Examining Bioaccumulation & Biomagnification: Implications for Ecosystems and Human Health

Persistent Organic Pollutants Chemicals and by-products generated through their production and use can be released to the environment, potentially impacting wildlife and humans. Persistent organic pollutants or POPs, are long-lived in the environment and if bioavailable, they can make their way into animals and be stored in fat. Examples include PCBs, DDT, dioxins

POPs: Relevance to Human Health Interact with macromolecules within the body Impair or inhibit metabolic processes Induce mutations in DNA (mutagenic) May increase the risk of cancer by altering cellular metabolism or damaging DNA directly (carcinogenic) Impair reproduction Induce birth defects (teratogenic)

Journey of a Persistent Organic Pollutant

Chapter 6 follows a (PCB) molecule from its creation in a Monsanto chemical plant near Anniston, Alabama, to its entry into a polar bear in the Arctic. This hypothetical journey may differ in detail from the movement of any specific molecule, but it describes in general the way one type of especially potent and persistent endocrine disrupting compound, the PCBs, have become ubiqutious contaminants in virtually every ecosystem on planet Earth.

Interactive: A Toxic Journey

POPs in Polar Bears Arctic Monitoring and Assessment ProgramArctic Monitoring and Assessment Program.

Inuit People In 1997, Inuit breast milk was discovered to contain seven times the amount of PCBs than the typical infant from the US or Southern Canada.

Bioaccumulation vs Biomagnification Bioaccumulation Concentration of a pollutant within an organism Pollution of the human body begins before birth Body Burden refers to the amount of pollution present in an organism Biomagnification Concentration of a pollutant within a food chain PCBs, DDT, Mercury, Arsenic, Dioxin

Biomagnification Activity Primary Consumer Tertiary Consumer Secondary Consumer Enter Number of PCBs acquired during activity XX

Body Burden

On Contaminated Sediment The U.S. Environmental Protection Agency estimates that approximately 10 percent (over a billion cubic yards) of the sediment underlying our nation's surface water is sufficiently contaminated with pollutants to pose potential risks to fish and to humans and wildlife that eat fish. EPA’s Contaminated Sediment Management Strategy (1998)

Bioavailability Bioavailability processes are the individual physical, chemical, and biological interactions that determine the exposure of plants and animals to chemicals associated with soils and sediments. These processes modify the amount of chemical in soil or sediment that is actually absorbed and available to cause a biological response. National Research Council, 2003.

Research has shown that the bioavailability of many of these contaminants is less than the total amount of contaminant in the sediment.

“The current regulatory paradigm for characterizing the level of contamination in soils and sediments generally does not include measures of the actual bioavailability of these contaminants to human or ecological receptors.” SERDP & ESTCP Expert Panel Workshop on Research & Development Needs for Understanding & Assessing the Bioavailability of Contaminants in Soils & Sediments (2008)

Evaluating Risk “Incorporating bioavailability considerations in the calculation of risk can: optimize the extent of cleanup required to be protective, improve site decision-making, and can be an important factor in balancing the risks caused by remedial action with the risks addressed by remedial action.” Interstate Technology and Regulatory Council (ITRC)