NORTH GALLOWAY ROAD
YAKIMA, YAKIMA COUNTY, WASHINGTON
This health consultation was prepared at the request of a resident to evaluate the potential healthhazard posed by lead and arsenic contamination resulting from past use of lead arsenate pesticide onproperty located in Yakima, Yakima County, Washington. DOH prepares health consultationsunder a cooperative agreement with the Agency for Toxic Substances and Disease Registry(ATSDR).
Acid lead arsenate (PbHAsO4) was the primary insecticide used to control the codling moth inWashington fruit orchards between 1905 and 1947.1,2 Lead arsenate solution was sprayed directlyonto the trees using hand sprayers, and any excess spray dripped from the trees contaminating soilsbeneath or near them. Use of lead arsenate dropped drastically in 1948 when DDT became widelyavailable.3 High levels of arsenic in soil resulting from lead arsenate use rendered much of the landin central Washington unproductive for agriculture due to arsenic's toxicity to vegetation.1 Potentialconcern for human health arose when old orchard lands began to be converted to other land usepurposes such as schools or residential areas. Lead and arsenic, the primary constituents of leadarsenate pesticide, are highly toxic to humans.
A resident became concerned about chemical contamination in the area when two relatively youngmembers of her family developed cancer (one with pancreatic cancer and the other with stomachcancer). One of the cancer victims also complained that he had difficulty growing plants in thegarden. Several other people from across the highway also suffered from cancer (one brain cancer,others general cancer). In addition, an oncologist that treated one of them made a comment that thereseemed to be a lot of cancers from that part of the state. He suggested testing the drinking water forarsenic and other metals, and the soil for lead and arsenic
The petitioner sampled the soil from the home of one of the cancer victims. Soil samples wereanalyzed for lead and arsenic. Both lead and arsenic levels in soil were above background levels.The owner of the drinking water system that supplied the residence had the drinking water analyzedfor several inorganic contaminants. No contaminants were present at levels of concern. Table 1summarizes the analytical results for lead and arsenic in soil and water.
|Comparison a Value (ppm)|
|Soil 2||back yard||arsenic||28||20|
|Soil 3||front yard||arsenic||44||20|
|Soil 4||back yard(patio)||arsenic||41||20|
|Soil 6||front yard(front door)||arsenic||56||20|
|Water 1||communitywell||arsenic||ND||10 mg/l|
a - Comparison values for soil are MTCA cleanup levels. Drinking water values are EPA's Maximum Contaminant Levels (MCLs)
ND = Not Detected
Lead and arsenic are both toxic to humans. The presence of lead and arsenic at elevated levels in soil, however, does not necessarily indicate that adverse health effects are expected to occur to people living on or near the site. In order for chemical contaminants to cause harm, they must first enter the body through ingestion, inhalation or dermal absorption. Metals do not pass easily through the skin and inhalation of resuspended soil is not thought to be a significant contributor to exposure. Therefore, the most likely route of exposure to lead and arsenic at the N. Galloway Rd. residence is inadvertent ingestion of contaminated soil through direct contact.4,5
Consumption of produce grown in contaminated garden soil is another potential pathway, and willalso be addressed. The following discussion will address the potential health hazards to children andadults associated with exposure to lead and arsenic found in soil on the property. The issue of cancer will also be discussed in general terms.
Past uses of lead in paint, gasoline, plumbing, pesticides and canning have contributed to wide spread dispersion of lead and subsequent human exposure. Elimination of lead in gasoline and solder used in canning has greatly reduced exposure to lead through inhalation and ingestion pathways. As a result, the number of one to 5-year-old children in the U.S. with elevated blood lead levels has dropped from 88.2% in the late 1970s, to 4.4% in the early 1990s.6 Currently, the main pathways of lead exposure in children are ingestion of paint chips, contaminated soil and house dust, and drinking water in homes with old plumbing.
Natural background levels of lead in Yakima basin soil range from 2-17 ppm.7 All samples from the N. Galloway Rd. property exceed background levels. Only one sample, however, exceeds a level that the EPA considers to be a potential hazard (400 ppm in bare soil of areas where children play).
Lead causes a wide array of health effects in different systems of the body, but the primary target is the nervous system. Children less than seven years old are more susceptible to lead exposure and more sensitive to its toxicity than adults. Health effects include decreased IQ, decreased attention span, and irritability.8
The EPA has classified lead and lead compounds as a probable human carcinogen based onsufficient evidence from animal studies, but inadequate evidence from human studies. Animalsexposed to very high doses of lead compounds in drinking water developed renal tumors.6 Thecarcinogenicity of lead has not been documented in humans.
The levels of lead found in soil on the N. Galloway Rd. property do not appear to be of concern to adults. Children, on the other hand, are likely to ingest larger amounts of soil, and they are more susceptible to lead's toxicity. Therefore, lead in soil at the property represents a potential concern. A recent blood lead survey conducted by the Washington State Department of Health in the fall of 1999 found very low incidence of elevated blood lead in children living in agricultural areas of central Washington despite past widespread use of lead arsenate in the region.9 Cases of elevated blood lead levels in these children were often traced to eating paint chips, Mexican folk remedies, or Mexican candies that contained high levels of lead, and could not be attributed to past use of lead arsenate pesticide.
Sources of arsenic contamination in the U.S. are primarily from pesticide use or industrial emissions(i.e., smelters). Background levels for arsenic in central Washington soils are normally less than 6ppm.5 Arsenic levels detected in all soil samples collected from the N. Galloway Rd. property wereabove natural background levels. Furthermore, arsenic levels in all soil samples were above MTCAcleanup levels.
The majority of information concerning the health effects of arsenic exposure in humans comes from studies of populations that were chronically exposed to arsenic in their drinking water and occupational studies in which workers were exposed to arsenic trioxide dust in the workplace. Several studies have indicated that workers exposed to arsenic trioxide (As2O3) dust in air at smelters have an increased risk of lung cancer.10,11 Furthermore, a positive dose response between cumulative exposure to arsenic and lung cancer risk was observed. In other words, the more arsenic workers were exposed to, the more likely they were to develop lung cancer. Chronic exposure to arsenic in drinking water has occurred in large populations in Taiwan, Chile, Mexico, Argentina, and Bangladesh.12,13 In Bangladesh, where the water concentrations were frequently greater than 0.5 mg/l and as high as 3.8 mg/l, symptoms included dermatological effects (hyperpigmentation, hypopigmentation, keratosis, cracking skin, lesions, and skin cancers), bladder cancer, and black foot disease that ultimately leads to gangrene. Studies in U.S. populations exposed to arsenic in drinking water have not shown increased cancer incidences, but arsenic concentrations in water were generally less than those reported in Taiwan and Bangladesh. The effects of chronic exposure to arsenic in soil have not been studied.
Arsenic levels found at the N. Galloway Rd property, though elevated, do not appear to be at levelsthat would adversely affect adults. The levels, however, are a potential health concern for childrenbecause they are more likely to contact contaminated soil through playing, and inadvertently ingestit through frequent hand to mouth contact. Soil arsenic levels surrounding active and inactive copperand lead smelters are often much higher than levels found on old orchards. Children living nearformer smelters have had elevated urinary arsenic levels compared to a background population. Noadverse health effects have been attributed to exposure to arsenic in soil in any studies.
Thousands of acres in central Washington have been contaminated by past use of lead arsenate. While adverse health effects have not been linked to lead or arsenic exposure on old orchard land,the Washington State Department of Ecology (Ecology) realizes that the contamination maypotentially represent a hazard to people over their lifetime. Ecology is currently investigatingstrategies with which to address the area-wide contamination of central Washington soil with leadand arsenic.
Gardening on lead and arsenic contaminated soil
Root uptake of lead and arsenic by vegetable plants and subsequent ingestion by humans is another potential source of human exposure. There is limited evidence that root crops such as carrots might absorb more metals than previously thought,14 but the overwhelming majority of information suggests that lead and arsenic are less of a concern for uptake by plants than other metals such as cadmium.
Washington State University has published a bulletin for gardeners that grow produce in lead and arsenic contaminated soils.15 The bulletin provides several recommendations with which to reduce exposure to lead and arsenic in/on produce and garden soil. The bulletin can be found on the Internet at http://soils.tfrec.wsu.edu/lead%20papers.htm . A hard copy will be provided to the petitioner with this consultation.
Cancer is a common disease that will affect about 1/3 of people in the U.S. The cause of many types of cancer is unknown; however, numerous factors including diet, lifestyle, environmental exposure, and genetics may be associated with the occurrence of cancer. Additionally, cancer risk increases with age. While cancer is often spoken of in a general sense, as if all forms of cancer were manifestations of the same disease, scientists and health professionals acknowledge that there are many different types of cancer that result from different causal mechanisms. Because it is a common disease, it is not uncommon for people to know one or more people that have been affected by cancer. When several people within close geographic proximity develop cancer, a cancer cluster is often reported. A cluster is the occurrence of a greater than expected number of cases of a particular disease within a group of people, a geographic area, or a period of time. A suspected cancer cluster is more likely to be a true cluster if it involves a large number of cases of one type of cancer, rather than several different types; a rare type of cancer, rather than common types; or a number of a certain type of cancer cases in age groups not usually affected by that type of cancer.16 Even when a greater than expected number of specific cancer types is identified, it is often determined that the cluster occurred by chance, and is not the result of an identifiable cancer causing mechanism.
It is difficult to assign a single environmental cause to the cancers reported by the resident in Yakima. The types of cancers reported (pancreatic, stomach, and brain) affect different organ systems of the body. Furthermore, none of these cancer types have been found to be associated with long-term exposure to arsenic or lead in epidemiological and toxicological studies. Therefore, it is not likely that exposure to lead- and arsenic-contaminated soil in the area has led to the cancers observed by the petitioner.
Child Health Initiative
ATSDR recognizes that infants and children may be more vulnerable to exposures than adults when faced with contamination of air, water, soil, or food.17 This vulnerability is a result of the following factors:
- Children are more likely to play outdoors and bring food into contaminated areas.
- Children are shorter and their breathing zone is closer to the ground, resulting in a greater likelihood to breathe dust, soil, and heavy vapors.
- Children are smaller and receive higher doses of chemical exposure per body weight.
- Children's developing body systems are more vulnerable to toxic exposures, especiallyduring critical growth stages in which permanent damage may be incurred.
Children are not currently living at this residence. As previously mentioned, the levels of lead andarsenic in soil at the N. Galloway Rd. residence would be of slight concern if children were livingthere. Even should children dwell at the residence in the future, adverse health effects would notlikely result, but attempts should be made to reduce exposure to contaminated soil.
Based on the information evaluated in this consult, this site is categorized as a no apparent public health hazard for residents exposed to arsenic and lead in soil and drinking water at the Galloway Road home. Arsenic and lead levels found in soil, though elevated, were not detected at levels that would adversely affect adults. A water sample from the well that supplied drinking water to the residence did not contain inorganic contamination at levels of health concern. Although measured levels of lead and arsenic in soil represent more of a concern for young children, young children are not currently living at this residence. Elevated levels of lead in the garden suggest that precautionary measures be taken should children reside here in the future.
Several factors indicate that lead and arsenic in soil at this residence, and other residences in thearea, are not responsible for the cancers observed by the petitioner. The varying types of cancernoted by the resident indicate varying causes and are not currently known to be associated with leador arsenic exposure. In addition, doses estimated from exposure to arsenic in soil, the primarycontaminant of concern with respect to cancer, are relatively low compared to drinking water arsenicexposures that have been associated with cancer.
Exposure to lead- and arsenic-contaminated soil should be reduced through the following measures:
- Remove shoes before entering the home. This will help to limit the amount of soilcontaminants that are tracked into the home.
- Limit contact with soil when gardening. (See WSU Bulletin "Gardening on lead- andarsenic-contaminated soils).
- Wear protective clothing while gardening or working in the yard. Protective clothing should be removed before entering the house.
- Thoroughly wash produce grown in the garden. Peel carrots and other root crops beforeconsumption.
The WSU Bulletin "Gardening on lead- and arsenic-contaminated soils" has been sent to the petitioner as an attachment with this health consultation.
Site Assessment Section
Office of Environmental Health Assessments
Washington State Department of Health
DOH Designated Reviewer
Robert Duff, Manager
Site Assessment Section
Office of Environmental Health Assessments
Washington State Department of Health
ATSDR Designated Reviewer
Technical Project Officer
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry
1. Benson, N. R. (1968). Arsenic in Soil. Washington State Horticultural Association, Wenatchee, Washington.
2. Peryea, F. J. (1991). "Estimation of Soil Arsenic and Lead Concentrations Resulting from use of Arsenical Pesticides in Apple Orchards: (I) Model Development, and (II) Application to and Discussion of the Proposed Building Sites for New Schools in Wenatchee School District No. 246." Wenatchee, Washington, Tree Fruit Research and Extension Center Washington State University.
3. Peryea, F. J. (1998). Historical Use of Lead Arsenate Insecticides, Resulting Soil Contamination and Implications for Soil Remediation. 16th World Congress of Soil Science, Montpellier, France.
4. Hostynek J, R Hinz, C Lorence, M Price, and R Guy (1993). "Metals and the Skin." Critical Reviews in Toxicology 23(2): 171-235
5. Polissar L, K Lowry-Koble, D Kalman, J Hughes, G van Belle, D Covert, T Burbacher, DBolgiano and N Mottet (1990). "Pathways of Human Exposure to Arsenic in a CommunitySurrounding a Copper Smelter." Environmental Research 53(1): 29-47.
6. Center for Disease Control. CDC's Lead Poisoning Prevention Program.http://www.cdc.gov/nceh/lead/factsheets/leadfcts.htm . Last Updated March 3, 2001.
7. San-Juan, C. (1994). Natural Background Soil Metals Concentrations in Washington State. Olympia, Washington Department of Ecology.
8. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Lead. July 1999.
9. Ossiander E. Washington State Department of Health. Report pending.
10. Enterline, P. E. and G. M. Marsh (1982). "Cancer Among Workers Exposed to Arsenic and Other Substances in a Copper Smelter." American Journal of Epidemiology 116(6): 895-911.
11. Jarup, L., G. P. G and S. Wall (1989). "Cumulative Arsenic Exposure and Lung Cancer in Smelter Workers: A Dose-Response Study."
12. Tseng, W. P., H. M. Chu,S. W. How, S. W. Fong, J. M. Fong, C. S. Lin and S. Yeh (1968). "Prevalence of Skin Cancer in an Endemic Area of Chronic Arsencicism in Taiwan." Joural of National Cancer Institute 40: 453-463.
13. Dhar, R. K., B. K. Biswas,G. Samanta,B. K. Mandal,D. Chakraborti,S. Roy,A. Jafar,A. Islam, G. Ara,S. Kabir,A. W. Khan,A. Ahmed and A. Hadi (1997). "Groundwater Arsenic Calamity in Bangladesh." Current Science 73(1): 48-59.
14. Washington State Department of Agriculture. News Release: Group Working to Prevent Crop Planting in High Lead Soil. January 29, 1999. Available at Internet:http://www.wa.gov/agr/News/1999/news9903.pdf .
15. Peryea FJ, Gardening on lead- and arsenic-contaminated soils. Washington State University bulletin EB1884. Updated July 2001.
16. National Cancer Institute. Cancer Facts - Cancer Clusters. Last reviewed November 19, 2001. Available at Internet: http://cis.nci.nih.gov/fact/3_58.htm
17. Agency for Toxic Substances and Disease Registry. Interim guidance on including child health issues in Division of Health Assessment and Consultation Documents. Atlanta: US Department of Health and Human Services, Public Health Service, July 1998.
This Health Consultation was prepared by the Washington State Department of Health under acooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It isin accordance with approved methodology and procedures existing at the time the healthconsultation was begun.
Technical Project Officer,
SPS, SSAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health consultation and concurs with the findings.
Lisa C. Hayes
for Richard Gillig