Operator exposure data

Occupational exposure to higher than background levels of chloroform can be expected to occur in some occupations although few quantitative exposure data were located. Populations with the highest potential exposures appear to be workers employed in or persons living near industries and facilities that manufacture or use chloroform operators and individuals who live near municipal and industrial waste water treatment plants and incinerators, and paper and pulp plants and persons who derive their drinking water from groundwater sources contaminated with leachate from hazardous waste sites. 

The risk assessment comprises an effect assessment (hazard identification and hazard characterization) and an exposure assessment. The principles for the effect assessment of the active substances are in principle similar to those for existing and new chemicals and are addressed in detail in Chapter 4. Based on the outcome of the effect assessment, an Acceptable Daily Intake (ADI) and an Acceptable Operator Exposure Level (AOEL) are derived, usually from the NOAEL by applying an overall assessment factor addressing differences between experimental effect assessment data (usually from animal studies) and the real human exposure situation, taking into account variability and uncertainty for further details the reader is referred to Chapter 5. As a part of the effect assessment, classification and labeling of the active substance according to the criteria laid down in Directive 67/548/EEC (EEC 1967) is also addressed (Section 2.4.1.8). 

According to the 1981-83 National Occupational Exposure Survey (NOES, 1997), as many as 2 million workers in the United States were potentially exposed to toluene (see General Remarks). Occupational exposures to toluene may occur in painting, varnishing, various cleaning operations, laboratories, car repair shops and many other workplaces where toluene is produced or used as solvent or intermediate to prepare other chemicals. Extensive occupational exposure data are presented in a previous monograph (lARC, 1989a). 

PRINCIPLES OF OPERATOR EXPOSURE MODELLING 175 PHED PESTICIDE HANDLERS EXPOSURE DATABASE 176 General Description 176 Qnality of Data 177 Formnlations and Use Scenarios 177 Use in Risk Assessment 178 Exposnre Rednction Measures 178 Model Updates 179 Comments on the Model 179 GERMAN MODEL 180 General Description 180 Formulations and Use Scenarios 181 Use in Risk Assessment 182 Exposure Reduction Measures 182 Model Updates 182 Comments on the Model 183... 

Exposure estimates that are required for risk assessment may be obtained from chemical-specific field studies, or from extrapolations from other field studies. This requires high-quality exposure data that have been obtained under conditions relevant for the exposure and use scenarios under consideration (Krieger et al, 1992 Eenske and Teschke, 1995 Krieger, 1995 Turnbull et al, 1995). For risk assessment purposes, the exposure data obtained for relevant use scenarios can be compared with an appropriate accepted exposure level (e.g. Acceptable Operator Exposure Level (AOEL)) based on the toxicological profile of the compound. 

Figure 5.1 Tiered data requirements for estimating operator exposure for use in risk assessment and regulation of pesticides (AOEL, acceptable operator exposure level)...

Risk certification accompanied by data requirements, such as individual product operator exposure studies, dermal absorption data and/or the range of results from biological monitoring of those exposed. This tier recognizes that where the best available knowledge used in the second tier still indicates risks, then exposure measurements for the actual product will be necessary. Exposure surveys need to be of adequate size, sufficiently reported and representative in order to be convincing. Exposure surveys may gather data that can be used for statistical relations, such as transfer coefficients, which may be used for other products in the lower tiers. 

Boyle, C.A., E.A. Braun and The Selected Cancers Co-operative Study Group (1992). IVoxy Respondents and the Validity of Occupational and Other Exposure Data, Am. J. Epidem., 136, 712-721. 

In order to assess risk to individuals following dermal exposure to a pesticide, dermal absorption data are often required to convert dermal deposition data to estimates of systemic exposure. These estimates of systemic exposure are then compared with the No Observed Adverse Effect Levels (NOAELs) from oral toxicity studies or limit values (for instance. Acceptable Operator Exposure Levels (AOELs)) derived from these oral data (Bos et at., 1998 Rennen et al 1999). As noted in the introduction, oral studies are generally used because the toxicology database is typically focused on the oral route of exposure. 

The harmonization of the regulation of plant protection products throughout the EU has resulted in harmonized data requirements for occupational, bystander and worker exposure assessment. These requirements are outlined in Annex III of Council Directive 91/414/EEC. This annex lists product-related exposure data requirements and, consistent with the tiered approach outlined above, provides some advice as to when different data are required (Harney, 2000). An estimation of operator exposure, using, where available, a suitable calculation model, must always be made and reported. Actual exposure data must be provided where the risk assessment indicates that a health-based value is exceeded or where no appropriate calculation model exists to estimate exposure. 

Acceptable Operator Exposure Level (AOEL) The acceptable operator exposure level is the maximum amount of active substance to which the operator may be exposed without any adverse health effects. The AOEL is expressed in mg of the chemical per kg of body weight of the operator. The AOEL is based on the highest level at which no adverse effect is observed in tests in the most sensitive relevant animal species or, if appropriate data are available, in humans. Appropriate safety factors (SEs) are also taken into consideration, i.e. NOAEL/SE = AOEL (UKPSD, 2003). 

Chronic exposure to ANTU led to the investigation of two cases of bladder cancer in two rodent operators. Therefore, the use of ANTU was restricted to professional operators. Available data were inadequate to evaluate carcinogenicity in humans. Chronic sublethal exposure may result in antithyroid activity and hyperglycemia. 

The establishment of a statistically sound data-set on usage allows an evaluation of likely operator exposure, as realistic work rates can be derived from the data collected, such as average field size, area sprayed per operator per day, amount of pesticide handled per day, etc. All of these factors are vital in refining predicted operator exposure models, and are discussed at length by Hamey (2001). 

Based on exposure data from previous AFIERA studies, fuel tank repair operations of single-point-entry fuel bladders containing fire suppressant foam were determined as the worst-case exposure situations. The highest exposure results were measured in operations performed inthe C-130 Hercules transport aircraft s auxiliary fuel tanks. 

There is an abundance of compatibility information provided by resin manufacturers. The information can be of two kinds. One is actual coupon exposure data with no judgement as to the suitability, and other is a list of chemicals against which a rating system (A, B, C, etc.) is given. Often the maximum operating temperature is also given as additional useful information. 

This appendix contains extensive chemical resistance data for a number of commercial fluoropolymers. Most of the chemicals are frequently encountered in processing operations. The data for each fluo-ropolymer are organized alphabetically, using the common name of each chemical. The reader should review the next section (Sec. V.2) to understand the basis for the PDL Rating. Exposure conditions for each chemical have been listed because the same chemical could behave in a different way if the conditions of exposure (such as temperature or concentration) are altered. Where data have been available, the effect of exposure on the physical properties such as weight change and tensile properties have been listed. 

As a result of the Eleventh Circuit Court of Appeals decision (AFL-CIO versus OSHA), OSHA s permissible exposure level for tetrachloroethylene, which was lowered to 25 ppm in 1989, was returned to 100 ppm (OSHA 1993). Based on human exposure data, Stewart etal. (1981) concluded that a TLV of 100 ppm contained no safety factor for individuals more susceptible to the subjective and neurological symptoms of tetrachloroethylene. Based on human data, the ACGIH (ACGIH 1995) TLV-TWA is 25 ppm. The geometric mean exposure of dry cleaning machine operators was 22 ppm (Ludwig et al. 1983), a value close to the ACGIH TLV-TWA. 

No quantitative data regarding absorption in humans after dermal exposure to chlordane were located. Kazen et al. (1974) reported that chlordane tends to persist on the hands of pest control operators (exposure duration not reported) for at least 2 years after exposure to the pesticide has... 

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