Arsenic in tube well water and health consequences, phase 2

Understanding the dynamics of arsenic exposure, arsenic-related diseases and the shift to arsenic-free drinking water

An ongoing research project Arsenic in tube well water and health consequences (2001-015) includes the screening of the entire population of 220,000 under the Health and Demographic Surveillance System (HDSS) in Matlab for arsenic-induced skin lesions, measuring the arsenic concentration in all 15,000 tube wells, and initiating mitigation activities in the entire Matlab area in collaboration with BRAC. An arsenic database has been added to the Matlab HDSS that includes the geographical coordinates, age and depth, and arsenic content of all tube wells. The database also includes information on individuals skin lesions and their water consumption pattern over the years. The competence of field workers, study physicians, laboratory staff, mitigation teams, etc,. has been systematically built during the project.

In this proposed study, to be conducted during 2003-2006, we would like to follow up some issues addressed in the earlier study, specifically assess variations in arsenic exposure through tube well water in terms of seasonal variations and time trends of arsenic concentration in tube wells, variations due to differences in the behaviour in the collection, storage and use of water; assess reversibility of arsenic-induced skin lesions when shifting to arsenic-free water; and further study the mitigation process, especially through ethnographic perspectives on water and mitigation options, equity in the shift to arsenic-free water, safety in the use of surface water as an alternative, and costs of the various options used. We would also address some new issues such as assessing the contribution of rice to arsenic exposure, arsenic exposure in young children, and study the health effects of arsenic contaminated water, particularly the occurrences of chronic obstructive pulmonary disease, diabetes, and psycho-motor development of young children.

As a part of the earlier study (during 2001-2003), arsenic concentration was measured in a sample of 600 randomly selected tube wells from the Matlab area three times each year (in March, July and November), and we propose to continue this activity for another three years. We would invite individuals found to have arsenic-induced skin lesions in the earlier study (2001-2003) for a follow-up clinical evaluation to assess reversibility of their skin lesions and collect urine samples for determining current levels of arsenic. There is an ongoing study (2000-013) for screening of pulmonary tuberculosis that has identified five hundred individuals (cases) with chronic cough. We would include them in our study and select another five hundred age-and sex-matched referents from the HDSS. These cases and referents will be clinically examined at home visits with an emphasis on assessing their respiratory status and smoking habits. There is another ongoing study that screens individuals for diabetes and impaired glucose tolerance. We would include 140 of these individuals with glucosuria and/or impaired glucose tolerance and randomly select two age-and sex-matched referents per case from the HDSS database. Arsenic exposure information will be obtained from the database of the earlier project (2001-2003). Another study (2002-031) involves a cohort of pregnant women and their infants in Matlab. We propose to follow this cohort of 2,500 infants to determine their exposure to arsenic, by assaying their urine samples for arsenic, at 1 and 2 years of age. As a part of the earlier study BRAC has initiated various mitigation options and are implementing them. Studies have also been initiated during the period 2001-2003 on an ethnographic perspective on water, water use, and arsenic in water that would continue to investigate the mitigation process, and community involvement. We propose a follow up study to assess changes in drinking water habits, cost-effectiveness and equity in the distribution of the different mitigationoptions, and safety of the alternative water sources.

The results on health effects of arsenic will help estimate disease burden and would have direct relevance to arsenic-related programmes in Bangladesh and in other countries. The experiences from the mitigation process would be very important in finding a cost-effective solution to the widespread problem of arsenic contaminated drinking water in Bangladesh