Lab Matters Winter 2019 - Page 12

ENVIRONMENTAL HEALTH New Hampshire Assesses Exposure to Arsenic and Uranium from Private Wells by John Schneider, Toxicologist IV, New Hampshire Public Health Laboratories and Kimberly Aviado, PhD, Toxicologist II, New Hampshire Public Health Laboratories New Hampshire is known as “the Granite State”—but that granite can be a source of potentially harmful arsenic in groundwater that poses a significant public health risk. According to the US Centers for Disease Control and Prevention (CDC), New Hampshire has the highest rate of bladder cancer in the nation, and exposure to arsenic through drinking contaminated well water is a contributing factor. Nearly half of all residents use a private well as their primary source of drinking water, and many of those wells contain naturally- occurring arsenic and uranium that may exceed the maximum contaminant level recommended by the US Environmental Protection Agency (US EPA) for safe drinking water. Arsenic and uranium concentrations were determined using inductively coupled plasma-mass spectrometry (ICP-MS), a highly sensitive technique for measuring trace metals. In 2016, BiomonitoringNH launched an investigation to assess exposure to arsenic and uranium from private well water. The primary objectives of this study were to identify which groups of people are most at risk for coming into contact with arsenic and uranium, and to educate New Hampshire residents on ways to reduce or eliminate their exposure to these environmental contaminants. At the conclusion of the study in October 2018, a total of 566 people from 296 households participated, including a small comparison population of 50 individuals on a public water supply (i.e., whose drinking water is treated to remove contaminants by their municipality). top: Biosafety cabinet and automatic diluter/dispenser provide clean environment for urine specimen preparation Study Design bottom: Example of a water sample and specimen collection kit from Biomonitoring NH Participating households were selected using probability mapping developed by the US Geological Survey, which identified 25 cities and towns across southern and southeastern New Hampshire that had greater than a 35% chance of arsenic concentrations in groundwater above the US EPA’s maximum contaminant level of 10 parts per billion. Program staff, including the study’s two epidemiologists, 10 LAB MATTERS Winter 2019 met one-on-one with each participant to conduct a health and exposure survey and provide urine and water collection kits. The purpose of the well water testing was two-fold: it provided critical information about a major exposure route to arsenic and uranium in the home, and also served as an incentive for participating in the study. Through collaboration with the Water Analysis Laboratory at the New Hampshire Public Health Laboratories, participants were offered free well water testing for a suite of water quality measurements that included lead, arsenic, uranium, copper, hardness, iron, manganese, bacteria and pH. Testing for additional potential contaminants provided a more complete picture to well owners, or, in the case of households on public water supply, could alert them to the possibility of contamination from household plumbing. Testing and Challenges Urine specimens collected by each participating member of a household were analyzed by biomonitoring program staff at the New Hampshire Public Health Laboratories. Arsenic and uranium concentrations were determined using inductively coupled plasma-mass spectrometry (ICP-MS), a highly sensitive technique for measuring trace metals. Selectively measuring arsenic in urine required removing significant mass spectral interferences caused by salts present in urine. This was achieved by pressurizing the ICP-MS collision cell with inert helium gas, which collides with interfering ions and allows for their removal through kinetic energy filtering. Measuring uranium posed unique challenges, as it was often present in urine at extremely low concentrations— typically parts per trillion—making its detection and measurement sometimes difficult. At such low detection levels, significant measures were taken to avoid PublicHealthLabs @APHL APHL.org