Porter, WP, JW Jaeger and IH Carlson. 1999. Endocrine, immune and behavioral effects of aldicarb (carbamate), atrazine (triazine) and nitrate (fertilizer) mixtures at groundwater concentrations. Toxicology and Industrial Health 15: 133-150.

Porter et al. identify six important shortcomings in the current procedures used to assess pesticide safety.

1. Current testing protocols do not require chemicals to be tested at low dose exposures in pulses. "Pulse dose of low levels of pesticides at critical times when developmental windows are open and body defences are unable to respond may lead to permanent changes in the fetus."
2. Standard toxicological tests evaluate only one route of exposure at a time. People accumulate exposures through multiple routes simultaneously.
3. Many important endpoints are excluded, as toxicological tests have typically focused on cancer and mutation endpoints, without considering other endpoints such as endocrine and immune system effects.
4. Most toxicological testing is done with highly pure forms of pesticidal active ingredients. In the real world, however, the active ingredient of a pesticide is mixed with three other types of addition. First, pesticide manufacturing involves unavoidable contamination of the pure compound during the manufacturing process. Second, toxic waste from chemical reactor cleaning processes is sometimes deliberately added to pesticide mixtures. No testing is done for these random additions. Third, the active compound is mixed with so-called "inert" ingredients to assist the pesticide's penetration through biological surfaces. Some of these "inerts" are extremely active biologically, including several powerful endocrine disruptors.
5. Very little is known about the exposure impacts from chemical mixtures. Not only are pesticides purposefully mixed with other compounds (3, above), people invariably encounter multiple compounds and carry several hundred synthetic chemicals in their bodies.
6. Testing of compounds is carried out on well-cared for laboratory animals, living in an environment where climate, nutritional and disease stress are limited, if not absent. Experiments show that "when these stresses are present, toxic responses to registered chemicals show up that do not appear under current standard testing procedures (Porter et al. 1984)."

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