Teratogenic substances

HI 0 Teratogenic substances and preparations which, if they are inhaled or ingested or if they penetrate the skin,... 

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]. 

Methoxyethyl acetate is hydrolyzed in vivo to form 2-methoxyethanol, which is subsequently metabolized to 2-methoxyacetic acid, a proported teratogenic substance. Consequently, the acetate is expected to show profiles of developmental and reproductive toxicity similar to those of 2-methoxyethanol (qv). In a case report, a woman who was extensively exposed to 2-methoxyethyl acetate, both dermally and probably by inhalation during pregnancy, gave birth to two sons with hypospadias. Because family history and medical examination showed no overt risks other than the significant exposure of the mother, and because 2-methoxyethyl acetate can cause teratogenic effects in animals, the malformations were attributed to the exposure. 

But despite the stipulated duties for industrial companies, circumstances may arise in which authorities conclude that additional measures still need to be initiated in order to improve human health and environmental protection. For this purpose, different processes are laid down in REACH as well as in the CLP Regulation and reproductive toxicants often take a special position within them. This is because reproductive toxicity is considered a particularly serious health hazard. The three procedures explained below show in more detail how substances with reproductive toxic properties are taken into particular consideration. In this context, teratogenic substances are not explicifly named by the legal texts but, as they constitute as developmental toxicants a hazard differentiation of reproductive toxicity, they are implicitly always included by the provisions. 

With respect to improved protection of public health, special restrictions on can-cerogenic and teratogenic substances and their corresponding preparations have been established by the 14th amendment of EEC Council Directive EEC 76/769... 

Table 1. Some Potentially Teratogenic Substances Used in General Chemistry Laboratories... 

Recent studies have indicated that humans may be exposed to 2,3,7,8-tetrachlorodibenzo-p- dioxin(2,3,7,8-TCDD), a toxic and teratogenic substance in laboratory animals (1). A fraction of beef fat samples from cattle known to have grazed on pasture treated with herbicide 2,4,5-T (which contains trace quantities of 2,3,7,8-TCDD) have been reported to contain low part per trillion (ppt) levels of 2,3,7,8-TCDD (2,3) Two studies of bovine milk reported no detectable chlorodioxins however (4,5). Combustion processes have been reported to produce chlorinated dioxins which enter the air as fly ash and soot (6.7.8). Three different studies of human milk have been carried out by various workers to determine if humans contain detectable concentrations of 2,3,7,8-TCDD (9,20,22). 

Classification based solely upon lethality can communicate a false sense of security because other determinants of toxicity are not addressed in such a classification system. For example, a teratogenic substance such as thalidomide could be classified as slightly toxic based upon its LDJ0 but highly toxic on the basis of producing fetal malformations. Therefore, classification schemes must always be assessed with their inherent limitations in mind. 

At the present time there are no rapid lower tier , i.e., nonmammalian screening systems which have been validated as capable of detecting teratogenic substances. The basic problem is that an applicable screening test must differentially detect substances to which the conceptus is uniquely susceptible . Virtually any toxic substance is capable of affecting the fetus at doses that are close to those which are toxic to the adult, but such coeffective teratogens would not necessarily pose a developmental hazard. 

A highly toxic substance by ingestion, and possibly by most other routes of exposure moderately toxic by inhalation and skin contact cholinesterase inhibitor toxic effects are similar to those of other carbamate pesticides and include excessive salivation, lacrimation, slow heart rate, blurred vision, twitching of muscle and lack of coordination, nausea, weakness, diarrhea and abdominal pain oral intake of probably 1.5-3 g could be fatal to adult humans a teratogenic substance, producing adverse reproductive effects in experimental animals. 

A derivative of DDT structurally aud toxic properties are similar to those of DDT however, the acute effects are somewhat milder moderately toxic by ingestion a teratogenic substance adequate evidence of carcinogenicity in experimental animals... 

Mildly toxic by ingestion the oral median lethal doses in all experimental animals were >5000 mg/kg however, produced moderate to severe effects when administered intravenously toxic properties are somewhat similar to those of DDT susceptible to storage in fat also bioaccumulative a teratogenic substance sufficient evidence of carcinogenicity in mice, but inadequate evidence in other animals cancer-causing effects in human unknown. 

Highly toxic by oral, dermal, and possibly other routes of exposure toxic properties similar to those of Mirex however, more toxic than the latter symptoms include tremors, ataxia, hyperactivity, muscle spasms, and skin changes highly injurious to liver, kidney, and central nervous system a teratogenic substance caused testicular atrophy, sterility, low sperm count, and breast enlargement in experimental animals sufficient evidence of carcinogenicity in experimental animal also, possibly carcinogenic to humans. (lARC... 

Meyers and Meyers (77) list 527 teratogenic substances but their list is based on human or animal data. 

Dawson, D. A., McCormick, C.A Bantle, J.A. (1985). Detection of teratogenic substances in acidic mine water samples using the frog embryo teratogenesis assay - Xenopus (FETAX). J. Appl. Toxicol. V. 5. N 4. pp. 234-44. 

Teratogens. Substances that lead to a birth defect. Examples of teratogens are cigarette smoke, alcohol, thalidomide, and others. 

Teratogenic substances cause abnormahties in the foetus developing in the womb, resulting in birth defects. The word teratogenic means cairsing monsters but not all birth defects are as serious as that. 

Teratogenic substances can function in mammalian systems as either struc-tural/anatomic or behavioral teratogens. The former define the conventional... 

Quinine is a protoplasmic toxin (adversely damaging Hving cells), which inhibits various important enzymes. The ADI value for quinine hydrochloride for adults is 40 mg/kg. Quinine is a teratogenic substance and should never be used by pregnant women, as birth... 

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