Final answer:
The harmfulness of a pollutant to the environment is determined by its chemical nature, concentration, and persistence. Persistent organic pollutants are particularly concerning as they are toxic and accumulate in the food chain. During an industrial spill, the pollutant with the longest residence time poses the greatest long-term risk.
Step-by-step explanation:
Factors that influence how harmful a pollutant will be to the environment include its Chemical Nature, the Concentration of the pollutant, and its Persistence in the environment. The chemical nature of a pollutant determines its potential toxicity and how it interacts with the environment.
The concentration of the pollutant is crucial because even substances that are harmless in small amounts can become detrimental at higher concentrations. Finally, persistence refers to how long a pollutant remains in the environment before it breaks down. Pollutants that are persistent can accumulate over time and cause more extended damage.
Persistent organic pollutants (POPs), like DDT and PCBs, are not only toxic but also tend to accumulate in higher trophic levels through the process known as biomagnification.
When looking at an industrial spill involving carcinogens, those with longer residence times pose a greater risk; for example, a spill involving a chemical with a residence time of 17.2 hours is less concerning over the course of a week than a pollutant with a residence time of 2.8 days, assuming equal toxicity and amounts.