Short- and Long-Term Lead Release after Partial Lead Service Line

Article pubs.acs.org/est

Short- and Long-Term Lead Release after Partial Lead Service Line Replacements in a Metropolitan Water Distribution System Elise Deshommes,* Laurent Laroche,† Dominique Deveau,‡ Shokoufeh Nour,§ and Michèle Prévost§ †

City of Montreal, Technical Expertise Division, 8585 boulevard de la Vérendrye, H8N 2K2, Montréal, Quebec, Canada City of Montreal, Water infrastructure Department Direction, 1555 Carrie-Derick, H3C 6W2, Montréal, Quebec, Canada § NSERC Industrial Chair on Drinking Water, Polytechnique Montreal, 2900 boulevard Edouard Montpetit, H3T 1J4, Montréal, Quebec, Canada ‡

S Supporting Information *

ABSTRACT: Thirty-three households were monitored in a fullscale water distribution system, to investigate the impact of recent (5 days.28 The volume of digestion was recorded. Duplicate aliquots were then collected and diluted (0.5% HNO3) for further ICP/MS analysis.36 The mean particulate concentration released by the LSL over the period of filtration was calculated as follows: mean concentrationμgmetal/L =

mass of metal in the POE filterμgmetal volume of filtered water during filter useL

Sampling on the Day of PLSLR. Eight households were monitored before and after LSLR (Table 1) using different LSLR techniques (SI Table S4). For four households, tap water was collected immediately after reconnection to the main, including one household with POE filtration. For the remaining households, sampling could not be performed, although one of them had POE filtration capturing lead release during PLSLR. Sampling method consisted of collecting first-draw consecutive samples and fully flushed samples at the outside tap (when possible) to avoid particle accumulation in the premise plumbing, then from the kitchen tap, as soon as possible after reconnection of the service line to the water main (SI Table S5).

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RESULTS AND DISCUSSION System-Wide Analysis of total WLLs. Figure 1 presents the total WLLs measured after (a) 6HS (profile), (b) 30MS (2L), and (c) 5MF (2L) as a function of the service line configuration and PLSLR age. The data are distributed equally among the seasons. All samples from 6HS profiles were considered in order to reflect the variability of WLLs at the tap. Also, worst-case wartime homes with long LSLs in the system studied are included in all categories of LSL configurations.36,37 As expected, WLLs were the highest in 6HS profile samples, with median values of 14−37 μg/L in households with LSL. Median concentrations were lower after 30MS (8−18 μg/L), and still lower after 5MF (3−8 μg/L). WLLs were significantly lower in households with PLSLRs as compared to no replacements, especially for PLSLRs > 2 yrs. Indeed, the 90th percentile varied from 17 μg/L after 5MF to 70 μg/L after 6HS in recent PLSLR, as compared to 6.5 to 50 μg/L in old PLSLRs. These differences were significant (Kruskal−Wallis test, p < 0.05) although the effect was more pronounced for 6HS samples (p < 0.001). Moreover, 30MS and 5MF 2L samples were not significantly different in households with recent PLSLR as compared to no replacement (p > 0.05), which is consistent with first- and second-draw concentrations in Halifax.31 After 6HS and 5MF, WLLs were significantly lower in old Cu−Pb configuration households (median of 3−

Figure 1. Total lead concentrations (μg/L) measured after (a) 6HS (profile, all samples), (b) 30MS (2L), and (c) 5MF (2L), and length of lead pipes (m) in 26 households with different service line configurations. Notes box plots: 10th-90th percentile, vertical bars: min-max, crosses: raw data, horizontal bars, dash line: median values; data distributed between summer (n = 320), winter (n = 310), and fall/spring (n = 311); Kruskal-Wallis test comparing full LSLs to the other configurations significant at † p < 0.05, ‡ p < 0.001

14 μg/L) than in old Pb−Cu configurations (median of 6−22 μg/L) (p < 0.001). This effect can be partly explained by differences between the households, because high 5MF levels typical of more problematic households37 were measured for C

DOI: 10.1021/acs.est.7b01720 Environ. Sci. Technol. XXXX, XXX, XXX−XXX

Article

Environmental Science & Technology

the type of sampling bottles.37,39 Furthermore, repeat sampling increases the probability of capturing sporadic particulate lead release at the tap.40 Results do not however indicate a higher particulate lead release in PLSLRs. Indeed, erratic particulate lead spikes were measured for all configurations of LSLs, with maximum values reaching 52, 66, and 152 μg/L in homes with full LSLs, recent and old PLSLRs, respectively. Particulate WLLs were also significantly lower in households with older PLSLR as compared to full LSLs (Kruskal−Wallis, p < 0.01) and decreased even more after full LSLR (≤2.6 μg/L). The distribution of the mean particulate concentrations estimated for the period of filtration was computed using total water usage and expressed as equivalent concentrations that can be compared to WLLs from repeat sampling. The POE filtration results show trends similar to those of the repeat sampling results. Indeed, concentrations are comparable between homes with full LSL and with recent PLSLR, and decrease slightly with old PLSLR configurations (not statistically significant, p > 0.05) (Figure 2). POE filtration was implemented to capture sporadic release of leaded particles otherwise missed by repeat sampling. However, mean POE concentrations (0.32−0.72 μg/L) were lower by a factor of 2−3 times than those of 6HS and 30MS sampling, and were more comparable to 5MF concentrations. Moreover, particulate WLLs measured from repeat sampling varied more than 4 orders of magnitude, especially after extended stagnation. Although informative, averaging out the particulate lead retained in the POE devices does not indicate the extent of the peak particulate levels that may have been released. Indeed, with this method of monitoring, peak WLLs are averaged with lower particulate levels occurring with various usage patterns (flushing, stagnation) over the period of usage in the house. In addition, POE filters do not capture lead particles released from premise plumbing as compared to sampling after stagnation. In this system, solders and brass fixtures have been shown to contribute to particulate WLLs in households with full and partial LSLs.36 These factors explain the higher WLLs measured through repeat sampling as compared to POE filtration. The low means estimated from POE suggest that the occurrence of particulate lead spikes released from the LSLs was low in this study. Nonetheless, POE-estimated concentrations are surprisingly slightly lower than 5MF levels. This cannot be explained by the factors cited above as 5MF sampling does not reflect water quality from premise plumbing or typical consumption patterns. Therefore, POE monitoring would underestimate particulate WLLs. This would be attributed to the 1-μm filters which are not able to capture smaller carbonate scale particles (2 yrs). Although presenting some scatter, WLLs after 5MF and 6HS remained overall correlated to the length of the LSL, in agreement with previous reports37 (SI Figure S1). Notwithstanding the overall decrease of WLLs after PLSLR, the fraction of samples exceeding the 10 μg/L WHO reference level remained high, varying from 17% (5MF) to 78% (6HS profile). For comparison, these fractions varied from 38% to 89% in households with full LSL, while only 6% of all samples collected after FLSLR exceeded 10 μg/L (Figure 1). System-Wide Analysis of Particulate WLLs. The increase in particulate lead release for an indefinite period of time has been identified as the major concern with PLSLR.10,11 Figure 2 presents the particulate WLLs measured through

Figure 2. Particulate lead concentrations as a function of the monitoring procedure in 33 households (repeat sampling, POE filtration), for different service line configurations. Notesbox plots: 10th-90th percentile, bars: median values, crosses: raw data; PLSLR include Pb-Cu and Cu-Pb configurations; 6HS WLLs include all samples from profile; POE data collected during PLSLR period excluded.

repeat sampling at the tap (6HS, 30MS, 5MF) and POE filtration for different service line configurations. Particulate WLLs varied with sampling protocol and increased in 6HS profile samples. Indeed, the 90th percentile varied from 8.0 to 14 μg/L after 6HS depending on the LSL configuration, as compared to 1.8−11 μg/L after 30MS and 1.5−5.1 μg/L after 5MF (Figure 2). In this study, the 30MS and 5MF concentrations exceed those from previous sampling (2006− 2007) after 30MS, 5MF, or random daytime in the same system in which 90th percentile varied from 0.56 to 4.9 μg/L depending on the sampling protocol (maximum of 12 μg/ L).36 Such variations may be partly attributable to differences in the households studied, the volume of samples collected and D


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Figure 3. Concentrations of total lead (Pbtotal) and particulate lead (Pbpart) in tap water profiles after 6 h of stagnation (all samples), absolute (μg/L; left axis) or relative to the lead pipe length (μg/L/m; right axis), before and after replacement of the public side of the LSL. Notes*mean (minmax); † mean ± stdev; monitoring before and after PLSLR over 20 months (#61, #63, #64); monitoring >2 years after PLSLR in neighboring “twin” household #60 (time 0 set at 1135 days); mean ± stdev of water temperature of 11 ± 7.8 °C before PLSLR, and 9.6 ± 8.0 °C after PLSLR.

this system.43 As expected, the correlation increases in the 6HS profile samples with long stagnation time, the conditions which are favorable to sorption and better reflect water quality from the LSL. Scale detachment could induce various phenomena including (1) simultaneous release of iron scales in the main and lead scales in the LSL; (2) detachment of lead-rich iron scales present in the LSL;42,44,45 (3) generation of lead−iron particles by the friction of iron particles released by the main onto LSL scales. Site-Specific Analysis of PLSLRs. Considering that WLLs vary with household configuration,37 total and particulate WLLs in the households sampled before and after replacement of the public side of the LSL for copper were investigated in detail. Seasonal impact was not considered since for these households, the water temperature for the periods before (11 ± 7.8 °C) and after (9.8 ± 8.0 °C) PLSLR was similar. As observed in Figure 3, following a short-term increase of approximately 2 weeks (mean ± stdev of 77 ± 44 μg/L, as compared to 61 ± 27 μg/L before PLSLR), the total WLLs after 6HS (profile, all samples) decreased slightly over 18 months after PLSLR (48 ± 31 μg/ L). The total lead release was much lower in the old PLSLR (18 ± 11 μg/L). Although WLLs remained high, they were significantly higher before than after PLSLR (Kruskal−Wallis, p < 0.001). When adjusting for the length of LSL, WLLs after PLSLR were not statistically different than before PLSLR, considering whether or not old PLSLR was in the comparison (p > 0.34). The same trend was observed for particulate WLLs (Figure 3). However, sporadic particulate lead spikes were more frequent after PLSLR, with concentrations of 51, 34, and 66 μg/L measured 5, 194, and 234 days after PLSLR, as compared to only one sample before PLSLR (42 μg/L). For comparison, in the households monitored before and after PLSLR with filtration, mean POE-estimated particulate WLLs remained stable (excluding the PLSLR period). Concentrations varied from 0.93 ± 0.52 μg/L to 1.19 ± 0.31 μg/L before and after PLSLR for household #36; and from 0.33 ± 0.46 μg/L to 0.34 ± 0.16 μg/L for household #62. Considering that half of the LSL was removed for both households, the LSL contribution to particulate WLLs doubled over one year after PLSLR. Such observations are consistent with the transient

increase and limited reduction of WLLs up to one year following PLSLR in other full-scale studies.29−31 In this study, the older PLSLR investigated were however associated with lower WLLs at the tap. The total and particulate lead masses released from the LSL were calculated for each household monitored before and after full or partial LSLR, using the 6HS profiles (Table 2). In this analysis, all PLSLR configurations (Cu−Pb and Pb−Cu) and neighboring households with old PLSLR were included. The mass of lead released per meter of LSL (relative) was calculated to evaluate the extent of galvanic corrosion. Although it may appear appealing to consider only the samples directly for the LSL section, as for previous analysis the complete profile was considered including peak WLLs from the LSL since it provides a better indication of the variability of exposure. Identifying peak concentrations from LSLs in field investigations adds also uncertainty considering plumbing volume evaluations, mixing considerations, 2L sampling bottles volumes (dilution), and other factors.37 Obviously, fewer samples contain water from the LSL after PLSLR. Therefore, if the mass balances are comparable before and after LSLR, this would indicate that a higher amount of lead is released from the service line configuration with the smallest length of lead pipe. As observed in Table 2, the total lead mass released by the LSL decreased slightly but not significantly in recent PLSLRs (10th−90th percentile of 121−476 μg, as compared to 139−606 μg before PLSLR), while the particulate lead mass was slightly higher (9.7−125 μg, as compared to 4.8−93 μg before PLSLR). Conversely, old PLSLRs and recent FLSLRs presented significantly lower total and particulate lead mass release as compared to before replacement work. After adjusting the mass balance relative to the LSL length before and after PLSLR, only one significant difference persists (Table 2). Such results can be partly explained by the contribution of galvanic corrosion, because lead release increases at copper−lead junctions and is no longer proportional to the LSL length.10,15,18 Short-Term Acute Release After PLSLR. Dissolved and particulate WLLs measured in the samples collected immediately after PLSLR are presented in Figure 4. Extreme WLLs were measured with particulate lead as the dominant form E


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Environmental Science & Technology Table 2. Total and Particulate Lead Mass Balance (6HS Profiles), Absolute or Relative to the Length of LSL for Households Monitored before/After PLSLR and/or FLSLRa Total Pb mass  μg: Median 10th-90th 392 139−606 283 121−476 135 82−223 45 24−102 Particulate Pb mass  μg:

Max 667 701 243 102

K−W test p = 0.09e p < 0.001e p < 0.001e

Max N Median 10th-90th Before PLSLRb 26 30 4.8−93 116 Recent PLSLRb 28 29 9.7−125 156 Old PLSLRc 20 11 5.4−35 64 Recent FLSLRd 6 7.1 1.4−13 13 Total Pb mass per meter of LSLg  μg/m:

K−W test p = 0.48f p < 0.01e p < 0.01e

Before PLSLRb Recent PLSLRb Old PLSLRc Recent FLSLRd

N 26 28 20 6

Max K−W test N Median 10th-90th Before PLSLRb 25 15 5.0−21 35 Recent PLSLRb 27 14 6.7−37 69 p = 0.42f Old PLSLRc 20 7.7 4.5−14 15 p < 0.01e Recent FLSLRd n/a n/a n/a Particulate Pb mass per meter of LSLg  μg/m: b

Before PLSLR Recent PLSLRb Old PLSLRc Recent FLSLRd

N 25 27 20 -

Median 1.4 1.7 0.62 n/a

10th-90th 0.17−3.4 0.44−6.3 0.30−2.1 n/a

Max 4.0 8.6 4.1 n/a

K−W test p = 0.11f p = 0.26e -

a

Significant differences are indicated in bold (p < 0.05). bHouseholds #61, #63, #64, #82 and #50. cHouseholds #60 (Cu−Pb) and #65 (Pb−Cu) of similar configuration as #61, #63, #64 (neighboring households). dHouseholds #65 and #50. eLead mass before PLSLR > after PLSLR. fLead mass after PLSLR > before PLSLR. gAdjusted according to Table S7 in SI; K−W−Kruskal−Wallis test (comparison to values measured before PLSLR).

Figure 4. Dissolved and particulate lead concentrations in μg/L measured in tap water samples collected the day of PLSLR in four households. NotesPLSLR and reconnection to the water main on the same day for all households; POE filtration in function while collecting the samples at the outside and kitchen tap in household #36

The masses of lead, copper, iron, and zinc in the samples collected on the day of PLSLR, and in POE filters over the PLSLR period, are presented in Table 3. For comparison, the masses of main metals in collected 6HS samples or POE filters, before and after PLSLR, are indicated. Particulate metals increased significantly at the time of PLSLR, especially for household #61 (no preflush) and POE-monitored households. Indeed, the mean lead mass increased by a factor of 297 as compared to 6HS samples before PLSLR, and by a factor of 42−46 for POE monitoring. Iron release increased also by a factor of 5−347 depending on the households, whereas the effect was less pronounced for copper and zinc. The mass of accumulated lead in the POE was much greater than for the samples collected on the day of PLSLR, since POE retained 365−799 mg of Pb as compared to 159 mg for the worst case household (#61). Therefore, the acute WLLs presented in Figure 4 would underestimate potential lead release immediately after PLSLR and for this situation it was better to adopt POE filtration. Moreover, overall greater increases were noted for lead and iron specifically (Table 3). This can be explained by the destabilization of iron scale deposits in the water main, and lead scales in the LSLs with replacement work. An elevated simultaneous increase of lead and iron release was observed for POE-monitored household #36 (compared to #62), although the length of the remaining LSL was shorter (5.5 m versus 9.7 m). This was attributed to the type of replacement work, since for household #62, a new main was installed (reconstruction) and water service was

released. This is especially noted for household #61 with total WLLs ranging from 533 to 30 485 μg/L at the outside tap before flushing. Following 15 min of flushing (outside), WLLs varied within 266−25 664 μg/L at the kitchen tap, and then decreased to levels representative of 5MF concentrations in this household (22−23 μg/L) after flushing the kitchen tap for another 15 min. Considering that WLLs were comparable inside and outside of the home, the outside tap (brass) contribution was therefore negligible in this situation. For this house, it was necessary to flush ≥30−35 min to stabilize WLLs. Lead was however still mainly particulate after >45 min of flushing, suggesting insufficient flushing time/flow rate. For household #63 (10 min preflush outside) and #82 (1 min preflush inside), the highest WLLs were measured in the firstand second-draws. Although much lower than for #61, the values are still not acceptable for drinking water consumption (147−486 μg/L). For these households, the particulate lead fraction decreased after 15 min of flushing. Finally, the WLLs measured at household #36 with POE filtering of tap water (0.45 μm), indicating that POEs retained most of the lead particles but that a fraction of them passed through the outlet water in addition to the dissolved lead release. The outside tap could have also contributed to the slightly higher WLLs in the first-draw sample. It can be noted that these levels were much higher than particulate WLLs released dominantly from premise plumbing in a previous study36 (maximum 12 μg/L). F


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Table 3. Total Mass of Total Lead, Copper, Iron, and Zinc (μg) Collected before, During and After PLSLR for the Five Households Sampled on the Day of PLSLRa lead

copper

iron

zinc

ID

before PLSLRb

#61 #82 #63 #36 #62

536 ± 141 (n = 10) 218 (n = 1) 333 ± 185 (n = 4) 18932 ± 17373 (n = 4) 7922 ± 11487 (n = 4)

#61 #82 #63 #36 #62

during PLSLRc

after PLSLRb

monitoring

159 385 1422 476 798 698 365 076

426 ± 167 (n = 9) 392 (n = 1) 211 ± 103 (n = 12) 23028 ± 5059 (n = 4) 10203 ± 7394 (n = 4)

repeat sampling

817 ± 203 (n = 10) 1387 (n = 1) 350 ± 116 (n = 4) 9436 ± 10109 (n = 4) 40741 ± 66586 (n = 4)

117 739 1555 964 380 296 34 312

1320 ± 223 (n = 9) 2763 (n = 1) 904 ± 533 (n = 12) 23580 ± 7038 (n = 4) 16048 ± 7515 (n = 4)

repeat sampling

#61 #82 #63 #36 #62

320 ± 140 (n = 10) 188 (n = 1) 109 ± 21 (n = 4) 60834 ± 60397 (n = 4) 20024 ± 22739 (n = 4)

111 294 1473 573 4 354 980 91 669

255 ± 64 (n = 9) 297 (n = 1) 165 ± 70 (n = 12) 96245 ± 46001 (n = 4) 25203 ± 10568 (n = 4)

repeat sampling

#61 #82 #63 #36 #62

112 ± 34 (n = 10) 269 (n = 1) 293 ± 193 (n = 4) 3182 ± 4365 (n = 4) 1938 ± 2418 (n = 4)

80 182 144 54 31 912 3349

95 ± 49 (n = 9) 307 (n = 1) 259 ± 180 (n = 12) 2585 ± 1056 (n = 4) 1331 ± 621 (n = 4)

repeat sampling

POE filtration

POE filtration

POE filtration

POE filtration

Notes  Bold cases indicate increases of 5 to >40 times the levels observed before PLSLR. bmass (mean ± stdev) and number of sampling events (n) from 6HS profile sampling or POE filtration. cmass from sampling on the day of PLSLR or from POE filters over the PLSLR period (1 sampling event).

a

harvested LSLs from the same distribution system and exposed to the same water quality, dissolved WLLs were consistent with field-measured concentrations in this study, however particulate WLLs were much higher.19 Although field monitoring conditions differ from controlled pilot-scale conditions (flow rate, stagnation, conductivity of the media surrounding service lines and its moisture), long-term repeat sampling combined with POE filtration (495 samples) and detailed characterization of households did not evidence long-term adverse impact. Although limited to 33 households, this suggests that, in this system, the impact of galvanic corrosion is small or limited to a few households with specific water usage patterns comparable to certain large buildings prone to galvanic corrosion issues.47 Preliminary observations of the scales developed inside copper−lead pipes from both the field and pilot studies suggest scale detachment at pilot-scale due to different hydraulic patterns. The PLSLR junctions are also tighter in field-collected pipes as compared to pilot-made pipes. This is because the lead pipe had become molded by the brass union over the years the pipes were underground. Such unions may be less susceptible to crevices that increase galvanic corrosion.27 Finally, fieldcollected full LSLs always included a brass fixture as opposed to pilot-made full LSLs (no brass union). The differences between these field results and other pilot-studies can be explained by the same factors, although other parameters such as the water quality, lead pipe scales, and brass couplings might have also contributed.15,16,24,27 Pilot studies on PLSLR are useful for investigating trends and impact factors, however they may not provide accurate information on real-WLLs at the tap. Implications for LSL Management. Considering the small reduction and the absence of long-term increase in WLLs recorded in this study after PLSLRs, PLSLRs do not represent a

disconnected prior to digging (SI Table S4). This might have reduced iron particle release in the LSL and further scale destabilization as compared to #36, for which the old main was disturbed and not replaced (renovation).41 This might also have prevented the dislodgment of LSL particles into the home prior to water service disconnection. In this study, the kitchen and outside taps were flushed immediately after LSLR. Although results are limited to four households, flushing duration varied from one household to another, and >30 min was necessary to reduce the release from lead scale reservoirs and to stabilize WLLs. The flushing of all inside taps at maximal flow rate may have more efficiently reduced WLLs.46 As observed with POE filtration, the dominant form was particulate lead >1 μm. Considering this, and the co-occurrence of lead and iron, the water main material and corrosion state, the timing for water service disconnection and the flushing procedure applied after LSLR would be key factors determining the duration and magnitude of particulate lead release after LSLR. Comparison to Pilot-Scale Results. In this study, WLLs (especially particulate) increased immediately after PLSLR to levels sufficient to raise serious exposure risks. Over time after PLSLR, WLLs decreased but remained >10 μg/L in 61% of PLSLR samples. Lead released by the service lines was not significantly different before and after PLSLRs, this can be explained by the occurrence of scale destabilization and galvanic corrosion at the copper−lead junctions. Galvanic corrosion effects were less pronounced than expected, and did not have strong impacts on the WLLs to which consumers are exposed at the tap. Based on the pilot-scale experiments, higher particulate lead spikes were expected over longterm.10,17−19,25,28 As compared to pilot-scale results using G


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(3) Sandvig, A.; Kwan, P.; Kirmeyer, G.; Maynard, B.; Mast, D.; Rhodes Trussell, R.; Trussell, S.; Cantor, A.; Prescott, A. Contribution of Service Line and Plumbing Fixtures to Lead and Copper Rule Compliance Issues, 91229; AwwaRF: Denver, CO, 2008; p 523. (4) Levallois, P.; St-Laurent, J.; Gauvin, D.; Courteau, M.; Prévost, M.; Campagna, C.; Lemieux, F.; Nour, S.; D’Amour, M.; Rasmussen, P. E. The impact of drinking water, indoor dust and paint on blood lead levels of children aged 1−5 years in Montreal (Québec, Canada). J. Exposure Sci. Environ. Epidemiol. 2014, 24, 185−191. (5) Cornwell, D. A.; Brown, R. A.; Via, S. H. National Survey of Lead Service Line Occurrence. J. Am. Water Works Assoc 2016, 108, E182− E191. (6) Nour, S.; Deshommes, E.; Gagnon, G.; Andrews, R. C.; Prévost, M. In Lessons and Experience on the Management of Lead Service Lines by Utilities and Public Perception; AWWA-WQTC, Salt Lake City, UT, USA, Nov 15−19, 2015. (7) Jusko, T. A.; Henderson, C. R., Jr.; Lanphear, B. P.; Cory-Slechta, D. A.; Parsons, P. J.; Canfield, R. L. Blood lead concentrations < 10 microg/dL and child intelligence at 6 years of age. Environ. Health Perspect. 2008, 116 (2), 243−248. (8) Canfield, R. L.; Henderson, C. R., Jr.; Cory-Slechta, D. A.; Cox, C.; Jusko, T. A.; Lanphear, B. P. Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter. N. Engl. J. Med. 2003, 348 (16), 1517−1526. (9) EPA National Drinking Water Advisory Council (EPA NDWAC) Report of the lead and copper rule working group to the National Drinking Water Advisory Council - Final; August 24, 2015; p 49. (10) Triantafyllidou, S.; Edwards, M. Galvanic corrosion after simulated small-scale partial lead service line replacements. J. Am. Water Works Assoc. 2011, 103 (9), 85−99. (11) United States Environmental Protection Agency (USEPA) Science Advisory Board evaluation of the effectiveness of partial lead service line replacements, EPA-SAB-11-015; Science Advisory Board (SAB): Washington, DC, September 28, 2011; p 62. (12) Britton, A.; Richards, W. N. Factors influencing plumbosolvency in Scotland. Journal of the Institution of Water Engineers and Scientists 1981, 35 (5), 349−364. (13) DeSantis, M. K.; Welch, M. M.; Schock, M. R. Mineralogical Evidence of Galvanic Corrosion in Domestic Drinking Water Pipesdrinking Pipes; AWWA-WQTC, Seattle, WA, November 15−19, 2009. (14) DeSantis, M. K.; Schock, M. R. In Ground Truthing the ″Conventional wisdom″ of Lead Corrosion Control Using Mineralogical Analysis; AWWA-WQTC: New Orleans, LA, November 16−20, 2014. (15) Wang, Y.; Mehta, V.; Welter, G. J.; Giammar, D. E. Effect of connection methods on lead release from galvanic corrosion. J. Am. Water Works Assoc. 2013, 105 (7), E337−E351. (16) Wang, Y.; Jing, H.; Mehta, V.; Welter, G. J.; Giammar, D. E. Impact of galvanic corrosion on lead release from aged lead service lines. Water Res. 2012, 46 (16), 5049−5060. (17) Cartier, C.; Arnold, R. B., Jr; Triantafyllidou, S.; Prévost, M.; Edwards, M. Effect of flow rate and lead/copper pipe sequence on lead release from service lines. Water Res. 2012, 46 (13), 4142−4152. (18) Cartier, C.; Doré, E.; Laroche, L.; Nour, S.; Edwards, M.; Prévost, M. Impact of treatment on Pb release from full and partially replaced harvested lead service lines (LSLs). Water Res. 2013, 47 (2), 661−671. (19) Doré, E.; Cartier, C.; Edwards, M.; Nour, S.; Laroche, L.; Prévost, M. Impact of Stagnation Patterns on Particulate and Dissolved Lead Release from Full and Partial LSLs; AWWA-WQTC, New Orleans, LA, USA, Nov 16−20, 2014. (20) Sastri, V. S.; Subramanian, K. S.; Elboujdaini, M.; Perumareddi, J. R. Inhibition of release of lead into water owing to galvanic corrosion of lead solders. Corros. Eng., Sci. Technol. 2006, 41 (3), 249−254. (21) Nguyen, C. K.; Stone, K. R.; Edwards, M. A. Chloride-to-sulfate mass ratio: Practical studies in galvanic corrosion of lead solder. J. Am. Water Works Assoc. 2011, 103 (1), 81−92. (22) Nguyen, C. K.; Stone, K. R.; Dudi, A.; Edwards, M. A. Corrosive microenvironments at lead solder surfaces arising from galvanic

health concern that requires immediate action in this distribution system. Although these results cannot be extended to any system, they provide evidence that some systems are less prone to galvanic corrosion, or that this phenomenon is limited to households with low water usage patterns. Lead concentrations are however still too high, exceeding reference levels depending on the length of remaining LSL. This emphasizes the need to implement incentives, such as funding, support to find contractors, and increased risk communication, to promote FLSLR and reduce lead exposure especially for children and pregnant women. Data collected immediately after a PLSLR raises concerns regarding health issues, considering that drinking water with such WLLs would result in lead poisoning. Although these effects were short-term, the findings support the urgency of implementing corrective measures such as recommended post-LSLR flushing procedures, communication with citizens and contractors on the importance of implementing flushing for public health protection, and verification of WLLs following flushing. In preparation for such interventions, particular attention should be paid to the disturbances caused on old water mains and LSLs at the time of replacement.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.est.7b01720. Details on the monitoring design, household characteristics, lead pipe replacement techniques and complementary results (K−W tests, mass balances before/after replacement, relationship between WLLs and length of LSL, relationship between lead and iron release) (PDF)

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AUTHOR INFORMATION

Corresponding Author

*Phone: (+1) 514-340-4711 (2236); fax: (+1) 514-340-5918; e-mail: [email protected]. ORCID

Elise Deshommes: 0000-0002-8812-2744 Author Contributions

The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was funded by the Canadian Water Network (proposal MW2012-1). We acknowledge the participants’ implication in the study. They also acknowledge technical support of Yves Fontaine and Marie-Claude Desmarais (Polytechnique Montreal), Magalie Joseph, Alicia Bannier, Chantale Potvin, and staff from the City of Montreal.

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REFERENCES

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Short- and Long-Term Lead Release after Partial Lead Service Line

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