Pakistan-US Science and Technology Cooperation Program  Phase 6 (2015 Deadline) Understanding the Mechanism of Arsenic and Fluoride and Reducing Exposure by Targeting Low Arsenic and Fluoride Aquifers in Rural Punjab, Pakistan US partner: Alexander Van Geen, Columbia University Pak partner: Abida Farooqi, Quaid-i-Azam University, Islamabad Progress Reports 2016: Elevated concentrations of arsenic (As) and fluoride (F) in groundwater drawn by millions of handpumps cause serious health problems in several regions of Pakistan including Punjab province. Rocks and sediments are the natural source of As and F entering groundwater, although the buildup of concentrations in certain areas could have been enhanced by human modification of the hydrological cycle in the area. A key feature of the distribution of As and F in handpump water is that it is spatially highly variable but relatively stable through time. Many rural households of Punjab with an unsafe handpump therefore live within walking distance of a safe handpump. The problem is that most households do not know this because the vast majority of handpumps have never been tested. The premise of this collaboration between Quaid-i-Azam University and Lamont-Doherty Earth Observatory of Columbia University is that distinguishing individual handpumps that are safe from those that are not using field-kits is an effective way of lowering exposure of the rural population in the short- to medium term, more so than any attempts to treat groundwater at the household level. The scientific objectives of the research described in this proposal are to determine to what extent the spatial distribution of As and F in groundwater of eastern Punjab can be predicted and on what timescale groundwater As and F concentrations are likely to vary over time if at all. To start documenting the variability of As and F concentrations in groundwater, over 6000 handpumps have so far been tested with field-kits along two transects across a range of spatial scales to provide context for detailed process studies in the field that are required to make predictions. The spatial patterns indicate that one of the sampled floodplains is highly affected by arsenic but two others are not. No spatial pattern has been observed to date in the case of fluoride and the overall proportion of affected wells is much lower than for arsenic. 2017: This project aims to identify the safe and unsafe wells for arsenic and fluoride in the Indus Plain of Pakistan. More than 17,000 wells have been tested along the selected transect lines and the results show that the areas/villages along the Ravi River are more contaminated as compared to other areas. Most of wells affected by elevated arsenic levels are located within the floodplain of the Ravi River rather than the Jhelum and Chenab rivers. The reason for this will be the focus of the final year’s investigation, using drilling and aquifer sediment analysis. 2018: As a powerful example of scientific collaboration overcoming political disagreements between two neighboring countries, a workshop involving scientists and graduate students from Pakistan and India involved in well testing and drilling in the Punjab plains was held in Dubai November 8-10, 2017. Discussions during this workshop led to a manuscript with well-water arsenic data from both sides of the Pakistan-India border submitted to a well-regarded peer-reviewed scientific journal entitled “Field testing of over 30,000 wells for arsenic across 400 villages of the Punjab plains of Pakistan and India: Implications for prioritizing mitigation”. The main point of the paper is that reducing exposure to arsenic is more likely to be achieved by blanket testing of wells and encouraging the sharing of the subset of safe wells rather than by much costlier water treatment and piped water supply projects that will take much longer to have a comparable impact. In addition to additional field-kit testing conducted in 27 villages along main Indus River (Thal Doab), drilling was conducted in five previously blanket-tested villages to recover aquifer sediments collected every 5 feet up to 100 feet. The cuttings are being analyzed in the laboratory by various methods to shed new light on the processes leading to contamination of groundwater with arsenic and fluoride of natural origin. One PhD student from Pakistan completed a six-month research visit at Columbia University and another is expected to arrive later this year.