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The photochemical degradation of the herbicide isoproturon in aqueous and non-aqueous solutions and in soils has been investigated. Four new photometabolites were formed in non-aqueous solution and three in soil. These were characterised by spectroscopic methods and identified by comparison with authentic synthetic samples such as 3-(4-isopropylphenyl)-1-methylurea; 3-(4-isopropylphenyl)urea; 4,4′-diisopropylazobenzene and 4,4′-diisopropylazoxybenzene. The pathway of formation of these photo products is depicted. 相似文献
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Dissipation of dithiopyr in soil was monitored after application to wheat crop as pre- or post-emergence applications at two rates, viz 100 and 200 g AI ha(-1). The level of dithiopyr in the soil was assessed by gas chromatography, and its disappearence was found to follow a first-order decay curve irrespective of rate or method of application. The half-life in soil ranged between 17.3 and 25.0 days and residues at harvest (150 days after application) ranged between 4.0 and 8.8% of amounts applied. Investigation of microbial degradation of dithiopyr was conducted in minimal salt and Czapek Dox media in which 80% of the compound degraded within 15 days. Residues were not detected in wheat grain at harvest. 相似文献
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OBJECTIVE: This study employed a multilevel design to test the contribution of individual, social and environmental factors to mediating socio-economic status (SES) inequalities in fruit and vegetable consumption among women. DESIGN: A cross-sectional survey was linked with objective environmental data. SETTING: A community sample involving 45 neighbourhoods. SUBJECTS: In total, 1347 women from 45 neighbourhoods provided survey data on their SES (highest education level), nutrition knowledge, health considerations related to food purchasing, and social support for healthy eating. These data were linked with objective environmental data on the density of supermarkets and fruit and vegetable outlets in local neighbourhoods. RESULTS: Multilevel modelling showed that individual and social factors partly mediated, but did not completely explain, SES variations in fruit and vegetable consumption. Store density did not mediate the relationship of SES with fruit or vegetable consumption. CONCLUSIONS: Nutrition promotion interventions should focus on enhancing nutrition knowledge and health considerations underlying food purchasing in order to promote healthy eating, particularly among those who are socio-economically disadvantaged. Further investigation is required to identify additional potential mediators of SES-diet relationships, particularly at the environmental level. 相似文献
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Effects of repeated metolachlor applications on its persistence in field soil and degradation kinetics in mixed microbial cultures 总被引：1，自引：0，他引：1
The persistence of metolachlor, a soil-applied herbicide, was studied under field conditions involving repeated herbicide
applications. The test field received four applications of metolachlor over an 8-month period, which included two cropping
seasons. There was a trend for more rapid rates of degradation with increasing numbers of previous treatments, with fifty
percent dissipation time (DT50) of metolachlor declining from 18 days in the first spray to 2.5 days in the fourth spray. An effort was made to isolate
the microbial population which had become acclimated to the herbicide from this field soil. A fungal community isolated from
this soil showed the capacity to degrade up to 99.6% of the metolachlor within a span of 20 days. The bacterial community
isolated could also degrade up to 81.5% of the metolachlor. Hence, this study clearly indicated that repeated applications
of metolachlor to soil resulted in the generation of an adapted microbial population with an enhanced ability to degrade the
applied herbicide.
Received: 13 November 1998 相似文献
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The organophosphorus insecticide, chlorpyrifos, has been widely applied in agriculture; in veterinary, against household pests;
and in subterranean termite control. Due to its slow rate of degradation in soil, it can persist for extended periods in soil
with a significant threat to environment and public health. The mixed and pure fungi were isolated from three soils by enrichment
technique. The enriched mixed fungal cultures were capable of biodegrading chlorpyrifos (300 mg L−1) when cultivated in Czapek Dox medium. The identified pure fungal strain, Acremonium sp., utilized chlorpyrifos as a source of carbon and nitrogen. The highest chlorpyrifos degradation (83.9%) by Acremonium sp. strain GFRC-1 was found when cultivated in the nutrient medium with full nutrients. Desdiethyl chlorpyrifos was detected
as a major biodegradation product of chlorpyrifos. The isolated fungal strain will be used for developing bioremediation strategy
for chlorpyrifos-polluted soils. 相似文献
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OBJECTIVE: To examine associations between shopping, food preparation, meal and eating behaviours and fruit and vegetable intake among women. DESIGN: Cross-sectional survey. SETTING: Community-based sample from metropolitan Melbourne, Australia. SUBJECTS: A sample of 1136 women aged 18-65 years, randomly selected from the electoral roll. RESULTS: Food-related behaviours reflecting organisation and forward-planning, as well as enjoyment of and high perceived value of meal shopping, preparation and consumption were associated with healthier intakes of fruits and vegetables. For example, women who more frequently planned meals before they went shopping, wrote a shopping list, enjoyed food shopping, planned in the morning what they will eat for dinner that night, planned what they will eat for lunch, reported they enjoy cooking, liked trying new recipes and who reported they sometimes prepare dishes ahead of time were more likely to consume two or more servings of vegetables daily. Conversely, women who frequently found cooking a chore, spent less than 15 minutes preparing dinner, decided on the night what they will eat for dinner, ate in a fast-food restaurant, ate takeaway meals from a fast-food restaurant, ate dinner and snacks while watching television and who frequently ate on the run were less likely to eat two or more servings of vegetables daily. CONCLUSIONS: Practical strategies based on these behavioural characteristics could be trialled in interventions aimed at promoting fruit and vegetable consumption among women. 相似文献
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