Document wDL9BRXowqpBxJma724KLva4o

HEALTH AND CORROSION IMPACT OF SOFT WATER Prepared for: A/C PIPE PRODUCERS ASSOCIATION 1600 Wilson Blvd., Suite 1308 Arlington, Virginia 22209 Prepared by: Energy and Environmental Analysis, Inc. 1111 North 19tli Street Arlington, Virginia 22209 August 28, 1979 `Copies o: the complete report nrc available, upon request , from the A/C Pipe Producer r. Assoc in t.ion. CTD001964 I. EXECUTIVE SU:;.T,EY 1.1 INTRODUCTION Certain chemical constituents released into public drinking water systems by corrosive action can pose potential health hazards. Further, extensive epidemiological research has strongly suggested that consumption of soft and sometimes aggressive drinking water may be related to increased incidence of cardiovascular disease. It has also been recognized that aggressive water in distribution systems rapidly increases corrosion rates and thereby increases the rate of pipe replacement and the costs associated with it. The purpose of this report is: o to delineate the health issues involved in consumption of soft and/or corrosive water o to elucidate mechanisms by which soft water is implicated in cardiovascular disease o to quantify health and corrosion costs of aggressive water o to examine corrosion treatment options in terms of cost-effec tiveness and health benefits. 1.2 SUMMARY OF FINDINGS -H-*ealth Imp--a--c--t-s- o Medical studies have shown a high statistical correlation between soft water and cardiovascular heart disease (CVD). o All known risk factors account for only 50 percent of the incidence of cardiovascular disease, excluding the risk from the consumption of drinking water. Drinking eater may account for a significant fraction of the remaining 50 percent. o As shown in Table 1-1, the cause and effect mechanisms of this relationship can be hypothesized into three classes. CTD001965 TABLE 1.1 CLASSIFICATION OF RELATIONS!! II'S OF DRINKING WAFER TO CARDIOVASCULAR DISEASE Class I Class 2 tlass 3 One or rocc of the major components of h2rd water are protective. These beneficial elements are lacking in soft water. o Magnesium o Calcium One or more of the minor components ("trace" elements) that tend to be present in hard water, but absent or deficient in soft water,-are protective. o Lithium o Chromium o Vanadium i o Selenium o Manganese o St*, ontium One or marc components in soft water are harmful -- this includes metal ions that are leached from the distribution system. o Cadmium, o Couper o Loud o Friyl1ium CTD001966 1-2 0 As shown in Table 1 -2 , wnt.LT treatmerit tcchriique:. may reduce the incidence of CVl).- o Over 55 million people are exposed to soft water (less than 60 ppm hardness CaCO -equivalents) in the United States (see Figure 1-1 and Table 1-3). o The death rate from CVD can potentially be decreased in soft water areas by 0.65 deaths per 100,000 population for each increase of 1 ppm of hardness (CaCO^). o By increasing the hardness (greater than 60 ppm) through pH adjustment, 13,825 lives could be saved annually in soft water areas. This amounts to a minimum annual health savings of $3-5 billion per year. o Health benefits from hardening soft water exceed treatment costs by about 300 times. Corrosion Related Impacts o Soft water may be corrosive to water distribution systems, leading to significant damage of pipes, pumps, meters, and storage equipment, as well as household plumbing appliances. o Past studies have shown an increase in certain toxic trace metals from corrosion due to leaching of pipes. These ele ments, particularily lead and cadmium, can represent a potential health hazard. o Costs for replacement of water-related pipe corrosion in distribution systems with aggressive water can- range up to $20.16 per capita annually, with an average of $2.67 per capita annually. \ o Water loss from leakage of pipes in distribution systems can amount to as much as 50 percent. A nationwide water loss average is 15 percent. Of these water losses, 38 percent (equivalent to six percent of distributed water) may be due to corrosion as a result of aggressive water areas. o Power requirements are higher in many aggressive water 3reas because of decrease flow capacity in corroded pipes. Corrosion Control Techniques o There arc two major corrosion control techniques: pll adjust ment and addition of corrosion inhibitors. CTD001967 TABLE 1-2 WATER TREATMENT EFFECTS ON CVD MEG LAN I SMS Theory la Calcium lowers CVD. lb Magnesium lowers CVD. 2a Lithium beneficial. 2b Strontium' beneficial. 3a Cadmium related to CVD. 5b Lead related to CVD. Treatmen t Type I II III IV B Nc PB NE NE PB PA PA BB B B- PB NE NE NE PA PA PA PA BB B B .\E - No Effect - Treatment will not low er or increase inciden CVD. B - Beneficial - Treatment will lower incident of CVD P3 - Potentially 5ensficial - Treatment may lower incident of CVD A - Adverse - Treatment will increase incident of CVD". PA - Potentially Adverse - Treatment nay increase incident of CVD Treatment Types I - pH adjustment using lime. II - pH adjustment using sodium hydroxide or soda ash. Ill - addition of corrosion inhibitors - polyphosphates. IV - addition of corrosion inhibitors - silicates. 1-3 CTD001968 PJlIIJUJ: 1-1 'SOFT WATER AREAS IN THE UNITED STATES Those s ta re s may huvo p o p u la tio n s exposed to s o ft w ater. CTD001969 TAi'M 1-3 nu: o': in th UMT'M.O S' i ATE 5 UL) I 0 i>-Jy j r. iN 19 70 Eastern States Connecticut Del aware District of Columbia Maine Maryland Massachusetts New Hampshire New Jersey New York Pennsylvania Rhode Island Vermont - Virginia Southern States Alabama Arkansas Florida Georgia Kentucky Louisana Mississippi North Carolina South Carolina Tennessee Texas Western States California Hawaii Idaho Nevada Oregon Washington United States SOURCE: EEA Population Exposed . (in millions} 30-9 2.9 0.5 0.7 1.0 3.0 5.7 0.8 4.5 5.6 0.9 0.9 0.4 4.0 21.4 - 1.0 0.3 . 0.1 2.7 0.3 0.3 2.2 4.4 2.2 2.0 S.9 3.7 1.0 o.s 0.2 0.003 1.5 0.2 56.0 P-ercentag e or Population Exposed ss% 96% 100% 100% 100% 7S% 100% 100% 63% 31% 7% 100% 91% 8S% 38% 31% 17% 1% S9% 10% 8% 100% 86% 83% 52% 53% 7% S% 100% 25% 0.6% 74 % S% 27% J-6 CTD001970 o {'II arJjusLment using lime has beneficial health effects. o Corrosion control by deposition of CaCO^ films on the interior surfaces of the wafer conveyors provides the broadest and most general protection to water systems and plumbing materials. o .Any of the stability indices, Langlier Saturation Index (LSI), Aggressive Index (AI), or Ryznar Saturation Index (RSI), can be used interchangeably to measure the stability and corrosion potential of water. o Annual treatment costs to control corrosion range from $0,185 to $0.47 per capita. o The benefit to cost ratio of using corrosion control to reduce pipe damage ranges from 1.2:1 to 15.4:1. Regulatory findings o EPA has the authority under the Safe Drinking Water Act to regulate soft corrosive water. 1.3 CONCLUSIONS Soft and/or corrosive water represents a substantial health risk to those dependent on it for drinking water. Several different water treatment methods can lessen the potential adverse health impacts. Technology to decrease water corrosivity is readily available and economically feasible. Not only could the use of this technology result in significant public health benefits, but it could also have the addi tional benefit of lowering corrosion in public water distribution systems EPA lias the authority, in the Safe Drinking h'atcr Act, to include a minimum hardness requirement and to establish an MCL based on corrosion indices. This authority should be exercised to protect public health, considering the potential adverse health effects of increased cardio- vascvilar disease in soft water areas and increased toxic contaminants in corrosive water areas. Given the large percentage of the United States population exposed to soft or corrosive water, a minimum hardness require meat and a maximum contamin.int level based on any one of tlie corrosion indices should he implemented nationwide. CTD001971