Release of Metals from Different Sections of Domestic Drinking Water Installations

Effect of Community Water Service on Lead in Drinking Water in an Environmental Justice Community

Multiple recent studies have found elevated lead (Pb) concentrations in tap water in U.S. homes relying on unregulated private wells. The main Pb source is dissolution from household plumbing, fixtures, and well components. Here, we leverage a natural experiment and citizen science approach to evaluate how extending community water service to an environmental justice community relying on private wells affects Pb in household water. We analyzed Pb in 260 first-draw kitchen tap water samples collected by individual homeowners over a 5-month period in residences that did and did not connect to the community system. Before the community water system was extended, 25% of homes had Pb > 15 μg/L (the U.S. regulatory action level for community water systems) in first-draw water samples. Pb was significantly correlated with nickel (ρ = 0.61), zinc (ρ = 0.50), and copper (ρ = 0.40), suggesting that corrosion of brass fittings and fixtures is the main Pb source. Among homes that connected to the community system, Pb decreased rapidly and was sustained at levels well below 15 μg/L over the study period. Overall, connecting to the municipal water supply was associated with a 92.5% decrease in first-draw tap water Pb.

Human Health Risk Assessment of Trace Elements in Tap Water and the Factors Influencing Its Value

(1) Background: The influence of tap water fittings construction and internal pipe-work on the release of heavy metals was investigated. (2) Methods: A statistical approach was applied for the examination of the chemistry of tap water in five different cities in southern Poland. In total, 500 samples were collected (from 100 to 101 samples in each city). The sampling protocol included information on the construction of the water supply network and the physicochemical parameters of measured tap water. (3) Results: The statistical analysis allowed to extract the crucial factors that affect the concentrations of trace elements in tap water. Age of connection, age of tap, age of pipe-work as well as material of connection, material of pipe-work and material of appliance reveal the most significant variability of concentrations observed for As, Al, Cd, Cu, Fe, Mn, Pb, and Zn. Calculated cancer risks (CRs) decrease with the following order of analysed elements Ni > Cd > Cr > As = Pb and can be associated with the factors that affect the appearance of such elements in tap water. The hazard index (HI) was evaluated as negligible in 59.1% of the sampling points and low in 40.1% for adults. For children, a high risk was observed in 0.2%, medium in 9.0%, negligible in 0.4%, and low for the rest of the analysed samples.

Assessment of a batch-flow free water surface constructed wetland planted with Rhynchospora corymbosa (L.) Britton for campus greywater treatment

A pilot-scale batch-flow free water surface (FWS) constructed wetland (CW) system planted with Rhynchospora corymbosa (L.) Britton was developed with a hydraulic retention time (HRT) of 2.5 days. The average porosity of the substrate was 0.55 and calculated hydraulic loading rate (HLR) was 3.96 (g BOD/m²-day). Quantitative and qualitative characterization of the greywater were done. The concentrations of pollutants in the greywater before and after it was fed into the FWS CWs were measured using standard sampling and analyses methods. The average daily per capita water use estimated was 162 L, out of which 72.5 L was greywater. The mean removal efficiencies (RE) of the CWs were 81% COD, 85% TN, 82% TK, 10% TP, 0.2% pH, 81% TSS, Zn 91%, 81% Al, 94% Mg, and 90% Fe. It was observed that the FWS with batch-flow configuration tested in the study was slightly different in terms of results reported on the conventional continuous flow system. R. corymbosa as a macrophyte has roots that can provide a surface area for microbial growth and oxygen exchange and can be used as emergent macrophytes in phytoremediation of greywater. The result provided information on the performance and pollutant removal efficiency of a batch-operated FWS CW system planted with R. corymbosa.

Evaluation of Changes in Lead Levels in Drinking Water Due to Replacement of Water Mains: A Comprehensive Study in Chicago, Illinois

Disturbances to water treatment and distribution systems using lead service lines have been reported to increase water lead levels. This study evaluates effects from one type of physical disturbance, namely, water mains replacement. Lead concentrations at 542 homes in Chicago, Illinois were measured using partial profile sampling (1^st, 4^th, 6^th and 5^th min 1-L samples) after 6-h stagnation, both before and after mains replacement; a subset had monthly follow-up sampling for an additional 12 months. Concentrations were correlated from month-to-month and depended on household water consumption, temperature, residence age, and other factors. The sampling event maximum yielded considerably higher concentrations than first-draw samples, and 5 min flush samples had the lowest concentration at nearly all homes. Mains replacement was associated with less than a 1 μg/L increase in median and 90^th percentile concentrations; changes were smaller or not seen after controlling for other factors. Transient lead peaks were identified in a subset of residences and visits. These findings in Chicago indicate that mains replacement did not produce large changes in Pb concentrations in samples collected 1 to 12 months following the disturbance. We recommend continued outreach to promote flushing and other actions to minimize lead exposure, and routine use of profile sampling.

The first example of multi-elemental analysis of water samples from urban monumental fountains-a case study from Zagreb (Croatia)

Water fountains are usually present in the urban public places and often draw the attention of citizens and tourists. Their water is often, in various ways, used by adults and children, but water from fountains is not usually a subject of researchers' interest. This paper describes the analytical procedure and the results of the multi-elemental characterisation of the waters from the selected public water fountains in the city of Zagreb, Republic of Croatia. Twenty-eight chemical elements (Al, As, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, P, Pb, S, Sb, Se, Sr, Ti, Tl, V, Zn and Ca, K, Mg and Na) were quantified by means of ICP-AES technique. In addition to the multi-elemental analysis, determination of pH values was performed too. Pearson's correlation coefficients suggest that Al, Cu, Fe, Mn and Pb originate from the plumbing system and their leaching is strongly negatively correlated with the pH values of the tested samples. On the other hand, alkali and alkaline-earth metals as well as Mo, Ti, Zn and B, P and S are most probably of a natural origin in the water samples tested in this study. The results lead to the conclusions that (i) trace and major element content in squirt of a monumental water fountain is analogous to their content in water of the same origin and (ii) a pool of a fountain which is made of a high-quality stone, in the context of the herein performed testings, generally does not affect the quality of water which is contained in it.

Case study: Fixture water use and drinking water quality in a new residential green building

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.