Recent Publication Announcements

August 15 2016

Virtual Special Issue of STOTEN Highlights Three Articles by Columbia SRP Scientists and Government Partners on Arsenic in Private Well Water

Columbia SRP scientists and their government partners in New Jersey and Maine published three articles in the August 15, 2016 issue of Science of the Total Environment, which have been selected by the editor for a Virtual Special Issue on Drinking Water Contaminants. The first of the three papers “Arsenic in private well water part 1 of 3: Impact of the New Jersey Private Well Testing Act on household testing and mitigation behavior” is authored by CU SRP scientists Sara Flanagan (CEC/RTC), Yan Zheng (CEC/RTC), Steven Chillrud (RTC/Project 5), and Stuart Braman (RTC/CEC), in collaboration with Steven Spayd and Nicholas Procopio of the New Jersey Department of Environmental Protection (NJDEP). This paper reports their investigation of the influence of a policy intervention, the New Jersey Private Well Testing Act (PWTA), on private well testing and water treatment behavior for arsenic. Since 2002, New Jersey’s PWTA has required testing of untreated groundwater for a variety of parameters prior to home sales and rentals, including arsenic testing in 12 counties in northern and central New Jersey. New Jersey is one of only two states that require testing of private wells for arsenic at the time of real estate transactions. The article presents the findings from a mailed survey of private well households in 17 towns in northern New Jersey, where about 25% of wells have faced the PWTA’s requirement for arsenic testing. Survey respondents answered questions on their water testing and treatment practices, preferences, and opinions. The authors conclude that New Jersey’s PWTA has led to significantly higher arsenic testing rates in at-risk areas and the identification of many more contaminated wells. Furthermore, the requirement to test among new homeowners addresses the socioeconomic gaps in testing that otherwise arise and has the unintended benefit of reaching higher proportions of families with children. The authors recommend more public resources be made available to support private well testing among socially and biologically vulnerable groups as well as more support for households after testing to promote arsenic exposure reduction through consistent water avoidance or treatment, regular maintenance, and monitoring.

In the second article “Arsenic in private well water part 2 of 3: Who benefits the most from traditional testing promotion?” authors Flanagan, Spayd, Procopio, Chillrud, James Ross (RTC/Core C), Braman, and Zheng report that, based on their survey of private well households in New Jersey, residents of towns with a history of arsenic testing promotion have tested their wells at higher rates than residents of areas where there has been no arsenic testing promotion. They conclude, however, that arsenic testing promotion at the community level may contribute to socioeconomic status (SES) disparities in arsenic testing since those with higher incomes and more education are more likely to take advantage of testing programs. The authors recommend that arsenic testing promotion and community engagement be better targeted to more socially vulnerable populations and suggest that policy changes at state and local levels may be needed to overcome the SES disparities observed when testing is not required.

In the third article of the series, “Arsenic in private well water part 3 of 3: Socioeconomic vulnerability to exposure in Maine and New Jersey,” Columbia SRP scientists Flanagan, Chillrud, Braman, and Zheng in collaboration with Spayd (NJDEP), Procopio (NJDEP), Robert Marvinney (Maine Geological Survey), and Andrew Smith (Maine Department of Health and Human Services, Center for Disease Control and Prevention) analyze data obtained from private well household surveys carried out in central Maine and northern New Jersey to investigate the association between SES and arsenic exposure risk, considering residential location, testing and treatment behavior, and psychological factors influencing behavior. The investigators find that while the environmental distribution of arsenic exposure risk is socioeconomically random, SES disparities in exposure likely arise from differing rates of protective behaviors such as testing well water for arsenic, water treatment, and avoiding contaminated water. They recommend that social vulnerability factors be incorporated into arsenic risk modeling and identifying priority areas for intervention.


Flanagan SV, Spayd SE, Procopio NA, Chillrud SN, Braman S, Zheng Y. Arsenic in private well water part 1 of 3: Impact of the New Jersey Private Well Testing Act on household testing and mitigation behavior. Science of the Total Environment. 2016 August 15; 562:999–1009.

Flanagan SV, Spayd SE, Procopio NA, Chillrud SN, Ross J, Braman S, Zheng Y. Arsenic in private well water part 2 of 3: Who benefits the most from traditional testing promotion? Science of the Total Environment. 2016 August 15; 562:1010–1018.

Flanagan SV, Spayd SE, Procopio NA, Marvinney RG, Smith AE, Chillrud SN, Braman S, Zheng Y. Arsenic in private well water part 3 of 3: Socioeconomic vulnerability to exposure in Maine and New Jersey. Science of the Total Environment. 2016 August 15; 562:1019–1030.

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June 22 2016

Importance of Young Dissolved Organic Carbon to the Release of Arsenic in Arsenic Impacted Aquifers

On June 22, 2016, the journal Environmental Science & Technology published a paper by Columbia SRP scientists Brian Mailloux, Alexander van Geen, Benjamin Bostick and colleagues Kelly Whaley-Martin, Greg Slater, Rachel Silvern, Carol Kim, Kazi Matin Ahmed, and Imtiaz Choudhury titled, “Stimulation of Microbially Mediated Arsenic Release in Bangladesh Aquifers by Young Carbon Indicated by Radiocarbon Analysis of Sedimentary Bacterial Lipids.” Arsenic contamination affects the drinking water of millions of people around the world. In the majority of these environments, arsenic is released from sediments to the water through biological respiration that changes the chemical form of the closely associated arsenic and iron. This respiration requires organic carbon, yet the sources of this organic carbon driving the microbially-mediated release of arsenic to shallow groundwater, remain poorly understood. The study reported in this publication sheds light on this question using a novel method of characterizing the radiocarbon age of phospholipid fatty acids (PLFAs), molecules that are part of cellular wall material in all living organisms and are indicative of living organisms. This method established that the microbial respiration in aquifers containing arsenic uses carbon that is much younger than the carbon in the sediments, and similar in age to dissolved organic carbon, much of which is derived from near-surface environments. This observation implies that these young carbon substrates are used in the microbial reduction of sedimentary iron oxides that are known to release arsenic into solution. The methods used in this study are particularly powerful because they allow scientists to study these microbiological processes in complex field environments, establishing which carbon is being used for respiration, and to gain insight into how those processes effect aquifer water quality. The research findings suggest that near-surface sources of organic carbon are central in microbial metabolism even in aquifers that are spatially separated from the land surface from which this carbon is derived. This indicates that dissolved organic carbon is efficiently and rapidly transported into the aquifer. Since this dissolved organic carbon is transported in water, there must be a hydrological connection between shallow sources and the aquifer, and water must be efficiently transported from shallow sources to depth. Given that one of the sites examined in this study is covered by a thick clay that is laterally extensive, it appears that groundwater can circumvent this barrier, and that these barriers may not be as protective of water quality as previously believed. This field study establishes that young organic carbon derived from the surface can negatively affect arsenic concentrations and water quality within an aquifer. In the United States half of all Superfund sites are contaminated with arsenic. In these Superfund sites, similar changes in groundwater hydrology and/or the input of other organic wastes (for example, in landfills) or organic chemicals at industrial sites, also has the potential to adversely impact groundwater arsenic levels and overall water quality. These radiocarbon methods can also be applied to these other areas to understand the origin of arsenic contamination and how to target and optimize remediation efforts at these contaminated sites.


Whaley-Martin KJ, Mailloux BJ, van Geen A, Bostick BC, Silvern RF, Kim C, Ahmed KM, Choudhury I, Slater GF. Stimulation of Microbially Mediated Arsenic Release in Bangladesh Aquifers by Young Carbon Indicated by Radiocarbon Analysis of Sedimentary Bacterial Lipids. Environmental Science & Technology. 2016 Jun 22; 50:7353–7363.

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March 31 2016

How would arsenic behave in sulfidic environment?

Contributing to the development of solutions to the difficult problem of remediating aquifers with elevated dissolved arsenic concentrations, Columbia SRP postdoctoral researcher Jing Sun in collaboration with Andrew Quicksall of Southern Methodist University and Columbia SRP scientists from Projects 4 and 5 Steven Chillrud, Brian Mailloux, and Benjamin Bostick have published an article in the June 2016 issue of Chemosphere titled “Arsenic mobilization from sediments in microcosms under sulfate reduction.” The team is focused on designing and evaluating enhanced remediation approaches for sites with arsenic contaminated groundwater. Arsenic sulfide precipitation has often been suggested as a remediation option for such sites. In this paper, they reported results from laboratory studies where they stimulated microbial sulfate reduction within microcosms containing contaminated sediments, and evaluated whether this process would immobilize arsenic for use in groundwater remediation. The sediments used were collected from two distinct sites: the Vineland Chemical Company Superfund site in southern New Jersey and a former heavy metal sulfide mining site, the Coeur d’Alene mining district in northern Idaho. The research team found that although transient arsenic removal from solution occurred in microcosms with these sediments, overall arsenic was released from sediments to solution. Based on this study and other published studies on sulfate reduction, the research team has proposed a generalized conceptual model that describes how iron and sulfur are cycled in a sulfidic environment, which includes both insoluble sulfide minerals and soluble sulfide complexes, to better ascertain conditions under which sulfide phases immobilize arsenic. The article was initially published online on March 31, 2016.


Sun J, Quicksall AN, Chillrud SN, Mailloux BJ, Bostick BC. Arsenic mobilization from sediments in microcosms under sulfate reduction. Chemosphere 2016 June; 153:254–261.

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