Health assessment finds decreased potential cancer risk in air

Also found, a shift in hydrocarbon types

October 19, 2015

GARFIELD COUNTY, CO – Garfield County commissioners today received the results of a human health risk assessment of air quality, showing a decreasing potential for cancer risk and non-cancer risk over the years 2008-12.

The assessment was requested by the Garfield County Health Department and completed by the Colorado Department of Public Health and Environment, based on data collected over five years (2008-12) at Garfield County’s air monitoring sites.

The results of the report also concludes there appeared to be a shift in the types of volatile organic compounds (VOCs) driving human health risk. The top three cancer risk contributors are crotonaldehyde, formaldehyde, and benzene over the 2009 to 2012 monitoring period, and some non-cancer hazard contributors are formaldehyde and acetaldehyde.

The report notes it is not possible to attribute emissions to specific sources, and that emissions measured include all sources of VOCs in the air sampled, including those from oil and gas operations.

Raj Goyal, author of the health assessment and toxicologist at the Colorado Department of Public Health and Environment, said, “A health risk assessment is a process to scientifically evaluate the increased likelihood that adverse health effects will occur if people are exposed to toxics or chemicals. It considers the exposure pathways, the likelihood of adverse health effects, the expected types of health effects, and the toxicity of individual chemicals. The air quality data shows a declining health risk during 2008-12.”

“CDPHE also conducted previous health risk assessments for Garfield County in 2008 and 2010,” said Garfield County Environmental Health Specialist Morgan Hill. “The recommendations made in these studies helped inform the direction of the air quality monitoring program in Garfield County. The decreasing concentrations of VOCs and health risks are consistent with what we have observed in the 2012, 2013 and 2014 air quality monitoring reports as well.”

The site-by-site comparison of the estimated risks from 2008 to 2012 outlined in this report includes three monitoring sites. The three sites assessed in the report were the Bell Ranch south of Silt, the town of Parachute, and downtown Rifle. Other county monitoring sites did not have data for all five years from 2008 to 2012.

There is uncertainty associated with health risk estimates, due to potential underestimation of risk. There is a lack of air monitoring data for other chemicals, lack of a toxicity value for some measured chemicals, and potential increase in exposure for individuals living near emission sources. A health risk assessment cannot determine whether adverse health effects have occurred, or will occur, as a result of site-specific chemicals. It also cannot identify particular individuals likely to suffer health problems.