2014 Progress Report: Evaluation of Lead Service Line Lining and Coating TechnologiesEPA Grant Number: R834865
Title: Evaluation of Lead Service Line Lining and Coating Technologies
Investigators: Peltier, Edward F. , Adams, Craig D. , Cuppett, Jonathan , Randtke, Stephen J. , Roberson, J. Alan
Current Investigators: Case, Traci L. , Adams, Craig D. , Peltier, Edward F. , Randtke, Stephen J. , Roberson, J. Alan
Institution: University of Kansas , American Water Works Association , University of Missouri - Rolla , Water Research Foundation
Current Institution: Water Research Foundation , American Water Works Association , University of Kansas
EPA Project Officer: Hiscock, Michael
Project Period: January 1, 2011 through December 31, 2016
Project Period Covered by this Report: January 3, 2014 through January 3,2015
Project Amount: $600,000
RFA: Advancing Public Health Protection through Water Infrastructure Sustainability (2009) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
The objectives of this research project are to: (1) comprehensively evaluate lead service line (LSL) lining and coating technologies as alternatives to full or partial LSL replacement, and as a means of protecting and repairing both lead and copper service lines (CSLs); and (2) provide water utilities, engineering consultants, state regulators, consumers, and other interested parties with information and supporting documentation needed to make informed decisions regarding lining and coating of both LSLs and CSLs.
We evaluated technologies for lining or coating LSLs, identified issues decision makers should consider when lining or coating LSLs, and conducted fill-and-dump tests on a commercially available epoxy coating and a polyethylene terephthalate (PET) liner system. Our data (and that of others) indicate that properly applied epoxy coatings and properly installed PET liners effectively control release of Pb and Cu from LSLs and CSLs, respectively, into drinking water. Cu increased slightly in water exposed to epoxy coatings, perhaps due to small amounts of Cu in the epoxy (8 mg/kg); but the increases (0.4-22 μg/L) were far below those observed in uncoated controls (270-910 μg/L) and the action level for Cu (1,300 μg/L). Epoxy-coated pipe specimens exerted significant demand for free and combined chlorine, when fresh and after being stored wet or dry for more than 6 months, as did the uncoated control pipe sections.
In fill-and-dump experiments on PET-lined LSL and CSL pipe sections, we found the mean antimony (Sb) increase in extraction water samples, with a holding time of 6 hours to 4 days, to be 0.16 μg/L for LSLs and 0.20 μg/L for CSLs, far below the MCL of 6 μg/L and well below levels found in samples from the unlined LSL control specimen (0.42-3.94 μg/L). There was no significant increase in TOC. None of 10 phthalate esters determined using GC-MS and none of phthalic acids determined using LC-MS/MS were detected; nor were these compounds detected in solvent extracts of a PET liner. PET liners exhibited very little chlorine demand in the first set of fill-and-dump tests and no measurable demand in later tests.
Freshly applied epoxy coatings were found to leach an average of 0.50 mg/L TOC into the extraction waters, as well as low concentrations of BADGE (bisphenol A diglycidyl ether), BPA-like compounds, and trace amounts of BPA. The presence of BADGE is significant because epoxy coatings are widely used in water distribution systems and there are concerns regarding the potential effects of bisphenol compounds on the human endocrine system. For this reason, additional experiments were conducted to examine hydrolysis and chlorination of BADGE, BFDGE (bisphenol F diglycidyl ether, another common epoxy ingredient), and bisphenols, and to characterize and identify the observed BPA-like compounds.
BADGE hydrolysis was studied as a function of pH (2-12) at 15-40°C. BADGE hydrolyzed to BADGE-H2O and then to BADGE-2H2O, the major end product under these conditions. Experimentally measured BADGE hydrolysis rates agreed well with modeled rates, thus the model (publication pending) can be used to estimate BADGE concentrations in water over time, facilitating exposure assessments. The half- lives of BADGE at pH 7 and 15, 25, 35, and 40°C were 11, 4.6, 2.0, and 1.4 days, respectively. The half-life of BFDGE was 5 days at pH 7 and 25°C. No hydrolysis or decay of BPA was observed over 30 days.
BADGE was unreactive with free or combined chlorine at pH values of 7.6-9.0 at 25°C, but the bisphenols reacted relatively rapidly with free chlorine. BPA half-lives with a free chlorine residual of 1mg/L as Cl2 ranged from 3-35 minutes at pH 6-11 and 10-25°C; half-lives of 1-10 days were estimated for monochloramine (3.5 mg/L as Cl2) under similar conditions. These results and a model based on them can be used to characterize the concentrations of bisphenols and BADGE in drinking water distribution systems, after leaching from epoxy coatings, thereby facilitating future risk assessments.
The BPA-like compounds we found leaching from epoxy coatings appear to differ from BPA only in their retention times on an LC column and may therefore be adducts of BPA. This is significant because analytical methods used to detect trace contaminants often look for them only within a specific time window; thus, it is possible that these compounds are being overlooked or misidentified in studies of BPA in various matrices, including drinking water, foods, and beverages in contact with epoxy coatings.
A major objective of this project is to provide water utilities, engineering consultants, state regulators, consumers, and others with information helpful in making informed decisions regarding lining and coating of LSLs and CSLs. Recommendations will be developed for utilities, engineering consultants, state regulators, and consumers considering the use of these technologies to protect human health, to reduce the cost of repairing or replacing service lines, and to improve the aesthetic qualities of drinking water. Ultimately, this research will provide the drinking water community with practical information to assist efforts to ensure reliable supplies of safe drinking water for consumers.