Lead-contaminated drinking water in bulk-water storage tanks - Arizona and California, 1993

Morbidity and Mortality Weekly Report, Oct 21, 1994

Lead poisoning is a major environmental health problem for children in the United States[1,2]: during 1988-1991, approximately 1.7 million U.S. children aged 1-5 years had elevated blood lead levels (BLLs) ([greater than or equal to]10 [mu]g/dL)[3]. To determine the s exposure for children with BLLs [greater than or equal to]20 [mu]g/dL, the Arizona Department of Hea (ADHS) conducts environmental investigations. In 1993, as a result of investigations of increased BLLs in two children in southwestern Arizona, ADHS detected lead levels approximately 30 times the Environmental Protection Agency (EPA) action level of 15 parts per billion (ppb) in bulk-delivered drinking water in the homes of these children. Because two of the three companies that supplied bulk water to southwestern Arizona were based in California, ADHS notified the California State Department of Health Services (CSDHS) about the problem. As a result, CSDHS conducted a separate investigation and identified one child with an elevated BLL whose drinking water sources included bulk-delivered water with lead levels exceeding EPA standards. This report summarizes the investigations of elevated BLLs in these three children and high lead levels in bulk-delivered drinking water in Arizona and California.

Arizona

In July 1993, routine screening by ADHS for lead poisoning detected a BLL of 42 [mu]g/dL (CDC BLL of concern=10 [mu]g/dL) in a 6-month-old infant in Yuma County, Arizona. To determine the source of lead exposure, ADHS initiated an environmental investigation. Lead was not detected in a first-draw water sample from the kitchen faucet, which was connected to a private well. However, the parents reported that the child's formula was prepared using bulk-stored water, and a first-draw water sample taken through the brass fitting of a bulk-water storage tank contained 495 ppb lead. Other potential environmental sources of lead included peeling lead paint on the outside of the house and on one kitchen wall covered with wallpaper. ADHS advised the parents to stop drinking bulk-stored water, informed them about professional paint removal and encapsulation, recommended measures to prevent lead exposure, and notified the water-delivery company about the high lead level in the bulk-stored water.

In August 1993, a BLL of 37 [mu]g/dL was detected in a 12-month-old child in Yuma County who was tested by ADHS for lead poisoning following a complaint of abdominal pain. Lead was not detected in a first-draw water sample from the kitchen faucet, which was connected to the municipal water supply. However, the parents reported that the child's source of drinking water was bulk-delivered water, and a first-draw water sample obtained from a kitchen faucet supplied by a bulk-water storage tank contained 450 ppb lead. The investigation also identified lead-contaminated soil (68 ppm) at a relative's home where the child routinely stayed during the day. ADHS advised the parents to stop drinking bulk-stored water, recommended measures to prevent lead exposure, and notified the water-delivery company about the high lead levels in the bulk-delivered water. Two weeks after the first-draw sample was obtained, lead levels in water taken through the brass fitting on the tank and directly from the tank were 1050 ppb and 602 ppb, respectively.

Because the source of bulk-delivered water for both cases was a California-based water-delivery company, ADHS notified CSDHS about the potential problem of leadcontaminated bulk-delivered water.

California

In November 1993, a newspaper report about lead-contaminated bulk-delivered water prompted parents in imperial County, California, to have their 14-month-old child screened for lead poisoning by the county health department. A BLL of 15 [mu]g/dL was detected in the child. The parents reported that the child's drinking water sources were bulk-delivered water and surface water. A first-draw water sample from the kitchen faucet, which was connected to a bulk-water tank supply, contained 66 ppb lead. After running the water for 3 minutes, a second-draw water sample from the same faucet contained 9 ppb lead. A first-draw water sample from the refrigerator faucet, also connected to the bulk storage tank, contained 50 ppb lead. First-draw water samples obtained from two other faucets in the house, which were connected to a surface water supply, had lead levels lower than the detection limit of 5 ppb. No other potential sources of lead exposure were identified. The county health department advised the parents to stop drinking bulk-delivered water and recommended measures to prevent lead exposure.

Investigation of Bulk-Water Sources

ADHS identified three water companies (two based in California and one based in Arizona) that supplied bulk water to southwestern Arizona. ADHS obtained water samples from 96 residential and business storage tanks serviced by the two California water companies; no water samples were obtained from the Arizona company because the company used plastic tanks and fittings. Samples were drawn directly from the tanks, from the brass fittings on the tanks, and from the kitchen sinks. Twenty-two (23%) of the 96 water samples contained lead levels exceeding EPA's action level. Samples from three bulk-water delivery trucks containing the source water for the storage tanks met EPA drinking water standards (i.e., <15 ppb lead).