Development of Interim CCME PCB Soil Quality Guidelines for Missing - - PowerPoint PPT Presentation

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

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

Project Background

Project Background

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 = 291.99 g/mole – Log(Kow) = 7.1 – Vapour Pressure = 0.000494 mm Hg – Henry’s Law Constant = 0.000415 atm-m3/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.

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

CCME Requirements - Ecological

CCME 2006

CCME Requirements - Ecological

Route of Exposure Agricultural Residential / Parkland Commercial Industrial Guideline [mg/kg] 0.5 1.3 33 33 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

Interim from 1991 ???

CCME Requirements – Human Health

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

No Guideline Available

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

• n the chicken

Total Exposure – All Sources Included

• Exposure limit; or
• Toxicity Reference Value; or
• Reference Dose.

CCME 2006

Background Residual Portion Allocated to Soil Guideline

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

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 0.00174 0.0514 0.0138 Toddler 0.0018 0.0359 0.013 Child 0.00456 0.0178 0.00966 Adolescent 0.00231 0.013 0.006 Adult 0.00116 0.0936 0.0040 Tolerable Daily Intake - TDI 0.13

Bolded values represent the average daily intakes of PCBs that were used in the assessment

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)

Soil Ingestion Guideline

​𝑇𝑅𝐻↓𝐸𝐼 = ¡​(𝑈𝐸𝐽−𝐹𝐸𝐽)×𝑇𝐵𝐺×𝐶𝑋/[(​𝐵𝐺↓𝐻 ×𝑇𝐽𝑆)+(​𝐵𝐺↓𝑀 ×​𝐽𝑆↓𝑇 ×​𝐹𝑈↓2 )+(​𝐵𝐺↓𝑇 ×𝑇𝑆)]×​ 𝐹𝑈↓1 ¡+𝐶𝑇𝐷

CCME 2006

Residual Soil Allocation Soil Dust Dermal

Soil Contact Guideline

Description Agricultural Land Use Residential/ Parkland Land Use Commercial Land Use Industrial Land Use Direct Contact PCB Soil Quality Guideline (SQGDH) [mg/kg] 4 4 7 75 Alberta Direct Soil Contact Guideline [mg/kg] 22 22 33 160

• 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)

Consumption of Produce, Meat & Milk

​𝑇𝑅𝐻↓𝐺𝐽 = ¡​(𝑈𝐸𝐽−𝐹𝐸𝐽)×𝑇𝐵𝐺×𝐶𝑋/(​𝑄↓𝐼 ×​𝑄↓𝐷 ×​𝐶↓𝑊 )+ ¡(​𝑁↓𝐼 ×​𝑁↓𝐷 ×​𝐶↓𝑄 ×​𝑇𝐽𝑆↓𝐷 )+(​ 𝑁𝐿↓𝐼 ×​𝑁𝐿↓𝐷 ×​𝐶↓𝑁 ×​𝑇𝐽𝑆↓𝐷 ) ¡+𝐶𝑇𝐷

CCME 2006

Residual Soil Allocation Vegetation Soil Milk

Consumption Guideline

• Assumes no spatial averaging or foraging by cattle

Description Agricultural Land Use Residential/ Parkland Land Use Commercial Land Use Industrial Land Use Consumption Guideline SQGFI [mg/kg] 0.11 7.4 Not Applicable Not Applicable

Primary Consumer Guideline

​𝑇𝑅𝐻↓1𝐷 = ¡​0.75×​𝐸𝑈𝐹𝐸↓1𝐷 ×​𝐶𝑋↓1𝐷 /(​𝑇𝐽𝑆↓1𝐷 ×𝐶𝐺)+(​𝐺𝐽𝑆↓1𝐷 ×​𝐶𝐷𝐺↓1 ) ¡

• 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

0.056 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

CCME 2006

Other Considerations

• Bioavailability
• Food preparation
• Area use factor

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).

Other Considerations – Combined

• Soil bioavailability, Milk bioavailability & Food preparation

Guideline Ingestion of Contaminated Produce, Meat, and Milk PCB Soil Quality Guidelines (SQGFI) (mg/kg) Agricultural Land Use Residential/Parkland Land Use Revised 0.21 7.4 Original 0.11 7.4

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 (SQGFI) (mg/kg) Agricultural Land Use Residential/Parkland Land Use 10 1.1 74 50 0.22 15 100 0.11 7.4

Summary of PCB Guidelines [mg/kg]

Soil Guideline Agricultural Residential / Parkland Commercial Industrial Human Health Soil ingestion 4 4 7 75 Produce, meat and milk 0.11 7.4 NA NA Ecological Soil Contact 33 33 33 33 Primary Consumer (Chicken) 25 25 NA NA Primary Consumer (Cow) 31 31 NA NA Secondary Consumer 1.8 1.8 NA NA Tertiary Consumer 1.3 1.3 NA NA Guidelines CCME Guideline 0.5 1.3 33 33 Revised Guideline 0.11 1.3 7 33

Yellow highlights project-specific soil quality guidelines that were calculated.

Comparison to Measured PCB

Location Concentration [mg/kg] Exceeds Guideline Min Mean Max SQGDH - 4 mg/kg SQGFI - 0.11 mg/kg A <0.05 <0.05 <0.05 No Yes B <0.05 0.04 0.16 No Yes C <0.05 0.5 35 Yes Yes D <0.05 0.3 4 No Yes E <0.05 3.6 250 Yes Yes F <0.05 0.2 15 Yes Yes

References

• Bowman et al. 1981. Locomotor hyperactivity in PCB-exposed rhesus monkeys. Available at:

http://www.ncbi.nlm.nih.gov/pubmed/6798510

• CCME (Canadian Council Of Ministers of the Environment). 2006. 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. 2013. Relative bioavailability of soil-

bound polychlorinated biphenyls in lactating goats. J. Dairy Sci. 96:3916-3923 http://dx.doi.org/10.3168/jds.2012-6319

• Health Canada. 2004. Contaminated Sites Program, Federal Contaminated Site Risk Assessment in Canada; Part II: Health Canada

Toxicological Reference Values (TRVs).

• Health Canada. 2010. Part II: Health Canada Toxicological Reference Values (TRVs) and Chemical-Specific Factors, Version 2.0.
• NEPI (National Environmental Policy Institute). 2000. 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. 2000. Ecological Risk Assessment for Contaminated Sites. Lewis

Publishers, CRC Press. Boca Raton, FL.

• US EPA (United States Environmental Protection Agency). 2003. 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. 1987. Health and Productivity of Dairy Cows Fed Polychlorinated
• Biphenyls. Toxicological Sciences. 9(1):60-68.