The project has been financed by the Australian Center for International Agricultural Research (ACIAR) and the Ministry of Education, GoB. The project has been a joint research activity of the Department of Soil, Water and Environment of Dhaka University and CSIRO, Land and Water, Adelaide, Australia. The Team Leader was Dr. Ravi Naidu from CSIRO, Adelaide, Australia. Team Leader for Bangladesh: Dr. S.M. Imamul Huq, Professor, Dept. of Soil, Water and Environment, Dhaka University. The Project period was January 2000 to December 2002 with a further extension up to June 2006.

 Objectives

The main objective of the project was to asses the As load on soil due to irrigation with As-containing ground water and its impact on the accumulation of As in different vegetables, fodder and other plants with a view to identify the exposure pathways of As ingestion and the transfer through food chain.

The laboratory is equipped to analyze As and other heavy metals in water, soil, plant and other organic samples with AAS. The QC/QA is maintained and assured with CRMs and inter laboratory analyses.

 Achievements

During the last few years the project has covered 73 villages in 29 upazillas of 15 districts. More than 3000 water, soil and plant samples have been analyzed for As and other related elements. Net house experiments have also been performed to verify the field observations and also to study various remedial approaches for As toxicity in soil and plants. Questionnaire surveys have also been made to identify the ingestion pathways and relationship of As poisoning and nutritional, food habit and other aspects. Effect of As treatment on the phytotoxicity and Siderophore release in Barley and rice.

Findings

So far it has been found that the average As content of Bangladesh soil is below the average value of 10 mg/kg. surface 0-15 cm soils contain more As than the sub-surface 15-30 cm soils. As content in soils is less where the ground water contamination of As is less. In some cases, there is a soil build-up of As where ground water irrigation is practiced. In some cases values up to 80 kg As/kg soil has been found. Retention of As by soil depends on soil characters, more particularly on the clay content.

Some leafy vegetables have been identified to be As accumulator while a great many numbers have been found to be non-accumulators. As accumulation in plants has been found to be related to the As in water or soil solution rather than the As content of soil. On the basis of the findings, vegetables have been categorized as accumulators, moderate accumulators and non-accumulators.

Rice and wheat have been found to avoid accumulation of As in their grains.

Fodders and some grasses have also been analyzed for As and some have been found to accumulate AS in elevated quantities.

Fish samples, market basket for vegetables and rice varieties have also been analyzed for As content in them.

Cooked food (as the people in affected areas take) has also been analyzed for As.

Strategies are being looked at for avoiding As accumulation by crops receiving As-contaminated water.

To continue the activities of the project, the Bangladesh-Australia Centre for Environmental Research (BACER-DU) has been set up. The centre is a self financed one.

Future Need

Field experimentation with varying soil conditions and varying crops along with interaction reaction effect of other nutrient elements with As vis-à-vis plant quality as well as some fundamental research on the topic are envisaged for the next two years.