Childhood lead poisoning near abandoned lead mining and smelting areas: a case study of two affected households.

In 1858 lead mining began in an area just north and west of present day Joplin (1), which is located in Jasper County in southwest Missouri. This mine marked the start of what became the Tri-State Mining District which ultimately covered portions of southwest Missouri, southeast Kansas and northeast Oklahoma. Mining continued in the district until the mid 1900s with little or no reclamation efforts attempted. The result of this activity is apparent in approximately 240 square miles of mine tailings and open, flooded mine shafts that remain in Jasper County.

Site characterization of this area in 1986 by the U.S Environmental Protection Agency (EPA) (2) showed lead and cadmium to be the primary contaminants and led to the addition of the Jasper County mining area to the National Priority List in 1990 (3). In October, 1990 the federal Agency for Toxic Substances and Disease Registry (ATSDR) contracted with the Missouri Department of Health (DOH) to conduct an exposure study on residents of those mining areas to determine if living near them caused increased levels of lead or cadmium in the residents.

The process of counseling the participants for exposure reduction yielded dramatically different levels of concern among the parents and varying solutions to the problem. Two of the households in which children with elevated blood lead levels lived will be presented and contrasted.

Methods

The study began early in 1991 and venous blood was collected from 413 participants. Participants signed informed consent forms for biologic and environmental sampling, completed questionnaire information, gave blood and urine samples, and some participants had an environmental assessment of their homes. Each participant was given $10 for participating in the study.

All participants with blood lead levels greater than 10 ||micro~gram~/dl were considered elevated (4) and were retested. Any participant with levels over 15 ||micro~gram~/dl was visited by a representative of DOH. Home visits included discussion of the potential sources of exposure, ways of reducing exposure, and the need for medical follow-up, along with environmental sample collection of water, soil and paint where applicable. In some homes, the EPA collected additional environmental samples, which included first draw water samples, interior dust (composite from floors in child's bedroom, living areas and window sills), XRF measurements of interior paint (mean of readings taken on walls and trim in rooms most frequented by children), and composite soil samples composed of numerous samples taken throughout the yard (5).

All participants in the study were selected randomly from the study population and the two homes which will be presented in this study were no exception. These two homes each had two children participating in the study; all four had elevated blood lead levels; lived in the same general area of the study; and were visited repeatedly by DOH personnel to collect environmental samples and to interview and counsel the parents.

Results

In the first home (H1) two brothers were tested and found to have elevated blood lead levels: the first (H1A) was found to have a blood lead level of 21 ||micro~gram~/dl and was 29 months of age. The second child (H1B) had a blood lead level of 19 ||micro~gram~/dl and was 47 months old. According to the Centers for Disease Control and Prevention (CDC) guidelines of October 1991 (4), these children were considered to have Class III and Class IIB blood lead levels, respectively. Both siblings were retested for blood lead levels in September 1991, and both DOH and EPA collected environmental samples at the home.

The second home (H2) also had two brothers, one of which (H2A) was 40 months of age and the other (H2B), 62 months. These children, who had blood lead levels of 39 and 21 ||micro~gram~/dl, respectively, also were retested and environmental samples collected from their homes in September, 1991. Both children in H2 were considered as CDC Class III.

Follow-up blood samples confirmed elevated blood lead levels in all four children. Results showed H1A was 20 ||micro~gram~/ml and H1B was still 19 ||micro~gram~/dl; while H2A showed an increase to 41 ||micro~gram~/dl and H2B increased to 26 ||micro~gram~/dl. Each of these children remained in their respective CDC class ranking category.

Environmental samples collected by DOH at house H1 included a midstream water sample, and a soil sample collected in an unvegetated area where the children frequently played. Lead in the water was considered non-detectable at |is less than~.005 mg/L and the soil was 1,340 ||micro~gram~/g as analyzed by the Missouri Public Health Laboratory. This home was estimated to have been built prior to 1910 and the exterior paint appeared to be lead-based, although sampling was not conducted. Both the interior and exterior of the home appeared in relatively good repair, and the level of sanitation was moderate to good.

At house H2, a midstream water sample, a soil sample from an unvegetated area away from the house where the children played, and a sample of peeling exterior paint were collected by DOH personnel. Results of these samples showed lead in water as non-detectable, soil lead as 1,190 ||micro~gram~/g, and exterior paint as 189,500 ||micro~gram~/g lead. H2 was estimated to have been built prior to 1920. Both the interior and exterior of the home were in poor repair, and general sanitation was poor.

Results from the EPA sampling were not available to DOH personnel until May 1992, and, therefore, were not beneficial for initial consultation with the property owners. Data received from EPA yielded the following results:

* House H1 -- Soil = 4,830 ||micro~gram~/g lead; household dust = 3,310 ||micro~gram~/g lead; water = 2 ||micro~gram~/L lead; and interior paint = 2.8 mg/|cm.sup.2~ lead.

* House H2 -- Soil = 1,850 ||micro~gram~/g lead; household dust = 37 ||micro~gram~/g lead; water = 2 ||micro~gram~/L lead, and interior paint = 4.2 mg/|cm.sup.2~ lead.

Discussion

Lead exposure in children may be from a variety of sources (4, 6) including paint, soil or dust, water, parental occupations or hobbies, air, food, or "traditional" medicines. Interior or exterior paint, especially in older homes, may be lead based and may flake or chalk, allowing ingestion or inhalation. Soils and dust may include residual lead from leaded automobile fuel emissions, industrial emissions (including mining and smelting operations), and lead paint particles, among other sources. Water may be contaminated at the source or through lead plumbing or solders used in the distribution system, especially in areas where the source is slightly acidic. Parental exposure through hobbies or occupations such as soldering, auto body or mechanic work, furniture refinishing or foundry work may increase a child's exposure if done in the home, or if the parent returns home after these activities without showering or changing clothes.

Air may be contaminated through industrial emissions, wind-blown soils, or lead paint abatement projects which are not properly contained. Ingestion of lead through food is becoming less common, but continues to occur through food being grown in contaminated areas, stored in lead soldered cans (...in 1989 only 1.4 percent of domestic cans contained lead in solder...) or poorly fired ceramic ware. Additionally, the food may be contaminated during preparation. Many "traditional" medications such as Pay-loo-ah or Greta contain large amounts of lead and are used primarily by some ethnic groups as home remedies.

During interviews with both households it was established that in neither home were there parental hobbies or occupations, traditional medicine use, or food storage or source problems which would indicate an obvious exposure route. Additionally, water sampling yielded no detectable lead level, and neither house was located near any current lead producing industry.

During visits to their respective homes, all four children were observed playing and digging in the soil in unvegetated areas, and at one point child H1A, who reportedly sucked his thumb, was observed to be eating soil. Both homes were assumed to contain lead-based paint which was confirmed by EPA sampling. At H1 the paint was primarily intact on the exterior; although the interior surfaces were paneled, a small amount of dusting appeared on the trim and window sills.

House H2 had severe flaking of the exterior leaded paint and although the interior was paneled, trim work was suspect and substantial amounts of dust were present throughout the home. In order to provide bedroom space for the children, renovation of a previously unused attic was taking place at H2. Although the attic had not previously been painted, the home was located within approximately three blocks of a primary lead smelter which was no longer in operation. Lead contamination of the attic space through smelter emissions was considered as a potential exposure source, although interior dust samples did not show excessive levels.

After several discussions between DOH staff and the parents of the children with elevated blood lead levels, several recommendations were made as interim actions. These included cleaning the interior of the home thoroughly using wet methods and high phosphate detergent; restricting the children's outside play to areas not near the house and in well-grassed areas; restricting children's access to painted surfaces such as window sills within the home; and watching carefully so the children did not place foreign objects or soiled hands and toys in their mouths. An emphasis on the necessity for good hygienic practices by the children, especially in handwashing; proper nutrition; and the need to maintain high levels of sanitation was directed at the parents. These practices were to be continued until longer term solutions could be implemented.

The parents in each home were very receptive to the recommendations and appeared to clearly understand the numerous exposure routes by which the children may be exposed. Both families, however, had reservations about their ability to restrict activities of the children.

In response to DOH sample results and counseling, the parents of H1A and H1B began cleaning the interior of the home with phosphate detergents and restricting the children's access to the yard. These parents reported it to be normal for their children to play as much as 10 hours per day in the yard; therefore, they were anxious to regain use of their back yard.

The back yard of H1 was well fenced on three sides and bordered the home on the fourth. The family initiated a remediation program for the fenced area by encapsulating the soils nearest the home by pouring a concrete slab the length of the house, extending from the structure eight feet into the yard. The family capped the remaining yard with six inches of soil which was tested by a private lab and found to contain only 10 ||micro~gram~/g lead.

The parents of H1A and H1B reported that this remedial work was completed in March 1992, at a cost of approximately $400. In May 1992 both children were retested by their pediatrician, at which time both had blood lead levels of 14 ||micro~gram~/dl which brought the children into CDC Class IIA. The children will continue to be rescreened periodically by the pediatrician.

Household H2 reported cleaning, improved hygienic practices, and restricted access of children to areas thought to be elevated in lead and unvegetated. Parents also indicated plans for completing interior construction in order to reduce interior dust, encapsulating or removing siding, revegetating the yard, and possibly providing shrubbery or some other type of barrier which would restrict access to soils near the house. During subsequent visits to the home, DOH representatives have been unable to validate that any of the reported activities have taken place. The family reported that in May 1992 the family pediatrician conducted follow-up blood testing which showed the blood lead level of child H2A had increased to 45 ||micro~gram~/dl, while H2B remained stable at 26 ||micro~gram~/dl. While H2B remained in CDC Class III, H2A moved upward into Class IV.

Summary

Household members at H1 made a conscious choice to make behavioral changes and more costly environmental modifications to protect the health of the children living in the home. The home was in relatively good condition initially, and household income was adequate to afford the cost of remedial activities. These modifications lowered overall blood lead levels of the affected children in the home.

The home where children H2A and H2B lived was in poor repair and showed poor sanitation practices, and poor personal hygiene was practiced by the children. Observations at the home did not give the appearance of significant activities occurring as a result of the DOH counseling. This lack of response is at least partially responsible for continuing high blood lead levels in the children. It was unclear whether this lack of response by H2 was due to failed educational efforts by DOH representatives in showing reasonable options to prevent exposure, or if real or self-imposed cost restraints were viewed as barriers. The parent subsequently began cooperating with the local health department, community development office, and the children's pediatrician to help solve the problem.

Conclusion

In conducting the Jasper County Lead and Cadmium Exposure Study it was the intent of DOH to gather information on a community which may be exposed to heavy metal contaminants and determine if there are health effects associated with this exposure. No provision was made to initiate remedial activities at individual homes, but only to report data to the household, offer interpretation of results, and refer the participants to their private physicians for medical follow-up and to local health agencies for any required environmental follow-up.

Not unlike many rural or smaller urban health units, a lead poisoning program does not exist in Jasper County, so in many cases local sanitarians or environmental health specialists will be called upon to investigate and help resolve environmental exposures to lead. Since the CDC guidelines for lead poisoning consider a child to be elevated at a blood lead level of 10 ||micro~gram~/dl, local health units will be called upon increasingly for help. This will even occur in areas where a known source contaminant is not apparent.

Although these households are not necessarily indicative of all homes in this study area, or all homes in any area, they indicate a range of responses which may be seen during an environmental assessment for lead exposure. In many cases, in order to ensure the health of children exposed to lead, more effort than just providing information to the parent will be required by the field personnel.

Investigators will, in many areas, require additional training in risk identification, routes of exposure, and proper remedial procedures. Many health units do not have ordinances which require abatement of lead hazards so they must rely on cooperation of the public or from complimentary governmental agencies, which should be prepared to assist in the resolution of lead exposure problems.

References

1. Ritchie, E. (1986), Guide Book to the Tri-State Mineral Museum, A&J Printing, Nixa, MO.

2. ... (1986), Potential Hazardous Waste Site, Site Inspection Report, U.S. Environmental Protection Agency Region 7, Kansas City, KS.

3. ... (1991), Confirmed Abandoned or Uncontrolled Hazardous Waste Disposal Sites in Missouri and Hazardous Waste Remedial Fund Statement of Revenues, Expenditures, and Changes in Fund Balance, Missouri Dept. of Natural Resources, Jefferson City, MO.

4. ... (1991), Preventing Lead Poisoning in Young Children, U.S. Dept. of Health and Human Services, Centers for Disease Control and Prevention, Atlanta, GA.

5. ... (1991), Sampling Protocol for the Jasper County Blood Lead and Cadmium Exposure Study, U.S. Environmental Protection Agency Region 7, Kansas City, KS.

6. ... (1986), Toxicological Profile for Lead, Doc. No. PB90-267378, Agency for Toxic Substances and Disease Registry, Atlanta, GA.

Anthony Moehr, Jasper County Health Dept., 115 N. Madison, Webb City, MO 64870.