Through exposure from air, water, or land, a food supply may be contaminated with certain residues, which may eventually be consumed by humans. Some contaminations may be residues of compounds purposely used to protect crops from insects (insecticides) or destroy competing plants (herbicides). Other contaminations may be from industrial waste or pollution, by accident, ignorance, or recklessness. Some contaminations may be naturally found in the food supply, such as those derived from the soil as food plants are grown, e.g., some heavy metals. Residues or contaminants found in foods differ widely in chemical structure, but all possess toxic properties that may be a threat to human health. Some of these chemicals tend to accumulate in the food supply, being more toxic. For example, fish and crustaceans can tolerate much higher tissue levels of arsenic and mercury than can humans.
Last modified: Thursday, 23 February 2012, 11:43 AM