Transcript Low Dose Linearity and Hormesis for Radiation
The arsenic Catastrophe: An outsider’s update Dhaka Community Hospital Wednesday January 4th 2006 comments by David Christiani Professor Harvard Medical School and Harvard School of Public Health Richard Wilson Mallinckrodt Research Professor of Physics Harvard University http://arsenic.ws http://arsenicfoundation.com http://physics.harvard.edu/~wilson/arsenic/arsenic_project_inroduc tion.html 1998 (DCH conference) urged immediate action: (1) Measure every well Green for OK Red for dont use Encourage well switching (2) Purify Water at House level with simple equipment (3) Encourage deep wells (below clay layer) (4) Keep accurate data and make them publicly available (5) Encourage solutions that lead to the long term Progress has been slow Yet international funds (World Bank, Kuwait Fund) can be available to GoB if requested clearly Problem is probably local implementation Difference in cost between options is NOT the issue (1) Labelling wells was only partially successful 30% of people switched wells 67% switched after a massive education campaign (Columbia-U.Dhaka) Most important step so far. 10 million people have better water. Therefore: Continue education Emphasize major efforts in villages with no good well (2) Uncritical use of Arsenic Removal Systems (ARS) has been a disaster. In West Bengal several hundred have been installed. 80% are not functional. (6th report: Jadavpur University John Macarthur (UCL) agrees.) DCH tests give only small reduction NOT a long term solution (Grainger Prize and US National Academy of Engineering notwithstanding) (3) Deep wells may be fed from the Himalaya further north. Badly installed wells could bring water down from upper aquifer. Some locations (Jessore?) aquifers may not be distinct Many have been abandoned Aquifer could be depleted Measure arsenic levels frequently, understand AND INVOLVE THE LOCAL PEOPLE (4) Making data and information available has been unsatisfactory International websites (arsenic.ws, ACIC.com) depend upon information supplied locally Government sites have not beendated and kept up to date. The APSU site may solve these problems (5) Bangladesh Policy Use surface water when possible We must avoid bacteria and know we have avoided bacteria Rainwater Collection Improved (sanitary) Dugwells Pond Sand Filters River Sand Filters Key is reliable measurement and making them available Cheapest when a large number supplied from one unit Many wells have been abandoned as unsatisfactory No evidence that they were properly constructed Dhaka Community Hospital has been installing Sanitary surface “dugwells” Covered; WHO standards; measured villagers involved clear instructions to custodian Pumped to tank and pipeline to give running water VERY POPULAR Why is it taking so long? Where is the bottleneck? Maybe the set up of village committees Solution: Go at once to tank and pipeline even though more expensive Villagers (especially women) like it Early measurements from DCH looked good. Recent measurements (with different equipment) look different This is crucial for understanding how often disinfectant , lime or chloride, must be used. The whole job can be done for ONLY $300 million! 30 cruise missiles!