Pentachlorophenol Environmental Exposures
Pentachlorophenol Environmental Exposures
Pentachlorophenol can enter the environment (in air, water, and soil) via evaporation from treated woods, industrial spills, and disposal at hazardous waste sites. The general population is most likely exposed to PCP in the vicinity of hazardous waste sites, as well as in older homes that may contain PCP-treated wood. Therefore, low level exposure to PCP may occur by ingesting contaminated indoor or outdoor air, ground water, and food, or via dermal contact with contaminated wood and soil.
People who work or live near a wood treatment facility or where utility poles, railroad ties, or wharf pilings are produced may be exposed to PCP.
Data on Canadian environmental PCP concentration and exposure are limited. CAREX Canada’s environmental exposure estimates suggest that PCP concentrations in outdoor air, indoor air, indoor dust, drinking water, and food or beverages do not result in an increased risk of cancer in Canada (very low data quality).
Pentachlorophenol was one of the substances selected for Cycle 2 of the Canadian Health Measures Survey (CHMS), an ongoing joint project of Statistics Canada and Health Canada to establish the current level of exposure to environmental contaminants. Biomonitoring data from the CHMS on Canadians was released in 2013 in the Second Report on Human Biomonitoring of Environmental Chemicals in Canada.
Cancer Risk Estimates
Potential lifetime excess cancer risk (LECR) is an indicator of Canadians’ exposure to known or suspected carcinogens in the environment. When potential LECR is more than 1 per million in a single pathway, a more detailed risk assessment may be useful for confirming the need to reduce individual exposure. If measured levels of pentachlorophenol in relevant exposure pathways (outdoor air, indoor air, indoor dust, drinking water, and food and beverages) decrease, the risk will also decrease.
Potential LECR is calculated by multiplying lifetime average daily intake (the amount inhaled or ingested) by a cancer potency factor or unit risk factor. More than one cancer potency factor may be available, because agencies interpret the underlying health studies differently, or use a more precautionary approach. Our results use cancer potency factors from Health Canada, the US Environmental Protection Agency (US EPA), and/or the California Office of Environmental Health Hazard Assessment (OEHHA).
The calculated lifetime daily intake and LECR results for pentachlorophenol are provided in the tables below. For more information on supporting data and sources, click on the Methods and Data tab below.
Calculated Lifetime Daily Intake
Lifetime Excess Cancer Risk (per million people)
*LECR based on average intake x cancer potency factor from each agency
Compare substances: Canadian Potential Lifetime Excess Cancer Risk, 2011
The data in this table are based on average intake and Health Canada’s cancer potency factor, assuming no change in measured levels. When Health Canada values are not available, United States Environmental Protection Agency values are used.
Click the second tab to view LECR data.
**Exposure not applicable: For indicated pathways, substance not present, not carcinogenic, or exposure is negligible
**Gap in data: No cancer potency factor or unit risk factor, or no data available
IARC Group 1 = Carcinogenic to humans, IARC Group 2A = Probably carcinogenic to humans, IARC Group 2B = Possibly carcinogenic to humans
NOTE: Chromium (hexavalent) estimates assume that 5% of total chromium measured in outdoor air is hexavalent and 8% total chromium measured in indoor dust is hexavalent.
Potential LECR assumes exposure occurs at the same level, 24 hours per day, for 70 years. This is rarely true for any single individual, but using a standard set of assumptions allows us to provide a relative ranking for known and suspected carcinogens across different exposure routes. While ongoing research continually provides new evidence about cancer potency and whether there is a safe threshold of exposure, our approach assumes there are no safe exposure levels.
Methods and Data
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