Assessment of dermal pesticide exposure with fluorescent tracer: A Nicaraguan modification of a Visual Scoring System
A. Aragon*1, L. Blanco1, A. Funez1, C. Ruepert3, C. Lidén4, G. Nise2, C. Wesseling3
1Occupational and Environmental Health Program, Department of Preventive Medicine and Public Health, Faculty of Medicine, UNAN-León, Leon, Nicaragua
2Department of Public Health Sciences, Division of Occupational Medicine, Karolinska Institutet, Stockholm, Sweden
3Central American Institute for Studies on Toxic Substances, Universidad Nacional, Heredia, Costa Rica
4Department of Medicine, Occupational and Environmental Dermatology, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
Background
A semi-quantitative dermal exposure assessment method based on visual observations of fluorescence images was presented by Fenske in 1988. We adapted the method to Nicaraguan working conditions and evaluated its performance.
Methods
Thirty-two farmers applied pesticides marked with Tinopal CBS-Xâ. Skin fluorescent depositions were observed with a portable UV lamp in a foldaway darkened room (Figure 1).
We modified the two components of the original system, extension by weighting the size of exposed body parts according to total body surface using Lund & Browder chart for Burns. We established intensity criteria for reading fluorescent images.
This resulted in Body Segment Scores (BSS) for 31 separated body parts as well as two summary measures. Contaminated Body Area (CBA) as the percentage of contaminated skin in relation to total body surface and Total Visual Score (TVS) as an overall score combining extension and intensity of contamination. The scoring of intensity was evaluated with quantitative chemical residue analyses.
Figure 1. Foldaway dark room for fieldwork
Results
All farmers had fluorescent depositions. The number of contaminated body segments per farmer ranged from 2 to 28. The CBA ranged from 1 to 66% of the total body surface, with a mean of 25.7 (SD 16.4). Depositions were most frequently observed on the front and backsides of hands (> 87% of the farmers), the front side of the left forearm (75%), and the backside of the trunk (75%). Depositions were less frequently observed on the front side of the right upper arm (19%) and the backside of the right thigh (19%). The highest BSS among contaminated farmers, by far, was observed for the back (mean 28.6, range 2.6 - 65.0). The right and left side of the face, front of the neck and backside of the right upper arm had, in general, the lowest scores. The mean TVS was 74.7, ranging between 0.5 – 270. The highest TVS represented 60% of the maximum possible. Residues increased with increasing fluorescence intensities with some misclassification.
The most frequent contamination pattern was smear followed by splash and then mist; furthermore combinations of patterns were often observed. As illustrations of how these patterns are indications of pathways of exposure, figure 2 (sequence a, b and c) shows the transfer of the contaminant from the source to the skin by direct contact and redistribution from one part to another part of the skin (smears)
Fig. 2.
a. (upper left) Leakage of the spade.
b. (up right) Farmer fixing the spade.
c. (lower) After application: Fluorescent smear images on farmer's fingers.
Conclusions
The visual score, as modified by us, provides information on the body segments most contributing to dermal exposure and degree of skin contamination during pesticide applications. Fluorescence patterns reflect exposure routes. The system is low-cost and practical for developing countries. Further improvements are recommended.
Content last modified: 25 May 2005
