Documents toxicity evaluation 189 results

"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.

"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 detailed evaluation of the principles and methods currently used to explore the association between exposure to chemicals and the development of adverse neurobehavioural changes. Emphasis is placed on the use of animals as systems to model and predict adverse reactions in the human nervous system.
The book has five sections. The first deals with general factors to be considered in the design of neurotoxicity studies and in the statistical analysis of their results. Experience acquired in the recent outbreaks of poisoning from methyl mercury and carbon disulfide are used to demonstrate both the importance of evaluating the neurotoxicity of chemicals and the power of animal studies to predict human responses. The remaining sections provide extensive information on methods developed in each of the four major research disciplines that contribute to the neurotoxic assessment of environmental chemicals. "

"For hazard assessment of NPs quantitative nanoecotoxicological data are required. The objective of this review was to evaluate the currently existing literature data on toxicity (L(E)C50 values) of synthetic NPs in environmentally relevant species in order to: (i) identify tentatively most harmful NPs and most sensitive organism groups, and (ii) to provide relevant ecotoxicological information for further risk assessment. The focus was set on selected synthetic NPs (nano TiO(2), nano ZnO, nano CuO, nano Ag, SWCNTs, MWCNs and C60-fullerenes) and organism groups representing main food-chain levels (bacteria, algae, crustaceans, ciliates, fish, yeasts and nematodes). Altogether 77 effect values were found, mostly for nano TiO(2) (31%), C60 (18%), nano ZnO (17%), nano Ag (13%), SWCNTs and nano CuO (both 9%). Only 3% of the available quantitative ecotoxicological information concerned MWCNTs. Organism-wise, 33% of the data concerned crustaceans, 27% bacteria, 14% algae and 13% fish. For all organism groups studied, solubility of CuO- and ZnO-NPs was a key factor in their aquatic toxicity. On the basis of the 34 median L(E)C50 values derived from 77 individual values, NPs were ranked according to their lowest median L(E)C50 value for the above described organism groups: the most harmful were nano Ag and nano ZnO that were classified "extremely toxic", (L(E)C50<0.1mg/l), followed by C60 fullerenes and nano CuO that were classified "very toxic", (L(E)C50 0.1-1mg/l). SWCNTs and MWCNTs were classified "toxic" (L(E)C50 1-10mg/l). Nano TiO(2) was classified as "harmful", (L(E)C50 10-100mg/l). Throughout, algae and crustaceans (daphnids) were most sensitive and thus probably most vulnerable organism groups in aquatic exposure to NPs. Very low L(E)C50 values should deserve thorough attention of environmental risk assessors for evaluation of the potential adverse effects of synthetic NPs on ecosystems. As the quantitative nanoecotoxicological data are still rare, further studies are needed."

"L'évaluation et le contrôle des risques pour la santé des divers toxiques industriels ont connu, ces dernières années, des avancées notables. C'est à la lumière de ces nouvelles connaissances que cet ouvrage présente l'ensemble des aspects toxicologiques des substances chimiques utilisées dans l'industrie et/ou libérées dans l'environnement. Pour chaque substance présentée, sont indiqués les usages et sources d'exposition, le métabolisme, la toxicité, le traitement, l'évolution et la prévention. Ce livre s'adresse aux médecins du travail, aux hygiénistes industriels et aux toxicologues. Il s'intéresse, en effet, aux méthodes modernes d'évaluation de la toxicité des agents chimiques, ainsi qu'aux effets cliniques de ces polluants sur la santé des travailleurs qui y sont exposés de manière aiguë ou prolongée. Il s'adresse également aux médecins généralistes et spécialistes en médecine interne, qui ont à connaître les affections déclenchées, favorisées ou aggravées par un toxique industriel. Les spécialistes en biologie clinique y trouveront, également des éléments d'interprétation des analyses effectuées pour évaluer l'exposition des sujets aux substances toxiques."