The study aimed to evaluate the current status and potential risks of pesticide use of 23 chili growing households in the Thanh Binh district, Dong Thap province, Vietnam. The result shows that farmers used a total of 40 commercial pesticide names with 43 active ingredients, of which two active ingredients, i.e. Benomyl and Fipronil, were banned. The frequency of pesticide spraying for chili protection averaged at 8.93 times/crop, for weed control at 1.83 times/crop, for pests at 12.43 times/crop, for disease control at 14.48 times/crop and for chili growth promoting at 4.82 times/crop. Farmers sprayed pesticides with higher doses than recommended on the labels when pests and diseases occurred on chili farm. The active ingredients in powder and liquid pesticides of Mancozeb, Metalaxyl, Propined, Difenoconazole, Abamectin and Azoxystrobin have been frequently used with estimated concentrations of 5023±3886.36, 337.71±237.50, 4093.92±3628.57, 289.27±264.73, 31.60±29.02 and 652.57±468.35 g/L/ha, respectively. The predicted amounts of ineffective use of such pesticides as Benomyl, Cypermethrin, Fosetylaluminium, Propiconazole, Tebuconazole, Buprofezin, Chlorfenapyr and Difenoconazole, could pose great risks to the environment and humans. Burning is the main method chosen by chili farmers in the treatment of pesticide packaging after use. The study suggests local environmental managers should train farmers in the use and management of pesticide wastes more appropriately.
A total of 316 soil samples in the An Giang province were collected from the industrial zone (48 samples), mining (40 samples), farming (112 samples), landfills (88 samples) and cemeteries (28 a samples) to analyze toxic elements, including Cu, Zn, Pb, Cd and As. The geoaccumulation index (Igeo), pollutant load index (PLI) and potential ecological risk index (RI) were used to assess pollution levels and ecological risks. The results showed that the concentrations of heavy metals were almost still within the allowable limits of national standards. Cd was not detected. Heavy metals were detected in the soil in the following order: As < Pb < Cu < Zn, mining < industrial < landfill < cultivation < cemetery areas. The heavy metals contributing to soil environmental variability were similarly identified in the cemetery with industry and landfill with farming. The value of Igeo shows that As has a high potential to accumulate in soil in all land uses. The ranges of PLI values presented that the soil in industrial, farming, mining and landfills areas were classified moderate, while the cemetery areas has been rated at a high level. The RI values identified very high, high, and moderate ecological risks for cemetery, industrial and farming land and landfill, mining, respectively. The combination of PLI and RI indices showed that the cemetery areas were at the highest levels of pollution and risk. The results of this study provide scientific information on pollution level and ecological risks in various land use types supporting environmental zoning and managing strategies in the An Giang province.
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