Effect of Parathion-Methyl on Amazonian Fish and Freshwater Invertebrates: A Comparison of Sensitivity with Temperate Data

Parathion-methyl is an organophosphorous insecticide that is widely used in agricultural production sites in the Amazon. The use of this pesticide might pose a potential risk for the biodiversity and abundance of fish and invertebrate species inhabiting aquatic ecosystems adjacent to the agricultural fields. Due to a lack of toxicity data for Amazonian species, safe environmental concentrations used to predict the ecological risks of parathion-methyl in the Amazon are based on tests performed with temperate species, although it is unknown whether the sensitivity of temperate species is representative for those of Amazonian endemic species. To address this issue, the acute toxic effect (LC50–96 h) of parathion-methyl was assessed on seven fish and five freshwater invertebrate species endemic to the Amazon. These data were used to compare their pesticide sensitivity with toxicity data for temperate species collected from the literature. The interspecies sensitivity was compared using the Species Sensitivity Distribution (SSD) concept. The results of this study suggest that Amazonian species are no more, or less, sensitive to parathion-methyl than their temperate counterparts, with LC50 values ranging from 2900 to 7270 μg/L for fish and from 0.3 to 319 μg/L for freshwater arthropods. Consequently, this evaluation supports the initial use of toxicity data of temperate fish and freshwater invertebrate species for assessing the effects of parathion-methyl on Amazonian freshwater ecosystems

Effects of malathion and carbendazim on Amazonian freshwater organisms: comparison of tropical and temperate species sensitivity distributions

The risk assessment of pesticides for freshwater ecosystems in the Amazon has relied on the use of toxicity data and water quality criteria derived for temperate regions due to a lack of ecotoxicological studies performed with indigenous species. This leaves an unknown margin of uncertainty for the protection of Amazonian ecosystems, as differences in environmental conditions and species sensitivity are not taken into account. To address this issue, the acute toxic effects of malathion (an organophosphorus insecticide) and carbendazim (a benzimidazole fungicide) were assessed on five fish and five freshwater invertebrates endemic to the Amazonian region. Subsequently, the intrinsic sensitivity of Amazonian and temperate freshwater species was compared using the species sensitivity distribution (SSD) concept. Amazonian species sensitivity to malathion was found to be similar to that of their temperate counterparts, with LC50 values ranging between 111 and 1507 μg/l for fish species and 2.1–426 μg/l for arthropod species. However, Amazonian fish appeared to be slightly less sensitive for carbendazim than temperate fish with LC50 values ranging between 1648 and 4238 μg/l, and Amazonian invertebrates were found to be significantly more resistant than their temperate counterparts, with LC50 values higher than 16000 μg/l. The results of this study suggest that for these compounds, the use of water quality criteria derived with laboratory toxicity data for temperate species will result in a sufficient protection level for Amazonian freshwater organisms. Recommendations for further research include the validation of threshold concentrations derived with temperate standard test species and with the SSD model with semi-field experiments considering larger assemblages of indigenous species under local environmental conditions

Investment Incentives Under Emission Trading: An Experimental Study

This paper presents the results of an experimental investigation on incentives to adopt advanced abatement technology under emissions trading. Our experimental design mimics an industry with small asymmetric polluting firms regulated by different schemes of tradable permits. We consider three allocation/auction policies: auctioning off (costly) permits through an ascending clock auction, grandfathering permits with re-allocation through a single-unit double auction, and grandfathering with re-allocation through an ascending clock auction. Our results confirm both dynamic and static theoretical equivalence of auctioning and grandfathering. We nevertheless find that although the market institution used to reallocate permits does not impact the dynamic efficiency from investment, it affects the static efficiency from permit trading

Intoxicações e uso de pesticidas por agricultores do Município de Paty do Alferes, Rio de Janeiro, Brasil Pesticide use and poisoning among farmers from the county of Paty do Alferes, Rio de Janeiro, Brazil

Este trabalho é parte de um estudo mais amplo sobre as conseqüências para a saúde da exposição a pesticidas. Em 1997, no Município de Paty do Alferes, Rio de Janeiro, 55 agricultores foram entrevistados sobre o uso de pesticidas, equipamentos de proteção e medidas de higiene, ocorrência de intoxicações, destino das embalagens vazias e o tipo de orientação técnica recebida pelos usuários destes produtos. Os pesticidas mais usados foram inseticidas como a abamectina, os compostos organofosforados e os piretróides, e os fungicidas como o mancozeb, o clorotalonil e produtos à base de cobre. Entre os trabalhadores envolvidos no preparo e/ou aplicação de pesticidas, 92% informaram não usar qualquer tipo de equipamento de proteção individual. 62% dos agricultores entrevistados informaram já ter "passado mal" ao preparar ou aplicar pesticidas. Os sintomas mais freqüentemente citados foram dor de cabeça, enjôo, vômitos, vertigem, irritação da pele e visão embaçada. Destes agricultores, 21% necessitaram de assistência médica e em mais da metade dos casos (51%), em que os lavradores identificaram os pesticidas que usavam quando "passaram mal", foram citados inseticidas organofosforados da classe toxicológica I.<br>This survey is part of a more comprehensive study on the health consequences of pesticide exposure. In the county (municipality) of Paty do Alferes, Rio de Janeiro State, Brazil, 55 agricultural workers were interviewed on the use of pesticides, use of personal protective equipment, data on health status, and symptoms related to pesticide exposure, disposal of agrochemical containers, and technical assistance. The most widely used pesticides were insecticides such as abamectin, organophosphate compounds, and pyrethroids, and fungicides such as mancozeb, chlorothalonil, and copper products. As a rule, pesticides are handled carelessly, and 92% of workers involved in the mixing, loading, and spraying of insecticides and fungicides used no protective clothing or equipment whatsoever. Some 62% of workers reported at least one illness associated with mixing or spraying pesticides. The most frequently reported symptoms were headache, nausea, vomiting, dizziness, skin irritation, and blurred vision, and 21% of affected workers required medical care. In more than half (51%) of the cases, workers reported using organophosphate insecticides from toxicological class I when they felt sick