containing it. 3. Exposure Assessment 3.1 Measured environmental concentration Media No. of points detected / No. of points measured No. of samples detected / No. of samples measured Detection range 95th percentile Detection limit Year of investigation, Institution Air River water (microg/l) 1/44: o- 0/44: m- 1/44: p Ministry of the Environment 2000 Seawater (microg/l) 0/11: o- 0/11: m- 2/11: p- nd nd nd Ministry of the Environment 2001 Drinking water (microg/l) (as underground water) 0/15: o- 0/15: m- 1/15: p Ministry of the Environment 2000 Food nd :not detected For calculation of the 95th percentile, data less than the detection limit are replaced with a value equal to 1/2 of the detection limit

4 Oral Inhalation 3.2 Estimated environmental concentration Media Estimated concentration Description Air (microg/m 3 ) 0.57 River water (microg/l) 0.72 Calculated by mathematical model / Atmospheric Dispersion Model for Exposure and Risk Assessment (AIST-ADMER) ver.1.0 Calculated by mathematical model / Initial Assessment System for the PRTR chemicals (IAS) 3.3 Estimated environmental concentration in water (EEC) EEC(microg/L) The cresol concentration in river water is estimated by model as 0.72microg /L. The Ministry of the Environment reported that the 95 th percentiles of measured concentrations of o-cresol and p-cresol in aquatic environments were both microg /L, and m-cresol was not detected. The value equal to 1/2 of the detection limit of m-cresol was reported as 0.015microg /L. The aggregate value (0.045microg /L) of the concentrations of the two detected isomers and the value equal to 1/2 of the detection limit of m-cresol is used as the measured concentration for the risk assessment. 1). 3.4 Estimated human intake Intake route Concentration used for estimation of intake Estimated intake (microg/person/day) Estimated intake (microg/kg-bodyweight (BW)/day) 0.57 (microg/m 3 ) Air Estimated concentration in air (0.57 microg/m 3 ) was used for the risk assessment, since no measured concentration in air was available. Drinking water 0.22 (microg/l) Concentrations in ground water are used, since concentrations in tap water were not available. Neither o-cresol nor m-cresol was detected in the survey by the Ministry of the Environment in In this case, the concentrations of o-cresol and m-cresol are assumed as 1/2 of each detection limit. The value equal to 1/2 of detection limits of both o-cresol and m-cresol (both not detected) was microg/l. Whereas, the 95 th percentile of measured concentrations of p-cresol was microg/l. The aggregated value (0.22 microg/l) of the concentrations of the three isomers, that is 1/2 of detection limits of both o-cresol and m-cresol, 95 th percentile of measured concentrations of p-cresol, is used. Food (microg/g)

5 -Data of intake via food were not available. -The concentration of cresol in fish was estimated as a product of the concentration in seawater and a BCF. -Results from a study completed by the Ministry of the Environment in 2000 were used for this estimation. In this study, both o-cresol and m-cresol were not detected. The value equal to 1/2 of the detection limit of o-cresol was 0.015microg /L. The value equal to 1/2 of the detection limit of m-cresol was also 0.015microg /L. The 95 th percentile of measured concentrations of p-cresol was 5microg /L. The aggregate value (0.065microg /L) of the concentrations of the three isomers (including the values equal to 1/2 of the detection limits of o-cresol and m-cresol) is used for the risk assessment. Subtotal Total route ) This substance is assessed based on the Guideline for Initial Risk Assessment Version1.0. If adequate measured concentrations are available, they are given priority and used as values for risk assessment. If they are not available, an estimated value calculated using a mathematical model is used. 4. Hazard assessment 4.1 Effects on organisms in the environment Acute or Chronic Species Endpoint Concentration Algae Acute Scenedesmus subspicatus 48 hours EC 10 Growth rate 4.6 (mg/l) (p-group) Crustacea Chronic Daphnia magna 21days NOEC Reproduction 0.52 (mg/l) (p-group) Fish Acute Oncorhynchus kisutch 72 hours NOEC Mortality 1.65 (mg/l) (Cresol) Key study Data of crustacea (Daphnia magna) was chosen for a key study since the effects were observed in the lowest concentration - 5 -

6 4.2 Human health toxicity Toxicity Exposure route Species Duration / Dose method Toxic effects (Key study is underlined) NOAEL or LOAEL (converted) Inhalation Repeated dose toxicity Oral Rat 13 weeks Decreased RBC, Hgb and Hct in females, increased relative kidney weights in males, decreased food consumption, reduced body weight gains, tremor, coma, lethargy, convulsion, epithelial metaplasia of trachea, increased serum AST and ALT activities NOAEL: 50 mg/kg/day Dermal Reproductive and developmental toxicity Oral Rat mating, gravid and lactation period before ten weeks of mating on F 0 animal, for 11 weeks after the delactation, mating, gravid and lactation period on F 1 animal in gavage administration Reduced body weight gains, decreased food consumption, labored respiration, hypoactivity, ataxia, convulsion, and tremors in offspring LOAEL: 30 mg/kg/day Carcinogenicity Genotoxicity Evaluation by IARC : Cresol has not been evaluated by IARC. Probably not genotoxic 5. Risk Assessment 5.1 Environmental organisms Risk character -ization EEC (microg/l) NOEC * (mg/l) MOE (NOEC * /EEC) Product of uncertainty factors Conclusion NOEC: , No immediate concern Product of uncertainty factors (UF): Extrapolation from laboratory test (10) * Toxicity data on one nutritional stage (10) = 100 Recommendation : The substance is considered to be of no immediate concern for the moment, and low priority for further work. NOEC* means NOEC, LOEC, EC 50, etc

7 5.2 Human health Repeated dose toxicity Exposure route Intake (microg/kgbw/ day) NOAEL (mg/kgbw/day) MOE Risk characterization Product of uncertainty factors Conclusion Inhalation 0.22 No adequate data Oral ,200, No immediate concern Total (Oral) 220, No immediate concern Product of uncertainty factors (UF): Oral/Total: Interspecies (10) * Intraspecies (10) * Duration of test (5) = Reproductive and developmental toxicity Exposure route Intake (microg/kgbw/ day) NOAEL (mg/kgbw/day) MOE Risk characterization Product of uncertainty factors Conclusion Total 0.23 LOAEL: ,000 1,000 No immediate concern Product of uncertainty factors (UF): Interspecies (10) * Intraspecies (10) * Using LOAEL (10) = 1, Carcinogenicity Recommendation for Human Health Although no adequate toxicity data for the inhalation route, MOE of total route of inhalation and oral is larger than the product of uncertainty factor. Thus, the substance is considered to be of no immediate concern for the moment, and low priority for further work. 6. Supplement - 7 -