The authors report that the overall interpretation of the studies reviewed was hampered by the crude exposure assessment used. Most of the studies did not include quantitative exposure variables, and those that had that information did not provide evidence of a dose-response relationship. They conclude that further studies are needed to overcome the practical difficulties of identifying adequate numbers of cases of childhood cancer and the possible limitations of the available epidemiological investigations. Less well understood and more difficult to study is the risk to residents in nearby communities who are exposed to pesticides that drift when crops are sprayed from airplanes or trucks. A new study combines historical records with remote sensing and GIS technologies to estimate the risk to surrounding communities from crop spraying with pesticides.
Many rural residents live within a few hundred yards of fields where pesticides are sprayed.
In the past, studies primarily focused on pesticide applicators and exposure was estimated by using questionnaires or biological monitoring. Questionnaires have limitations in that respondents may be unaware of the types of agricultural pesticides in use near their homes. Providing some of this information is where sensing and mapping technologies may help. Using Landsat satellite images of vegetation, the researchers were able to classify the different types of crops that had been planted in a three-county area of south central Nebraska. A Landsat satellite sensor detects reflected energy in infrared, red, and green wavelengths.