Agency for Toxic Substances and Disease Registry

This report to Congress and the Administrator of the Environmental Protection Agency (EPA) is submitted by the Agency for Toxic Substances and Disease Registry (ATSDR) in response to Section 104 (i)(10) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund), as amended, which states:

Two years after the date of the enactment of the Superfund Amendments and Reauthorization Act of 1986, and every 2 years thereafter, the Administrator of ATSDR shall prepare and submit to the Administrator of EPA and to the Congress a report on the results of the activities of ATSDR regarding--

(A) health assessments and pilot health effects studies conducted;

(B) epidemiologic studies conducted;

(C) hazardous substances which have been listed under paragraph (2), toxicological profiles which have been developed, and toxicologic testing which has been conducted or which is being conducted under this subsection;

(D) registries established under paragraph (8); and

(E) an overall assessment, based on the results of activities conducted by the Administrator of ATSDR, of the linkage between human exposure to individual or combinations of hazardous substances due to releases from facilities covered by this Act or the Solid Waste Disposal Act and any increased incidence or prevalence of adverse health effects in humans.

ATSDR's 1991-1992 Biennial Report to Congress presented the following conclusions regarding evidence of an association between exposure to hazardous substances at waste sites and adverse health effects:

• Human health studies have shown that adverse health effects have occurred in persons exposed to hazardous substances released from some waste sites.

• People are being exposed to hazardous substances from a variety of sites and unplanned releases.

• By analyzing all existing data for hazardous waste sites and the most commonly encountered substances at those sites, ATSDR has determined where and how people are most likely to be exposed to substances from those sites and the adverse health effects most likely to result.

Additional public health assessments of hazardous waste sites and health studies completed by ATSDR during the past three years, along with an improved toxicological database on priority hazardous substances released from National Priorities List (NPL) sites, confirm and clarify the 1991-92 findings.

This executive summary is an overall assessment, based on the results of activities conducted by the administrator of ATSDR during the reporting period, of the link between human exposure to individual or combinations of hazardous substances due to releases from facilities covered by this legislation or the Solid Waste Disposal Act and any increased incidence or prevalence of adverse health effects in humans.

Site Assessment Findings

• During this reporting period, lead was found at 72% of sites and was also the predominant contaminant of concern in completed exposure pathways. Arsenic, chromium, and cadmium were the next three most commonly identified contaminants of concern.

• Soil was the most frequently contaminated medium (83% of sites assessed) in assessments conducted during this reporting period.

• Data accumulated indicate that more than 1 million people live within a 1-mile buffer of the sites assessed during the past 3 years, and that more than 8.5 million people live within a 1-mile buffer of the sites with population data assessed before FY 1993.

• ATSDR's analysis shows that approximately 11 million people live within 1 mile of the nation's 1,200 NPL sites. Moreover, the agency's demographics analysis of these people shows that a significantly higher percentage of minority populations live near the NPL site(s) than in the other parts of the affected counties. However, residential proximity to uncontrolled hazardous waste sites is at best only a surrogate for exposure information. The extent of exposure of the 11 million persons residing within 1 mile of NPL sites is unknown at this time.

• As off-site sampling has increased and more health data have become available to the agency, ATSDR has been better able to categorize risk to communities around waste sites. The most dramatic shift has been the growth in the percentage of sites ranked as either urgent public health hazards or public health hazards--from 21% before FY 1993 to 53% for sites assessed during the FY 1993-1995 reporting period.

Human Exposure Findings

Exposure assessment studies conducted by ATSDR during this reporting period show that some heavy metals, volatile organic compounds, and other specific substances occur at levels of health concern in the bodies of exposed people. Compounds such as lead, arsenic, mercury, polychlorinated biphenyls, and bromides are found at significant levels in people near some hazardous waste sites. The following examples illustrate how this information is useful in focusing public health responses:

• ATSDR exposure studies focusing on lead show that soil is the most common pathway of exposure of children at hazardous waste sites and that there is a link between contaminated soil and blood lead levels in children.

• ATSDR studies show that reduction of blood lead can be achieved through yard-soil cleanup. Soil cleanup offers a partial solution to the childhood lead problem.

• An Akwesasne, New York, study of PCB levels in lactating women and their nursing children indicated that urine PCB levels in the children were significantly higher. This information can be used to educate potentially affected women and possibly prevent and mitigate some health effects.

Health Effects Findings

• Although epidemiologic findings are still unfolding, when health data from many Superfund sites are evaluated in aggregate, proximity to hazardous waste sites seems to be associated with a small-to-moderate increased risk of some types of birth defects and cancers. Although none of the studies completed in this reporting period found evidence of cancer increases, one study added to our past birth defects findings. A 1995 follow-up study at the Lipari Landfill, Gloucester County, New Jersey, found a fivefold excess in low birthweight for gestational age in infants of mothers living immediately adjacent to the site during the same period studied earlier by the New Jersey Department of Health.

• Another significant health effects-related finding of ATSDR studies completed during this reporting period is from investigations of respiratory disorders at several sites. People living near smelters in Missouri, phosphate processing plants in Idaho, waste incinerators in North Carolina, and oil processing sites in Texas all reported increased respiratory problems. Pulmonary function tests in the Idaho and Missouri populations documented decreased air flow, confirming the self-reported respiratory problems.

• ATSDR's public health assessments and health studies have continued to document that young children are at particular health risk because of their exposure to substances released from sites. During this reporting period, several studies showed that children were part of the population affected by completed exposure pathways, and studies of the effects of substances released from smelters showed that children's respiratory health has been impacted.

• Additional linkage between documented exposure and related adverse health effects comes from ATSDR's analyses of its exposure registry and emergency events surveillance system. These analyses show a significant increase in health problems apparently related to long-term exposure to certain hazardous substances in the case of the registry populations, and related to acute exposures in persons exposed during emergency events. Although the findings from the registry program are based on self-reported data and are being followed up with epidemiologic studies, ATSDR considers the current registry findings indicative of increased health problems related to long-term, low-level exposure to hazardous substances. Following are summary findings from ATSDR's registry and surveillance programs:

Trichloroethylene (TCE) Subregistry--By comparing data gathered from registrants on the TCE Subregistry with national health data, ATSDR has identified an excess number of certain reported adverse health outcomes in the TCE Subregistry population. Of particular note was the excess number of speech and hearing impairments reported among young children. Other increases were reported in the following adverse health outcomes (some only in persons of a certain age and sex): urinary tract disorders, stroke, liver disease, diabetes, kidney disease, and anemia and other blood disorders.

Benzene Subregistry--ATSDR's initial analysis in FY 1995 of several health outcomes reported by Benzene Subregistry registrants found statistically significant increases in the number of cases of diabetes in males ages 10 through 17 years and in cases of childhood diabetes in general. Other increases were found for urinary tract disorders in females of all ages, skin rashes in the very young and males and females 65 years and older, kidney disease in males and females 55 through 64 years, and respiratory allergies in males and females 0 through 9 years. Significant decreases in numbers of cases of hearing impairments, asthma and emphysema, and arthritis were found for specific age groups and sexes.

Trichloroethane (TCA) Subregistry--Comparisons of TCA Subregistry participants' reporting rates (baseline and first followup) to national norms showed statistically significant increases in selected age groups for anemia and other blood disorders and urinary tract disorders in females, and for arthritis and urinary tract disorders in selected age groups in males. At followup, statistically significant increases were seen for anemia and urinary tract disorders in females (for specific age groups) and for urinary tract disorders in males (for specific age groups). However, although statistically significant differences were identified for some age groups at baseline and first followup, the results do not indicate a consistent pattern of toxicity across age groups; therefore, ATSDR found no overall excess reporting of any health outcome by TCA registrants compared with national norms.

• The Hazardous Substances Emergency Events Surveillance System has documented that unplanned releases occur most often at fixed facilities; the majority of events involve the release of a single substance; employees are usually the victims (substantial numbers of responders and the general public are also affected--in 1994, an equal number of employees and the general public were injured); and respiratory and eye irritation are the most common injuries (in some cases, more serious injuries and death have occurred).

• Another significant finding was the unexpectedly increased number of people living near sites contaminated by chemical mixtures including volatile organic compounds (VOCs) who had lymphocyte phenotypes that have been associated with B-cell chronic lymphocytic leukemia. This finding is significant and is being investigated through targeted epidemiological investigations of populations believed to be at highest risk because of their documented exposure to VOCs.

• Results of the ATSDR study on end-stage renal disease indicate that people living in the vicinity of hazardous waste sites might have an elevated risk of kidney disease. These findings are being pursued in follow-up epidemiological investigations.

Taking these health findings in the aggregate, ATSDR concludes that uncontrolled hazardous waste sites and unplanned releases of hazardous substances that constitute emergency events are a major environmental threat to human health. Although there remain significant gaps in the scientific database on the extent of human exposure to hazardous substances released from sites, and key toxicologic data gaps still exist, progress has been made in better characterizing both the exposure and toxicity databases. The human health findings accrued to date support the need for interdicting human exposure to and mitigating toxicity of hazardous substances released from hazardous waste sites and similar sources of exposure. The published scientific literature supports concern about the health effects associated with human exposure to hazardous substances released from sites: birth defects; lower birthweight; respiratory problems; chronic disease (diabetes, stroke, urinary tract disorders); and neurological problems in children and adults. The link between elevations in cancer rates in community populations and exposure to hazardous substances is less well documented. Nonetheless, the public remains concerned about cancer because 19 of the 56 hazardous substances found during this reporting period in completed exposure pathways at 10% or more of hazardous waste sites are known or likely to be human carcinogens. The cancer burden imposed by these substances is unknown at this time, but is being addressed in ongoing health investigations by ATSDR.

For more information on the work of ATSDR or for a complete FY 1993-1995 Report to Congress, please contact:

Office of Policy and External Affairs
Agency for Toxic Substances and Disease Registry
1600 Clifton Road, N.E. (E-60)
Atlanta, Georgia 30333

Telephone: (404) 639-0500

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