Unregulated disposal of asbestos contaminated shower water effluent: a question of public health risk.

The disposal of specific toxic wastes and other hazardous substances into a public sewer or storm drain system is prohibited, and regulatory compliance is achieved through a combination of federal, state and local statutes. The plethora of materials includes waste oils, industrial chemicals, heavy metals, solvents, and just about anything else that poses a risk to public health. Unfortunately, it appears that a seemingly innocuous and often overlooked substance, asbestos, is unregulated when it comes to the disposal of waste shower water generated within an asbestos abatement decontamination facility. Perhaps this is in part due to the general understanding that cause-effect associated illness is long-term, rather than immediate, which helps create the illusion that asbestos is not of the same magnitude of danger as those prohibited substances. Many regulatory authorities, including Massachusetts, consider asbestos as a special rather than hazardous waste when it is time for disposal.

Standard work practices in asbestos abatement require proper personal hygiene and decontamination, which are performed in a typical decontamination facility as described by the U.S. Occupational Safety and Health Administration (OSHA), 1926.58 (J)(2)(iii), (1)--specifically, the removal of contaminated worksuits and showering prior to entering the "clean room." This procedure is required to minimize fibers leaving the worksite and contaminating those outside.

Contaminated clothing, equipment and tools which may be re-used are cleaned in the "dirty room," while personal protective equipment such as respirators are wet-wiped and eventually washed in the shower area to remove residual fibers. Assuming that waste shower water does indeed contain asbestos fibers, contractors generally pass this water through a 5.0 micron filter before disposal into a public system or a holding tank for future disposal in an approved landfill. The logic of this practice is commendable since it can help minimize water contamination. However, it appears that there are no federal regulations specifically requiring the filtration of waste shower water generated within a decontamination facility. This practice probably results from interpreting broadly OSHA's 1926.58, Appendix F, or believing that the U.S. Environmental Protection Agency (EPA) has a regulation which may apply to this very specific form of environmental water pollution. Perhaps such regulations do not exist at the federal level because the health effects of asbestos in water have so far been incompletely ascertained (2).

To say, quantitatively, just what poses a health risk from asbestos-tainted water may remain unanswerable for some time. Many studies of domestic water supplies have been conducted since asbestos was first reported in the 1973-1974 Lake Superior study (3). This early study of asbestos in the drinking water supply of Duluth, Minnesota, verified the existence of asbestos mineral fibers in concentrations which ranged from approximately 20 x 106 fibers/liter of water (5 to 30 micrograms of asbestos fiber per liter of water). An upper limit of fiber concentration did not appear to be clearly established.

The study attributed the concentrations to a mining operation that discharged its waste products to the bottom currents of Lake Superior. Other investigations in Kentucky, Washington and Pennsylvania have detected asbestos contamination in the water supplies from a variety of sources.

Whether ingestion of asbestos fibers, either by food or water, will have adverse health effects is unclear. None of these studies attempts to quantify safe limits of ingestion. Unlike occupational exposure which causes asbestosis, mesothelioma, other lung ailments, and also poses an increased risk for cancer, no one really knows the health risk of drinking fiber-contaminated water.

It seems unlikely that shower water from asbestos abatement projects would contribute significantly higher concentrations of fibers to a public water supply, given the dilution factor in the volume of water. However, the possibility exists that part of the asbestos found in the drinking water may have been generated by these very projects. It would seem logical, therefore, to not only take preventive measures, but also to attempt to determine if there is a health risk created by not using filtration.

Table 1, from Millette's study (4), shows the distribution of reported asbestos concentration in drinking water of selected cities and states. Whether or not these numbers can be correlated with increased health risk and subsequent illness, remain unanswerable.

As such, OSHA's Appendix F, 1926.58 Work Practices and Engineering Controls for Major Asbestos Removal, Renovation, and Demolition--Non-Mandatory, simply provides guidelines for compliance with this regulation and indicates that further regulations may be required under the National Emission Standards for Hazardous Air Pollutants (NESHAPS) or EPA's Clean Water Act.

OSHA recommends filtering shower water from a portable shower: nothing is mentioned about filter type or size. Additionally, the word "filtration" does not appear in the text which describes the shower area in the decontamination facility. This non-mandatory appendix only states that showers must be drained properly after each use to ensure that contaminated water is not released to uncontaminated areas. OSHA states, "If waste water is inadvertently released, it should be cleaned up as soon as possible to prevent any asbestos in the area from drying and becoming airborne in areas outside the work area." There is no definition of "properly drained." This leaves one to interpret and/or not comply with OSHA's suggestion.

Furthermore, OSHA says that the water must be drained properly. Using the word "must" implies that this is a mandatory regulation: not so, since Appendix F is non-mandatory. This ambiguity needs clarification and the use of the word "must" should be deleted. Likewise, the term "properly drained" needs a definition. However, since OSHA's function is to protect the worker, rather than the environment and those outside the worksite, perhaps these suggestions will have to be undertaken by other agencies.

Table 1
Distribution of reported asbestos concentrations in drinking
water from 406 cities in 47 states, Puerto Rico, and the
District of Columbia, USA
Highest asbestos
concentration,                        Number of      Percentage
|10.sup.6~ fibers/liter                cities
Below detectable limits                  117         28.8
Not significant (|is less than~0.5)      103         25.4
|is less than~ 1                         113         27.8
1 - 10                                    33          8.1
|is greater than~ 10                      40          9.9
Total                                    406          100

It also appears that under the National Emission Standards for Hazardous Air Pollutants, Appendix C.40 CFR 61, Subpart M, no regulation is specific to shower water. NESHAPS is concerned primarily with water and the effluent that is within the abatement worksite itself rather than the decontamination facility. NESHAPS requires that no "visible emissions" occur (Section 61.141) and that all asbestos containing waste material which has been mixed with water to form a slurry (61.152) be properly contained in leaktight containers before transportation to a waste disposal site. Therefore, the slurry itself would be regulated by NESHAPS, but not the waste shower water, even though one might consider the waste water to be a slurry in the broadest terms.

Federal regulations appear non-existent for this particular type of contaminated water. Contractors, therefore, should research their respective state and local department of environmental protection or department of health regulations to determine whether or not they can simply discharge asbestos contaminated shower water into the nearest drain. These agencies would have the regulatory authority, if any, rather than state and local plumbing codes, which are primarily concerned with the physical and mechanical safety requirements of pipes and fixtures of a water or sewage system. If federal, state or local health agencies do not prohibit such activities, then perhaps such regulations exist elsewhere under water authorities.

In Connecticut, regulations require waste water generated during abatement to be filtered by best available technology. According to New York State's Industrial Code 56, a 5.0 micron filter is mandatory in the shower room. The Code states, "Shower water released should be cleaned, collected, and filtered through a system with at least 5.0 micron particle size collection capability. A system containing a series of several filters with progressively smaller pore size shall be used to avoid rapid clogging of the filtration system by large particles." A similar requirement exists in Pennsylvania, while other states do not have any regulations which focus on filtration of waste shower water. Although it appears that some filtration of asbestos occurs with a 5.0 micron filter, it would be difficult to quantify the amount due to the varying degree of decontamination on clothing, tools, equipment, and fiber concentrations in the ambient air.

Why, then, do contractors generally utilize a filtering system, specifically with a 5.0 micron filter? It seems that they either follow the guidelines, with modifications, as suggested by OSHA's Appendix F, or are following regulations as established by certain states. For others, liability and scare tactics may be the primary motivation for filtration. With the escalation of asbestos related lawsuits, contractors are taking this extra measure to reduce their potential liability, regardless of the existence statutory regulations.

Filtering waste shower water should be a standard work practice and required by regulatory compliance. It should not be something that is left for the contractor to interpret. In several states, as indicated, regulations do exist -- even though they may be somewhat ambiguous.

In summary, no one really knows quantitatively what may create a health risk and subsequent illness resulting from the ingestion of asbestos-contaminated drinking water. Studies done in San Francisco by Kanarek (5, 6) and Conforti (7) revealed a positive relationship between chrysotile asbestos in drinking water and some esophageal, stomach, digestive organ and pancreatic cancers. Chrysotile belongs to the serpentine mineral group and was the most abundant and widely used type of asbestos. Other investigations (8, 9, 10, 11) have demonstrated similar correlations. In Duluth, Minnesota, when levels of asbestos in the drinking water were high, mortality rates also were elevated for gastrointestinal and pancreatic cancer. In the Puget Sound area of Washington state, odds ratios for tumors of the small intestine were consistently elevated when levels of asbestos in the water supply also were high.

From a public health preventive position, contractors should use filtration until a clearer picture is established by new studies, particularly when positive correlations between ingested asbestos and cancer have been demonstrated; and even though experiments with long term ingestion of asbestos fibers in animals (12) have not yet provided a definite reproducible organ-specific carcinogen.

Currently, there appears to be no federal statutory authority regarding disposal of asbestos-contaminated shower water effluent generated within an asbestos abatement decontamination facility. At best, several states have regulations that are somewhat vague. Public health officials should question this apparent oversight and recognize the human health risk potential. Hills (13) indicated that there is a growing demand to remove asbestos from drinking water. As such, prevention is the best medicine.

References

1. Occupational Safety and Health Administration, Code of Federal Regulations, 29, Part 1926.58 (revised July 1, 1988).

2. Klaasen, C.D., M.O. Amdur and M.D. Doull, editors (1986), Casarett and Doull's Toxicology, The Basic Science of Poisons, Third Edition, MacMillan, New York, NY.

3. Nicholson, W.J. (1974), "Analysis of the Amphibole Asbestiform Fibers in Municipal Water Supplies," Environ. Health Persp. 9:165-72.

4. Millette, J.R., P.J. Clark, M.F. Pansing and J.D. Twyman (1980), "Concentration and Size of Asbestos in Water Supplies," Environ. Health Persp. 34:1325.

5. Kanarek, M.S., P.M. Conforti, L.A. Jackson, R.C. Cooper and J.C. Murchio (1980), "Asbestos in Drinking Water and Cancer Incidence in the San Francisco Bay Area," Amer. J. of Epidem. 112:54-72.

6. Kanarek, M.S. (1983), "The San Francisco Bay Epidemiology Studies on Asbestos and Drinking Water and Cancer Incidence: Relationship to Studies in Other Locations and Pointers for Further Research," Environ. Health Persp. 53:105-106.

7. Conforti, P.M., M.S. Kanarek, L.A. Jackson, R.C. Cooper and J.C. Murchio (1981), "Asbestos in Drinking Water and Cancer in the San Francisco Bay Area," J. of Chronic Disability 34:211-24.

8. Polissar, L., R.K. Severson, E.S. Boatman and D.B. Thomas (1982), "Cancer Incidence in Relation to Asbestos in Drinking Water in the Puget Sound Region," Amer. J. of Epidem. 116:314-28.

9. Polissar, L., R.K. Severson and E.S. Boatman (1983), "Cancer Risk from Asbestos in Drinking Water, Summary of a Case-control Study in Western Washington," Environ. Health Persp. 53:57-60.

10. Polissar, L. (1984), "Case-control Study of Asbestos in Drinking Water and Cancer Risk," Amer. J. of Epidem. 119:456-71.

11. Sigurdson, E.R., B.S. Levy, J. Mandel, R. McHugh, L.J. Michienzi, H. Jagger and J. Pearson (1981), "Cancer Morbidity Investigations: Lessons from the Duluth Study of Possible Effects of Asbestos in Drinking Water," Environ. Research 25:50-61.

12. Condie, L.W. (1983), "Review of Published Studies of Orally Administered Asbestos," Environ. Health Persp. 53:3-9.

13. Hills, J.P. (l979), "Asbestos in Public Water Supplies, Discussion of Future Problems," Annals of the New York Academy of Science 330:573-78.

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