Development of Interim CCME PCB Soil Quality Guidelines for Missing Pathways of Exposure for the Protection of Human Health and Ecological Receptors

Transcription

1 Development of Interim CCME PCB Soil Quality Guidelines for Missing Pathways of Exposure for the Protection of Human Health and Ecological Receptors By: Karl Bresee, B.Sc., PBD, P.Biol. Intrinsik Environmental Sciences Inc., April 26, 2016 Le Centre Sheraton, Montreal

2 Outline Project background CCME* requirements What guidelines are available What guidelines are missing Project-specific requirements Toxicity of PCBs** Methods Interim guidelines Other considerations Guideline summary * Canadian Council of Ministers of the Environment ** Polychlorinated Biphenyls

3 Project Background

4 Project Background

5 CCME Requirements Chemical classification important at identifying pathways of exposure: Organic / inorganic Volatile / non-volatile Soluble / non-soluble Biomagnify / non-biomagnify Chemical Properties of PCBs: Molecular Weight = g/mole Log(Kow) = 7.1 Vapour Pressure = mm Hg Henry s Law Constant = atm-m 3 /mol Solubility = 0.7 mg/l PCBs are persistent, bio-accumulative and bio-magnify PCBs are highly toxic causing adverse effects on the immune, reproductive, nervous and endocrine system.

6 CCME Requirements Protects human and ecological receptors Includes aquatic and terrestrial pathways Designed for various land uses or exposure scenarios Applicable across Canada Generic and designed to be conservative

7 CCME Requirements - Ecological CCME 2006

8 CCME Requirements - Ecological Interim from 1991??? Route of Exposure Agricultural Residential / Parkland Commercial Industrial Guideline [mg/kg] Soil Contact Soil Nutrient Cycling Processes, Soil Invertebrates, Crops/Plants, Livestock/Wildlife Soil Nutrient Cycling Processes, Soil Invertebrates, Plants, Wildlife Soil Nutrient Cycling Processes, Soil Invertebrates, Plants, Wildlife, Offsite Migration Soil Nutrient Cycling Processes, Soil Invertebrates, Plants, Wildlife, Offsite Migration Soil and Food Ingestion Herbivores, Secondary and Tertiary Consumers* Herbivores, Secondary and Tertiary Consumers* Not Applicable Not Applicable Ingestion of Contaminated Water Livestock Not Applicable Not Applicable Not Applicable Contact with Contaminated Water Freshwater Life, Crops Irrigation Freshwater Life Freshwater Life Freshwater Life

9 CCME Requirements Human Health No Guideline Available Route of Exposure Agricultural Residential / Parkland Commercial Industrial Soil Contact Direct soil ingestion, Direct soil dermal contact, direct soil particulate inhalation Direct soil ingestion, Direct soil dermal contact, direct soil particulate inhalation Direct soil ingestion, Direct soil dermal contact, direct soil particulate inhalation Direct soil ingestion, Direct soil dermal contact, direct soil particulate inhalation Indirect Soil Exposure Indoor vapour inhalation, Consumption of produce, meat and milk* Indoor vapour inhalation, Consumption of backyard garden produce Indoor vapour inhalation, Offsite migration Indoor vapour inhalation, Offsite migration Protection of potable water Ingestion of groundwater Ingestion of groundwater Ingestion of groundwater Ingestion of groundwater

10 Project Specific Requirements Description Agricultural Land Use Residential/Parkland Land Use Commercial Land Use Industrial Land Use Will be calculating human guideline for Direct soil ingestion, soil dermal contact, soil particulate inhalation Consumption of produce, meat and milk Direct soil ingestion, soil dermal contact, soil particulate inhalation Consumption of produce, meat and milk Direct soil ingestion, soil dermal contact, soil particulate inhalation Direct soil ingestion, soil dermal contact, soil particulate inhalation Will be calculating ecological guideline for Soil and food ingestion for cattle Not calculating Not calculating Not calculating CCME Guideline available for primary consumer but based on the chicken

11 Total Exposure All Sources Included Exposure limit; or Toxicity Reference Value; or Reference Dose. Residual Portion Allocated to Soil Guideline Background CCME 2006

12 Estimated Daily Intake - Background Health Canada Total Diet Studies available from cities across Canada from 1992 to 2002 Included Toronto, Montreal, Halifax, Winnipeg Vancouver, Ottawa, Whitehorse, St. John s and Vancouver Food items obtained from 3 to 4 different supermarkets within each city Included dairy and beef products Combined with estimates of Canadians food intake rates

13 Estimated Daily Intake - Background Age Groups (Males and Females) Minimum Daily Intake (µg/kg bw/day) Maximum Daily Intake (µg/kg bw/day) Average Daily Intake (µg/kg bw/day) Infant Toddler Child Adolescent Adult Tolerable Daily Intake - TDI 0.13 Bolded values represent the average daily intakes of PCBs that were used in the assessment

14 Tolerable Daily Intake - TDI PCBs were administered to female rhesus monkeys through their diet Critical effect involved monitoring various aspects of locomotor activity in young rhesus monkey offspring (Bowman et al. 1981) Highest dose at which no adverse health effects were seen was 13 µg/kg bw/day TDI = NOAEL / uncertainty factor (UF) of 100 Interim TDI = 0.13 µg/kg bw/day (Health Canada 2010)

15 Soil Ingestion Guideline Residual Soil Allocation SQG DH = (TDI EDI) SAF BW/[( AF G SIR)+( AF L IR S ET 2 )+( AF S SR)] ET 1 +BSC Soil Dust Dermal CCME 2006

16 Soil Contact Guideline Description Direct Contact PCB Soil Quality Guideline (SQG DH ) [mg/kg] Alberta Direct Soil Contact Guideline [mg/kg] Agricultural Land Use Residential/ Parkland Land Use Commercial Land Use Industrial Land Use Current Alberta guideline based on older Health Canada (2004) TDI of 1 µg/kg/day, which was based on the LOAEL from the study by Bowman et al. (1981)

17 Consumption of Produce, Meat & Milk Residual Soil Allocation SQG FI = (TDI EDI) SAF BW/( P H P C B V )+ ( M H M C B P SIR C )+( MK H MK C B M SIR C ) +BSC Vegetation Soil Milk CCME 2006

18 Consumption Guideline Description Consumption Guideline SQG FI [mg/kg] Agricultural Land Use Residential/ Parkland Land Use Commercial Land Use Not Applicable Industrial Land Use Not Applicable Assumes no spatial averaging or foraging by cattle

19 Primary Consumer Guideline SQG 1C = 0.75 DTED 1C BW 1C /( SIR 1C BF)+( FIR 1C BCF 1 ) CCME 2006 Daily Threshold Effects Dose (DTED) based on NOAEL of 1.67 mg/kg/day derived from study by Willett et al. (1987), which consisted of: Three dose groups exposed to Aroclor 1254 including a control 4 Holstein cows per group exposed for 180 days Dosing occurred through lactation and non-lactation No apparent effect on health, productivity or calves Divided NOAEL of 1.67 mg/kg/day by uncertainty factor of 30 to derive DTED of mg/kg/day The PCB ingestion guideline for the protection of cattle was derived to be 31 mg/kg, which is close to the existing CCME guideline of 25 mg/kg based on the chicken. Cows appear to be less sensitive to PCB exposures than chickens

20 Other Considerations Bioavailability Food preparation Area use factor

21 Other Considerations: Bioavailability Soil bio-availability of PCB in rats ranged from 66 to 99% (NEPI 2000). Assumed a mid-point value of 83% Milk bio-availability of PCB in goats was 51% (Feidt et al. 2013) Approximately 27% of PCBs are lost during cooking and 24% after cooking (US EPA 2003).

22 Other Considerations Combined Soil bioavailability, Milk bioavailability & Food preparation Guideline Ingestion of Contaminated Produce, Meat, and Milk PCB Soil Quality Guidelines (SQG FI ) (mg/kg) Agricultural Land Use Residential/Parkland Land Use Revised Original

23 Other Considerations: Area Use Factor The AUF is defined as the ratio of the area that is contaminated (A) to the home range size (HR) such that AUF = A/HR (Suter et al. 2000) Proportion of Site Impacted by PCBs (%) Ingestion of Contaminated Produce, Meat, and Milk PCB Soil Quality Guidelines (SQG FI ) (mg/kg) Agricultural Land Use Residential/Parkland Land Use

24 Summary of PCB Guidelines [mg/kg] Soil Guideline Agricultural Residential / Parkland Commercial Industrial Human Health Soil ingestion Produce, meat and milk NA NA Ecological Soil Contact Primary Consumer (Chicken) NA NA Primary Consumer (Cow) NA NA Secondary Consumer NA NA Tertiary Consumer NA NA Guidelines CCME Guideline Revised Guideline Yellow highlights project-specific soil quality guidelines that were calculated.

25 Comparison to Measured PCB Location Concentration [mg/kg] Exceeds Guideline Min Mean Max SQG DH - 4 mg/kg SQG FI mg/kg A <0.05 <0.05 <0.05 No Yes B < No Yes C < Yes Yes D < No Yes E < Yes Yes F < Yes Yes

26 References Bowman et al Locomotor hyperactivity in PCB-exposed rhesus monkeys. Available at: CCME (Canadian Council Of Ministers of the Environment) A Protocol for the Derivation of Environmental and Human Health Soil Quality Guidelines. Feidt, C., Ounnas, F., Julien-David, D., Jurjanz, S., Toussaint, H., Jondreville, C. and Rychen, G Relative bioavailability of soilbound polychlorinated biphenyls in lactating goats. J. Dairy Sci. 96: Health Canada Contaminated Sites Program, Federal Contaminated Site Risk Assessment in Canada; Part II: Health Canada Toxicological Reference Values (TRVs). Health Canada Part II: Health Canada Toxicological Reference Values (TRVs) and Chemical-Specific Factors, Version 2.0. NEPI (National Environmental Policy Institute) Assessing the Bioavailability of Organic Chemicals in Soil for Use in Human Health Risk Assessments. Suter G.W. II, Efroymson, R.A., Sample, B.E. and Jones, D.S Ecological Risk Assessment for Contaminated Sites. Lewis Publishers, CRC Press. Boca Raton, FL. US EPA (United States Environmental Protection Agency) Exposure and Human Health Reassessment of 2,3,7,8- Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds National Academy Sciences (NAS) Review Draft, Volume 3: Site-Specific Assessment Procedures, Chapter 2: Estimating Exposure and Risks. Willett, L.B., Liu, T-T.Y., Durst, H.I., Smith, K.L. and Redman, D.R Health and Productivity of Dairy Cows Fed Polychlorinated Biphenyls. Toxicological Sciences. 9(1):60-68.