Remediation of DDT and Its Metabolites in Contaminated Sediment

Abstract

Chlorinated pesticides and chlorinated organics can be transformed or partially degraded in sediments under appropriate environmental conditions. Although 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT) is very persistent in the environment, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a degradation product of DDT, is generally the constituent most widely detected in the environment and DDE is also resistant to further biotransformation. DDT and its degradation products (DDTR) may be transported from one medium to another by sorption, bioaccumulation, dissolution, or volatilization. In sediments, DDT strongly adheres to suspended particles, but once metabolized, DDE, the primary product, is slightly soluble in water. The major migration process for DDTR in sediment-water systems is sorption to sediment or other organic matter and the primary distribution route is the transportation of the particulates to which the compound is bound. Understanding the fate and transport of DDTR in the natural environment based on its specific characteristics is important in determining appropriate remediation option. Common DDT-contaminated sediment remediation options include dredging, capping, and natural attenuation. Sediment washing and phytoremediation have also been used in contaminated sites. Dredging is the most common sediment remediation option to remove the contaminated benthic sediments but often suffers from technical limitations like incomplete removal, unfavorable site conditions, sediment resuspension, and disposal issues. Capping is an in situ, lowcost remediation option for immobilization of DDT in several contaminated sediment sites. Natural or anthropogenic materials containing reactive ingredients, as distinct from a conventional sand or gravel cap, involve placing reactive materials as part of the cap matrix to increase sorption, and to enhance chemical reactivity with DDTR, or accelerate degradation. Natural attenuation can treat the DDT-contaminated sediment, but the time frame for complete remediation may be relatively long. Addition of suitable co-metabolites and acclimatized microorganisms to DDTR-contaminated sediment and alteration of sediment-water micro-environment by manipulating soil pH, moisture content, and other chemical conditions may result in degradation of DDTR associated with sediments at rates faster than the natural attenuation rate.

Biomarkers of Exposure to Chemical Contamination in the Commercial Fish Species Lepidopus caudatus (Euphrasen, 1788): A Particular Focus on Plastic Additives

“…Instead, according to our data, BPA concentrations in fishes varied from 2 to 75 ng/g in the liver and 1–11 ng/g in the muscle (Belfroid et al, 2002; Fossi et al, 2012; Valton et al, 2014; Guerranti et al, 2016). Probably, the low concentration or absence of contaminants in muscle, gonad and liver could be explained by the strong conversion of these substances to their metabolites after their assimilation (Sackett et al, 2013; Chattopadhyay and Chattopadhyay, 2015). The liver first passage after ingestion convert largely the substances in their metabolites before they reach the other districts.…”

The nexus of fun and nutrition: Recreational fishing is also about food

“…Specifically, OCs are very stable and persistent chemicals that resist degradation in nature (half‐life >2 years). OCs are generally lipophilic and are known to bioaccumulate, bioconcentrate and even biomagnify within upper trophic levels of a food web (Baumann & Whittle, ; Chattopadhyay & Chattopadhyay, ; Jones & de Voogt, ). Furthermore, OCs can induce negative toxicological effects upon acute and chronic exposure in both fish and humans (Falk et al., ; Hanrahan et al., ; Knuth et al., ).…”

Effect of aging on bioaccessibility of DDTs and PCBs in marine sediment

“…However, this resuspension was likely restricted to approximately 0.1 cm depths, so biological processes were likely more prevalent (Wiberg et al, 2002). Out of all DDTs, the compound found at the highest concentrations in both cores was p,p'-DDE, followed by o,p'-DDE, and then p,p'-DDD, which are the main degradates of DDT (Chattopadhyay and Chattopadhyay, 2015). For PCBs, the compound found at the highest concentration was PCB 70 in both cores, followed by either PCB 52 or PCB 153.…”