Sorption and degradation of neonicotinoid insecticides in tropical soils

ABSTRACT

Neonicotinoids are the most widely applied class of insecticides in cocoa farming in Ghana. Despite the intensive application of these insecticides, knowledge of their fate in the Ghanaian and sub-Saharan African environment remains low. This study examined the behavior of neonicotinoids in soils from cocoa plantations in Ghana by estimating their sorption and degradation using established kinetic models and isotherms. Studies of sorption were conducted using the batch equilibrium method on imidacloprid, thiamethoxam, clothianidin, acetamiprid and thiacloprid, while degradation of imidacloprid, thiamethoxam and their respective deuterated counterparts was studied using models proposed by the European forum for coordination of pesticide fate and their use (FOCUS). Analytes were extracted using the quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure and quantified by liquid chromatography-tandem mass spectrometry (LC–MS/MS). Average recoveries were high (≥ 85%) for all analytes. The findings from the study suggest that neonicotinoid insecticides may be persistent in the soils studied based on estimated half-lives > 150 days. The study also revealed generally low-sorption coefficients for neonicotinoids in soils, largely influenced by soil organic carbon.     

Framework of multi-level regionalization schemes based on non-point source pollution to advance the environmental management of small watersheds

Environmental Science and Pollution Research - Regionalization exerts an important guiding role for sound environmental management, regional development, and schemes toward regionalizing ecological...     

狮群的悲情故事

落日正将坦桑尼亚塔兰吉尔公园傍晚的天空染得血红，这时，5头雌狮子来到离我们的帐篷不到50米的一棵金合欢树张开的大伞下面休息。直到午夜，一切都还算宁静，但这以后，一场听之令人悚然动容的“吼歌会”在草原上响起来了。我们这些“合唱队的女歌手们”与大约200米之外的一两头雄狮交替轮唱着。雄狮们虽然拥有更加洪亮的噪音，这时却并不加入这场歌唱大战。觉得甭想睡了。这些“动物界的女王”究竟有什么要讲的呢？     

寒冷地区滨岸缓冲带植物筛选

为在寒冷地区建立高效的滨岸缓冲带水体工程,选择早熟禾、高羊茅、3种本地耐寒性植物,研究剪股颖构建河流滨岸缓冲带植物的经济性、生长特性、光合作用及其对悬浮物、氮、磷的净化能力。结果表明,3种植物在经济性方面高羊茅与早熟禾差别不大,远低于剪股颖;在生长特性方面,早熟禾与高羊茅的表现相近,高羊茅略好,但比剪股颖表现优秀,早熟禾在净光合作用速率、蒸腾速率以及水分利用效率方面比高羊茅及剪股颖出色;在面源污染物去除率方面,地表径流悬浮物的去除中,早熟禾表现突出;在溶解性磷与总氮的净化中,3种植物表现差异不大,早熟禾略有优势。综合比较各项指标,早熟禾可作为寒冷地区构建滨岸缓冲带较为理想的备选植物。