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WATER QUALITY IN THE COPPER PIPE STUDY

WATER QUALITY IN THE COPPER PIPE STUDY

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Field data from various copper monitoring studies and Lead and Copper Rule compliance data are often inappropriate and misleading for reliably determining fundamental chemical relationships behind copper corrosion control. A comprehensive solubility model for copper in drinking water has been developed, that is consistent with available data for co...

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... the several experiments conducted thus far, one is particularly relevant to the issues of this investigation, and will be covered here. The water quality summary for this experiment is summa- rized in Table 8. ...
Context 2
... most directly-applicable data collected thus far for establishing verification of modeled pH/DIC effects were generated from the USEPA recirculation solubility experiments described above. A background water quality data summary for the experiments with DIC=5 mg C/L at pH 7, 8 and 9 is given in Table 8. Figures 21a-21c show the saturation indices for malachite, tenorite and cupric hydroxide versus time. ...

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... The average copper content of recent Icelandic basaltic lava is low, in the range of 10-200 ppm (μg/g) (Eason & Sinton, 2009;Gibson et al., 1982), with occasional higher values found in older Miocene volcaniclastic rocks . Similarly, the copper content of Icelandic groundwater is also low, ranging from 0.00015 to 0.00209 ppm (Gunnarsdottir et al., 2015) where the Cu(II) ion is the more common oxidation state (Schock et al., 1995). However, copper is a semi-volatile element that can partition into a volatile-rich fluid that can physically separate from magma (Candela & Holland, 1984). ...
... While Figure 8 and 10 show a single copper phase, Figure 9 boasts a more complex precipitate, with discrete layers of copper silicates, copper phosphates, manganese oxides, and carbonate-bearing species. The copper phases present are expected to be mostly in the Cu(II) oxidation state, as this is the ion more readily available in the groundwater (Schock et al., 1995), and because of the prominent blue color (Cu(I) minerals are generally red/brown). ...
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Lava tubes on Mars hold exciting potential for the preservation of biosignatures, which may survive on geological timescales in these isolated, stable environments. To support the development of future astrobiological mission concepts, we turn to terrestrial lava tubes, host to a variety of microbial communities and secondary minerals. Following a multidisciplinary sampling protocol, we retrieved biological, molecular, and mineralogical data from several lava tubes in Iceland. We report on blue‐colored copper‐rich secondary minerals and their associated bacterial communities using a multi‐method approach, and an amalgam of 16S rRNA gene sequencing, Raman spectroscopy, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy data sets. We found numerous bacterial genera known for their high metal resistance and ability to survive in low‐nutrient environments. Both are characteristics to be expected for any potential life in Martian lava tubes, and should be considered when checking for contaminants in Mars mission preparations. Associated with the microbial mats, we identified several types of copper‐rich secondary minerals, indicating localized copper enrichments in the groundwater, possibly stemming from overlying ash deposits and nearby hyaloclastite formations. Molecular analysis revealed carotenoid signals preserved within the copper speleothems. If found in Martian lava tubes, blue copper‐rich mineral precipitates would be deserving of astrobiological investigation, as they have potential to preserve biosignatures and harbor life.
... In oxic and disinfected drinking waters, Cu 2+ [Cu(II)] mineralogy and chemistry largely controls copper release into the water (Ferguson et al., 1996;MWH, 2005). The relationship between Cu(II) solubility in tap water and important water quality parameters such as pH and dissolved inorganic carbon (DIC) are well established (Ferguson et al., 1996;Schock et al., 1995aSchock et al., , 1995b. For example, Cu(II) solubility decreases with increasing pH, and DIC complexes in new plumbing (i.e., cupric hydroxide assumed to control copper solubility) have been found to dominate copper speciation above pH 6.5, resulting in increased Cu(II) solubility with increasing DIC (Schock et al., 1995a;Figure 1a). ...
... The relationship between Cu(II) solubility in tap water and important water quality parameters such as pH and dissolved inorganic carbon (DIC) are well established (Ferguson et al., 1996;Schock et al., 1995aSchock et al., , 1995b. For example, Cu(II) solubility decreases with increasing pH, and DIC complexes in new plumbing (i.e., cupric hydroxide assumed to control copper solubility) have been found to dominate copper speciation above pH 6.5, resulting in increased Cu(II) solubility with increasing DIC (Schock et al., 1995a;Figure 1a). Temperature also has an important role in copper solubility and water quality (Boulay & Edwards, 2001;Rushing & Edwards, 2004). ...
... The prediction of copper levels in tap water is complicated by the reported aging phenomena of copper minerals. Over time (years to decades), scale and its mineralogy changes which can result in decreased Cu(II) solubility Lagos et al., 2001;Schock et al., 1995a;Turek et al., 2011). The cupric hydroxide model provides a conceptual understanding of copper solubility changes as Cu(II) solids age in water (Schock et al., 1995a). ...
Article
The study goal was to better understand the risks of elevated copper levels at US schools and childcare centers. Copper health effects, chemistry, occurrence, and remediation actions were reviewed. Of the more than 98,000 schools and 500,000 childcare centers, only 0.2% had copper water testing data in the federal Safe Drinking Water Information System database. Of the facilities designated public water systems, about 13% had reported an exceedance. Schools that were not designated a public water system (PWS) also had exceedances. Few studies document levels in schools and childcare centers. Widely different sampling and remedial actions were reported. Flushing contaminated water was the most evaluated remedial action but was unreliable because copper quickly rebounded when flushing stopped. Building water treatment systems have been used, but some were not capable of making the water safe. The health risk was difficult to determine due to the limited occurrence data and lack of best management practice studies. A national drinking water testing campaign and field studies are recommended.
... Despite that, the chemical precipitation could depress the urease activity by strongly alkaline pH of surrounding conditions, degrading the degree of urea hydrolysis (Mobley and Hausinger, 1989;Schock et al., 1995;Ferris et al., 2004;Hu et al., 2021c) (see Figure 2D). On the other hand, NH 4 + concentration under any of the calcium sources always approaches 0 for Cu remediation (see Figure 2A). ...
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Heavy metal contamination can not only cause threats to human health but also raise sustainable development concerns. The use of traditional methods to remediate heavy metal contamination is, however, time-consuming, and the remediation efficiency may not meet the requirements as expected. The present study conducted a series of test tube experiments to investigate the effect of calcium source on the lead and copper removals. In addition to the test tube experiments, numerical simulations were performed using the Visual MINTEQ software package considering different degrees of urea hydrolysis derived from the experiments. The remediation efficiency degrades when NH4+ and OH- concentrations are not sufficient to precipitate the majority of Pb2+ and Cu2+. It also degrades when CaO turns pH into highly alkaline conditions. The numerical simulations do not take the dissolution of precipitation into account, and therefore, overestimate the remediation efficiency when subjected to lower Pb(NO3)2 or Cu(NO3)2 concentrations. The findings highlight the potential of applying the enzyme-induced carbonate precipitation to lead and copper remediations.
... The average copper content of recent Icelandic basaltic lava is low, in the range of 10-200 ppm (g/g) (Eason & Sinton, 2009;Gibson et al., 1982), with occasional higher values found in older Miocene volcaniclastic rocks . Similarly, the copper content of Icelandic groundwater is also low, ranging from 0.00015 to 0.00209 ppm (Gunnarsdottir et al., 2015) where the Cu(II) ion is the more common oxidation state (Schock et al., 1995). However, copper is a semi-volatile element that can partition into a volatile-rich fluid that can physically separate from magma (Candela & Holland, 1984). ...
... While Figure 8 and 10 show a single copper phase, Figure 9 boasts a more complex precipitate, with discrete layers of copper silicates, copper phosphates, manganese oxides, and carbonate-bearing species. The copper phases present are expected to be mostly in the Cu(II) oxidation state, as this is the ion more readily available in the groundwater (Schock et al., 1995), and because of the prominent blue color (Cu(I) minerals are generally red/brown). ...
... Phosphates are often added to drinking water supplies to minimise the corrosion of piping materials [21,28,47]. Increased water age influences the effectiveness of such corrosion control inhibitors by the provision of poorly buffered waters, which challenges pH management [48,49]. ...
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This review critically analyses the chemical and physical parameters that influence the occurrence of opportunistic pathogens in the drinking water distribution system, specifically in premise plumbing. A comprehensive literature review reveals significant impacts of water age, disinfectant residual (type and concentration), temperature, pH, and pipe materials. Evidence suggests that there is substantial interplay between these parameters; however, the dynamics of such relationships is yet to be elucidated. There is a correlation between premise plumbing system characteristics, including those featuring water and energy conservation measures, and increased water quality issues and public health concerns. Other interconnected issues exacerbated by high water age, such as disinfectant decay and reduced corrosion control efficiency, deserve closer attention. Some common features and trends in the occurrence of opportunistic pathogens have been identified through a thorough analysis of the available literature. It is proposed that the efforts to reduce or eliminate their incidence might best focus on these common features.
... In practical applications, only total and, in some instances (e.g., with high NOM), soluble Cu can be misleading in terms of quantifying biocidal action because water chemistry can strongly influence Cu solubility via precipitation and complexation. 21,36,37 Estimating the Chick−Watson model disinfectant coefficient from Lin et al.'s work, using soluble copper measured in their experiment, yielded 3.53 × 10 −4 L μg −1 min −1 , and this is approximately 100 times higher than that estimated herein, resulting in much faster Cu-induced L. pneumophila disinfection rates. Some key differences in experimental conditions likely contribute to this difference, including strains used 26 and life stage, as demonstrated herein. ...
... Out of 33 surveyed utilities, 11 had data on phosphate, pH, and alkalinity available to predict Cu 2+ levels in both 1990 and 2018 using MINEQL+ software with the assumption that all 90th percentile copper was soluble. 37,38 Overall, results from 1990 indicated a range of predicted Cu 2+ , from 0 to 293 μg/L, with a median level of 11 μg/L (Figure 7). The 2018 results indicated a range of Cu 2+ from 0 to 54 μg/L and a median level of 1 μg/L. ...
Article
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Copper (Cu) is a promising antimicrobial for premise plumbing, where ions can be dosed directly via copper silver ionization or released naturally via corrosion of Cu pipes, but Cu sometimes inhibits and other times stimulates Legionella growth. Our overarching hypothesis was that water chemistry and growth phase control the net effect of Cu on Legionella. The combined effects of pH, phosphate concentration, and natural organic matter (NOM) were comprehensively examined over a range of conditions relevant to drinking water in bench-scale pure culture experiments, illuminating the effects of Cu speciation and precipitation. It was found that cupric ions (Cu²⁺) were drastically reduced at pH > 7.0 or in the presence of ligand-forming phosphates or NOM. Further, exponential phase L. pneumophila were 2.5× more susceptible to Cu toxicity relative to early stationary phase cultures. While Cu²⁺ ion was the most effective biocidal form of Cu, other inorganic ligands also had some biocidal impacts. A comparison of 33 large drinking water utilities’ field-data from 1990 and 2018 showed that Cu²⁺ levels likely decreased more dramatically (>10×) than did the total or soluble Cu (2×) over recent decades. The overall findings aid in improving the efficacy of Cu as an actively dosed or passively released antimicrobial against L. pneumophila.
... Alkalinity can interact with pH and/or CSMR to influence the solubility of corrosion products and the extent of lead and copper release. 12,19,21 Natural Organic Matter. TOC and DOC are bulk measures of the quantity of organics in water, while UV254 provides semiquantitative measures of aromatic NOM. ...
... The combination of high NOM, low pH, and low to moderate alkalinity indicate that the water in these buildings, and throughout the drinking water system, is likely to be corrosive. 12,13,18,19,23 Implications of Findings on Lead and Copper Release and Transport. Taken as a whole, the results of this study indicate that the characteristics of the water supplied to buildings in Pond Inlet is conducive to the corrosion of premise plumbing components, copper and lead release, and metal transport to the tap. ...
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Access to clean and safe drinking water is a perpetual concern in Arctic communities due to challenging climatic conditions, limited options for the transportation of equipment and process chemicals, and the ongoing effects of colonialism. Water samples were gathered from multiple locations in a decentralized trucked drinking water system in Nunavut, Canada, over the course of one year. The results indicate that point of use drinking water quality was impacted by conditions in the source water and in individual buildings and strongly suggest that lead and copper measured at the tap were related to corrosion of onsite premises plumbing components. Humic-like substances were the dominant organic fraction in all samples, as determined by regional integration of fluorescence data. Iron and manganese levels in the source water and throughout the water system were higher in the winter and lower in the summer months. Elevated concentrations of copper (>2000 µg L-1) and lead (>5 µg L-1) were detected in tap water from some buildings. Field flow fractionation coupled with an ICP-MS and a UV-Vis spectrometer was used to demonstrate the link between source water characteristics (high organics, iron, manganese) and lead and copper in point of use drinking water. This paper is now open access and can be accessed at: https://pubs.acs.org/doi/abs/10.1021/acs.est.9b04691
... This is probably because predicted copper solubility is approximately 10 mg L −1 at pH 7 and 12 mg L −1 of dissolved inorganic carbon. 62 That is, most of the copper is predicted to occur as truly soluble species and would have passed through the membrane during focusing. A previous study found that 98% of manganese present in the 0.45 μm filtrate of dam water Table 1 Average detection limits, expressed as instantaneous concentrations (i.e., minimum fractogram peak heights in μg L −1 , except for NOM, which is reported as mg C L −1 ), and percent recoveries by element (ratio of total integrated signal with and without a cross-flow). ...
Article
Exposure to lead, copper, and manganese via drinking water is a public health concern. Modeling can account for solubility due to simple inorganic ligands but generally falls short in capturing the effects of natural organic matter, particles, and colloids; environmental data are needed to understand the importance of these species. Here, we demonstrate the use of asymmetric flow field flow fractionation with UV and ICP-MS detection to separate drinking water samples into ionic species, colloids, and metal-organic complexes. Colloidal iron appeared to be more important as a transport vector for lead, copper, and manganese than natural organic matter: estimated colloidal metals concentrations (Pb, Cu, Fe, Mn >1000 kDa) were at least 3 times greater than concentrations of these metals associated with the high apparent molecular weight (~1 kDa) organic signal. In transmission electron micrographs, two distinct populations of relatively dense colloids in the size range 50 - 200 nm were apparent, with morphologies typical of environmental iron oxides. Moreover, energy dispersive spectroscopy showed that sample colloids were rich in iron, copper, and oxygen. At equilibrium (e.g., during long stagnation periods in plumbing), high molecular weight organic and colloidal fractions represent additional capacity for drinking water to transport lead, which could have implications for water treatment to limit lead exposure.
... Following PLSLR simulation and after 16 h stagnation, copper concentrations decreased from week 20e155, after simulation of partial LSL replacements, for both PLSLR configurations and for all water qualities (Fig. 1). The formation of a passivating film is ex- pected after the installation of Cu pipes in a distribution system with the highest solubility associated with new un-passivated pipes ( Lagos et al., 2001;Schock et al., 1995;Turek et al., 2011). Copper concentrations in water are determined by the scales, and their solubility, formed at the interface between the pipe and the water ( Schock and Lytle, 2011). ...
... With the exception of the smaller diameter pipe in the Cu-Pb configuration in the first 104 weeks, 90 th percentile Cu concen- trations remained well below 2,000 mg Cu/L after 16HS, which is the new health-based maximum acceptable concentration (MAC) proposed by Health Canada (2018) The modest increase of pH from 7.9 to 8.3 decreased median Cu concentrations by 42e44% in both PLSLR configurations, in agree- ment with the low solubility of CuO ( Schock et al., 1995), one of the minerals detected. A similar decrease in copper concentrations, associated to an increase in pH (pH 7.15 to 7.8, alk. ...
... 200 mg CaCO 3 /L), was observed at bench scale in new copper pipes ) and in copper coupons in contact with synthetic water (Pehkonen et al., 2002). The addition of sulfate to decrease the CSMR from 0.9 to 0.3 did not influence Cu release in agreement with findings from Schock et al. (1995) stating that sulfate com- plexes are not likely to be significant for cuprosolvency. However, in copper pipes connected to Pb pipes at bench scale, Kogo et al. (2017) related an increase in CSMR to an increase in copper con- centrations after 30 min and 6 h of stagnation. ...
Article
Partial lead service line replacement (PLSLR) results in the addition of a new galvanic connection and can increase lead concentrations at the tap. Focus has been given to minimizing lead release after PLSLR, but little information is available on the impact of lead remedial actions on copper concentrations, especially before passivation occurs. The impact of water quality (decreased chloride-to-sulfate mass ratio from 0.9 to 0.3; addition of orthoP; pH increase to 8.3) on lead and copper concentrations was investigated after stagnation (30 min–336 h) in a pipe rig comparing full lead service line (LSL), and two configurations of partial LSLs (Cu-Pb and Pb-Cu). Results show different trends for lead and copper: maximum lead concentrations were reached in 16 h while copper concentrations continued to increase over 336 h. Lead release rates were also the highest in the first 16 h of stagnation and were strongly impacted by water quality and the configuration of PLSLR (Cu-Pb vs Pb-Cu). Increasing the sampling flow rate from 5 to 15 LPM drastically increased the particulate lead release (78-fold) in Pb-Cu configurations; this effect was however not observed in 100% Pb or Cu-Pb configurations. High velocity flushing prior to 16 h stagnation decreased total Pb release by a factor of 12-fold for Cu-Pb, 1.6-fold for Pb-Cu and 2.0-fold for 100% Pb. Results support the definition of sampling protocols targeted for the detection of lead and copper sources and the proscription of flushing prior to sampling.
... Hence, the leaching experiments were performed in three different ammoniacal medium (viz., chloride, carbonate, and sulfate) while maintaining a total ammonia concentration of 5.0 M, and a solution-to-salt concentration ratio of 4:1. The results presented in Fig. 4a and b (Schock, 1999;Schock et al., 1995). The figures also imply that leaching of both metals in the CO 3 2À medium could reach above 99% within 180 min, which was only <60% and 80% for Cu, and, <40% and <80% for Ni when using Cl À and SO 4 2À salt, respectively. ...
Article
The ammoniacal leaching of surface-coated metals from automobile-discarded ABS plastics followed by their recovery through solvent extraction has been investigated. The leaching of ABS (typically containing 4.1% Cu, 1.3% Ni, and 0.03% Cr) could efficiently dissolve the ammine complexes of Cu and Ni, leaving Cr unleached as fine particles. The optimization studies for achieving the maximum efficiency revealed that the leaching of metal ions in different ammoniacal solutions follows the order CO3²⁻ > Cl⁻ > SO4²⁻. The leaching carried out in a carbonate medium by maintaining the total NH3 concentration 5.0 M at a NH4OH/(NH4)2CO3 ratio of 4:1, pulp density of 200 g/L, agitation speed of 400 rpm, temperature of 20 °C, and time of 120 min yielded the optimum efficiency of >99% Cu and Ni (i.e., 8.14 g/L and 2.57 g/L, respectively, in the leach liquor). Subsequently, the solvent extraction of metals from ammoniacal leach liquor as a function of extractant (LIX 84-I) concentration and organic-to-aqueous (O:A) phase ratio was examined. Based on the extraction data, a three-stage counter-current extraction at O:A = 1:1 was validated using 0.8 M LIX 84-I, yielding the quantitative extraction of both metals into the organic phase. Thereafter, the stripping of metals in acid solutions indicated that 0.5 M H2SO4 could quantitatively strip Ni from the loaded organic phase; however, ∼27% Cu was also co-stripped. The rest of Cu from the Ni-depleted organic phase was separately stripped with 1.0 M H2SO4 that can be directly sent to the electrowinning process. On the other hand, the co-stripped metals from the acidic solution can be easily separated, again using LIX 84-I as the extractant, by adopting the pH-swing method. Finally, a process has been proposed for the hydrometallurgical recovery of surface-coated metals from waste ABS plastics; that does not affect the physicochemical characteristics of the polymer substances for their reuse.