A public health assessment tool used to analyze the health and safety effects of a major landfill landslide.
On March 9, 1996, a landslide of unprecedented magnitude occurred at Ohio's largest solid waste landfill. Approximately 20 acres of the existing grandfathered landfill slid into an 11-acre section of recently constructed but unlined landfill [ILLUSTRATION FOR PHOTO OMITTED]. The landslide exposed approximately 1.5 million cubic yards of old garbage. In addition, a 200-foot- high vertical scarp remained where the waste mass had broken away from the landfill.
The Rumpke Sanitary Landfill, located in Colerain Township, Hamilton County, Ohio [ILLUSTRATION FOR FIGURE 1 OMITTED], is licensed to operate by the Hamilton County General Health District and permitted by the Ohio Environmental Protection Agency (OEPA) to accept up to 8,600 tons of solid waste per day. The landfill accepts waste for disposal from 750,000 residential customers in 63 counties and 150 municipalities in three states (Ohio, Kentucky, and Indiana) and is also permitted to dispose of waste containing asbestos (1).
Within hours of the slide, the health commissioner and Hamilton County General Health District personnel arrived at the site. It looked as if a miniature Mount St. Helens had erupted. Gaseous vapors were observed emanating from the exposed garbage. The odor - a musty, rotting garbage smell - was strong. The possible release of hazardous substances, exposing people and the environment, concerned health district personnel. Worker safety became a focus of concern. Local media - TV, radio, and newspapers - started covering the Rumpke landslide. Citizens living near the landfill complained of odors and questioned the health effects. Children in nearby schools complained of nausea and headaches. In the eyes of many, the Rumpke Sanitary Landfill had become a public health hazard and nuisance.
The health district staff needed a decision-making tool that would enable them to quickly decide whether to order an evacuation, as well as to determine what kinds of health and safety measures to implement and to understand which residents were most affected by the landslide. The public health assessment process was that tool. The purpose of this article is to explain the process used to assess the severity of the public health hazard and to determine the public health response plan to be implemented.
Public Health Assessment
A public health assessment is a method of organizing and systematically reviewing environmental and health data to establish the presence and magnitude of a public health impact. This tool has a somewhat different focus than do risk assessments and comparative risk assessments. Public health assessments use data from a variety of sources to address community concerns and to determine the public health implications of the hazardous site; they are site-specific and qualitative. Risk assessments usually serve regulatory purposes, such as prioritizing site remediation efforts or establishing appropriate cleanup levels (2). Comparative risk assessments, which are used by communities to set their environmental priorities, involve diverse members of the community (e.g., lay people, scientists, elected officials) in comparing categories of risk.
Between March 11 and March 18, 1996, the Hamilton County General Health District convened an interdisciplinary team of professionals to conduct a public health assessment of the landslide site. The team consisted of the following district staff members: health commissioner; medical director; directors of nursing, water quality and waste management, and environmental health; public health nurses; and sanitarians. The health district consulted professionals from the Hamilton County Department of Environmental Services, the Cincinnati Health Department, OEPA, the Ohio Department of Health (ODH), the U.S. Environmental Protection Agency (U.S. EPA), the Centers for Disease Control and Prevention- Agency for Toxic Substances and Disease Registry (CDC-ATSDR), and the National Institute for Occupational Safety and Health (NIOSH).
The health commissioner facilitated the public health assessment for the Rumpke landslide using the ATSDR assessment model (3) as a basic guide. Three integrated components make up this assessment: review of existing environmental and medical data, exposure pathway analysis, and toxicological analysis.
Review of Environmental and Medical Data
Staff sanitarians provided the assessment team with environmental monitoring data and past inspection reports on the Rumpke Sanitary Landfill. Public health nurses reported medical-symptoms information from complaint records and individual case histories. The purpose of reviewing not only the current complaint records but also the prior compliance history of the site was to ensure that potential health threats were not overlooked. Table 1 shows a summary of this information.
The majority of the health complaints came from residents living adjacent to the landfill and from children in nearby elementary and middle schools. The health district public health nurses completed an individual case history for each of the children. Some children were sick; others were trying to get excused early to go home. All complaints, including those from our 24-hour hotline, were investigated by health district staff.
A review of the Rumpke Sanitary Landfill's compliance record informed the assessment team that the facility had disposed of infections and asbestos-type solid waste. The team also recognized that the landfill had been in operation before passage of the Resource Conservation and Recovery Act (RCRA). Waste streams classified today as hazardous probably had been disposed at the Rumpke site during the pre-RCRA era.
Exposure Pathway Analysis
The second component of the public health assessment process considered the source of contamination, the transport pathways (i.e., air, soil, surface water, groundwater, disease vectors, and food chain), the exposure area, the route of exposure, and the population affected. For human health effects to occur, an exposure route or transport pathway must exist. The transport pathway evaluation is shown in Table 2. This multimedia transport pathway evaluation must occur before addressing the other questions raised by the exposure pathway analysis.
The team determined that air was the transport pathway of greatest significance. Most of the complaints received involved odors. Methane, hydrogen sulfide, volatile organic compounds, airborne biological contaminants, and other particulate matter (e.g., asbestos), were the most likely contaminants. These contaminants could not only be spread by the air but also by disease vectors such as birds and insects.
The team also considered surface water as a possible transport pathway, because Banklick Creek flows through the Rumpke Sanitary Landfill site. Although none of the exposed waste reached the creek, the health district staff sampled the stream for pH, turbidity and conductivity, then resampled it for volatile organic compounds (VOCs), five-day biochemical oxygen demand (BOD), organic halogens (TOX), total organic carbon (TOC), and chemical oxygen demand (COD). The initial water monitoring indicated no impact.
The site's subsurface geology made groundwater an unlikely pathway. Likewise, soil, as a transport pathway, was dismissed since the garbage slid into an excavated area lying below the natural grade by at least 10 feet.
The exposure pathway analysis shown in Table 3 reveals the source of exposure as the solid waste in the uncovered landfill. This exposed solid waste varied in composition from recently disposed garbage to highly decomposed garbage deposited in the 1970s. The solid waste was interspersed with soil that had been deposited as daily cover. The assessment team also surveyed the vicinity for any other sources that could support the health symptoms data. The team concluded the solid waste in the landslide area of the landfill was the only source.
As stated earlier, the transport pathways representing the greatest concern were air and disease vectors. Vectors, primarily flies and birds, did not become the problem initially expected by the assessment team. A combination of a cold, wet spring with an absence of much intact food in the exposed solid waste discouraged most of the vectors from congregating at the landslide, and they did not become a transport pathway. The blowing winds disseminated any gases and particulates emanating from the exposed waste.
Determination of exposure area and route goes hand in hand with determination of affected populations. To be affected, a person must come into contact with a sufficient quantity of the harmful agent. The assessment team decided that on-site landfill workers and people living within a one-mile radius of the landfill would be most affected. Means of exposure would be inhalation.
The exposure pathway analysis was now complete. The analysis indicated that some residents and workers were exposed. The next question was: "Is there a significant potential for disease or injury from this exposure?" This question is answered with toxicological analysis.
The next step in the public health assessment process is the toxicological analysis. Toxicology deals with the science of poisons and their effects (4). Generally, it is the size of the dose that determines whether a substance is poisonous or harmful. The toxicological analysis considers both the presence of a potentially harmful substance and the dose (5). Other factors that are part of the toxicological analysis are as follows:
* exposure duration - acute (less than 14 days), intermediate (14-365 days), chronic (greater than 365 days);
* exposure frequency - number of hours per day of exposure;
* exposure fluctuation - constant exposure or intermittent;
* bioavailability - amount of substance absorbed in the body once inhaled;
* guideline values exceeded - comparison of sample results against other public and environmental health databases to determine if the substances of concern can cause harm; and
* potential for disease and injury - a public health risk rating assigned by the health district assessment team on the basis of the other factors listed above.
Each of these factors is addressed individually as a part of the toxicological analysis. Table 4 shows the toxicological analysis for the Rumpke Sanitary Landfill landslide.
[TABULAR DATA FOR TABLE 1 OMITTED]
TABLE 2 Environmental Transport Pathway Evaluation Transport Pathway Rumpke Landfill Air Odors present; low levels of methane and other volatile organic compounds found on site Disease Vectors Insects and birds Surface Water No contaminants found Groundwater Unable to sample - low volume of groundwater available Soil Not applicable TABLE 3 Exposure Pathway Analysis Exposure Pathway Rumpke Landfill Source Landfill solid wastes Transport Pathways Air and disease vectors Exposure Area On site to within one-mile radius of the site Exposure Route Inhalation Impacted Population Workers and residents within a one-mile radius
The contaminants of concern were identified from the initial air sampling results and a literature search. The initial air sampling results are shown in Table 5. The results are in parts per billion (ppb) and were compared with OSHA guidelines. The air-sampling instruments were located around the perimeter of the landfill. Both upwind (control) and downwind air samplers were set.
TABLE 4 Toxicological Analysis Analyses Rumpke Landfill - Colerain Township Transport Pathway Air Contaminants of Concern Methane, hydrogen sulfide, bioaerosols, VOCs (e.g., toluene, xylene) Exposure Duration Intermediate exposure risk (14-365 days) Exposure Frequency 24 hours/day - worse in the daytime hours Exposure Fluctuation Intermittent rainfall reduces odors Bioavailability High, for hydrogen sulfide and VOCs Guideline Values Exceeded None Potential for Injury and Disease Low potential
[TABULAR DATA FOR TABLE 5 OMITTED]
The magnitude of the landslide prevented the assessment team from knowing in March how long it would take to remediate the landslide and eliminate the source of contamination. Possibly, the remediation could take up to a year. Therefore, the team assigned the exposure risk as intermediate: 14-365 days.
Exposure to airborne contaminants would depend on the time of day, wind direction and velocity, and relative humidity. The assessment team assumed that human exposure could occur anytime. The team also believed that rainfall and high humidity would keep air emissions close to the source and at ground level. The first round of air sampling showed that no compounds exceeded any health effect guidelines; as a result of the low exposure risk, the bioavailability factor was not a problem.
The assessment team integrated all of the information collected. They decided that the potential for human injury and disease associated with the exposed solid waste was low. The team recognized, however, that new information could change their health assessment conclusions. Another landslide, an increase in disease vectors, an explosion, or a landfill fire would require a reassessment of the public health impact.
Public Health Response Plan
The public health assessment was completed on March 18, 1996. Although the public health assessment revealed a low risk of injury and disease, community residents remained alarmed. At times, odors were strong enough to warrant press releases advising residents with a history of respiratory disease to stay indoors. Several environmental advocacy groups held protests near the landfill. A daily newspaper, the Cincinnati Post, compared the landslide at the Rumpke Sanitary Landfill to "opening a cyst" (6).
The Hamilton County Board of Health wanted the health district staff to stay proactive. Consequently, the health district, in cooperation with the Hamilton County Department of Environmental Services, maintained the air-monitoring program used in the initial public health assessment. The air monitoring occurred weekly. The health district also monitored the surface streams weekly. This sampling frequency continued until June. Periodic press releases, public presentations and monthly Public Health Assessment Progress Reports were provided to the media, elected officials, and residents. Frequently informing the media and the residents about health district findings helped the community at large to keep the public health risk in proper perspective. Media sensationalism did not appear to alarm the general public or residents who lived near the landfill.
Several health and safety control measures were put in place. Heavy equipment cabs at the landfill were outfitted with air-monitoring equipment. A deodorizing spray system was installed on the windward side of the landslide area to assist in odor control. The exposed solid waste was sprayed with Posi-Shell[R], a material that assists in the control of odors, fire, and disease vectors. Air cannons were used for bird control. Additional monitoring and piezometer wells were installed to monitor leachate levels. The generation of methane from inside the waste mass was controlled and monitored through the gas extraction system. A manifest on personnel working in and around the landslide area was kept. The Rumpke Corporation provided methane monitors to citizens living near the landfill.
As previously mentioned, a landfill fire might change the public health assessment conclusions. Presently, four fires have occurred in the exposed solid waste. Fortunately, air monitoring was in place during the fires. The public health assessment tool was used. Health district activities during these fires will be covered in a subsequent article.
The Rumpke Sanitary Landfill landslide presented the Hamilton County General Health District with a unique opportunity to construct a public health assessment and response plan. The public health assessment tool provided a mechanism to compile and evaluate various health effects data associated with the Rumpke landslide. The assessment consisted of three parts: review of existing environmental and medical data, exposure pathway analysis, and toxicological analysis.
An interdisciplinary public health team was assembled to assess the public health effects of the Rumpke Sanitary Landfill landslide. The exposure of odoriferous solid waste resulting from the landslide alarmed many people. The assessment team determined that air was the transport pathway for exposure. No airborne contaminants were found in concentrations above OSHA health guidelines. The assessment team categorized the Rumpke Sanitary Landfill landslide as a low risk for human injury or disease.
The public health response plan involved weekly air and water monitoring. The health district maintained accountability to the public through news releases, monthly progress reports, and public presentations.
1. Kenter, R., K.R. Miller, and B.O. Schmucker (1996), "Initial and Long-Term Response Plans for 30-Acre Municipal Waste Landfill Landslide," 19th International Madison Waste Conference, September 24-26, 1996, Univ. of Wisconsin-Madison, p. 180.
2. Younger-Lewis, C.R. (1995), "Public Health Assessment - Process Overview," Clues to Unraveling the Association Between Illness and Environmental Exposure Short Course, Centers for Disease Control and Prevention-Agency for Toxic Substances and Disease Registry, conference materials, sponsored by Univ. of Cincinnati, College of Nursing and Health, Feb. 3, 1995.
3. Neufer, L., and D. Warkunas (1995), "Analyzing Potential Health Threats of Hazardous Substances Releases at the Community Level: A Practical Approach," Clues to Unraveling the Association Between Illness and Environmental Exposure Short Course, Centers for Disease Control and Prevention-Agency for Toxic Substances and Disease Registry, conference materials, sponsored by Univ. of Cincinnati, College of Nursing and Health, Feb. 3, 1995.
4. Klaassen, C.D., M.O. Amdur, and J. Doull, eds. (1986), Casarett and Doull's Toxicology: The Basic Science of Poisons, 3rd ed., New York, N.Y.: Macmillan Publishing Company.
5. Agency for Toxic Substances and Disease Registry (1992), Public Health Assessment Guidance Manual, Chelsea, Mich: Lewis Publishers.
6. Clark, M.O., and F. Griggs (March 19, 1996), "Sealing the Leaky Landfill," Cincinnati Post, p. 1A.
Corresponding author: Timothy I. Ingram, M.S., R.S., Health Commissioner, Hamilton County General Health District, 11499 Chester Road, Suite 1500, Cincinnati, OH 45246.
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|Publication:||Journal of Environmental Health|
|Date:||Sep 1, 1997|
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