Evidence of non-DDD pathway in the anaerobic degradation of DDT in tropical soil

Environmental Science and Pollution Research - DDT transformation to DDD in soil is the most commonly reported pathway under anaerobic conditions. A few instances of DDT conversion to products...     

Study of atrazine degradation in soil from Kenyan sugarcane-cultivated fields in controlled laboratory conditions

A study to compare the extent of atrazine mineralization in soils from Kenyan sugarcane-cultivated fields with and without history of atrazine use was carried out in the laboratory under controlled conditions. The study was testing the hypothesis that repeated atrazine application to soil will not result in enhanced atrazine mineralization. The study was carried out with ¹⁴C-uniformly ring-labeled atrazine in a laboratory under controlled conditions. Atrazine mineralization to ¹⁴CO₂ in soil with no history of atrazine use was negligible (0.16%) after 163 days of soil incubation. The three metabolites hydroxyatrazine, desisopropylatrazine, and desethylatrazine in the proportion of 17.7%, 1.3%, and 2.6%, respectively, were in the soil after 75 days. In the soil from the sugarcane-cultivated field with history of atrazine use, atrazine mineralization was 89.9% after 98 days. The same soil, amended with mature compost, showed a lag phase of eight days before rapid atrazine mineralization was observed.     

Impact of soil water regime on degradation and plant uptake behaviour of the herbicide isoproturon in different soil types

The environmental fate of the worldwide used herbicide isoproturon was studied in four different, undisturbed lysimeters in the temperate zone of Middle Europe. To exclude climatic effects due to location, soils were collected at different regions in southern Germany and analyzed at a lysimeter station under identical environmental conditions. ¹⁴C-isoproturon mineralization varied between 2.59% and 57.95% in the different soils. Barley plants grown on these lysimeters accumulated ¹⁴C-pesticide residues from soil in partially high amounts and emitted ¹⁴CO₂ in an extent between 2.01% and 13.65% of the applied ¹⁴C-pesticide. Plant uptake and ¹⁴CO₂ emissions from plants were inversely linked to the mineralization of the pesticide in the various soils: High isoproturon mineralization in soil resulted in low plant uptake whereas low isoproturon mineralization in soil resulted in high uptake of isoproturon residues in crop plants and high ¹⁴CO₂ emission from plant surfaces. The soil water regime was identified as an essential factor that regulates degradation and plant uptake of isoproturon whereby the intensity of the impact of this factor is strongly dependent on the soil type.