Microbial ecotoxicity and persistence in soil of the herbicide bensulfuron-methyl

Abstract

Changes in microbial numbers and activities in two non-flooded soils treated with bensulfiiron-methyl at 16 and 160 µg/kg were studied after 1 and 4 weeks of incubation under laboratory conditions. In addition to herbicide persistence, six general and functional microbial groups (numbers of culturable aerobic and anaerobic bacteria, aerobic N 2 fixers, autotrophic nitrifiers, aerobic and anaerobic cellulolytic microorganisms) and two activities (respiration and nitrification) were also studied. With respect to microbial numbers, only cellulolytic microorganisms in soil which had never been previously treated with pesticides significantly decreased in number. Only the higher dose of bensulfiiron-methyl in the second soil 381

Responses of Active Bacterial and Fungal Communities in Soils under Winter Wheat to Different Fertilizer and Pesticide Regimens

“…Decreases in soil bacterial numbers have been observed with sulfonurea herbicides, such as Ally, but only at high concentrations of the herbicide (Ͼ10 g kg Ϫ1 ) that are not within the GAP-recommended levels of application (0.34 g kg Ϫ1 was applied in this study) (26,27). The values for SIR and total DNA concentrations were in broad agreement, and both peaked in July.…”

“…These pesticides have been shown to adversely affect the numbers of organisms in the microbial community only when they are applied at rates that far exceed the recommended rates (26,27,58,68). As neither bacterial numbers nor community heterogeneity of the bacterial community was severely affected by pesticide application, it may be that microbial degradation and utilization of these products caused community differences.…”

Biodegradation of bensulfuron-methyl and its effect on bacterial community in paddy soils

“…Until now there are some reports about the influences of sulfonylurea herbicides on soil microorganisms (microbial biomass, soil respiration, soil enzymes activity, and nitrogen and carbon metabolism) by conventional culture methods (Gigliotti et al 1998;Yamamoto et al 1998;El-Ghamry et al 2002). Nevertheless, only a few researches have done on the influences of sulfonylurea herbicides on the soil microbial community structure diversity, especially the effects of BSM let alone bioremediation.…”

Co-metabolic degradation of bensulfuron-methyl in laboratory conditions

“…It is suggested that high concentration of BSM would cause toxicity to the growth of soil bacteria. Gigliotti et al [21] evidenced the addition of BSM at a 10-fold field rate would significantly decrease the number of cellulose-degrading bacteria. A negative effect of BSM on soil microbial activity, may be attributed to the toxicity of herbicide to the indigenous microorganisms [22,23], which was also found in other sulfonylurea herbicides [23].…”