How can pollution affect food chains?
Some chemicals are accumulated in food chain
Some metals and chemicals do not undergo decay reactions. They accumulate in sediment, biota, etc. According to Tietenberg (1996), "the most troublesome cases of pollution result from stock pollutants which merely accumulate in the environment. No natural process removes or transforms stock pollutants".
Some heavy metals, such as lead and cadmium, poison consumers in the food chain. According to Tietenberg (1996), one ocean discharge of industry was responsible for Minamata disease, named for the location where it is recorded. Until being traced by scientists to an organic form of mercury, fishermen and their families, cats were poisoned by it that had accumulated in the tissues of fish consumed.
Reference: Tietenberg, T. (1996). Environmental and Natural Resource Economics (4th edition). Harper Collins College Publishers. New York, NY, USA.