Sorption/desorption of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane(4,4′-DDT) on a sandy loam soil

Abstract

1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane(4,4'-DDT) is a pesticide well-known for its negative health and environmental effects. Despite being banned by a majority of world countries more than 30 years ago, its persistence in the environment is a continuing problem even today. The objective of the study was the investigation of sorption/desorption behavior of 4,4'-DDT in sandy loam soil. The impact of contaminant concentration and age was observed with three different experiments. The sorption percentages at the end of the short time step (8 h) were 50 and 92 %, for initial concentrations 2.26 and 5.28 mg/L, respectively. When freshly spiked soil was subjected to a conventional sorption study, 82 to 99.6 % of the initial aqueous DDT concentrations were sorbed within 24 h. When modeled with a Freundlich isotherm, the log K f was found to be 3.62. After six consecutive 24 h desorption steps, 33 to 96.6 % still remained in the soil. This was more pronounced for soils that had been aged for 60 days. After seven consecutive 24 h desorption steps of aged soil, the percent remaining sorbed to the soil were 44, 64, and 77 %, for 25, 250, and 500 mg/kg, respectively. All results show that 4,4-DDT has a tendency of sorbing to the soil rapidly and showing resistance to desorption. When comparing desorption values, aged soils were seen to desorb less than non-aged soils. This result was attributed to stronger binding to soil with increased contact time.

Black Carbon Facilitated Dechlorination of DDT and its Metabolites by Sulfide

“…Previous studies of black carbon and DDX has focused on adsorptive properties of black carbon, which serves as a passive sorbent in sequestering DDX from the aqueous phase, reducing toxcitiy of DDX to benthic organisms. , Intriguingly, Hale et al observed that the amount of DDT adsorbed to sediments from field measurements was 32-fold lower than the estimated amount using the activated carbon–water partitioning coefficient obtained from a clean water system . Moreover, Erdem et al reported that the desorption of DDT from fresh soils was much higher than from aged soils . This suggests that adsorbed DDX may undergo degradation by environmental reagents in soils and sediments.…”

“…25 Moreover, Erdem et al reported that the desorption of DDT from fresh soils was much higher than from aged soils. 26 This suggests that adsorbed DDX may undergo degradation by environmental reagents in soils and sediments.…”

Quantification of Residual Organochlorine Pesticides in Medicinal Plant Raw Materials Containing Terpenoids

“…В связи с ограничением использования ХОП в настоящее время на их содержание в лекарственном растительном сырье (ЛРС) влияют ХОП и их метаболиты, содержащиеся в почве, водах, донных отложениях и др. К сожалению, последствия длительного использования приводят к постоянному обнаружению ХОП в объектах окружающей среды [8][9][10][11][12][13].…”