Using the example of the peregrine falcon and DDT, explain why ecotoxicology is
ID: 207943 • Letter: U
Question
Using the example of the peregrine falcon and DDT, explain why ecotoxicology is a sub-discipline of ecology, rather than toxicology
Consider this situation (yes, it has really happened, near Rotterdam, The Netherlands): Houses were built on a site where landfill with dredge sludge from a harbor was used to elevate the ground. The new owners started growing foods in their gardens, only to find that their lettuce had unacceptably high levels of cadmium in it. Further study revealed that the soils were highly contaminated, not just with cadmium, but with other metals and arsenic, and organic compounds, such as polycyclic aromatic hydrocarbons (PAHs).
Using the terms chemical speciation, extractability, fractionation and bioavailability, explain how you would go about investigating the site, and what considerations you might have for the design of a remediation and management strategy. (NOTE: I am not asking you to design a remediation and management strategy, but to write about what considerations you might take into account).
Explanation / Answer
1. Peregrine Falcons historically known as duck hawks are spread throughout North America, ranging from the great lakes to Alabama. They primarily hunt other birds and nest on high and remote cliffs. They can live up to 15 years or more having less natural threats in the wild. Before World War II the population of Peregrine Falcon was thriving in the United States, but post-WW the population was estimated to decline by 90% and the cause was the usage of a new insecticide DDT. Dichlorodiphenyltrichloroethane was vastly used as an effective pesticide to control the harmful insect population, but its effect on other animals was hardly measured at that time. It would take years to understand fully how DDT acts as a toxic compound, accumulating in every trophic level and catastrophically affect the topmost predators of the food chain. High levels of DDT prevented Ca++ production, resulting in fragile eggshells which would break during incubation. The Falcons, being on the top of the food chain were hit really hard. Their population almost perished before DDT was finally banned from the USA. This case study demonstrates how the harmful effect of a toxic compound is biomagnified at such a level that it negatively influenced animals from each trophic level, not just one species. Hence ecotoxicology can clearly be stated as a subdiscipline of Ecology as it directly deals with toxic elements and majorly focusing on how it affects the surrounding life.
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