Question

You are a risk assessor working for EPA Region X and have been asked to look at the risks posed by a leaking municipal waste dump. The dump was created and lies right along the shore of Mombasa. There are families living less than one mile away. Although there are hundreds of chemicals leaking from this dump, the primary chemicals of concern are polychlorinated biphenyls (PCBs) and chromium, both of which are known to be hazardous to human and ecological health. These chemicals are known to be present in soil on top of the dump as well as in groundwater and surface water in the Columbia River. Discuss the potential exposure pathways that might be important for this site. Your boss has asked you to be very thorough and consider all the possible targets for these chemicals, both human and animal. Hint: A good way to do this is to sketch out the pathway from the contaminated media to the particular target (human or animal).

Answer 1

The assessment of risks from a leaking waste dump in Mombasa must consider exposure pathways such as direct soil contact, ingestion of contaminated water, consumption of contaminated fish and wildlife, and bioaccumulation in the food chain for both humans and animals. PCBs and chromium are contaminants of concern that can lead to significant health issues.

Step-by-step explanation:

Potential Exposure Pathways for Chemical Contamination

When assessing the risks posed by a leaking municipal waste dump near Mombasa, several potential exposure pathways are important for consideration. The primary chemicals of concern, polychlorinated biphenyls (PCBs) and chromium, can impact both human and animal health through various channels.

Human Exposure Pathways

Direct contact with contaminated soil from the dumpsite.

Ingestion of contaminated groundwater or surface water - an important consideration as these chemicals are known to be present in the Columbia River.

Consumption of fish and wildlife that have bioaccumulated PCBs and chromium.

Incidental contamination of food with industrial chemicals.

Animal Exposure Pathways

Direct contact or ingestion of contaminated soil and water by terrestrial and aquatic animals.

Bioaccumulation in the food chain, which can lead to high levels of contamination in apex predators.

Toxic chemicals like PCBs not only pose a hazard for the immediate area but can also disrupt the natural ecosystem and biomagnify through the food chain, leading to elevated concentrations in apex predators. In the case of heavy metals such as chromium, they can accumulate in the bodies of aquatic life and eventually be consumed by humans or other animals.

The epidemiology of areas with chemical pollution from waste has shown that contaminants like PCBs and heavy metals can lead to serious health consequences, including an increased risk of cancer and disruption of biological systems.

Conclusively, both humans and animals are at risk from these chemicals via contamination of air, water, or soil, and the interaction with these contaminated elements through daily activities or food consumption.