A GIS-based method for household recruitment in a prospective pesticide exposure study

Abstract

Background: Recent advances in GIS technology and remote sensing have provided new opportunities to collect ecologic data on agricultural pesticide exposure. Many pesticide studies have used historical or records-based data on crops and their associated pesticide applications to estimate exposure by measuring residential proximity to agricultural fields. Very few of these studies collected environmental and biological samples from study participants. One of the reasons for this is the cost of identifying participants who reside near study fields and analyzing samples obtained from them. In this paper, we present a cost-effective, GIS-based method for crop field selection and household recruitment in a prospective pesticide exposure study in a remote location. For the most part, our multi-phased approach was carried out in a research facility, but involved two brief episodes of fieldwork for ground truthing purposes. This method was developed for a larger study designed to examine the validity of indirect pesticide exposure estimates by comparing measured exposures in household dust, water and urine with records-based estimates that use crop location, residential proximity and pesticide application data. The study focused on the pesticide atrazine, a broadleaf herbicide used in corn production and one of the most widely-used pesticides in the U.S.

An effective and efficient approach for manually improving geocoded data

“…We argue that no matter what initial geocoder is used, some level of manual intervention/interactive geocoding will always be required within any geocoded datasets because address data are routinely reported in vague terms and even the highest quality address data will be beholden to the accuracy of the geocoding process used. The frequent use of the manual methods for improving inaccurate geocodes in the available literature seems to support this [ 2 , 11 , 14 , 15 , 17 - 19 , 26 - 29 , 34 - 36 ].…”

“…The accuracy of the satellite imagery, road vectors, and geocoding used for the Google Maps API is dependent on the underlying Navteq and Tele Atlas data. However, manual geocoding with aerial/satellite imagery has been proposed as a substitute for ground truth data in the literature [ 34 , 42 ] and has been used as such on numerous occasions [ 2 , 6 , 11 , 15 , 18 , 19 , 25 , 28 , 29 , 35 , 36 ]. Our approach also assumes that the Google Maps API and associated data are available in the region(s) of interest.…”

“…Pertinent questions are how much improvement can be gained through manual intervention, and how much effort is required to obtain that improvement (i.e., is it worth it)? Although the practice is used throughout the health literature [ 2 , 11 , 14 , 15 , 17 - 19 , 26 - 29 , 34 - 36 ] and elsewhere [ 37 - 40 ], little quantitative research exists on the benefits or drawbacks of employing a manual intervention approach for improving the quality of one's geocodes in terms of the effort required. Manual approaches have typically been applied to small scale problems [ 11 , 19 , 26 , 27 , 33 - 36 ], and/or to samples of addresses representing a population with a single characteristic, e.g., all within a single area [ 15 , 26 , 27 , 36 ], all rural addresses [ 15 , 26 , 34 ], all addresses of individuals with a particular type of cancer e.g., breast cancer [ 14 ], or all industrial complexes [ 35 ].…”

Development of GIS Database for Insecticide Usage and Toxicity among Thai Farmers in Ubon Ratchathani Province, Thailand

“…In 1996 an algorithm was developed for use in a GIS to model the surface movement of insecticide in response to rainfall as modulated by slope, soil, management practices, and time of insecticide application. This algorithm estimated the loss of pesticides from field areas, run-off flow patterns, and the accumulation of pesticides at lower levels in response to rainfall [17]. GIS was also utilized to visualize and analyze four residual pesticides, endosulfan, diazinon, dichlorvos, and deltamethrim, in both land and water.…”

Parkinson’s Disease

“…Remote sensing technologies such as geographic information systems, which better tracks pesticide and other environmental exposures, as opposed to relying on records-based data and residential proximity to associated pesticide applications, may provide more statistical power and plausibility of exposure paradigms to epidemiologic and associative studies [152]. Combining several of these approaches, as well as subsequent computational biology and functional studies of identified variants, should improve understanding and diagnostic techniques related to PD.…”