In August 1987, Jamaican public health officials learned that 19 (86%) of 22 recently hospitalized children with lead poisoning in Kingston lived near small automobile-battery repair shops. Nine of these children had acute encephalopathy and seizures, and four were treated for recurrent symptoms of lead toxicity between January 1986 and March 1987. Because of the large number of severe cases and the unusual suspected exposure, the Jamaican Ministry of Health requested assistance from CDC in October 1987 to assess the prevalence and causes of excessive lead absorption among workers and household members exposed to battery repair shops.

At least 50 shops repair or rebuild car batteries in Jamaica; approximately 30 are located in Kingston. These shops typically employ one or two workers and share a yard with one or more residences. For evaluation of worksite exposures, 11 shops in Kingston were chosen for a survey (one shop was no longer in business, but the residential area was included in the study). For evaluation of exposure to airborne lead, seven air samples (three from breathing zones of individual workers and four from general work areas) were collected at each of the five shops that were repairing batteries on the day they were visited. Blood samples were drawn from workers at all 10 active shops. For evaluation of household exposures, 17 residences on repair-shop premises, including five in which repair-shop workers lived, and seven residences of repair-shop workers not on shop premises were identified. Eighteen neighborhood-matched control residences were also surveyed. At study residences, samples of soil and house dust and venous blood specimens from household members greater than 6 months of age were analyzed for lead (1,2). Participants or their guardians were notified of elevated blood lead (PbB) levels and referred for medical evaluation if indicated.

Levels of exposure. Air-lead levels in repair shops averaged 0.021 mg/m3 (geometric mean), and one sample exceeded the U.S. Occupational Safety and Health Administration (OSHA) permissible exposure limit of 0.050 mg/m3 (3). In contrast, potentially hazardous levels of lead in soil and house dust were common at residences on repair-shop premises, where 11 (85%) of 13 yards had soil-lead levels greater than 500 ppm (range: 51-54,000 ppm), and 11 (73%) of 15 homes tested had dust-lead levels greater than 1500 ug/m2 (range: 190-62,800 ug/m2) (Table 1). These levels of lead in soil and house dust have been associated with increased lead absorption in children (4,5). Geometric mean soil- and dust-lead levels were significantly higher (p less than 0.005) at residences located on repair-shop premises than at control residences.  Levels of lead absorption. Blood samples were obtained from all 23 workers at the surveyed repair shops. The geometric mean PbB concentration was 64 ug divided by L, and 18 workers (78%) had a PbB concentration of greater than 50 ug divided by L.

Blood samples were obtained from 186 (67%) of 279 study household members. Of 86 household members at repair-shop premises, 58 (67%) had PbB levels greater than or equal to 25 ug divided by L (Table 1). The prevalence of persons with high levels decreased with increasing age: 0-5 years, 100%; 6-11 years, 94%; greater than or equal to 12 years, 47%. Geometric mean PbB levels were lower among members of control households (p less than 0.0005, t-test), in which less than 10% of persons in each age group had PbB greater than or equal to 25 ug divided by L (maximum detected, 33 ug divided by L). Among persons greater than or equal to 6 years of age, PbB levels were higher in those who lived in worker households located away from repair-shop premises than in those from control households.

PbB levels in persons were strongly correlated with lead concentrations in soil and house dust. The correlation was strongest among children less than 6 years old (r=0.72 (p less than 0.0001) for soil lead and r=0.55 (p=0.0002) for dust lead). Two residences located on the premises of the closed repair shop were among those with elevated soil lead, and all three children less than 6 years of age who lived there had PbB greater than or equal to 25 ug divided by L (range: 48-65 ug divided by L). Reported by: JP Figueroa, MBBS, Principal Medical Officer (Epidemiology), Ministry of Health, Jamaica. RA Keenlyside, MBBS, Caribbean Epidemiology Centre, Trinidad. Div of Environmental Hazards and Health Effects, Center for Environmental Health and Injury Control; Div of Surveillance, Hazard Evaluations, and Field Studies, and Office of the Director, National Institute for Occupational Safety and Health, CDC.

Editorial Note

Editorial Note: Small-scale workplaces, which are common in developing countries (6), may be located in or near homes, and often they lack measures to protect workers and nearby residents from hazardous exposures. Lead is sometimes used in "cottage" industries, and lead poisoning has occurred both in workers and in household members exposed to processes such as recycling car batteries (7), making lead type, tempering cutlery (8), and making pottery (9). Lead poisoning of household members from lead dust brought home on work clothes has also been reported from moderate-sized workplaces (10).

Adverse health effects of lead include acute and chronic central nervous system toxicity, peripheral neuropathy, impairment of hemoglobin synthesis and anemia, chronic renal disease, and impairment of male and female reproductive functions. Children are especially susceptible to lead neurotoxicity, and CDC guidelines for childhood lead screening recommend intervention when the PbB level is greater than or equal to 25 ug divided by L (4). PbB levels well below this screening threshold have been associated with impaired cognitive development in early life, especially when exposure occurs to the developing fetus (11,12).

Exposed workers absorb lead mainly by inhaling airborne lead particulate and, to a lesser extent, by unintentionally ingesting lead dust that has contaminated hands, food, or cigarettes. Most repair-shop workers in this survey had PbB levels that exceeded both the World Health Organization PbB limit for adult males (40 ug divided by L) (13) and the U.S. OSHA medical removal level (50 ug divided by L averaged over 6 months) (3). Because air-lead levels exceeded 0.05 mg/m3 at only one of five shops tested, ingestion may be an important route of exposure in repair-shop workers.

Persons living on the premises of battery repair shops appear to be at high risk for elevated PbB levels, and children are at risk for PbB levels sufficiently high ( greater than 50 ug divided by L) to cause overt symptoms (14). The findings of this investigation are consistent with those of other studies indicating that ingestion of lead-contaminated soil and dust is an important route of lead exposure for children (15). Direct contamination of repair-shop premises by lead emissions from battery repair and by inappropriate handling of lead scrap appears to be a greater environmental hazard than lead dust carried on work clothes to homes distant from the repair shops.

Measures to control lead exposure in the workplace include providing controlled ventilation for processes that generate airborne lead dust and fume; wet sweeping or vacuuming to remove lead dust from environmental surfaces; avoiding eating or smoking in lead-contaminated areas; washing hands before eating or smoking; using proper respirators when air-lead levels cannot be reduced to safe levels; and showering and changing clothes before leaving work so that lead dust is not carried home (3). Workers at battery repair shops need to be informed of safe work practices. Although these measures may also reduce contamination of the home environment, their effectiveness in reducing household exposures in homes where lead work is done is not known. Soil contamination near shops using lead presents a continuing hazard unless the soil is removed or covered. Ideally, lead-related work should not be done on residential premises.

Small-scale battery repair shops have also been described in Nigeria (16) and the Republic of Trinidad and Tobago (17) and are likely be found in other developing countries. Public health officials should be alert to the possibility of lead poisoning among both workers and nearby residents exposed to such shops and should take preventive action when lead exposure is identified.

References

1. National Institute for Occupational Safety and Health. NIOSH manual of analytical methods. 3rd ed. Cincinnati, Ohio: US Department of Health and Human Services, Public Health Service, 1984; DHHS publication no. (NIOSH)84-100.

2. Searle B, Chan W, Davidow B. Determination of lead in blood and urine by anodic stripping voltammetry. Clin Chem 1973;19:76-80.

3. Occupational Safety and Health Administration. Standard for occupational exposure to lead. Washington, DC: US Department of Labor, Occupational Safety and Health Administration, 1978. (29 CFR Section 1910.1025). References 4-17 may be obtained from the Office of the Director, NIOSH, Mailstop D26, Centers for Disease Control, Atlanta, GA 30333.

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