Seasonal Fluctuations in Nitrate Levels Can Trigger Lead Solder Corrosion Problems in Drinking Water
Ontology highlight
ABSTRACT:
SUBMITTER: Lopez K
PROVIDER: S-EPMC9835880 | biostudies-literature | 2022 Dec
REPOSITORIES: biostudies-literature
Similar Datasets
Project description: Not available
| S-EPMC11320579 | biostudies-literature
Project description:Galvanic corrosion of lead-tin solder in copper plumbing can be a major contributor to water lead contamination. Here, we report the electrochemical reversal of the copper-solder galvanic couple, in which the normally anodic solder becomes cathodic to copper via a reaction with free chlorine. This reversal occurred after a few months of exposure to continuously circulating water with relatively low pH and low alkalinity, causing dramatically decreased lead release and the formation of a Pb(IV) scale. Chloramine did not similarly inhibit solder corrosion over the 4-9 month test duration, resulting in up to 100 times more lead contamination of the water relative to free chlorine. These findings have major implications for corrosion control and public health and can help explain anomalously low levels of lead contamination in some waters with free chlorine that are normally considered corrosive to solder.
| S-EPMC11526352 | biostudies-literature
Project description:Galvanic corrosion as a mechanism of toxic lead release into drinking water has been under scientific debate in the U.S. for over 30 years. Visual and mineralogical analysis of 28 lead pipe joints, excavated after 60+ years from eight U.S. water utilities, provided the first direct view of three distinct galvanic corrosion patterns in practice: (1) no evidence of galvanic corrosion; (2) galvanic corrosion with lead cathode; (3) galvanic corrosion with lead anode. Pattern 3 is consistent with empirical galvanic series (lead → brass → copper in order of increasing nobility) and poses the greatest risk of Pb exposure. Pattern 2 is consistent with galvanic battery reversion. The identification of copper-sulfate minerals (Pattern 2), and lead-sulfate and lead-chloride minerals (Pattern 3) in galvanic zones illustrated the migration of chloride and sulfate toward the anode. Geochemical modeling confirmed the required pH drop from the bulk water level to at least pH 3.0-4.0 (Pattern 2) and pH < 5.5 (Pattern 3) in order to form these minerals. Despite joints being over 60 years old, galvanic zones in Pattern 3 were active and possibly posed an important source of lead to drinking water. Importantly, Pattern 3 was not observed in samples from systems representing water qualities favoring PbO2 formation.
| S-EPMC6363004 | biostudies-literature
Project description:Monitoring lead in drinking water is important for public health, but seasonality in lead concentrations can bias monitoring programs if it is not understood and accounted for. Here, we describe an apparent seasonal pattern in lead release into orthophosphate-treated drinking water, identified through point-of-use sampling at sites in Halifax, Canada, with various sources of lead. Using a generalized additive model, we extracted the seasonally varying components of time series representing a suite of water quality parameters and we identified aluminum as a correlate of lead. To investigate aluminum's role in lead release, we modeled the effect of variscite (AlPO4·2H2O) precipitation on lead solubility, and we evaluated the effects of aluminum, temperature, and orthophosphate concentration on lead release from new lead coupons. At environmentally relevant aluminum and orthophosphate concentrations, variscite precipitation increased predicted lead solubility by decreasing available orthophosphate. Increasing the aluminum concentration from 20 to 500 μg L-1 increased lead release from coupons by 41% and modified the effect of orthophosphate, rendering it less effective. We attributed this to a decrease in the concentration of soluble (<0.45 μm) phosphorus with increasing aluminum and an accompanying increase in particulate lead and phosphorus (>0.45 μm).
| S-EPMC9112280 | biostudies-literature
Project description:In this study, the effects of pH, dissolved inorganic carbon (DIC), and flow on changes in surface chemistry (pH, dissolved oxygen, and free chlorine) of lead-brass joints at initial stages of corrosion were investigated using microelectrodes. Surface measurements showed that the water chemistry at the metal surfaces was highly heterogeneous. At pH 7 and during water stagnation, local pH difference between anodic (leaded-solder) and cathodic (brass) regions differed by as much as 7.5 pH units. High DIC water under the water flowing condition showed minimal pH changes on the surface, whereas in low DIC water, a pH range of 7.6-5.4 (ΔpH 2.2) was observed over the surface. Free chlorine consumption near the lead-brass surface was greater under stagnation, regardless of bulk pH. It was also found that flow can move the low pH plume that originated at the anode. Overall, this study provides direct evidence for highly localized galvanic corrosion in a chlorinated drinking water environment.
| S-EPMC7906095 | biostudies-literature
Project description:Increases in phosphate availability in drinking water distribution systems (DWDSs) from the use of phosphate-based corrosion control strategies may result in nutrient and microbial community composition shifts in the DWDS. This study assessed the year-long impacts of full-scale DWDS orthophosphate addition on both the microbial ecology and density of drinking-water-associated pathogens that infect the immunocompromised (DWPIs). Using 16S rRNA gene amplicon sequencing and droplet digital PCR, drinking water microbial community composition and DWPI density were examined. Microbial community composition analysis suggested significant compositional changes after the orthophosphate addition. Significant increases in total bacterial density were observed after orthophosphate addition, likely driven by a 2 log 10 increase in nontuberculous mycobacteria (NTM). Linear effect models confirmed the importance of phosphate addition with phosphorus concentration explaining 17% and 12% of the variance in NTM and L. pneumophila density, respectively. To elucidate the impact of phosphate on NTM aggregation, a comparison of planktonic and aggregate fractions of NTM cultures grown at varying phosphate concentrations was conducted. Aggregation assay results suggested that higher phosphate concentrations cause more disaggregation, and the interaction between phosphate and NTM is species specific. This work reveals new insight into the consequences of orthophosphate application on the DWDS microbiome and highlights the importance of proactively monitoring the DWDS for DWPIs.
| S-EPMC10702490 | biostudies-literature
Project description:BackgroundHealth issues have been associated with the consumption of high levels of nitrates in drinking water. Rural agricultural communities in Belize play a large role in the economic growth of the country. These communities obtain drinking water directly from the ground and may be susceptible to nitrate consumption and at risk of developing diseases associated with nitrates.ObjectivesThe present study examined nitrate levels in Belize's rural water supply with the aim of assessing its suitability for human and livestock consumption. The study also provides baseline data for monitoring the concentration of nitrates to prevent public health hazards in Belize.MethodsForty-three (43) water samples from reservoirs, wells, vats, and standpipes were collected from 40 villages in Belize and analyzed for nitrates using the cadmium reduction method. Nitrates were detected with an Orion® AquaMate® 8000 UV-Vis spectrophotometer at 520 nm. The Belize Coastal Zone Management Authority and Institute laboratory analyzed all water samples for nitrates.ResultsExcept for four water samples from four different sites, all analyzed water samples were found to contain nitrate levels below 10 mg/L. Nitrate levels above 10 mg/L were seen in a few samples in the northern part of the country, probably due to agricultural activities in these areas.ConclusionsBelize's rural drinking water contains low levels of nitrates, except for a few villages where the levels exceeded the acceptable limit of 10 mg/L. Higher levels of nitrates detected in a few villages need regular evaluation and monitoring to avoid public health issues as well as prevent harm to livestock.Competing interestsThe authors declare no competing financial interests.
| S-EPMC7453821 | biostudies-literature
Project description:BackgroundLow-income and minority communities often face disproportionately high pollutant exposures. The lead crisis in Flint, Michigan, has sparked concern about broader socioeconomic disparities in exposures to drinking water contaminants. Nitrate is commonly found in drinking water, especially in agricultural regions, and epidemiological evidence suggests elevated risk of cancer and birth defects at levels below U.S. EPA's drinking water standard (10 mg/L NO3-N). However, there have been no nationwide assessments of socioeconomic disparities in exposures to nitrate or other contaminants in U.S. drinking water. The goals of this study are to identify determinants of nitrate concentrations in U.S. community water systems (CWSs) and to evaluate disparities related to wealth or race/ethnicity.MethodsWe compiled nitrate data from 39,466 U.S. CWSs for 2010-2014. We used EPA's Safe Drinking Water Information System (SDWIS) to compile CWS characteristics and linked this information with both city- and county-level demographic data gathered from the U.S. Census Bureau. After applying multiple imputation methods to address censored nitrate concentration data, we conducted mixed-effects multivariable regression analyses at national and regional scales.Results5.6 million Americans are served by a CWS that had an average nitrate concentration ≥ 5 mg/L NO3-N between 2010 and 2014. Extent of agricultural land use and reliance on groundwater sources were significantly associated with nitrate. The percent of Hispanic residents served by each system was significantly associated with nitrate even after accounting for county-level cropland and livestock production, and CWSs in the top quartile of percent Hispanic residents exceeded 5 mg/L nearly three times as often as CWSs serving the lowest quartile. By contrast, the percent of residents living in poverty and percent African American residents were both inversely associated with nitrate.ConclusionsEpidemiological evidence for health effects associated with drinking water above 5 mg/L NO3-N raises concerns about increased risk for the 5.6 million Americans served by public water supplies with average nitrate concentrations above this level. The associations we observed between nitrate concentrations and proportions of Hispanic residents support the need for improved efforts to assist vulnerable communities in addressing contamination and protecting source waters. Future studies can extend our methods to evaluate disparities in exposures to other contaminants and links to health effects.
| S-EPMC6335696 | biostudies-literature
Project description:Drinking water maximum contaminant levels (MCL) are established by the U.S. EPA to protect human health. Since 1975, U.S. public water suppliers have reported MCL violations to the national Safe Drinking Water Information System (SDWIS). This study assessed temporal and geographic trends for violations of the 10 mg nitrate-N L-1 MCL in the conterminous U.S. We found that the proportion of systems in violation for nitrate significantly increased from 0.28% to 0.42% of all systems between 1994 and 2009 and then decreased to 0.32% by 2016. The number of people served by systems in violation decreased from 1.5 million in 1997 to 200 000 in 2014. Periodic spikes in people served were often driven by just one large system in violation. On average, Nebraska and Delaware had the greatest proportion of systems in violation (2.7% and 2.4%, respectively), while Ohio and California had the greatest average annual number of people served by systems in violation (278 374 and 139 149 people, respectively). Even though surface water systems that serve more people have been improving over time, groundwater systems in violation and average duration of violations are increasing, indicating persistent nitrate problems in drinking water.
| S-EPMC5764095 | biostudies-literature
Project description:Following an exceedance of the lead action level for drinking water in 2016, the Pittsburgh Water and Sewer Authority (PWSA) undertook two sampling programs: the required biannual Lead and Copper Rule (LCR) compliance testing and a home sampling program based on customer requests. The LCR sampling results, at locations expected to be elevated when corrosion is not well controlled, had higher concentrations than customer-requested homes, with 90th percentile values for the LCR sites exceeding the action level through 2019 (except for June 2018). Customer-requested concentrations showed greater variability, with the median lead concentration for customer-requested samples below detection for each year of sampling, suggesting only some homes show elevated lead when corrosion control is not fully effective. Corrosion control adjustments brought the utility back into compliance in 2020 (LCR 90th percentile of 5.1 ppb in June 2020); customer-requested sampling after the addition of orthophosphate indicated below detection levels for 59% of samples. Monte Carlo simulations indicate LCR samples do not all represent high lead risk sites, and the application of corrosion control more significantly affects higher lead concentration sites. Broader water quality sampling provides information about specific homes but is not well suited to assessing the efficacy of corrosion control efforts by utilities.
| S-EPMC9835881 | biostudies-literature