Tiny zebras at your serviceFebruary 03, 2004Before new pesticides can be approved, their environmental impact must be assessed. Due to the complexity of ecological systems, researchers require simple yet representative laboratory models. Among vertebrates, schools of zebra fish are especially suitable. --- Studying the ways substances affect living organisms in their environment is the job of the ecotoxicologist. Particularly with deliberately produced toxic substances such as pesticides, the practical aim of these scientists is developing standardized test procedures that are easy to run, yet capable of providing clear results. Such tests form the basis for developing manufacturer regulations and user information. For pesticides used in or near bodies of water, fish toxicity must be assessed. One aspect that has increasingly gained importance over the past few years relates more to subtle endocrine effects than acute toxicity. Some pesticides are suspected of interfering with vertebrate hormone systems. This can negatively affect the reproductive capacity of fish, disrupting egg development and upsetting the ratio of adult males to females. One species of fish frequently used as a model organism is the zebra fish (Danio rerio). A favorite of aquarium owners, this small, hardy fish is easy to maintain and breeds rapidly. This makes it possible to observe the impact of substances over several generations. Researchers at the Fraunhofer Institute for Molecular Biology and Applied Ecology IME are investigating the effect of new pesticides on the vital parameters of these animals, under realistic exposure conditions. "Our aquariums have artificial sediment beds," emphasizes Dr. Christoph Sch'¤fers, IME department manager. "This is because, in the case of pesticides, we need to know the long-term consequences of short periods of peak exposure. In other words, how quickly are these substances released from the sediment and ingested by the fish? We can observe this by using pesticides that are radioactively marked." These tests provide essential information for protecting natural fish resources, for the fishing industry and finally for human health as well. The IME studies reveal a clearer picture of the potential impact of pesticides than other commonly used methods. The results are much more meaningful because three life stages are examined - egg, larva and mature adult. A reliable indication can be given of the concentration below which a pesticide has no discernable effect. To date, the IME has conducted studies on behalf of several of the world's leading pesticide manufacturers, representing a total contract volume of EUR 700,000. The IME's studies of endocrine effects and on the capacity of sediment to store and release pesticides enjoy high international esteem. Fraunhofer-Gesellschaft |
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| Related Pesticide Current Events and Pesticide News Articles An inexpensive 'dipstick' test for pesticides in foods Scientists in Canada are reporting the development of a fast, inexpensive "dipstick" test to identify small amounts of pesticides that may exist in foods and beverages. Pesticides exposure linked to suicidal thoughts A new study in China has found that people with higher levels of pesticide exposure are more likely to have suicidal thoughts. Getting plants to rid themselves of pesticide residues Scientists in China have discovered that a natural plant hormone, applied to crops, can help plants eliminate residues of certain pesticides. The study is in the current issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication. Study shows more corn for biofuels would hurt water More of the fertilizers and pesticides used to grow corn would find their way into nearby water sources if ethanol demands lead to planting more acres in corn, according to a Purdue University study. New computing tool could lead to better crops and pesticides say researchers A new computing tool that could help scientists predict how plants will react to different environmental conditions in order to create better crops, such as tastier and longer lasting tomatoes, is being developed by researchers. Getting plants to rid themselves of pesticide residues Scientists in China are reporting the "intriguing" discovery that a natural plant hormone, applied to crops, can help plants eliminate residues of certain pesticides. Organic weed control for dandelions Spring and summer often find homeowners out in their yards, busily attempting to control the onslaught of dandelions in a quest for green, weed-free lawns. Environmental effects of cold-climate strawberry farming Strawberries are America's fifth-favorite fruit, according to consumption rates. California and Florida grow more than 95% of the nation's strawberries; an additional 12,000 acres are planted in other states. Pesticides -- easier detection of pollution and impact in rivers The long-term effects of pesticides on living organisms in rivers and on water quality can now be assessed more easily. Pitt research suggests EPA pesticide exposure test too short, overlooks long term effects The four-day testing period the U.S. Environmental Protection Agency (EPA) commonly uses to determine safe levels of pesticide exposure for humans and animals could fail to account for the toxins' long-term effects, University of Pittsburgh researchers report in the September edition of Environmental Toxicology and Chemistry. More Pesticide Current Events and Pesticide News Articles |
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