Post-application exposure residential

The application of pesticides is widespread in agriculture and elsewhere, and the concomitant risks depend on their toxicity, and duration and frequency, as well as the level of exposure (Henderson et al., 1993 Krieger and Ross, 1993). Exposure may be incidental or almost continuous. This is true not only for workers (occupational exposure), but also for the general public and people who may be considered as bystanders, who are not involved in the actual occupational activities with pesticides, but are close enough to get exposed. In this present chapter, only operator exposure will be discussed because agricultural re-entry modelling is discussed in Chapter 2 and residential post-application exposure modelling in Chapter 6 of this book. 

USEPA (1997a). Post Application Exposure Monitoring Test Guidelines, Series 875 - Group B - Occupational and Residential Exposure Test Guidelines, Version 5.3,... 

The USEPA has spearheaded a similar tiered approach for application and post-application in residential exposure scenarios. With the US Food Quality Protection Act (FQPA) as impetus, the USEPA has developed a series of algorithms which yield Tier 1 estimates for a broad range of residential application and post-application exposure scenarios. Approximately 40 unique scenarios are addressed in the USEPA s draft Standard Operating Procedure for Residential Exposure Assessment (USEPA, 1997c). Although some jurisdictions, including Canada, have adopted some of these algorithms. Tier 1 approaches for residential scenarios have not been the subject of substantial international discussion to date. 

USEPA (1998a). Post-Application Exposure Guidelines Series 875 - Group B - Occupational and Residential Exposure Test Guidelines, Version 5.4, United States Environmental Protection Agency, Office of Pievention, Pesticides and Toxic Substances, Washington, DC, USA (website http //www.epa.gov/oscpmont/sap/1998/march/contents. htm). 

Residential Post-Application Pesticide Exposure Monitoring... 

RESIDENTIAL POST-APPLICATION PESTICIDE EXPOSURE MONITORING 73... 

Measurement of the post-application residential exposure is, in many ways, more complicated than the agricultural re-entry since there may be multiple sources and routes of exposure, varying amounts of time spent in contact with these sources and a much wider age and health range in the exposed population (USEPA, 1991, 1999a). Chemicals such as pesticides that are released into or otherwise enter the residential enviromnent tend to partition into various compartments, either through direct dispersion in indoor air or through adsorption onto surfaces that serve as sinks from which material can subsequently be released into the air (Ross et al., 1990, 1991). A detailed discussion of the measurement of pesticides in the residential enviromnent is presented in Chapter 3. 

Compared with the occupational exposnre of applicators and workers following pesticide application in the field, post-application residential exposure to pesticides used in and around the home is lower in level, but encompasses a wider variety of scenarios, such as age distribution, activity patterns and product use. Typically, few data are available on residential exposure, while a large body of data does exist for occupational exposures. Residential exposure assessment and modeling may benefit from the new data requirements under the United States Food Qnality Protection Act of 1996 (Lewis et al, 1994 Hill et al., 1995 Lu and Fenske, 1998 USEPA, 1990 Whitmore et al., 1994). In occupational exposnre assessment, a database approach is favored, while in residential exposure assessment a mechanistic and statistical modeling approach is dominant. 

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