HUMAN HEALTH EFFECTS ASSOCIATED WITH PCB EXPOSURE

Introduction | Health Effects of PCBs | Exposure to PCBs in Great Lakes | Health Effects in Great Lakes Areas of Concern

Introduction

While PCBs are found in many environmental media in the Great Lakes, sediments and fish and other aquatic-based organisms, are sources of most concern. As a result, Great Lakes residents are at the top of the bioaccumulation food chain when consuming PCB-contaminated fish. Bioaccumulation occurs when persistent and stable compounds, such as PCBs, are taken up by predators (in this case fish) and accumulate all their prey's levels of PCBs, resulting in a higher concentration in animals and fish as you go up the food chain. Given the large number of fish advisories in the Great Lakes for PCBs, consumption of Great Lakes fish is the pathway of most concern for PCB exposure.

Exposure to PCBs has been shown to be associated with adverse health effects in individuals who consume Great Lakes fish, and effects have also been noted in these individuals' offspring. Adverse health effects that may be associated with this exposure include disruption of reproductive function; neurobehavioral and developmental deficits in children; systemic effects such as liver disease, diabetes, and effects on thyroid and immune systems; and increased cancer risks (Johnson, et al., undated (post-1998) and US EPA, 2000b). In addition, several sub-populations have been identified as having a potentially higher risk of short- and long-term health effects because of elevated exposure or sensitivity to contaminants in Great Lakes fish. These include sports anglers, Native Americans, pregnant women, fetuses and nursing infants of mothers who consume contaminated Great Lakes fish, infants and children, the elderly, and the urban poor (Hicks, et al., undated).

Consumption of fish is the most significant exposure route contributing to cumulative PCB health risks in Great Lakes Basin residents. Some of the literature supporting these findings in the Great Lakes includes Serum PCB and DDE Levels of Frequent Great Lakes Sport Fish Consumers-A First Look (Hanrahan et al., 1999), and Motor Function in Aging Great Lakes Fisheaters (Schantz, et al., 1999). Additional studies include the Oswego Newborn and Infant Development Project, the New York State Angler Study, the Cognitive and Motor Effects of PCB Exposure in Older People from the Michigan Fisheater Cohort, Great Lakes Fish as a Source of Maternal and Fetal Exposure to Chlorinated Hydrocarbons, the Michigan Sport Fisherman Study, Wisconsin Sport Fish Consumer Study, Michigan Maternal and Infant Study, Dar's Wisconsin Maternal and Infant Study, and the New York Ecologic Epidemiologic Study (GLC, 1997).

A summary of the health effects associated with exposure to PCBs in Great Lakes Fish has been published by the Agency for Toxic Substances and Disease Registry (ATSDR). The major findings are as follows (ATSDR http://www.atsdr.cdc.gov/toxprofiles/tp17.html)

• Susceptible human populations are being exposed to PCBs via fish consumption.

• Many residents in the Great Lakes basin ate more fish than 6.5 g/day (i.e. the amount estimated for the general US population).

• High consumption of PCB-contaminated Great Lakes sport fish is associated with increased body burden levels of PCBs, which are higher than the levels observed in the general U.S. population.

• Men eat more fish than women, and both men and women eat Great Lakes fish during most of their reproductive years.

• Neurobehavioral and developmental deficits occur in newborns exposed in utero to PCBs and continue in school-aged children.

• Current fish intake rates and derived PCB exposures for some persons are similar to those associated with adverse health effects among children in epidemiologic studies.

• Reproductive function might be disrupted by exposure to PCBs, although more research is required to resolve this possibility.

• Exposure to PCBs in fish places adult men, women beyond their reproductive years, and the elderly at increased risk for cancer; they might also be at increased risk for immune and endocrine system effects.

• Exposure to PCBs might increase the risk for clinical effects such as non-Hodgkin's lymphoma, diabetes, and liver disease.

• Although PCBs are the primary contaminants associated with increased risk resulting from consumption of Great Lakes sport fish, other compounds that also contribute to the overall increased risk include organochlorine pesticides, mercury, dioxin, and dibenzofurans.

In 1989 Health Canada started the Great Lakes Health Effects Program (GLHEP) as part of Canada’s Great Lakes Action Plan. The aims of this ten-year program were to determine the health effects in the Great Lakes basin associated with environmental contaminants. This involved compiling existing information, and embarking on an “innovative and interrelated program of scientific research and public education.”¹ Of the $125 million that the federal government allocated for the Great Lakes Action Plan, $20 million was to be for the GLHEP.

The GLHEP did not achieve its potential because federal budget cuts resulted in this funding being substantially reduced. In her 2001 report on the Great Lakes, Canada’s Commissioner of the Environment and Sustainable Development concluded that “Health Canada spent less than half the amount it had committed to spend, and it had to suspend work and cancel contracts.”²

At the end of the active period of the GLHEP, Health Canada released two major reports: State of Knowledge Report on Environmental Contaminants and Human Health in the Great Lakes Basin [1997] and Persistent Environmental Contaminants and the Great Lakes Basin Population: An Exposure Assessment [1998]. In these reports, Health Canada compiled the information that they had gathered from research that they conducted or commissioned and that they had gathered from other sources. The next two parts of this report are based on pulling out the information related to PCBs from these reports.

² Report of the Commissioner of the Environment and Sustainable Development to the House of Commons: Chapter 1: Great Lakes and St. Lawrence River Basin, 2001, p. 281.