Concentrations of Urinary Dialkyl Phosphate Metabolites of Organophosphorus Pesticides in Colombian Floriculturists Open Access

Fernandez, Carolina (2011)

Permanent URL: https://etd.library.emory.edu/concern/etds/dv13zt73z?locale=en
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Abstract

BACKGROUND: Previous studies have documented the use of organophosphorous (OP)
pesticides in the Colombian floriculture industry. However, limited data are available to
characterize worker exposures.


OBJECTIVES: The objective of the present study was to describe the levels of urinary
dialkylphosphate (DAP) metabolites of OP pesticides in urine collected from workers in
two flower-growing regions of Colombia. A secondary objective was to determine
whether these levels differ significantly by sample collection period, geographic region,
or worker task.


METHODS: A convenience sample of 358 floriculturists was recruited from farms in
Sabana de Bogota and Antioquia. Participants provided three spot urine samples
(collection periods: morning, pre- and post-shift) and answered a questionnaire collecting
demographic and occupational data. Samples were analyzed for six DAP metabolites and
creatinine. The two sample t-test, the Mann-Whitney U-test; the Chi-Square and the
Fisher's Exact test were used to determine statistically significant differences in
demographic and exposure characteristics between the two regions. A mixed-effects
linear regression model was used to test whether log-transformed urinary composite
dimethyl alkylphosphate (ΣDMAP), composite diethyl alkylphosphate (ΣDEAP) and
summed DAP (ΣDAP) concentrations varied by collection period, task and/or region.

RESULTS: Of the total participants, 298 (83%) worked on Sabana de Bogota farms,
while 60 (17%) worked on Antioquia farms. ΣDMAP concentrations (nmol/L) of the
Sabana de Bogota samples (36.6 (±2.7) morning, 15.1 (±2.9) pre-shift, 26.0 (±2.9) post-
shift) were generally higher than the Antioquia samples (GMs not calculated due to low
detection frequency). Conversely, geometric mean ΣDEAP concentrations (nmol/L) were
higher in Antioquia (14.6 (±5.2) morning, 8.8 (±5.3) pre-shift, 12.8 (±5.6) post-shift) than
the Sabana de Bogota samples (7.2 (±5.0) morning, pre-shift-- not calculated due to low
detection frequency, 7.5 (±4.8) post-shift samples). ΣDMAP concentrations varied
significantly by collection period (p<0.0001) and region (p< 0.0147) while ΣDEAP
concentrations varied significantly by collection period (p=0.0014) and marginally
significantly by region (p=0.0839). Worker task did not significantly explain variance in
urinary DAP metabolite levels.

CONCLUSIONS: We detected urinary OP pesticide metabolites in the majority of
farmworkers in our study, with levels varying significantly by region and collection
period. These factors could be taken into consideration in the development of pesticide
safety education and training programs for Colombian floriculture workers

Table of Contents

Background............................................................................................1 Materials and Methods.............................................................................5 Study population....................................................................................5 Interviews.............................................................................................6 Sample collection, transport and storage.....................................................6 Sample analysis......................................................................................7 Quality control (QC)................................................................................8 Statistical analysis..................................................................................9 Results.................................................................................................11 Demographic and exposure characteristics..................................................11 Urinary DAPs concentrations and mixed-effects model results.........................12 DISCUSSION.........................................................................................14 CONCLUSIONS.......................................................................................19 REFERENCES..........................................................................................20 TABLES Table 1 Sociodemographic characteristics..................................................28 Table 2 Pesticide exposure and safety behavior characteristics......................29 Table 3 Unadjusted dialkylphosphate concentrations by region.......................30 Table 4 Mixed-effects model results for collection times, region and task.........31 FIGURES Figure 1 NHANES vs. Colombian Flower Growers..........................................32 SUPPLEMENTAL MATERIAL Table S1 Additional pesticide exposure and safety behavior characteristics......33 Table S2 Dilution-adjusted dialkylphosphate concentrations by region.............34 Figure S1 Study site locations map...........................................................35 Figure S2 U.S. cut flower imports from Colombia vs. sampling periods..............36

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