Ethylbenzene Environmental Exposures

Ethylbenzene Environmental Exposures

Overview

According to Health Canada, the primary route of ethylbenzene exposure is inhalation.[1] CAREX Canada estimates that ethylbenzene levels in indoor air result in an increased risk of cancer (high data quality).

 
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Ethylbenzene has also been detected in outdoor air, drinking water, soil, and food.[1] CAREX Canada estimates that ethylbenzene levels in outdoor air (high data quality), drinking water (moderate data quality), and food and beverages (very low data quality) do not result in increased risks of cancer.

Sources of atmospheric ethylbenzene include petroleum and coal refining, evaporation from solvents and thinners, and vehicle emissions.[2] Tobacco and wood smoke also contain ethylbenzene.[2]

In the environment, ethylbenzene typically exists as a vapour. It can also bind to some soils and clay minerals, but is mobile enough to cause concern as a potential groundwater contaminant.[3] Sources of soil and groundwater contamination include leaking underground gasoline storage tanks, landfill sites, transportation spills, municipal waste, industrial discharges, and pesticide
use.[2,4] Ethylbenzene is allowed to be used as a formulant in pesticide preparations in Canada.[4,5]

Ethylbenzene has been detected in numerous consumer products including acrylic enamel aerosol spray paint, latex wall paint, gasoline, and cigarettes.[1] In Ontario, ethylbenzene is typically 1.4% of regular unleaded gasoline and 1.7% of premium unleaded gasoline.[1]

Estimates of daily intake for the general population were also calculated using values for indoor and outdoor air, drinking water, food and beverages, and soil. Estimates ranged from 9.83 to 28.7 µg/kg-body weight per day depending on age.[1]

Searches of Environment Canada’s National Pollutant Release Inventory (NPRI) and the US Household Products Database yielded the following results on current potential for exposure to ethylbenzene in Canada:

NPRI and US Household Products Database

NPRI 2015[6]
Substance name: ‘Ethylbenzene’
Category Quantity Industry
Released into Environment 378 t Oil sands, vehicle manufacture,
petroleum and coal product manufacturing,
metal manufacturing (224 facilities)
Disposed of 223 t
Sent to off-site recycling 1,956 t
t = tonne
US Household Products 2016[7]
Search Term Quantity Product Type
‘Ethylbenzene’ >449 Hobby paints, home interior and exterior paints,
decorative snow materials, and five insecticides

Mapping

This map shows predicted levels of ethylbenzene in outdoor air at residential locations by health region in Canada as of 2011. The average (median) concentration of ethylbenzene within the health regions measured in outdoor air for 2011 was 0.864 µg/m3, but concentrations of ethylbenzene can be higher or lower than average in many locations. Concentrations should be compared to the applicable jurisdictional guidelines and standards for ambient air quality based on chronic, carcinogenic effects (or non-carcinogenic effects, if cancer is not the point of interest).

Predicted annual average ethylbenzene concentrations in outdoor air at residential locations by health region, 2011

*Measured at the National Air Pollution Surveillance (NAPS) monitors in 2011

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 ethylbenzene in relevant exposure pathways (outdoor air, indoor air, 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 ethylbenzene 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

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

Our Environmental Approach page outlines the general approach used to calculate lifetime excess cancer risk estimates and includes documentation on our mapping methods.

Data sources and data quality for ethylbenzene can be found in the PDF below.

Supplemental data – Ethylbenzene [PDF]

Sources

2. Health Canada. Ethylbenzene and Health (2007) (PDF)
3. The Canadian Legal Information Institute (CanLII). Yukon’s Occupational Health Regulations, O.I.C. 1986/164 (2012) (PDF)
4. Health Canada. Ethylbenzene (2016)
6. Environment and Climate Change Canada. National Pollutant Release Inventory (NPRI) Facility Search (Substance name: ‘Ethylbenzene’)
7. US Household Products Database (HPD). Household Products (Search term: ‘Ethylbenzene’)
       

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