Drinking Water Supply (drinking + water_supply)

Distribution by Scientific Domains

Selected Abstracts

The use of technical knowledge in European water policy-making

Perry J. M. van Overveld
Abstract Environmental policy-making often involves a mix of technical knowledge, normative choice and uncertainty. Numerous actors, each with their own distinct objectives, are involved in these policy-making processes. One question these actors face, is how they can effectively communicate their technical knowledge and represent their interests in policy-making. The objective of this paper is to identify the factors that influence the use of technical knowledge and its impact on decision-making in the European Union. This is done for case of water policy-making for organic micropollutants, such as pesticides and pharmaceuticals. These pollutants enter the surface water in many ways and although concentrations are low, adverse effects cannot be ruled out. Via the EU Water Framework Directive, legislation has been developed to reduce the emissions of pollutants that pose a risk to ecology or public health. Using the advocacy coalition framework, the formal EU decision-making processes are analyzed for the identification of priority pollutants (Priority Substances) and the derivation of maximum allowable concentrations (Environmental Quality Standards). To enable a detailed analysis, the focus is on three specific micropollutants that pose health risks via drinking water supply. The findings show the extent to which actors can influence the decision-making process with technical knowledge. Early involvement in the drafting process that is led by the European Commission is important to influence decision-making outcomes. For this, organizational capacity in coalitions to mobilize and coordinate the required targeted contribution of technical knowledge is crucial. Copyright 2010 John Wiley & Sons, Ltd and ERP Environment. [source]

Oral toxicity of the cyanobacterial toxin cylindrospermopsin in male Swiss albino mice: Determination of no observed adverse effect level for deriving a drinking water guideline value

A. R. Humpage
Abstract The cyanobacterial toxin cylindrospermopsin (CYN) is a frequent contaminant of freshwaters throughout the world, including those that are sources of drinking water. The first cases of human poisoning attributed to this toxin occurred from a treated drinking water supply in Queensland, Australia, in 1979. The toxin causes extensive damage to the liver, kidneys, spleen, heart, and other organs. It is known to be a potent protein synthesis inhibitor, but there is mounting evidence for genotoxicity and that it metabolizes to even more toxic forms. As part of a risk assessment process leading to a guideline for a safe drinking water level for this toxin, we performed a series of experiments to determine a no-observed-adverse-effect level (NOAEL) for this toxin. In the first trial male mice were exposed to CYN-containing cyanobacterial extract in their drinking water (0,657 ,g CYN kg,1 day,1) for 10 weeks. In the second trial mice received purified CYN by daily gavage (0,240 ,g CYN kg,1 day,1) for 11 weeks. Body and organ weights were recorded; urine, serum, and hematology analyses were performed; and histopathological examination of tissues was carried out. Body weights were significantly increased at low doses (30 and 60 ,g kg,1 day,1) and decreased at high doses (432 and 657 ,g kg,1 day,1). Liver and kidney weights were significantly increased at doses of 240 ,g kg,1 day,1 and 60 ,g kg,1 day,1, respectively. Serum bilirubin levels were significantly increased and bile acids significantly decreased at doses of 216 ,g kg day,1 and greater. Urine total protein was significantly decreased at doses above 60 ,g kg,1 day,1. The kidney appeared to be the more sensitive organ to this toxin. If it is assumed that increased organ weights and changes in functional capacity are responses to an underlying toxic effect, then the NOAEL based on this data is 30 ,g kg,1 day,1, which, with standard calculations and uncertainty factors, provides a proposed guideline safety value of 1 ,g/L in drinking water. 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 94,103, 2003. [source]

Arsenic in Glacial Drift Aquifers and the Implication for Drinking Water,Lower Illinois River Basin

GROUND WATER, Issue 3 2001
Kelly L. Warner
The lower Illinois River Basin (LIRB) covers 47,000 km2 of central and western Illinois. In the LIRB, 90% of the ground water supplies are from the deep and shallow glacial drift aquifers. The deep glacial drift aquifer (DGDA) is below 152 m altitude, a sand and gravel deposit that fills the Mahomet Buried Bedrock Valley, and overlain by more than 30.5 m of clayey till. The LIRB is part of the USGS National Water Quality Assessment program, which has an objective to describe the status and trends of surface and ground water quality. In the DGDA, 55% of the wells used for public drinking-water supply and 43% of the wells used for domestic drinking water supply have arsenic concentrations above 10 ,g/L (a new U.S. EPA drinking water standard). Arsenic concentrations greater than 25 ,g/L in ground water are mostly in the form of arsenite (AsIII). The proportion of arsenate (AsV) to arsenite does not change along the flowpath of the DGDA. Because of the limited number of arsenic species analyses, no clear relations between species and other trace elements, major ions, or physical parameters could be established. Arsenic and barium concentrations increase from east to west in the DGDA and are positively correlated. Chloride and arsenic are positively correlated and provide evidence that arsenic may be derived locally from underlying bedrock. Solid phase geochemical analysis of the till, sand and gravel, and bedrock show the highest presence of arsenic in the underlying organic-rich carbonate bedrock. The black shale or coal within the organic-rich carbonate bedrock is a potential source of arsenic. Most high arsenic concentrations found in the DGDA are west and downgradient of the bedrock structural features. Geologic structures in the bedrock are potential pathways for recharge to the DGDA from surrounding bedrock. [source]

Application of Direct Push Methods to Investigate Uranium Distribution in an Alluvial Aquifer

Wesley McCall
The U.S. EPA 2000 Radionuclide Rule established a maximum contaminant level (MCL) for uranium of 30 g/L. Many small community water supplies are struggling to comply with this new regulation. At one such community, direct push (DP) methods were applied to obtain hydraulic profiling tool (HPT) logs and install small diameter wells in a section of alluvial deposits located along the Platte River. This work was conducted to evaluate potential sources of elevated uranium in the Clarks, Nebraska drinking water supply. HPT logs were used to understand the hydrostratigraphy of a portion of the aquifer and guide placement of small diameter wells at selected depth intervals. Low-flow sampling of the wells provided water quality parameters and samples for analysis to study the distribution of uranium and variations in aquifer chemistry. Contrary to expectations, the aquifer chemistry revealed that uranium was being mobilized under anoxic and reducing conditions. Review of the test well and new public water supply well construction details revealed that filter packs extended significantly above the screened intervals of the wells. These filter packs were providing a conduit for the movement of groundwater with elevated concentrations of uranium into the supply wells and the community drinking water supply. The methods applied and lessons learned here may be useful for the assessment of unconsolidated aquifers for uranium, arsenic, and many other drinking water supply contaminants. [source]


Article first published online: 24 SEP 200
Hu, Q.1, Sommerfeld, M.1 Lowry, D.1, Dempster, T.1, Westerhoff, P.2, Baker, L.3, Bruce, D. & Nguyen, M. L.2 1Department of Plant Biology and 2Department of Civil and Environmental Engineering, Arizona State University, Tempe, Arizona 85287; 3Baker Environmental Consulting, 8001 Greenwood Drive, Moundview, MN 55112 Geosmin is a common component of the off-flavors detected in the drinking water supply sources of metropolitan Phoenix (Arizona). A cyanobacterium, Oscillatoria splendida, was isolated from source water during incidents of elevated geosmin production and was implicated as a cause of earthy/musty off-flavors in the drinking water. Production of geosmin was found to be constitutive in O. splendida during all growth stages. Effects of environmental parameters on the growth characteristics, and on production and release of geosmin by O. splendida, was studied under laboratory conditions. The specific growth rate and cell-bound geosmin increased with increasing temperature from 12 to 26 C, the range of water temperatures that occur in the drinking water supply. On a per-chlorophyll a basis, however, more geosmin was released from the cells at lower temperatures. An inverse relationship was evident between light intensity and O. splendida growth and the release of geosmin. Cell-bound geosmin, however, was higher at higher light intensities. Dark incubation initially stimulated the biosynthesis of geosmin, whereas a prolonged period of darkness (2-3 weeks) resulted in massive release of geosmin into the culture medium from lysis and cellular decomposition. Dissolved nitrogen appeared to be the limiting nutrient for O. splendida in the local water supply source. When nitrate was added to laboratory cultures, both growth and geosmin production increased. These results will be discussed in context with episodes of off-flavors in drinking waters in metropolitan Phoenix, Arizona. [source]

An appraisal of methods for measurement of pesticide transformation in the groundwater zone,

Minze Leistra
Abstract Laboratory and field studies show that pesticides may be transformed in the groundwater zone. Possible reaction mechanisms are chemical hydrolysis, catalytic reduction and aerobic or anaerobic microbial transformation. Transformation in the groundwater zone can be an important element in the advanced evaluation of the potential risk arising from a pesticide in the public drinking water supply. However, rate and pathway of transformation can show large differences, depending on the bio-geochemical conditions in the groundwater zone. Knowledge of the reaction mechanisms and the effect of aquifer conditions would allow vulnerable and low-vulnerable application areas for a pesticide to be delimited. An outline is given of possible approaches to quantifying these transformation processes and using the results in registration procedures, especially in the EU and its member states. Furthermore, areas where there is need for continued research and better understanding are highlighted. 2001 Society of Chemical Industry [source]