23
Jul
(Beyond Pesticides, July 23, 2007) New research finds several species of freshwater fish have lower temperature tolerances when exposed to the widely used pesticides endosulfan and chlorpyrifos. The discovery reveals another key pesticides issue in the global warming debate. The study, “The Effects of Three Organic Chemicals on the Upper Thermal Tolerances of Four Freshwater Fishes” (Environmental Toxicology and Chemistry, July 2007), is the work of Ronald Patra of Australia’s Department of Environment and Conservation and colleagues. The study establishes the upper temperature tolerances of both unexposed and exposed silver perch, eastern rainbowfish, western carp gudgeon and rainbow trout. Exposed fish were given sublethal doses of endosulfan, chlorpyrifos or phenol. The results show exposure to endosulfan cause a decrease of temperature tolerance in silver perch by 2.8 °C, eastern rainbowfish 4.1 °C, western carp gudgeon 3.1 °C, and rainbow trout 4.8 °C. Chlorpyrifos decreases temperature tolerance in silver perch by 3.8 °C, eastern rainbowfish 2.5 °C, western carp gudgeon 4.3 °C, and rainbow trout 5.9 °C. Phenol is not shown to cause a significant decrease in tolerance. The authors conclude, “The reduction in thermal tolerance of fish in the presence of endosulfan and chlorpyrifos suggest that, not only does temperature […]
Posted in Chlorpyrifos, Climate Change, Endosulfan, Wildlife/Endangered Sp. | No Comments »
22
May
(Beyond Pesticides, May 22, 2007) In a study published in the latest issue of Environmental Toxicology and Chemistry, scientists found that seafood products from southern China contain high concentrations of DDT and hexachlorocylohexane (HCH). While banned in China since 1983, humans are being exposed to organochlorine pesticides (OCP) at rates high enough to pose health threats. The study responded to high rates of DDT and HCH found in sediment, water and biota in the Pearl River delta and neighboring coast, where land is being rapidly industrialized, urbanized, and transferred from agriculture to commercial development. Researchers tested 212 seafood products, including shrimp, crabs, and mollusks, from 11 coastal cities for 21 OCPs, including DDT, HCH, heptachlor, dieldrin, and endosulfan. The highest concentrations of DDT were found in four species of shellfish, although concentrations varied widely depending on sampling location. The study reported, “These results suggest that bioaccumulation of DDTs in seafood products was highly species-specific, probably due to different feeding habits and habitats.” By taking a large sample of one indicator species, it also concluded “the coastal region of southern China is probably one of the most DDT-polluted areas in the world.” Researchers also found HCH to be more widely prevalent […]
Posted in DDT, Dieldrin, Disease/Health Effects, Endosulfan, International | No Comments »
30
Mar
(Beyond Pesticides, March 30, 2007) A committee of experts advising the United Nations Environment Programme and the Food and Agriculture Organization (FAO) has recommended adding endosulfan and tributyl tin compounds (TBT) to a list of substances that are considered so harmful they can only be traded in special circumstances. On March 27, 2007, the United Nations said that the toxic chemicals would only be allowed to be exported to countries that have explicitly chosen to permit them, a measure aimed at protecting humans and the environment in developing countries. Endosulfan, a chemical sprayed onto food crops and cotton, and TBT, used in “antifouling paint” for ships’ hulls, are already banned in many countries. However, they may be traded freely in countries lacking tight environmental regulations. According to David Santillo who works at the research center for Greenpeace at Britain’s Exeter University, “It’s great that these two have been added to the list so countries have the choice whether to import them or not.” Endosulfan has been linked with testicular cancer, prostate cancer, breast cancer, and defects in male sex organs. According to a recent study conducted in Costa Rica’s mountain forests, findings show that surprisingly high concentrations of pesticides are […]
Posted in Chemicals, Endosulfan, International, Pesticide Regulation | No Comments »
18
Jan
(Beyond Pesticides, January 18, 2007) A new study conducted in Costa Rica’s mountain forests indicates that surprisingly high concentrations of pesticides are accumulating far above the low altitudes at which they are used. Previously thought to be safe from pesticides applied to distant agricultural areas, some remote mountain forests of Costa Rica were found to have pesticide levels almost ten times greater than those in low-lying areas closer to farms and plantations. The study, led by University of Toronto, Scarborough professor Frank Wania, Ph.D., measured air and soil pesticide levels at 23 sites across Costa Rica in order to produce a model to predict potential accumulation of chemicals at high altitudes. The insecticide endosulfan and the fungicide chlorothalonil were found in the largest concentrations, with up to 1 part per billion (ppb) of chlorothalonil and 3 ppb endosulfan in soil. The high concentrations can be explained by a process in which polluted air above the farms and plantations is pushed up into the mountains, where it then cools and becomes polluted rainwater or fog. The hydrophilic nature of modern pesticides makes the occurrence of this phenomenon much more likely; as Crispin Halsall, Ph.D., of Lancaster University (U.K.) explains, “Most currently […]
Posted in Chemicals, Chlorothalonil, Endosulfan, International, Water, Wildlife/Endangered Sp. | No Comments »
