Research Partnerships with Developing Countries
A Programme funded by Swiss National Science Foundation (SNSF) and Swiss Agency for Development and Cooperation (SDC)

Evaluation of Activated Carbon Amendment for Reclamation of a DDT-Contaminated Site in Pakistan

The insecticide DDT was used in many countries in agriculture and against endemic malaria. It is considered as persistent, bioaccumulative, and toxic and was banned in 1972 in the United States, Western Europe and Japan. Today, the Stockholm Convention on persistent organic pollutants demands to restrict its production and use for disease vector control, with the goal of ultimate elimination. DDT was produced from 1963 to 1994 in a factory in Amangargh near Nowshera, North West Frontier Province, Pakistan. The factory was then officially closed, but was still in operation for many years. Afterwards, a few thousand kilograms of DDT in worn out bags remained on the floor of the storehouse, still contaminating the direct vicinity. Consequently, concentrations of DDT in soil within a distance of a few 100 meters around the factory are up to 7 ug/g DDT in dry soil, and as high as >1800 ug/g close by. Two thirds of 81 samples taken from ca. 85 hectares in and around the factory were above the Pakistan minimum risk level of 0.05 ug/g for DDT in soil. To reduce DDT exposure of the environment and humans, this site has to be remediated. The aim of ACDC is to test a remediation strategy that substantially reduces the bioavailable fraction of the aged DDT in the soil: we propose to bind and immobilize DDT in the soil by activated charcoal (AC) amendment. AC has proven to significantly reduce the bioavailability of organic contaminants due to its high adsorption affinity and capacity. Within the three years of ACDC, we pursue the following actions: 1) Survey and characterization of environmental conditions at the remediation site. 2) In laboratory experiments with different soils and different kinds of added AC, the accessibility and chemical activity of DDT will be assessed by Tenax® beads and polyoxymethylene (POM) strips, respectively. 3) Selected plots will be used for pilot field studies. After the AC has been added to the soil, DDT concentrations in the soil pore water, river water and in the air will be monitored and the availability of DDT tested in the lab with Tenax® and POM over two years. 4) Evaluation of the results in terms of feasibility, implying cost-effectiveness and practicability. 5) Dissemination of results in scientific publications and conferences, and to local authorities, policy makers, and stake holders. ACDC is a collaboration between Agroscope ART Zürich, the University of Zürich, and the Sustainable Development Policy Institute (SDPI), Islamabad.

Contact addresses:
Dr. Thomas Daniel Bucheli
Forschungsanstalt Agroscope
Reckenholz-Tänikon ART
Reckenholzstrasse 191
CH-8046 Zürich
thomas.bucheli(at)art.admin.ch

Dr. Mahmood A. Khwaja
SDPI
Sustainable Development Policy Institute
# 3, UN Boulevard, Diplomatic Enc
PK-44000 G-5, Islamabad
Pakistan
khwaja(at)sdpi.org

           
Pakistani ph.D student is cleaning some soil sample extracts for DDT analysis in the ART Swiss laboratory