Maine Geological Survey

Whitehouse Station, ME, United States

Maine Geological Survey

Whitehouse Station, ME, United States
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PubMed | Maine Geological Survey, Lamont Doherty Earth Observatory and Centers for Disease Control and Prevention
Type: | Journal: The Science of the total environment | Year: 2016

Arsenic is a naturally occurring toxic element often concentrated in groundwater at levels unsafe for human consumption. Private well water in the United States is mostly unregulated by federal and state drinking water standards. It is the responsibility of the over 13 million U.S. households regularly depending on private wells for their water to ensure it is safe for drinking. There is a consistent graded association with health outcomes at all levels of socioeconomic status (SES) in the U.S. Differential exposure to environmental risk may be contributing to this persistent SES-health gradient. Environmental justice advocates cite overwhelming evidence that income and other SES measures are consistently inversely correlated with exposure to suboptimal environmental conditions including pollutants, toxins, and their impacts. Here we use private well household surveys from two states to investigate the association between SES and risks for arsenic exposure, examining the potentially cumulative effects of residential location, testing and treatment behavior, and psychological factors influencing behavior. We find that the distribution of natural arsenic hazard in the environment is socioeconomically random. There is no evidence that higher SES households are avoiding areas with arsenic or that lower SES groups are disproportionately residing in areas with arsenic. Instead, disparities in exposure arise from differing rates of protective action, primarily testing well water for arsenic, and secondly treating or avoiding contaminated water. We observe these SES disparities in behavior as well as in the psychological factors that are most favorable to these behaviors. Assessment of risk should not be limited to the spatial occurrence of arsenic alone. It is important that social vulnerability factors are incorporated into risk modeling and identifying priority areas for intervention, which should include strategies that specifically target socioeconomically vulnerable groups as well as all the conditions which cause these disparities in testing and treatment behavior.

PubMed | Maine Geological Survey, U.S. Geological Survey, Monash University, Syracuse University and McGill University
Type: Journal Article | Journal: Ground water | Year: 2016

Heat is a powerful tracer to quantify fluid exchange between surface water and groundwater. Temperature time series can be used to estimate pore water fluid flux, and techniques can be employed to extend these estimates to produce detailed plan-view flux maps. Key advantages of heat tracing include cost-effective sensors and ease of data collection and interpretation, without the need for expensive and time-consuming laboratory analyses or induced tracers. While the collection of temperature data in saturated sediments is relatively straightforward, several factors influence the reliability of flux estimates that are based on time series analysis (diurnal signals) of recorded temperatures. Sensor resolution and deployment are particularly important in obtaining robust flux estimates in upwelling conditions. Also, processing temperature time series data involves a sequence of complex steps, including filtering temperature signals, selection of appropriate thermal parameters, and selection of the optimal analytical solution for modeling. This review provides a synthesis of heat tracing using diurnal temperature oscillations, including details on optimal sensor selection and deployment, data processing, model parameterization, and an overview of computing tools available. Recent advances in diurnal temperature methods also provide the opportunity to determine local saturated thermal diffusivity, which can improve the accuracy of fluid flux modeling and sensor spacing, which is related to streambed scour and deposition. These parameters can also be used to determine the reliability of flux estimates from the use of heat as a tracer.

Thompson W.B.,Maine Geological Survey | Griggs C.B.,Cornell University | Miller N.G.,140 Cultural Education Center | Nelson R.E.,Colby College | And 3 more authors.
Quaternary Research | Year: 2011

Excavations in the late-glacial Presumpscot Formation at Portland, Maine, uncovered tree remains and other terrestrial organics associated with marine invertebrate shells in a landslide deposit. Buds of Populus balsamifera (balsam poplar) occurred with twigs of Picea glauca (white spruce) in the Presumpscot clay. Tree rings in Picea logs indicate that the trees all died during winter dormancy in the same year. Ring widths show patterns of variation indicating responses to environmental changes. Fossil mosses and insects represent a variety of species and wet to dry microsites. The late-glacial environment at the site was similar to that of today's Maine coast. Radiocarbon ages of 14 tree samples are 11,907±31 to 11,650±5014C yr BP. Wiggle matching of dated tree-ring segments to radiocarbon calibration data sets dates the landslide occurrence at ca. 13,520+95/±20calyr BP. Ages of shells juxtaposed with the logs are 12,850±6514C yr BP (Mytilus edulis) and 12,800±5514C yr BP (Balanus sp.), indicating a marine reservoir age of about 1000yr. Using this value to correct previously published radiocarbon ages reduces the discrepancy between the Maine deglaciation chronology and the varve-based chronology elsewhere in New England. © 2011 University of Washington.

O'Shea B.,University of San Diego | O'Shea B.,Lamont Doherty Earth Observatory | Stransky M.,University of San Diego | Leitheiser S.,University of San Diego | And 4 more authors.
Science of the Total Environment | Year: 2015

Arsenic is enriched up to 28 times the average crustal abundance of 4.8mgkg-1 for meta-sedimentary rocks of two adjacent formations in central Maine, USA where groundwater in the bedrock aquifer frequently contains elevated As levels. The Waterville Formation contains higher arsenic concentrations (mean As 32.9mgkg-1, median 12.1mgkg-1, n=38) than the neighboring Vassalboro Group (mean As 19.1mgkg-1, median 6.0mgkg-1, n=38). The Waterville Formation is a pelitic meta-sedimentary unit with abundant pyrite either visible or observed by scanning electron microprobe. Concentrations of As and S are strongly correlated (r=0.88, p<0.05) in the low grade phyllite rocks, and arsenic is detected up to 1944mgkg-1 in pyrite measured by electron microprobe. In contrast, statistically significant (p<0.05) correlations between concentrations of As and S are absent in the calcareous meta-sediments of the Vassalboro Group, consistent with the absence of arsenic-rich pyrite in the protolith. Metamorphism converts the arsenic-rich pyrite to arsenic-poor pyrrhotite (mean As 1mgkg-1, n=15) during de-sulfidation reactions: the resulting metamorphic rocks contain arsenic but little or no sulfur indicating that the arsenic is now in new mineral hosts. Secondary weathering products such as iron oxides may host As, yet the geochemical methods employed (oxidative and reductive leaching) do not conclusively indicate that arsenic is associated only with these. Instead, silicate minerals such as biotite and garnet are present in metamorphic zones where arsenic is enriched (up to 130.8mgkg-1 As) where S is 0%. Redistribution of already variable As in the protolith during metamorphism and contemporary water-rock interaction in the aquifers, all combine to contribute to a spatially heterogeneous groundwater arsenic distribution in bedrock aquifers. © 2014 Elsevier B.V.

Kirshen P.,University of New Hampshire | Merrill S.,University of Southern Maine | Slovinsky P.,Maine Geological Survey | Richardson N.,Batelle Memorial Institute
Climatic Change | Year: 2012

The development of successful coastal adaptation strategies for both the built and natural environments requires combining scenarios of climate change and socio-economic conditions, and risk assessment. Such planning needs to consider the adaptation costs and residual damages over time that may occur given a range of possible storm conditions for any given sea level rise scenario. Using the metric of the expected value of annual adaptation costs and residual damages, or another metric that can be related to the elevation of flooding, a simplified method to carry this out is presented. The approach relies upon developing damage-flooding depth probability exceedance curves for various scenarios over a given planning period and determining the areas under the curves. While the approach does have limitations, it is less complex to implement than using Monte Carlo simulation approaches and may be more intuitive to decision makers. A case study in Maine, USA is carried out to illustrate the method. © 2011 Springer Science+Business Media B.V.

Flanagan S.V.,Lamont Doherty Earth Observatory | Flanagan S.V.,City University of New York | Marvinney R.G.,Maine Geological Survey | Johnston R.A.,Maine Geological Survey | And 4 more authors.
Science of the Total Environment | Year: 2015

Private wells in the United States are unregulated for drinking water standards and are the homeowner's responsibility to test and treat. Testing for water quality parameters such as arsenic (As) is a crucial first step for homeowners to take protective actions.This study seeks to identify key behavioral factors influencing homeowners' decisions to take action after receiving well As test results. A January 2013 survey of central Maine households (n. = 386, 73% response) who were notified 3-7. years earlier that their well water contained As above 10. μg/L found that 43% of households report installing As treatment systems. Another 30% report taking other mitigation actions such as drinking bottled water because of the As, but the remaining 27% of households did not act. Well water As level appears to be a motivation for mitigation: 31% of households with well water level between 10 and 50. μg/L did not act, compared to 11% of households with well water >. 50. μg/L. The belief that the untreated water is not safe to drink (risk) and that reducing drinking water As would increase home value (instrumental attitude) were identified as significant predictors of mitigating As. Mitigating As exposure is associated with less worry about the As level (affective attitude), possibly because those acting to reduce exposure feel less worried about As. Use of a treatment system specifically was significantly predicted by confidence that one can maintain a treatment system, even if there are additional costs (self-efficacy).An assessment of As treatment systems used by 68 of these households with well water As >. 10. μg/L followed up within August-November 2013 found that 15% of treatment units failed to produce water below As 10. μg/L, suggesting that there are continued risks for exposure even after the decision is made to treat. © 2014 Elsevier B.V.

Flanagan S.V.,Lamont Doherty Earth Observatory | Flanagan S.V.,City University of New York | Marvinney R.G.,Maine Geological Survey | Zheng Y.,Lamont Doherty Earth Observatory | And 2 more authors.
Science of the Total Environment | Year: 2015

In 2001 the Environmental Protection Agency (EPA) adopted a new standard for arsenic (As) in drinking water of 10. μg/L, replacing the old standard of 50. μg/L. However, for the 12% of the U.S. population relying on unregulated domestic well water, including half of the population of Maine, it is solely the well owner's responsibility to test and treat the water. A mailed household survey was implemented in January 2013 in 13 towns of Central Maine with the goal of understanding the population's testing and treatment practices and the key behavior influencing factors in an area with high well-water dependency and frequent natural groundwater As. The response rate was 58.3%; 525 of 900 likely-delivered surveys to randomly selected addresses were completed. Although 78% of the households reported that their well has been tested, half of it was more than 5. years ago. Among the 58.7% who believe they have tested for As, most do not remember the results. Better educated, higher income homeowners who more recently purchased their homes are most likely to have included As when last testing. While households agree that water and As-related health risks can be severe, they feel low personal vulnerability and there are low testing norms overall. Significant predictors of including As when last testing include: having knowledge that years of exposure increases As-related health risks (risk knowledge), knowing who to contact to test well water (action knowledge), believing that regular testing does not take too much time (instrumental attitude), and having neighbors who regularly test their water (descriptive norm). Homeowners in As-affected communities have the tendency to underestimate their As risks compared to their neighbors. The reasons for this optimistic bias require further study, but low testing behaviors in this area may be due to the influence of a combination of norm, ability, and attitude factors and barriers. © 2014 Elsevier B.V.

Yang Q.,Queens College, City University of New York | Yang Q.,Lamont Doherty Earth Observatory | Jung H.B.,Queens College, City University of New York | Marvinney R.G.,Maine Geological Survey | And 3 more authors.
Environmental Science and Technology | Year: 2012

A high percentage (31%) of groundwater samples from bedrock aquifers in the greater Augusta area, Maine was found to contain greater than 10 μg L -1 of arsenic. Elevated arsenic concentrations are associated with bedrock geology, and more frequently observed in samples with high pH, low dissolved oxygen, and low nitrate. These associations were quantitatively compared by statistical analysis. Stepwise logistic regression models using bedrock geology and/or water chemistry parameters are developed and tested with external data sets to explore the feasibility of predicting groundwater arsenic occurrence rates (the percentages of arsenic concentrations higher than 10 μg L -1) in bedrock aquifers. Despite the under-prediction of high arsenic occurrence rates, models including groundwater geochemistry parameters predict arsenic occurrence rates better than those with bedrock geology only. Such simple models with very few parameters can be applied to obtain a preliminary arsenic risk assessment in bedrock aquifers at local to intermediate scales at other localities with similar geology. © 2012 American Chemical Society.

Yang Q.,Lamont Doherty Earth Observatory | Yang Q.,Queens College, City University of New York | Culbertson C.W.,U.S. Geological Survey | Nielsen M.G.,U.S. Geological Survey | And 6 more authors.
Science of the Total Environment | Year: 2015

To understand the hydrogeochemical processes regulating well water arsenic (As) evolution in fractured bedrock aquifers, three domestic wells with [As] up to 478μg/L are investigated in central Maine. Geophysical logging reveals that fractures near the borehole bottom contribute 70-100% of flow. Borehole and fracture water samples from various depths show significant proportions of As (up to 69%) and Fe (93-99%) in particulates (>0.45μm). These particulates and those settled after a 16-day batch experiment contain 560-13,000mg/kg of As and 14-35% weight/weight of Fe. As/Fe ratios (2.5-20mmol/mol) and As partitioning ratios (adsorbed/dissolved [As], 20,000-100,000L/kg) suggest that As is sorbed onto amorphous hydrous ferric oxides. Newly drilled cores also show enrichment of As (up to 1300mg/kg) sorbed onto secondary iron minerals on the fracture surfaces. Pumping at high flow rates induces large decreases in particulate As and Fe, a moderate increase in dissolved [As] and As(III)/As ratio, while little change in major ion chemistry. The δD and δ18O are similar for the borehole and fracture waters, suggesting a same source of recharge from atmospheric precipitation. Results support a conceptual model invoking flow and sorption controls on groundwater [As] in fractured bedrock aquifers whereby oxygen infiltration promotes the oxidation of As-bearing sulfides at shallower depths in the oxic portion of the flow path releasing As and Fe; followed by Fe oxidation to form Fe oxyhydroxide particulates, which are transported in fractures and sorb As along the flow path until intercepted by boreholes. In the anoxic portions of the flow path, reductive dissolution of As-sorbed iron particulates could re-mobilize As. For exposure assessment, we recommend sampling of groundwater without filtration to obtain total As concentration in groundwater. © 2014 Elsevier B.V.

Johnston A.,University of Ulster | Slovinsky P.,Maine Geological Survey | Yates K.L.,University of Ulster | Yates K.L.,University of Queensland | Yates K.L.,Flinders University
Ocean and Coastal Management | Year: 2014

Sea level rise and climate change will have widespread impacts on coastal towns and cities, many of which have seen dramatic increases in development over recent decades. In addition to potential private property damage, the critical public infrastructure that supports these regions will become increasingly vulnerable to coastal flooding. This paper describes a straightforward, structured methodology for identifying and prioritizing critical infrastructure vulnerabilities in the coastal community of Scarborough, Maine, USA. The study uses GIS mapping and analysis techniques to identify infrastructure vulnerabilities in a coastal town under three different potential future flooding scenarios. A simple multi-criteria analysis matrix is used to explore the often hard to quantify, multifaceted consequences of infrastructure loss. Numerical scores are attributed to represent the economic, social, health and safety and environmental impacts of coastal flooding, allowing vulnerable locations to be ranked in order of overall importance. The results are summarized in a series of tables, maps and data sheets that convey data in readily accessible formats. High traffic roads, including evacuation routes, and major utility corridors are identified as the most critical vulnerable infrastructure assets in the town. Targeted improvements are recommended in these critical areas to improve system and community resilience to climate change and sea level rise. Our approach makes use of standard techniques, requires limited data and is therefore readily transferable for use in infrastructure planning in other similar communities. The methodology encourages public engagement and education, and the results can be used by the local authorities to pursue external funding opportunities to support investment in proactive infrastructure adaptation. The identification of key system weaknesses will allow future infrastructure investment to be targeted to the most critical areas, and assist in improving emergency response plans. © 2014 Elsevier Ltd.

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