United States Environmental Protection Agency Office of Water 4601 EPA811-F-95-0021- T October 1995 National Primary Drinking Water Regulations Lead CHEMICAL/ PHYSICAL PROPERTIES SOLUBILITIES: CAS NUMBER: 7439-92-1 COLOR/ FORM/ODOR: Bluish-white, silvery, gray metal, lustrous when freshly cut. SOIL SORPTION COEFFICIENT: N/A; Low mobility in most soils, lowest at neutral pH and high organic matter. COMMON ORES: sulfide-Galena; oxide-Lanarkite; carbonate-Cerrusite; sulfate-Anglesite BIOCONCENTRATION FACTOR: Log BCFs for fish, 1.65; shellfish, 3.4 r acetate- . arsenate- carbonate- chloride- ' chromate- nitrate- oxide- dioxide- phosphate- . sulfate- sulfide- tetraethyl- thiocyanate- thiosulfate- 443 g/L at 20 deg C insoluble in cold water 0.0011 g/L at 20 deg C 10 g/L cold water 0.2 mg/L 376.5 g/L at 0 deg C 0.05 g/L at 20 deg C insoluble insoluble 0.4 g/L insoluble 0.29 mg/L at 25 deg C 0.5 g/L at 20 deg C 0.3 g/L cold water DRINKING WATER STANDARDS HCLG: zero Ktion Level: HAL(child): > 0.015 mg/L in more than 10 percent of tap water samples none - HEALTH EFFECTS SUMMARY Acute: Lead can cause a variety of adverse health effects in humans. At rela- tively low levels of exposure, these ef- fects may include interference with red blood'cell chemistry, delays in normal physical and mental development in ba- bies and young children, slight deficits in the attention span, hearing, and learning abilities of children, and slight increases in the blood pressure of some adults. It appears that some of these effects, par- ticularly changes in the levels of certain blood enzymes and in aspects of children's neurobehavioral development, may oc- cur at blood lead levels so low as to be essentially without a threshold. Chronic: Chronic exposure to lead has been linked to cerebrovascular and (flney disease in humans. Cancer Lead has the potential to cause cancer from a lifetime exposure at levels above the action level. October 1995 USAGE PATTERNS Lead is the fifth most important metal in the USA economy in terms of consump- tion. Of this approximately 85% of the primary lead is produced domestically. and 40-50% is recovered and recycled. Eighty eight percent of the lead mined in the US comes from seven mines in the New Lead Belt in southeastern Missouri; the rest coming from eight mines in Colo- rado, Idaho, and Utah. Three of the six USA lead smelters are from this region, the others are located in Idaho, Montana, and Texas. RELEASE PATTERNS Lead occurs in drinking water from two sources: (1) Lead in raw water supplies, i.e., source water or distributed water, and (2) corrosion of plumbing materials in the water distribution system (corrosion by-products)! Most lead contamination is from corrosion by-products. Occurrence In Source Water and Distributed Water. Based on a variety of water quality surveys, EPA now estimates that approximately 600 groundwater sys- tems and about 215 surface suppliers may have water leaving the treatment plant with lead levels greater than 0.005 Technical Version mg/L These two sources together indicate that less than 1 percent of the public water systems in the United States have water entering the distribution system with lead levels greater than 0.005 mg/L. These systems serve less than 3 percentof people that receive their drinking water from pub- lic water systems. From 1987 to 1993, according to the Toxics Release Inventory lead compound releases to land and water totalled nearly 144 million Ibs., almost all of which was to land. These releases were primarily from lead and copper smelting industries. The largest releases occurred in Missouri, Ari- zona and Montana. The largest direct releases to water occurred in Ohio. Occurrence as a Corrosion By Prod- uct. Lead in drinking Water results prima- . rily from corrosion of materials located Toxics Release Inventory - Water and Land Releases, 1987-93 Water Land TOTALS (in pounds) 970,827 143,058,771 Top Twelve States * MO 4,408 40.656,278 AZ 771 23,240,625 MT 0 20,822,517 UT 4,600 11,881,000 TX . 1,988 11,515,211 OH 127,990 5,196,522 IN 62,894 4,851,940 TN 7,140 2,095,489 IL 26,601 1,930,000 Wl 1.310 1,350,960 MN , 0 - 1,313,895 NM 0 1,060,880 Major Industries* Lead smelting/refining 31,423 68,996,819 Copper smelting 5,371 34,942,505 Steelworks/blast fum. 379,849 18,149,696 Storage batteries 0 1.867,292 China plumbing fixtures 1,310 1,350,960 Iron foundries 10,021 1,274,777 Copper mining 0 1,240,000 * State/Industry totals only include facilities with releases greater than 100,000 Ibs. 1^ Printed on Recycled Paper ------- throughout the distribution system con- taining lead and copper and from lead and copper plumbing materials used to plumb public- and privately-owned struc- tures connected to the distribution sys- tem. The amount of lead in drinking water attributable to corrosion by-products de- pends on a number of factors, including the amount and age of lead and copper bearing materials susceptible to corro- sion, how long the water is in contact with the lead containing surfaces, and how corrosive the water in the system is to- ward these material The potential sources of lead corrosion by-products found in drinking water can include: Water service mains (rarely), lead goosenecks or pigtails, lead service lines and interior household pipes, lead sol- ders and fluxes used to connect copper pipes, alloys containing lead, including some faucets made of brass or bronze. Most public water systems serve at least some buildings with lead solder and/ or lead service lines. EPA estimates that there are about 10 million lead service lines/connections. About 20 percent of all public water systems have some lead service lines/connections within their dis- tribution system. . The amount of lead in drinking vater depends heavily on the corrosivity of the water. All water is corrosive to metal plumbing materials to some degree, even water termed noncorrosive or water treated to make it less corrosive. The corrosivity of water to lead is influenced by water quality parameters such as pH, total alkalinity, dissolved inorganic car- bonate, calcium, and hardness. Galvanic corrosion of lead into water also occurs with lead-soldered copper pipes, due to differences in the electrochemical poten- tial of the two metals. Grounding of house- hold electrical systems to plumbing may also exacerbate galvanic corrosion. ENVIRONMENTAL FATE Lead may enter the environment dur- ing its mining, ore processing, smelting, refining use, recycling or disposal. The initial means of entry is via the atmo- sphere. Lead may also enter the atmo- sphere from the weathering of soil and volcanos, but these sources are minor compared with anthropogenic ones. Lead will be retained in the upper 2-5 cm of soil, especially soils with at least 5% organic matter or a pH 5 or above. Leach- ing is not important under normal condi- tions. It is expected to slowly undergo speciation to the more insoluble sulfate, sulfide, oxide, and phosphate salts. .Lead enters water from atmospheric fallout, runoff orwastewater; little is trans- ferred from natural ores. Metallic lead is attacked by pure water in the presence of oxygen, but if the water contains carbon- ates and silicates, protective films are formed preventing further attack. That which dissolves tends to form ligands. Lead is effectively removed from the wa- ter column to the sediment by adsorption to organic matter and clay minerals, pre- cipitation as insoluble salt, and reaction with hydrous iron and manganese oxide. Under most circumstances, adsorption predominates. Lake sediment microorganisms are able to directly rhethylate certain inor- ganic lead compounds. Under appropri- ate conditions, dissolution due to anaero- bic microbial action may be significant in subsurface environments. The mean per- centage removal of lead during the acti- vated sludge process was 82% and was almost entirely due to the removal of the insoluble fraction by adsorption onto the sludge floe and to a much lesser extent, precipitation. The most stable form of lead in natural water is a function of the ions present, the pH, and the redox potential. In oxidizing . systems, the least soluble common forms are probably the carbonate! hydroxide, and hydroxycarbonate. In reduced sys- tems where sulfur is present, PbS is the stable solid. The solubility of Pb is 10 ppb above pH 8, while near pH 6.5 the solubil- ity can approach or exceed 100 ppb. Pb(0) and Pb(+2) can be oxidatively methylated by naturally occurring compounds such as methyl iodide and glycine betaine. This can result in the dissolution of lead already bound to sediment or particulate matter. Lead does not appear to bioconcen- trate significantly in fish but does in some shellfish such as mussels. Evidence sug- gests that lead uptake in fish is localized in the mucous on the epidermis, the dermis, and scales so that the availability in edible portions do not pose a human health dan- ger. OTHER REGULATORY INFORMATION: MONITORING: MoNiroRmo PERIOD Initial . After corrosion' control installation Reduced monitoring • Conditional - Final ANALYSIS , REFERENCE SOURCE . EPA 800/4-83-043 FOR LEAD AT HOME TAPS Every 6 months Every 6 months Once a year Every 3 years FOR WATER QUALITY PARAMETERS WITHIN THE AT ENTRY TO THE DISTRIBUTION DISTRIBUTION SYSTEM SYSTEM Every 6 months Every 6 months Every 6 months Every 2 weeks Every 6 months Every 3 years Every 2 weeks Every 2 weeks METHOD NUMBER 239.2. 200.8; 200.9 TREATMENT: BEST AVAILABLE TECHNOLOGIES Source water. Ion exchange; lime softening; reverse osmosis; coagulation/filtration Corrosion Control: pH and alkalinity adjustment; calcium adjustment; silica- or phosphate-based corrosion inhibition . FOR ADDITIONAL INFORMATION: 4 EPA can provide further regulatory and other general information: • EPA Safe Drinking Water Hotline - 800/426-4791 * Other sources of toxicologies! and environmental fate data include: •Toxic Substance Control Act Information Line-202/554-1404 • Toxics Release Inventory, National Library of Medicine - 301/496-6531 • Agency for Toxic Substances and Disease Registry - 404/639-6000 October 1995 Technical Version Page 2 ------- |