Partner: Agroscope Reckenholz-Tänikon (ART), SNSF
Team Members: Dr. Mahmood A. Khwaja
The project is a joint research work carried out in collaboration with Agroscope Reckenholz Tänikon Research Station ART, Zurich, Switzerland and Environmental Science Department, University of Peshawar, Pakistan, with financial support from Switzerland National Science Foundation (SNSF).
Dichlorodiphenyltrichloroethane (DDT), a well-known insecticide, was produced from 1963 to 1994 in a factory in Nowshera, Khyber Pakhtoon Khawa (former NWFP), Pakistan. The factory was then closed and later on demolished. The production and distribution of the insecticide resulted in a DDT polluted area of about 85 ha. At the plant site, the soils contamination is up to 5000 mg/kg DDT in dry soil. To reduce DDT exposure of the environment and humans, this contaminated site must be remediated. The main objective of this joint research project is to test a remediation strategy that substantially reduces the bio-available fraction of the aged DDT in the soil. Efforts are underway to bind and immobilize the main contaminant, DDT and its metabolites in the soil by activated charcoal (AC) amendment. AC has proven to significantly reduce the bio-availability of organic contaminants in solid matrices due to its high adsorption affinity, capacity, and strength. The novelty of this project is the application and thorough evaluation of this remediation technique to a field soil contaminated by sequestered DDT and metabolites.
Specifically, in laboratory experiments with different soil contamination levels and different kinds of added AC (granulated AC (GAC), bio-char, and coke breeze as cheap and locally originated material), the bio-availability of DDT and metabolites has been assessed by depletive and non depletive extraction methods. Preparations are underway for the 2nd phase of the project in which pilot field studies will be performed after the AC is added to the soil according to the initial laboratory results. Overall, this technique presents, if successful, an economically sound, effective and feasible way to remediate organically contaminated hotspots in Pakistan and elsewhere.
Preliminary laboratory scale experiments have shown a considerable reduction of DDT of the desorbable fraction in the amended soil compared to the control soil. The reduction also shows that this remediation technique works in principle. Yet, many questions concerning the behaviour of AC in the field remain open and need to be further investigated before this remediation technique can be put into practice, specifically with regard to different AC materials and varying environmental factors like soil moisture and temperature.
For further details contact Dr. Mahmood Khwaja. firstname.lastname@example.org