Chowdhury S. Occurrences and changes of disinfection by-products in small water supply systems. Environ Monit Assess. 2017 Dec 20;190(1):32. doi: 10.1007/s10661-017-6410-8.
The small water supply systems (WSSs) often report high concentrations of disinfection by-products (DBPs) in drinking water. In this study, occurrences of trihalomethanes (THMs) and haloacetic acids (HAAs) in Newfoundland and Labrador (NL), Canada, were investigated from 441 WSSs for a period of 18 years (1999-2016). The WSSs were divided into groundwater (GWP) and surface water (SWP) systems, which were further classified into eight sub-groups (P1-P8) based on the population served (≤ 100; 101-250; 251-500; 501-1000; 1001-3000; 3001-5000; 5001-10,000; and 10,000+, respectively). The DBPs with probable and possible carcinogenic forms were estimated. Overall, 31.1% of WSSs were GWP, in which averages of THMs and HAAs were 32.2 and 27.7 μg/L, respectively, while the SWP had averages of THMs and HAAs of 97.6 and 129.2 μg/L, respectively. The very small WSSs (P1-P3) of GWP had averages of THMs and HAAs in the ranges of 29.1-43.5 and 15.8-64.3 μg/L, respectively. The P1-P3 of SWP had averages of THMs and HAAs in the ranges of 92.6-112.8 and 108.0-154.0 μg/L, respectively, which often exceeded the Canadian guideline limits. If the samples represented the populations homogenously, the total populations exposed to THMs or HAA5 above the guideline values would be in the range of 132.08-181.38 in thousands (30.3-41.6% of total populations). The probable and possible carcinogenic forms of THMs in GWP and SWP were in the ranges of 4.8-48.8 and 4.4-7.0% of THMs, respectively. In HAAs, carcinogenic forms were in the ranges of 82.6-98.4 and 97.6-98.7%, respectively. The findings indicated that the SWP might need further attention to better protect human health.
Gunnarsdottir MJ, Persson KM, Andradottir HO, Gardarsson SM. Status of small water supplies in the Nordic countries: Characteristics, water quality and challenges. International journal of hygiene and environmental health. 2017 Aug 24. pii: S1438-4639(17)30391-7. doi: 10.1016/j.ijheh.2017.08.006.
Access to safe water is essential for public health and is one of the most important prerequisites for good living and safe food production. Many studies have shown that non-compliance with drinking water quality standards in small water supply systems is much higher than in large systems. Nevertheless, people served by small water supply systems have the right to the same level of health protection. Actions are therefore needed to improve the situation. The objective of the present study was to carry out a baseline analysis of the situation in the Nordic region and provide recommendations for governmental policy and actions. Data were gathered on number of water supplies, population served, compliance with regulations and waterborne disease outbreaks from various sources in the Nordic countries. The collected data showed that there are about 12500 regulated water supplies, 9400 of which serve fewer than 500 persons. The number of unregulated and poorly regulated supplies is unknown, but it can be roughly estimated that these serve 10% of the Nordic population on a permanent basis or 2.6 million people. However, this does not tell the whole story as many of the very small water supplies serve transient populations, summerhouse dwellers and tourist sites, with many more users. Non-compliance regarding microbes is much higher in the small supplies. The population weighted average fecal contamination incidence rate in the Nordic region is eleven times higher in the smaller supplies than in the large ones, 0.76% and 0.07%, respectively. Registered waterborne disease outbreaks were also more frequent in the small supplies than in the large ones.
Scheili A, Rodriguez MJ, Sadiq R. Seasonal and spatial variations of source and drinking water quality in small municipal systems of two Canadian regions. The Science of the total environment. 2014 Dec 3. pii: S0048-9697(14)01663-5. doi: 10.1016/j.scitotenv.2014.11.069.
A one-year sampling program covering twenty-five small municipal systems was carried out in two Canadian regions to improve our understanding of the variability of water quality in small systems from water source to the end of the distribution system (DS). The database obtained was used to develop a global portrait of physical, chemical and microbiological water quality parameters. More precisely, the temporal and the spatial variability of these parameters were investigated. We observed that the levels of natural organic matter (NOM) were variable during different seasons, with maxima in the fall for both provinces. In the regions under study, the highest trihalomethane (THM) and haloacetic acid (HAA) levels were achieved in warmer seasons (summer, fall), as observed in previous studies involving large systems. Observed THM and HAA levels were three times higher in systems in the province of Newfoundland & Labrador than in the province of Quebec. Taste and odor indicators were detected during the summer and fall, and higher heterotrophic plate count (HPC) levels were associated with lower free chlorine levels. To determine spatial variations, stepwise statistical analysis was used to identify parameters and locations in the DS that act as indicators of drinking water quality. As observed for medium and large systems, free chlorine consumption, THM and HAA levels were dependant on their location in the DS. We also observed that the degradation of HAAs is more important in small systems than in medium or large DS reported in the literature, and this degradation can occur from the beginning of the DS. The results of this research may contribute to providing precious information on drinking water quality to small system operators and pave the way for several opportunities to improve water quality management.
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Jones, S.A., and Nicole, J. The inequity of the Revised Arsenic Rule for very small community drinking water systems. Environmental Science & Policy, Volume 9, Issue 6, October 2006, Pages 555-562
The U.S. Environmental Protection Agency (EPA) recently reduced the maximum contaminant level for arsenic in community drinking water systems from 50 to 10 ppb. EPA uses net benefit analyses aggregated at the national-scale to set drinking water standards. Such aggregation may result in compliance options that are not cost-effective for very small systems, and may limit opportunities for these communities to receive variances. We completed a benefit-cost analysis and an affordability analysis of 14 tribal communities in Arizona to better understand the regulation’s impact on very small water systems ranging from 6 to 95 service connections. Compliance alternatives included both technological and non-technological solutions. Health benefits were based on an EPA study of morbidity and mortality. The results show that all communities can comply with feasible alternatives; however, the tangible costs of the revised arsenic regulation far outweigh the expected health benefits and do not meet EPA’s affordability criteria. The results support other studies that suggest a more equitable regulatory-setting process is needed to consider both health and economic impacts. Otherwise, the unintended result is a shifting of resources among risks instead of actual risk reduction.
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The Chinese government has passed a 5 year plan to solve problems concerning drinking water safety for 298 million rural residents from 2011-2015….click here for news article..
Confidence intervals are not reported in the abstract. A typical ecological study that is not definitive…..
Gong, G., and S.E. Bryant. Low-level arsenic exposure, AS3MT gene polymorphism and cardiovascular diseases in rural Texas counties. Environ Res. 2012 Feb 15.
Abstract: Most Americans living in rural areas use groundwater for drinking. Exposure to low-level (around the current U.S. standard 10μg/L) arsenic in drinking water is associated with increased mortality of cardiovascular diseases. The current study was to determine if coronary heart disease, hypertension, and hyperlipidemia were associated with low-level arsenic exposure and AS3MT gene single nucleotide polymorphism (SNP) A35991G (rs10748835) in rural Texas. Subjects (156 men, 343 women, 40-96 years of age with a mean of 61) were residents from rural counties Cochran, Palmer, and Bailey, Texas. Groundwater arsenic concentration at each subject’s home was estimated with ArcGIS inverse distance weighted interpolation based on the residential location’s distances to surrounding wells with known water arsenic concentrations. The estimated groundwater arsenic concentration ranged from 2.2 to 15.3 (mean 6.2)μg/L in this cohort. Logistic regression analysis showed that coronary heart disease was associated with higher arsenic exposure (p<0.05) and with AS3MT genotype GG vs. AA (p<0.05) after adjustments for age, ethnicity, gender, education, smoking status, alcoholism, and anti-hyperlipidemia medication. Hypertension was associated with higher arsenic exposure, while hyperlipidemia was associated with genotype AG vs. AA of the AS3MT gene (p<0.05). Thus, coronary heart disease and its main risk factors were associated with low-level arsenic exposure, AS3MT polymorphism or both.
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The owner of this small water system in New York says he has abandoned it. Any takers? Click here….