Teratogenicity pesticides

In terms of toxicity, NIOSH recommends that endosulfan be recognized as a Group 1 Pesticide (NIOSH 1992). Pesticides in Group 1 pose a significant risk of adverse acute health effects at low concentrations or carcinogenic, teratogenic, neurotoxic, or reproductive effects (NIOSH 1992). 

NCI. 1968. Evaluation of carcinogenic, teratogenic and mutagenic activities of selected pesticides and industrial chemicals. Volume I Carcinogenic study. Prepared by Bionetics Research Labs, Inc., Bethesda, MD National Cancer Institute. NCI-DCCP-CG-1973-1-1. 

The detection of a potent dioxin impurity in a major herbicide has focused attention on the nature of chlorinated impurities in pesticides, and in a larger sense, impurities in all chlorinated industrial compounds used extensively in man s environment. The present 2,4,5-T controversy is overshadowed by the dioxin problem. Major disagreement still exists on their relative contributions to the teratogenic effects observed in chicks and the validity of interpretation of high dosage rates used to achieve these effects. We have avoided any assessment of the health-related aspects of dioxins but have dealt almost exclusively with dioxins as an environmental entity. 

The carcinogenic activity of chemical substances is important as well. They are present in pesticides of different classes OCPs (DDT, aldrine, heptachlor, methoxychlor), thiocarbamates (thiram, zineb, ziram), carbamides (monuron) [3], etc. Even if the official description of a given pesticide does not denote its carcinogenic (mutagenic, teratogenic, embryotoxic, etc.) activity, this merely means that this particular pesticide was not studied sufficiently. 

The transformation and metabolism products of pesticides in plants may not only be of acute toxicity, but also may have other properties. Phosmet, for example, transforms into phthalimide and phthalic acid, teratogenic substances [21]. 

Episodic pollution events can adequately be addressed by acute toxicity bioassays, however these are not sufficient to investigate the water quality for delayed toxicity effects of chemicals present. Chronic effects of pesticides can include carcinogenicity, teratogenicity, mutagenicity, neurotoxicity, and reproductive effects (endocrine disruption). 

Chronic exposure to GD causes forgetfulness, thinking difficulty, vision disturbances, muscular aches/pains. Although certain organophosphate pesticides have been shown to be teratogenic in animals, these effects have not been documented in carefully controlled toxicological evaluations for GD. 

Many activations involve compounds which are used as pesticides. In the case of N-nitrosation, the precursors are secondary amines and nitrate. The former are common synthetic compounds and the latter is an anion found in nearly all solid and aqueous phases. The N-nitrosation of a secondary amine [R-NH-R ] occurs in the presence of nitrite formed microbiologically from nitrate. The product is an N-nitroso compound (i.e., a nitrosamine [RR -N-N=0]). The reason for concern with nitrosamines is their potency, at low concentrations, as carcinogens, teratogens, and mutagens. 

Gourtney KD, Andrews JE, Springer J, et al Teratogenic evaluation of the pesticides Baygon, Garbofuran, Dimethoate, and EPN.7 Environ Sci Health B 20(4) 373-406, 1985... 

National Cancer Institute Evaluation of Carcinogenic, Teratogenic, and Mutagenic Activities of Selected Pesticides and Industrial Chemicals, Vol I. Carcinogenic Study, 1968... 

A book of interest is "Chemically Induced Birth Defects," by Schardein (ref. 6). This reference book contains data on human and animal studies on birth defects and teratogens. Drugs are covered extensively. Chemicals discussed are pesticides, metals, industrial solvents, diagnostic agents, dyes, radioactive chemicals, plastics, toxins, food additives, air-water-soil pollutants, personal chemicals, etc. 

TERATOGENICITY OF PESTICIDES AND OTHER ENVIRONMENTAL POLLUTANTS M.J. KLAND... 

While the literature abounds with reports of the undesirable reproductive consequences of DDT exposure at all levels of animal systems, little human research in this area has made its way into the open literature. Shepard s Catalog of Teratogenic Agents (ref. 86) and Nisbet-Karch (ref. 47) each list only the work of O Leary et al. (ref. 87), correlating spontaneous abortion in human females with human pesticide residues, and prematurity of human fetuses with DDE levels found in fetal whole blood. Perhaps the more serious risk with DDT and DDE is the significant presence of these two along with other... 

Ten of the 20 pesticides known to be teratogenic (Table 20) in animals are OPPs (starred). None is listed for teratologic studies in the latest published NTP Annual Plan and NTP Review of the National Toxicology Program (1986). A few, including Parathion are scheduled for neuro-behavioral, and/or pharmaco-kinetic/metabolism studies, but at relatively low (D) priority (ref. 172a,b). 

Carbamate pesticides are used as (1) insecticides, (2) fungicides and (3) herbicides. Insecticides are generally derived from carbamic acid fungicides, from thiocarbamic acid. The herbicide carbamates are a more complex class of compounds. Tables 21 and 22 list some commercial carbamate pesticides in approximate order of decreasing toxicity. It should be noted that the relative classification of highly and moderately toxic is no measure of the relative carcino-, muta- or teratogenicities of these carbamates, since it is based solely on acute LD q data (Morgan, ref. 20). 

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