Qu B, Zhang Y, Kang S, Sillanpää M. Water quality in the Tibetan Plateau: Major ions and trace elements in rivers of the “Water Tower of Asia”. Sci Total Environ. 2018 Aug 25;649:571-581. doi: 10.1016/j.scitotenv.2018.08.316.
As the “Water Tower of Asia”, rivers originating from the Tibetan Plateau provide water resources for more than one billion residents in both its local and surrounding areas. With respect to the essential role that this region plays in terms of water resources in Asia, we provide an overview of the mechanisms governing the water quality, including the major ions and trace elements release, in eleven rivers of the Tibetan Plateau. Overall, the rivers running on the Tibetan Plateau reflect an alkaline aquatic environment, with an average pH of 8.5; and the total dissolved solids (TDS, ~339 mg L-1) are much higher than the global average value. Over 80% of the water ionic budget in the rivers of the plateau is comprised of Ca2+, Mg2+, HCO3- and SO42-. The main mechanisms that control the river water chemistry on the Tibetan Plateau are natural processes and present a visible spatial heterogeneity. For instance, in rivers of the southern Tibetan Plateau, the water quality is mainly controlled by the rock-weathering, while rivers of the central and northern Tibetan Plateau are also largely affected by evaporation-crystallization processes. In general, most of the rivers on the Tibetan Plateau are uncontaminated and still in a pristine condition. However, it should be noted that due to the natural process such as rock-weathering and groundwater leaching, and anthropogenic activities such as urbanization and mining operations, the concentrations of several toxic elements (e.g., As, Cd, Pb, Mn, Hg and Tl) in some of the basins are higher than the China national standard (GB) and the World Health Organization (WHO) guidelines for drinking water. With increasing anthropogenic activities on the plateau and changes in the river basins, it is necessary to conduct the long-term monitoring of the river water chemistry of this climate-sensitive and eco-fragile region.
Salehi M, Abouali M, Wang M, Zhou Z, Nejadhashemi AP, Mitchell J, Caskey S, Whelton AJ. Case study: Fixture water use and drinking water quality in a new residential green building. Chemosphere. 2017 Nov 30;195:80-89. doi: 10.1016/j.chemosphere.2017.11.070.
Residential plumbing is critical for the health and safety of populations worldwide. A case study was conducted to understand fixture water use, drinking water quality and their possible link, in a newly plumbed residential green building. Water use and water quality were monitored at four in-building locations from September 2015 through December 2015. Once the home was fully inhabited average water stagnation periods were shortest at the 2nd floor hot fixture (90 percentile of 0.6-1.2 h). The maximum water stagnation time was 72.0 h. Bacteria and organic carbon levels increased inside the plumbing system compared to the municipal tap water entering the building. A greater amount of bacteria was detected in hot water samples (6-74,002 gene copy number/mL) compared to cold water (2-597 gene copy number/mL). This suggested that hot water plumbing promoted greater microbial growth. The basement fixture brass needle valve may have caused maximum Zn (5.9 mg/L), Fe (4.1 mg/L), and Pb (23 μg/L) levels compared to other fixture water samples (Zn ≤ 2.1 mg/L, Fe ≤ 0.5 mg/L and Pb ≤ 8 μg/L). At the basement fixture, where the least amount of water use events occurred (cold: 60-105, hot: 21-69 event/month) compared to the other fixtures in the building (cold: 145-856, hot: 326-2230 event/month), greater organic carbon, bacteria, and heavy metal levels were detected. Different fixture use patterns resulted in disparate water quality within a single-family home. The greatest drinking water quality changes were detected at the least frequently used fixture.
Islam MMM, Iqbal MS, Leemans R, Hofstra N. Modelling the impact of future socio-economic and climate change scenarios on river microbial water quality. International journal of hygiene and environmental health. 2017 Dec 4. pii: S1438-4639(17)30408-X. doi: 10.1016/j.ijheh.2017.11.006.
Microbial surface water quality is important, as it is related to health risk when the population is exposed through drinking, recreation or consumption of irrigated vegetables. The microbial surface water quality is expected to change with socio-economic development and climate change. This study explores the combined impacts of future socio-economic and climate change scenarios on microbial water quality using a coupled hydrodynamic and water quality model (MIKE21FM-ECOLab). The model was applied to simulate the baseline (2014-2015) and future (2040s and 2090s) faecal indicator bacteria (FIB: E. coli and enterococci) concentrations in the Betna river in Bangladesh. The scenarios comprise changes in socio-economic variables (e.g. population, urbanization, land use, sanitation and sewage treatment) and climate variables (temperature, precipitation and sea-level rise). Scenarios have been developed building on the most recent Shared Socio-economic Pathways: SSP1 and SSP3 and Representative Concentration Pathways: RCP4.5 and RCP8.5 in a matrix. An uncontrolled future results in a deterioration of the microbial water quality (+75% by the 2090s) due to socio-economic changes, such as higher population growth, and changes in rainfall patterns. However, microbial water quality improves under a sustainable scenario with improved sewage treatment (-98% by the 2090s). Contaminant loads were more influenced by changes in socio-economic factors than by climatic change. To our knowledge, this is the first study that combines climate change and socio-economic development scenarios to simulate the future microbial water quality of a river. This approach can also be used to assess future consequences for health risks.
Le Luu T. Remarks on the current quality of groundwater in Vietnam. Environmental science and pollution research international. 2017 Jul 24. doi: 10.1007/s11356-017-9631-z.
This paper reviews the current quality of groundwater in Vietnam. In Vietnam, groundwater is obtained primarily from tubewells, which have high concentrations of pollutants such as As, Fe, Mn, and NH4+. In the areas where groundwater tests were conducted, arsenic levels ranged from 0.1-3050 μg/L, which substantially exceed the standard of 10 μg/L which has been established by the WHO. Contamination sources are distributed over a large area from the Red River Delta in the north to the Mekong River Delta in the south, putting as many as ten million people at risk of adverse health effects. Levels of arsenic and iron in sediment are strongly correlated, which indicate that the presence of arsenic in groundwater results from the reduction of arsenic bound to iron oxyhydroxides. It is important to raise awareness of these issues among the Vietnamese public by disseminating information about the negative effects of contaminated drinking water, as well as carrying out long-term research projects to identify other sources of contamination and improving water treatment technology and water management capabilities.
MacDonald Gibson J, Pieper KJ. Strategies to Improve Private-Well Water Quality: A North Carolina Perspective. Environmental health perspectives. 2017 Jul 7;125(7):076001. doi: 10.1289/EHP890.
BACKGROUND: Evidence suggests that the 44.5 million U.S. residents drawing their drinking water from private wells face higher risks of waterborne contaminant exposure than those served by regulated community water supplies. Among U.S. states, North Carolina (N.C.) has the second-largest population relying on private wells, making it a useful microcosm to study challenges to maintaining private-well water quality.
OBJECTIVES: This paper summarizes recommendations from a two-day summit to identify options to improve drinking-water quality for N.C. residents served by private wells.
METHODS: The Research Triangle Environmental Health Collaborative invited 111 participants with knowledge of private-well water challenges to attend the Summit. Participants worked in small groups that focused on specific aspects and reconvened in plenary sessions to formulate consensus recommendations.
DISCUSSION: Summit participants highlighted four main barriers to ensuring safe water for residents currently relying on private wells: (1) a database of private well locations is unavailable; (2) racial disparities have perpetuated reliance on private wells in some urbanized areas; (3) many private-well users lack information or resources to monitor and maintain their wells; and (4) private-well support programs are fragmented and lack sufficient resources. The Summit produced 10 consensus recommendations for ways to overcome these barriers.
CONCLUSIONS: The Summit recommendations, if undertaken, could improve the health of North Carolinians facing elevated risks of exposure to waterborne contaminants because of their reliance on inadequately monitored and maintained private wells. Because many of the challenges in N.C. are common nationwide, these recommendations could serve as models for other states.
Bale AE, Greco SE, Pitton BJL, Haver DL, Oki LR. Pollutant loading from low-density residential neighborhoods in California. Environmental monitoring and assessment. 2017 Aug;189(8):386. doi: 10.1007/s10661-017-6104-2.
This paper presents a comparison of pollutant load estimations for runoff from two geographically distinct residential suburban neighborhoods in northern and southern California. The two neighborhoods represent a single urban land use type: low-density residential in small catchments (<0.3 km2) under differing regional climates and irrigation practices. Pollutant loads of pesticides, nutrients, and drinking water constituents of concern are estimated for both storm and non-storm runoff. From continuous flow monitoring, it was found that a daily cycle of persistent runoff that peaks mid-morning occurs at both sites. These load estimations indicate that many residential neighborhoods in California produce significant non-storm pollutant loads year-round. Results suggest that non-storm flow accounted for 47-69% of total annual runoff and significantly contributed to annual loading rates of most nutrients and pesticides at both sites. At the Southern California site, annual non-storm loads are 1.2-10 times higher than storm loads of all conventional constituents and nutrients with one exception (total suspended solids). At the Northern California site, annual storm loads range from 51 to 76% of total loads for all conventional constituents and nutrients with one exception (total dissolved solids). Non-storm yields of pesticides at the Southern California site range from 1.3-65 times higher than those at the Northern California site. The disparity in estimated pollutant loads between the two sites indicates large potential variation from site-to-site within the state and suggests neighborhoods in drier and milder climates may produce significantly larger non-storm loads due to persistent dry season runoff and year-round pest control.
Liu G, Zhang Y, Knibbe WJ, Feng C, Liu W, Medema G, van der Meer W. Potential impacts of changing supply-water quality on drinking water distribution: A review. Water Res. 2017 Mar 19;116:135-148. doi: 10.1016/j.watres.2017.03.031.
Driven by the development of water purification technologies and water quality regulations, the use of better source water and/or upgraded water treatment processes to improve drinking water quality have become common practices worldwide. However, even though these elements lead to improved water quality, the water quality may be impacted during its distribution through piped networks due to the processes such as pipe material release, biofilm formation and detachment, accumulation and resuspension of loose deposits. Irregular changes in supply-water quality may cause physiochemical and microbiological de-stabilization of pipe material, biofilms and loose deposits in the distribution system that have been established over decades and may harbor components that cause health or esthetical issues (brown water). Even though it is clearly relevant to customers’ health (e.g., recent Flint water crisis), until now, switching of supply-water quality is done without any systematic evaluation. This article reviews the contaminants that develop in the water distribution system and their characteristics, as well as the possible transition effects during the switching of treated water quality by destabilization and the release of pipe material and contaminants into the water and the subsequent risks. At the end of this article, a framework is proposed for the evaluation of potential transition effects.