Documents mutagenicity tests 46 results

Beryllium is a steel-grey, brittle metal, existing naturally only as the 9Be isotope. Its compounds are divalent. Beryllium has several unique properties. It is the lightest of all solid and chemically-stable substances, with an unusually high melting point, specific heat, heat of fusion, and strength-to-weight ratio. It has excellent electrical and thermal conductivities. Because of its low atomic number, beryllium is very permeable to X-rays. Its nuclear properties include the breaking, scattering, and reflecting of neutrons, as well as the emission of neutrons on alpha-bombardment.

The first part of this project, dealing with in vitro studies, was published in 1985 (Ashby et al., 1985) and was summarized in Environmental Health Criteria 47 (WHO, 1985). The second part, which is the subject of this report, was published in 1988 (Ashby et al., 1988a).The need for inter-laboratory collaborative studies on an international scale arose from the necessity t investigate the value of short-term tests for detecting mutagenic and carcinogenic chemicals.

"Evaluates the risks to human health and the environment posed by 1,3-dichloropropene, 1,2-dichloropropane and mixtures of these chemicals. Since the two compounds and mixtures have been widely used in agriculture as pre-plant fumigants applied by soil injection, the report gives particular attention to studies investigating behaviour in soil, risks of leaching and groundwater contamination, uptake by food crops, residues detected in drinking-water and food, and risks to agricultural workers and the general population. Over 300 studies, including proprietary toxicological data from the manufacturers, were critically assessed.
The report concludes that, when used at the recommended rate, 1,3-dichloropropene is unlikely to attain levels of environmental significance. Risks to the general population were judged negligible. Concerning occupational hazards, the report cites evidence, largely from case reports of poisoning, underscoring the need to follow appropriate safety precautions.
The report concludes that 1,2-dichloropropane poses a negligible risk to the general population. When used at the recommended rate, the compound is unlikely to attain levels of environmental significance. For workers, the compound is judged unlikely to pose a hazard, provided good work practices, hygienic measures, and safety precautions are followed.
Data on mixtures of dichloropropenes and dichloropropane are evaluated in the final monograph. This technical mixture previously enjoyed wide use as a soil nematocide before planting. Citing evidence of a significant potential for 1,2-dichloropropane derived from this mixture to leach from soil and contaminate well water and groundwater, the report recommends that mixtures of dichloropropenes and dichloropropane should not be used as a soil fumigant. "

"Evaluates the risks to human health and the environment posed by benomyl, a fungicide registered for use in 50 countries on over 70 crops, including cereals, cotton, soybeans, tobacco, mushrooms, grapes, bananas and other fruits. One of the most widely used members of the benzimidazole family of fungicides, benomyl is effective, at low usage rates, against more than 190 different fungal diseases. Because benomyl is rapidly converted to carbendazim in the environment and is extensively metabolized to carbendazim by experimental animals, data from studies of carbendazim, which is a fungicide in its own right, are also considered when evaluating the hazards of benomyl.
Concerning hazards to environmental organisms, the report cites data from laboratory and field studies indicating that benomyl, applied at recommended rates, has little effect on soil microbial activity, but some adverse effects on groups of fungi. Benomyl is toxic to earthworms in laboratory experiments at realistic exposure concentrations and as a result of recommended usage in the field; earthworm populations may take more than two years to recover. Although high toxicity to aquatic organisms has been demonstrated in laboratory tests, the report concludes that this effect is unlikely to be seen in the field, due to the low bioavailability of sediment-bound residues.
For the general population, the main source of potential exposure is noted to be through the ingestion of food crops containing residues of benomyl and carbendazim. Though benomyl has been shown to cause contact dermatitis and dermal sensitization in some farm workers, the report found no evidence that either of these compounds can cause systemic toxic effects in occupationally exposed subjects or the general population. The report cites findings from animal studies suggesting that both compounds pose a very low risk for acute poisoning in humans."

Evaluates the risks to human health and the environment posed by methyl parathion, a highly toxic organophosphorus ester insecticide. Close to 600 studies were critically assessed. Introduced as a commercial chemical in 1949, methyl parathion is used as a contact insecticide and acaricide for the protection of cotton, soybeans, cereals, tobacco, peanuts, vegetables, citrus fruits, and other crops. The compound is applied as a foliar spray by aircraft or ground equipment.

Because methyl parathion is a non-selective pesticide that kills beneficial species as well as pests, a section devoted to effects on environmental organisms concentrates on several studies documenting high toxicity for honey bees. These studies also show that incidents of bee kills were more severe with this insecticide than with others, underscoring the need to time spraying operations with extreme care. The report concludes that methyl parathion should never be sprayed under windy conditions, and that overspraying of water bodies must be avoided.

The most extensive section evaluates studies of toxic effects observed in experimental animals and in vitro test systems. The report found no evidence of carcinogenicity associated with long-term exposure, and no evidence that this insecticide acts as a primary eye or skin irritant. The final section evaluates effects on humans, drawing on a number of case reports of accidental and sometimes fatal poisoning. The report concludes that the only confirmed effects on humans are the signs and symptoms characteristic of systemic poisoning by cholinesterase-inhibiting organophosphorus compounds. No cases of organophosphorus-induced, delayed peripheral neuropathy have been reported. Concerning risks to workers, the report concludes that, with good work practices, hygienic measures, and safety precautions, methyl parathion is unlikely to present a hazard for occupationally exposed workers.

Evaluates the risks to human health and the environment posed by trichlorfon, a broad-spectrum organophosphorus insecticide which acts as a "slow release" source of dichlorvos in the mammalian body. Marketed since the 1950s, trichlorfon is used to protect field and fruit crops, to control forest insects, and to control internal and external parasites in domestic and farm animals. Trichlorfon, formulated as metrifonate, has also been used for the pharmacological treatment of Schistosoma haematobium in millions of patients. The compound is under investigation as a treatment for Alzheimer's disease.

A review of environmental levels and human exposure concentrates on the significance of residues detected in crops, the milk of treated cows, and other food items as possible sources of exposure for the general public. Noting that detected levels are far below the established acceptable daily intake, the report concludes that trichlorfon does not constitute a health hazard for the general population. Concerning effects on environmental organisms, the report cites evidence that trichlorfon is moderately toxic for fish and birds, and moderately to highly toxic for aquatic arthropods, supporting the conclusion that this insecticide should never be sprayed over water bodies or streams.

The remaining sections evaluate data from toxicity studies in laboratory animals and in vitro test systems, from several hundred case reports of accidental or intentional human poisoning, and from studies of schistosomiasis patients treated with metrifonate. Though poisoning may have serious effects, including delayed neurotoxicity, the report concludes that, when good work practices and safety precautions are followed, trichlorfon is unlikely to present a hazard for occupationally exposed workers. The report further notes that, in the millions of schistosomiasis patients treated with metrifo-nate, reported side effects have been mild and rare.

"Propylene oxide is a colourless, highly volatile, and flammable liquid primarily used as a chemical intermediate. Small amounts are used for the sterilization of medical equipment and for the fumigation of foodstuffs. The main route of human exposure is through inhalation at the workplace.

This report evaluates available scientific data on the risks posed by propylene oxide to human health and the environment. On the basis of this analysis, the report concludes that propylene oxide should be regarded, for practical purposes, as presenting a carcinogenic risk for man, and that levels in the environment should be kept as low as feasible."

"A methodological guide to short-term testing for mutagens and genotoxic carcinogens. In view of the acknowledged limitations in the capacity of short-term tests to screen for mutagenicity and carcinogenicity, the report attempts to explain the types of test that are commonly employed and the meaning that the results of such tests may have in the assessment of possible human hazards. The most extensive section contains descriptions, in phylogenetic order, of the most commonly used and most widely accepted assays. Emphasis is placed on the specific minimum scientific and technical criteria regarded as critical factors in obtaining data of acceptable quality and reliability. The next section provides additional criteria for good laboratory practice in genetic toxicology. The report concludes with guidelines for the application and interpretation of short-term tests."