Hazardous wastes exposure

The Panel has also concluded that chronic effects of hazardous waste exposure at Love Canal have neither been established or ruled out yet, in a scientifically rigorous manner. 

The studies conducted in the past two years have been inconclusive in demonstrating long term health effects due to hazardous waste exposure. 

Thiophene and 3-methylthiophene are Hsted on the TSCA chemical substances inventory. Thiophene is regulated as a hazardous material under OSHA and also regulated under the Clean Air Act, Section 110, 40 CFR 60.489, but there are no exposure limits or controls set for 3-methylthiophene. Both materials are regulated under sections 311/312 of the Superfund Amendments and Reauthorization Act, 1986 (SARA), as materials with an acute health and fire hazard, and under the Resource Conservation and Recovery Act, as ignitable hazardous wastes (DOOl). 

Workers involved in hazardous waste eleanup, handling hazardous materials or other hazardous substanees, faee a more serious safety and health risk than do most eonstruetion or manufaeturing operations. In addition to the typieal slips, trips, and falls found in other eonstruetion or manufaeturing operations, employees handling hazardous waste or ehemieals may eneounter a variety of other hazards ineluding fires, explosions, and health-related issues assoeiated with exposures to toxie substanees. 

HAZWOPER applies only where exposure to hazardous substanees or to health and safety hazards resulting from a hazardous waste operation is likely (see Eigure 2-1). This ean be determined by analysis of exposure monitoring data, hazard eharaeterization, hazard analysis, or exposure assessment [1]. Some of the speeifle examples of work aetivi-ties and situations will be eovered later. 

Any site-related activities such as bench-scale laboratory and R D activities should comply with the OSHA Laboratory Standard (29 CER 1910.1450). R D activities involving pilot- or full-scale field operations should comply with HAZWOPER when there is reasonable possibility for worker exposure to hazardous wastes or substances or emergency response. 

For most hazardous waste sites with proper planning the situation is known before remediation activities begin. The support zone location needs to be carefully considered at the planning stages of the project. A better solution to the theoretical problem at hand would be to move the support zone further from the source of contamination. If the support zone can be placed far enough away, the likelihood for exposure at the support zone is minimized. 

Handling hazardous ehemieals has beeome part of most people s everyday living. Just eonsider gasoline, and how most people fill their own tanks. In the manufaeturing arena, ehemieals are eommonplaee. On hazardous waste sites there are a variety of unknown ehemieal substanees and other hazards that may take the form of a solid, liquid, or gas. The eflfeets of exposure to toxie ehemieals may either be immediate (e.g., aeid burns) or delayed (e.g., lung damage from inhaling asbestos). There are four routes of ehemieal exposure that exist ... 

A medical surveillance program is designed to protect the workers health. Given the limitations of industrial hygiene monitoring data and the many hazards involved in hazardous waste activities, medical surveillance data may provide the only indication that worker exposure to toxic substances has occurred. 

Operations at hazardous waste activities worksites where use of a respirator due to potential radiological (as specified by Article 532 of the Draft DOE Radiological Control Technical Standard) or nonradio-logical exposure is recommended or required... 

Before work aetivity begins, all employees required to partieipate in a medieal surveillanee program for hazardous waste aetivities should undergo a baseline medieal examination (a physieal exam). This exam should be based on speeifie hazards identified during the preliminary hazard assessment. Periodie follow-up exams are required at the disere-tion of the attending physieian. Typieally, these follow-ups are eompleted annually, however, they ean be adjusted to more often or less often dependent on the exposure [1]. 

Nonemergency medical care should be arranged for hazardous waste site personnel who are experiencing health effects resulting from an exposure to hazardous substances. Off-site medical care should make sure that any potential job-related symptoms or illnesses are evaluated in the context of the employee s exposure. Off-site medical personnel should investigate and treat non-job-related illnesses that may put the employee at risk because of task requirements [1]. 

Unless employers ean demonstrate that their operation does not involve employee exposure or the reasonable possibility for employee exposure to safety or health hazards, they should eomply with the standard. To determine if your partieular situation is eovered by the emergeney response provisions of the standard, examine the tasks of your workers to determine if they will be assigned a role or funetion as part of a response to a release of hazardous waste [2]. 

Employers are required to develop and implement a program to inform workers performing hazardous waste operations of the level and degree of exposure they are likely to eneounter. This information needs... 

The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites make up the National Priorities List (NPL) and are the sites targeted for long-term federal cleanup activities. Methyl parathion has been found in at least 16 of the 1,585 current or former NPL sites. However, the total number of NPL sites evaluated for this substance is not known. As more sites are evaluated, the sites at which methyl parathion is found may increase. This information is important because exposure to this substance may harm you and because these sites may be sources of exposure. 

Methyl parathion can enter your body if you eat food or drink water containing it if you swim, bathe, or shower in contaminated water if you touch recently sprayed plants or soil if you touch contaminated soil near hazardous waste sites or if you breathe air that contains methyl parathion, such as near factories or recently sprayed farm fields (or in recent accounts of the illegal use of methyl parathion, if you breathe air or touch contaminated surfaces inside homes where methyl parathion has been used to kill insects). By any means of exposure, methyl parathion goes into your body quickly and gets into your blood. From your bloodstream, methyl parathion goes to your liver, brain, and other organs. Your liver changes some of methyl parathion to a more harmful chemical called methyl paraoxon. Both methyl parathion and methyl paraoxon can bind to enzymes of your nerves within minutes or hours. Your liver breaks down methyl parathion and methyl paraoxon into less harmful substances. These less harmful substances leave your body in urine within hours or days. For more information, see Chapter 3. 

To help public health professionals and others address the needs of persons living or working near hazardous waste sites, the information in this section is organized first by route of exposure (inhalation, oral, and dermal) and then by health effect (death, systemic, immunological, neurological, reproductive, developmental, genotoxic, and carcinogenic effects). These data are discussed in terms of three exposure periods acute (14 days or less), intermediate (15-364 days), and chronic (365 days or more). 

The significance of the exposure levels shown in the Levels of Significant Exposure (LSE) tables and figures may differ depending on the user s perspective. Public health officials and others concerned with appropriate actions to take at hazardous waste sites may want information on levels of exposure associated with more subtle effects in humans or animals (LOAELs) or exposure levels below which no adverse effects (NOAELs) have been observed. Estimates of levels posing minimal risk to humans (minimal risk levels or MRLs) may be of interest to health professionals and citizens alike. 

PBPK models improve the pharmacokinetic extrapolations used in risk assessments that identify the maximal (i.e., the safe) levels for human exposure to chemical substances (Andersen and Krishnan 1994). PBPK models provide a scientifically sound means to predict the target tissue dose of chemicals in humans who are exposed to environmental levels (for example, levels that might occur at hazardous waste sites) based on the results of studies where doses were higher or were administered in different species. Figure 3-4 shows a conceptualized representation of a PBPK model. 

Exposure of the general population to higher concentrations of methyl parathion may result from contact with, or ingestion of, contaminated hazardous waste site media, principally soils and water. No information was found in the available literature regarding the size of the human population potentially exposed to methyl parathion through contact with contaminated waste site media. 

What exposure conditions are likely to be of concern to humans, especially around hazardous waste sites ... 

However, a sample taken in the doctor s office can be properly packed and shipped to a special laboratory, if necessary. Because endosulfan leaves the body fairly quickly, these methods are useful only for finding exposures that have occurred within the last few days. At this time, these methods can only be used to prove that a person has been exposed to endosulfan. The test results cannot be used to predict if you wiU have any adverse health effects. Exposure to other chemicals at the same time at hazardous waste sites could cause some confusion in understanding these results. More information about tests to find endosulfan in the body is presented in Chapters 2 and 6. 

Overview. Humans living in areas surrounding hazardous waste sites may be exposed to endosulfan primarily via dermal contact with or ingestion of contaminated soils since this compound is found bound to soil particles. Although endosulfan can be found in water as colloidal suspensions adsorbed to particles, ingestion of contaminated finished drinking water is not expected to be a major route of exposure since endosulfan is not very water soluble. Likewise, inhalation exposure to endosulfan via volatilization from contaminated media is not a major route of exposure since endosulfan is not very... 

Anand et al. 1987). The authors hypothesized that the ocular effects associated with endosulfan may be a result of prolonged hypertension (although no data on blood pressure were presented, and there is no other information to indicate that chronically administered endosulfan induces hypertension) or an endosulfan-induced vitamin A deficiency (which was observed in this study). Although the rabbit may represent a uniquely sensitive species, the possibility that long-term exposure of persons at hazardous waste sites to endosulfan may result in adverse effects on ocular tissues cannot be eliminated. 

Since endosulfan is a cytochrome P450-dependent monooxygenase inducer, the quantification of specific enzyme activities (e.g., aminopyrine-A -demethylase, aniline hydroxylase) may indicate that exposure to endosulfan has occurred (Agarwal et al. 1978). Because numerous chemicals and drugs found at hazardous waste sites and elsewhere also induce hepatic enzymes, these measurements are nonspecific and are not necessarily an indicator solely of endosulfan exposure. However, these enzyme levels can be useful indicators of exposure, together with the detection of endosulfan isomers or the sulfate metabolite in the tissues or excreta. 

The most important routes of exposure to endosulfan for the general population are ingestion of food and the use of tobacco products with endosulfan residues remaining after treatment. Farmers, pesticide applicators, and individuals living in the vicinity of hazardous waste disposal sites contaminated with endosulfan may receive additional exposure through dermal contact and inhalation. 

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