Small-scale retrospective studies

For a small-scale retrospective study, participants enter and study a field in which a pesticide has been used over a period of time. The purposes of small-scale retrospective studies are to determine whether the pesticide(s) in question has leached to ground water in certain fields, and to characterize the leaching pattern in the soil profile at a given point in time. This section contains discussions on site selection, site characterization, the number and location of observation wells, well construction and sampling, and soil sampling. [Pg.178]

Groundwater monitoring study (small-scale retrospective)... [Pg.147]

For the purposes of a small-scale retrospective or prospective study, the hollow stem, continuous-flight auger is recommended. [Pg.182]

At least 17 pesticides have been found in ground water in a total of 23 states as a result of agricultural practice. These results have been obtained through three different types of monitoring studies (1) large-scale retrospective, (2) small-... [Pg.171]

Case-control and retrospective cohort studies have been very successful in identifying large scale determinants of cancer such as smoking which may be responsible for as much as 30% of all cancers in developed countries. These types of studies also have been successful in identifying several occupational carcinogens such as 2-napthylamine, asbestos, and vinyl chloride. Although only small numbers of individuals were exposed in these occupational cases it... [Pg.198]

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