Pena-Pereira, Francisco; Villar-Blanco, Lorena; Lavilla, Isela; Bendicho, Carlos. Test for arsenic speciation in waters based on a paper-based analytical device with scanometric detection. Analytica Chimica Acta 29 June 2018 1011:1-10 DOI: 10.1016/j.aca.2018.01.007
A rapid, simple and affordable method for arsenic speciation analysis is described in this work. The proposed methodology involves in situ arsine generation, transfer of the volatile to the headspace and its reaction with silver nitrate at the detection zone of a paper-based analytical device (PAD). Thus, silver nitrate acts as a recognition element for arsine in the paper-based sensor. The chemical reaction between the recognition element and the analyte derivative results in the formation of a colored product which can be detected by scanning the detection zone and data treatment with an image processing and analysis program. Detection and injection zones were defined in the paper substrate by formation of hydrophobic barriers, thus enabling the formation of the volatile derivative without affecting the chemical stability of the recognition element present in the PAD. Experimental parameters influencing the analytical performance of the methodology, namely color mode detection, composition of the paper-based sensor and hydride generation and mass transfer conditions, were evaluated. Under optimal conditions, the proposed method showed limits of detection and quantification of 1.1 and 3.6 ng mL−1, respectively. Remarkably, the limit of detection of the method reported herein was much lower than the maximum contaminant levels set by both the World Health Organization and the US Environmental Protection Agency for arsenic in drinking water, unlike several commercially available arsenic test kits. The repeatability, expressed as relative standard deviation, was found to be 7.1% (n = 8). The method was validated against the European Reference Material ERM®-CA615 groundwater and successfully applied to the determination of As(III), As(V) and total inorganic As in different water samples. Furthermore, the method can be used for the screening analysis of total arsenic in waters when a cut-off level of 7 ng mL−1 is used.
Brenda C. Minatel1, Adam P. Sage1, Christine Anderson, Roland Hubaux, Erin A. Marshall, Wan L. Lam, Victor D. Martinez. Environmental arsenic exposure: From genetic susceptibility to pathogenesis. Environment International Volume 112, March 2018, Pages 183–197
More than 200 million people in 70 countries are exposed to arsenic through drinking water. Chronic exposure to this metalloid has been associated with the onset of many diseases, including cancer. Epidemiological evidence supports its carcinogenic potential, however, detailed molecular mechanisms remain to be elucidated. Despite the global magnitude of this problem, not all individuals face the same risk. Susceptibility to the toxic effects of arsenic is influenced by alterations in genes involved in arsenic metabolism, as well as biological factors, such as age, gender and nutrition. Moreover, chronic arsenic exposure results in several genotoxic and epigenetic alterations tightly associated with the arsenic biotransformation process, resulting in an increased cancer risk. In this review, we: 1) review the roles of inter-individual DNA-level variations influencing the susceptibility to arsenic-induced carcinogenesis; 2) discuss the contribution of arsenic biotransformation to cancer initiation; 3) provide insights into emerging research areas and the challenges in the field; and 4) compile a resource of publicly available arsenic-related DNA-level variations, transcriptome and methylation data. Understanding the molecular mechanisms of arsenic exposure and its subsequent health effects will support efforts to reduce the worldwide health burden and encourage the development of strategies for managing arsenic-related diseases in the era of personalized medicine.
Nigra AE, Sanchez TR, Nachman KE, Harvey D, Chillrud SN, Graziano JH, Navas-Acien A. The effect of the Environmental Protection Agency maximum contaminant level on arsenic exposure in the USA from 2003 to 2014: an analysis of the National Health and Nutrition Examination Survey (NHANES). Lancet Public Health. 2017 Nov;2(11):e513-e521. doi: 10.1016/S2468-2667(17)30195-0.
BACKGROUND: The current US Environmental Protection Agency (EPA) maximum contaminant level (MCL) for arsenic in public water systems (10 µg/L) took effect in 2006. Arsenic is not federally regulated in private wells. The impact of the 2006 MCL on arsenic exposure in the US, as confirmed through biomarkers, is presently unknown. We evaluated national trends in water arsenic exposure in the US, hypothesizing that urinary arsenic levels would decrease over time among participants using public water systems but not among those using well water. We further estimated the expected number of avoided lung, bladder, and skin cancer cases.
METHODS: We evaluated 14,127 participants in the National Health and Nutrition Examination Survey (NHANES) 2003-2014 with urinary dimethylarsinate (DMA) and total arsenic available. To isolate water exposure, we expanded a residual-based method to remove tobacco and dietary contributions of arsenic. We applied EPA risk assessment approaches to estimate the expected annual number of avoided cancer cases comparing arsenic exposure in 2013-2014 vs. 2003-2004.
FINDINGS: Among public water users, fully adjusted geometric means (GMs) of DMA decreased from 3.01 µg/L in 2003-2004 to 2.49 µg/L in 2013-2014 (17% reduction; 95% confidence interval 10%, 24%; p-trend<0.01); no change was observed among well water users (p-trend= 0.35). Assuming these estimated exposure reductions will remain similar across a lifetime, we estimate a reduction of 200 to 900 lung and bladder cancer cases per year depending on the approach used.
INTERPRETATION: The decline in urinary arsenic among public water but not private well users in NHANES 2003-2014 indicates that the implementation of the current MCL has reduced arsenic exposure in the US population. Our study supports prior work showing that well water users are inadequately protected against drinking water arsenic, and confirms the critical role of federal drinking water regulations in reducing toxic exposures and protecting human health.
Crabbe H, Fletcher T, Close R, Watts MJ, Ander EL, Smedley PL, Verlander NQ, Gregory M, Middleton DRS, Polya DA, Studden M, Leonardi GS. Hazard Ranking Method for Populations Exposed to Arsenic in Private Water Supplies: Relation to Bedrock Geology. Int J Environ Res Public Health. 2017 Dec 1;14(12). pii: E1490. doi: 10.3390/ijerph14121490.
Approximately one million people in the UK are served by private water supplies (PWS) where main municipal water supply system connection is not practical or where PWS is the preferred option. Chronic exposure to contaminants in PWS may have adverse effects on health. South West England is an area with elevated arsenic concentrations in groundwater and over 9000 domestic dwellings here are supplied by PWS. There remains uncertainty as to the extent of the population exposed to arsenic (As), and the factors predicting such exposure. We describe a hazard assessment model based on simplified geology with the potential to predict exposure to As in PWS. Households with a recorded PWS in Cornwall were recruited to take part in a water sampling programme from 2011 to 2013. Bedrock geologies were aggregated and classified into nine Simplified Bedrock Geological Categories (SBGC), plus a cross-cutting “mineralized” area. PWS were sampled by random selection within SBGCs and some 508 households volunteered for the study. Transformations of the data were explored to estimate the distribution of As concentrations for PWS by SBGC. Using the distribution per SBGC, we predict the proportion of dwellings that would be affected by high concentrations and rank the geologies according to hazard. Within most SBGCs, As concentrations were found to have log-normal distributions. Across these areas, the proportion of dwellings predicted to have drinking water over the prescribed concentration value (PCV) for As ranged from 0% to 20%. From these results, a pilot predictive model was developed calculating the proportion of PWS above the PCV for As and hazard ranking supports local decision making and prioritization. With further development and testing, this can help local authorities predict the number of dwellings that might fail the PCV for As, based on bedrock geology. The model presented here for Cornwall could be applied in areas with similar geologies. Application of the method requires independent validation and further groundwater-derived PWS sampling on other geological formations.
Hong YS, Ye BJ, Kim YM, Kim BG, Kang GH, Kim JJ, Song KH, Kim YH, Seo JW. Investigation of Health Effects According to the Exposure of Low Concentration Arsenic Contaminated Ground Water. International journal of environmental research and public health. 2017 Nov 27;14(12). pii: E1461. doi: 10.3390/ijerph14121461.
Recent epidemiological studies have reported adverse health effects, including skin cancer, due to low concentrations of arsenic via drinking water. We conducted a study to assess whether low arsenic contaminated ground water affected health of the residents who consumed it. For precise biomonitoring results, the inorganic (trivalent arsenite (As III) and pentavalent arsenate (As V)) and organic forms (monomethylarsonate (MMA) and dimethylarsinate (DMA)) of arsenic were separately quantified by combining high-performance liquid chromatography and inductively coupled plasma mass spectroscopy from urine samples. In conclusion, urinary As III, As V, MMA, and hair arsenic concentrations were significantly higher in residents who consumed arsenic contaminated ground water than control participants who consumed tap water. But, most health screening results did not show a statistically significant difference between exposed and control subjects. We presume that the elevated arsenic concentrations may not be sufficient to cause detectable health effects. Consumption of arsenic contaminated ground water could result in elevated urinary organic and inorganic arsenic concentrations. We recommend immediate discontinuation of ground water supply in this area for the safety of the residents.
Ecologic studies such as this are not very informative because of limited exposure assessments. But they can certainly generate alarm. Even so, small associations such as this are questionable regardless of precise mathematical computations. Note the absence of confidence intervals on the estimates which sends a strong message to ignore the study altogether.
Saint-Jacques N, Brown P, Nauta L, Boxall J, Parker L, Dummer TJB. Estimating the risk of bladder and kidney cancer from exposure to low-levels of arsenic in drinking water, Nova Scotia, Canada. Environment international. 2017 Oct 28. pii: S0160-4120(17)31385-5. doi: 10.1016/j.envint.2017.10.014.
Arsenic in drinking water impacts health. Highest levels of arsenic have been historically observed in Taiwan and Bangladesh but the contaminant has been affecting the health of people globally. Strong associations have been confirmed between exposure to high-levels of arsenic in drinking water and a wide range of diseases, including cancer. However, at lower levels of exposure, especially near the current World Health Organization regulatory limit (10μg/L), this association is inconsistent as the effects are mostly extrapolated from high exposure studies. This ecological study used Bayesian inference to model the relative risk of bladder and kidney cancer at these lower concentrations-0-2μg/L; 2-5μg/L and; ≥5μg/L of arsenic-in 864 bladder and 525 kidney cancers diagnosed in the study area, Nova Scotia, Canada between 1998 and 2010. The model included proxy measures of lifestyle (e.g. smoking) and accounted for spatial dependencies. Overall, bladder cancer risk was 16% (2-5μg/L) and 18% (≥5μg/L) greater than that of the referent group (<2μg/L), with posterior probabilities of 88% and 93% for these risks being above 1. Effect sizes for kidney cancer were 5% (2-5μg/L) and 14% (≥5μg/L) above that of the referent group (<2μg/L), with probabilities of 61% and 84%. High-risk areas were common in southwestern areas, where higher arsenic-levels are associated with the local geology. The study suggests an increased bladder cancer, and potentially kidney cancer, risk from exposure to drinking water arsenic-levels within the current the World Health Organization maximum acceptable concentration.
Li F, Qiu Z, Zhang J, Liu C, Cai Y, Xiao M. Spatial Distribution and Fuzzy Health Risk Assessment of Trace Elements in Surface Water from Honghu Lake. International journal of environmental research and public health. 2017 Sep 4;14(9). pii: E1011. doi: 10.3390/ijerph14091011.
Previous studies revealed that Honghu Lake was polluted by trace elements due to anthropogenic activities. This study investigated the spatial distribution of trace elements in Honghu Lake, and identified the major pollutants and control areas based on the fuzzy health risk assessment at screening level. The mean total content of trace elements in surface water decreased in the order of Zn (18.04 μg/L) > Pb (3.42 μg/L) > Cu (3.09 μg/L) > Cr (1.63 μg/L) > As (0.99 μg/L) > Cd (0.14 μg/L), within limits of Drinking Water Guidelines. The results of fuzzy health risk assessment indicated that there was no obvious non-carcinogenic risk to human health, while carcinogenic risk was observed in descending order of As > Cr > Cd > Pb. As was regarded to have the highest carcinogenic risk among selected trace elements because it generally accounted for 64% of integrated carcinogenic risk. Potential carcinogenic risk of trace elements in each sampling site was approximately at medium risk level (10-5 to 10-4). The areas in the south (S4, S13, and S16) and northeast (S8, S18, and S19) of Honghu Lake were regarded as the risk priority control areas. However, the corresponding maximum memberships of integrated carcinogenic risk in S1, S3, S10-S13, S15, and S18 were of relatively low credibility (50-60%), and may mislead the decision-makers in identifying the risk priority areas. Results of fuzzy assessment presented the subordinate grade and corresponding reliability of risk, and provided more full-scale results for decision-makers, which made up for the deficiency of certainty assessment to a certain extent.