Operator Exposure Data Requirements

New regulations to protect the applicant of the plant protection products were brought into force, regulating data requirements, experimental details for the measurement and model calculations [47, 48]. 

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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. 

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. 

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. 

OCCUPATIONAL AND RESIDENTIAL RISK ASSESSMENT 371 AOELs Versus MOEs 371 Route Considerations 372 Uncertainty and Safety Factor Selection 372 Aggregation and Cumulative Risk Assessment 372 CO-OPERATIVE REGULATORY ACTIVITIES 373 SUMMARY AND CONCLUSIONS 374 Terminology 374 Framework 374 Data Requirements 374 Methodological Guidance 375 Development and Utility of Databases 375 Modeling Initiatives 375 Data Analysis 375 Metric Selection 376 Research Needs 376 Exposure Mitigation 376 Risk Assessment 376 REFERENCES 376... 

One of the major components of the operational dose uptake assessment process has been the development of a detailed plant operational model broken down to an individual task level. Preparation of the model commenced early in the project design and drew on the extensive experience gained by BNFL over many years of designing, operating, and decommissioning plutonium plants and more recent experience of operating MOX fuel fabrication plants. This experience provided valuable data on both the manpower requirements and task durations for both process and maintenance operations and on the main potential short- and long-term sources of operational exposure and how these exposures could be adequately controlled. 

Initial Exposure Assessment, (i) Each employer who has a workplace or work operation covered by this standard shall ensure that a competent person conducts an exposure assessment immediately before or at the initiation of the operation to ascertain expected exposures during that operation or workplace. The assessment must be completed in time to comply with requirements which are triggered by exposure data or the lack of a negative exposure assessment, and to provide information necessary to assure that all control systems planned are appropriate for that operation and will work properly. 

QRA is fundamentally different from many other chemical engineering activities (e.g., chemistry, heat transfer, reaction kinetics) whose basic property data are theoretically deterministic. For example, the physical properties of a substance for a specific application can often be established experimentally. But some of the basic property data used to calculate risk estimates are probabilistic variables with no fixed values. Some of the key elements of risk, such as the statistically expected frequency of an accident and the statistically expected consequences of exposure to a toxic gas, must be determined using these probabilistic variables. QRA is an approach for estimating the risk of chemical operations using the probabilistic information. And it is a fundamentally different approach from those used in many other engineering activities because interpreting the results of a QRA requires an increased sensitivity to uncertainties that arise primarily from the probabilistic character of the data. 

Data are available for plasticizers and ionophores, and indicate the operational stability (the higher the log P value, the higher the lipophilicity). The minimal lipophilicity log P required for membrane components with a lifetime of 30 x 24 h upon exposure to aqueous solution is estimated to be around 10 whereas it has to be as high as 25 for direct measurement in blood, serum and plasma. 

Ingestion Toxicity Data are available for the acute (single-dose) ingestion/oral toxicity of many toxic materials (National Institute for Occupational Safety and Health, Registry of Toxic Effects of Chemical Substances, 1983 Lewis, Sax s Dangerous Properties of Industrial Materials, 9th ed., 1996). However, very few data are available for prolonged ingestion or periodic doses of toxic materials. It is likely that metabolic processes would operate to increase the total burden required for toxic effects for such chronic exposures, except for some materials (such as mercury and lead) which apparently can accumulate in the body. 

Most specifications give a set strain and exposure period but it is preferable to examine test pieces at a series of times such that data can be obtained on the relationship between strain and time to appearance of cracks. ISO 1431 requires examination to be carried out with a lens of x7 magnification but, unfortunately, any examination of cracks is to some extent dependent on the eyesight of the operator. In practice, many workers say a crack is only a crack if they can see it with the naked eye. The alternative procedure of measuring relaxation in stress will be discussed later. An optical method of automatically detecting cracks has been described by Zeplichal51 but this is relatively complicated and has not been considered for standardisation. 

Evaluation of worker exposure requires samples in the breathing zone and in general room air or rest area. To define a potential hazard, check compliance with regulations or obtain data for control purposes, samples would normally be collected in the vicinity of the operation itself. In general, samples are collected in the vicinity of the workers directly exposed and also workers remote from the exposure who voice complaints. Sample duration requires that the sample contain sufficient matter for an accurate analysis and is based on the sensitivity of the analytical procedure and the estimated air concentration, as well as the current threshold limit value for the contaminant. Table 1 contains appropriate sampling duration, sample flow rates and sample volume. 

Inventory Update Rule (lUR) (40 CFR 710). The lUR was established in 1986 to require manufacturers and importers of chemicals listed on the master TCSA Inventory to report current data every four years on the production volume of chemicals imported or produced. Food and feed products produced from natural agricultural product, such as oilseeds, are not required to be reported but all oU and meal products obtained by solvent extraction that is sold for other than food or feed use (e.g., oils as chemical raw materials and meal as fertilizer) are. Cottonseed oil, soap stocks, acidulated soap stocks, deodorized distillates, hydrogenated cottonseed oil are some of the substances reported by extraction and refining operations under lUR. EPA amended this rule in 2003 (1/9/03 68 FR 848). Cottonseed oil is on the list of partially exempt substances, which are not subject to the new reporting requirements for processing and use data but continue to have to report the current lUR information as well as manufacturing exposure-related information. 

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