Environmental contaminants are chemicals that accidentally or deliberately enter the environment, often, but not always, as a result of human activities. Some of these contaminants may have been manufactured for industrial use, and because they are very stable, they do not break down easily. If released to the environment, these contaminants may enter the food chain. Other environmental contaminants are naturally occurring chemicals, but industrial activity may increase their mobility or increase the amount available to circulate in the environment, allowing them to enter the food chain at higher levels than would otherwise occur.

Environmental contaminants are chemicals that accidentally or deliberately enter the environment, often, but not always, as a result of human activities. Some of these contaminants may have been manufactured for industrial use, and because they are very stable, they do not break down easily. If released to the environment, these contaminants may enter the food chain. Other environmental contaminants are naturally occurring chemicals, but industrial activity may increase their mobility or increase the amount available to circulate in the environment, allowing them to enter the food chain at higher levels than would otherwise occur. Environmental contaminants influence the physiological cell reactions at different and heterogeneous basics and lead to altering in normal cell function primarily at the molecular and biochemical level. Molecular responses to such common environmental stresses have been studied intensively over the last few years, in which there is an intricate network of signaling pathways controlling perception of these environmental stress signals, the generation of second messengers and signal transduction. Recent advances in many areas of plant and microbial research, including genotyping, make scientists optimistic that valuable solutions will be found to allow deployment/commercialization of strategies better able to tolerate these environmental stresses.