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Exposures were assessed for seven small-scale farmers using chlorpyrifos on corn and ten banana plantation employees applying diazinon, and for one child of each worker. Metabolites (TCPYand IMPY) were measured in urine before and after applications. TCPY concentrations peaked at 27 and 8.5 hours post-application for applicators and children, respectively (geometric means, 26 and 3.0 microg/L). Proximity to spraying and spray mixture preparation in homes were important exposure factors. IMPY concentrations differed substantially across workers at two plantations (geometric means, 1.3 and 168 mirog/L); however, their children had little or no diazinon exposure. These workers and children were also exposed to chlorpyrifos, most likely through contact with chlorpyrifos-impregnated bags used in banana production. Several recommendations are offered: (1) monitor children's activities during applications; (2) do not store or prepare pesticides in homes; (3) institute sound occupational hygiene practices at banana plantations; (4) dispose of plastic insecticide bags properly at the worksite.

Objective This study assessed pesticide exposure of children in rural Nicaragua in relation to parental pesticide use, from around conception to current school age, as part of an epidemiological evaluation of neurodevelopment effects. Methods We included 132 children whose parents were subsistence farmers or plantation workers, or had an agricultural history. As proxies for children's long-term exposures, we constructed cumulative parental pesticide-specific use indices for periods before and after the child's birth from data obtained using an icon-calendar-based questionnaire, of application hours (h) for plantation workers and subsistence farmers, and of kilograms of active ingredients (ai) only for subsistence farmers. Pesticide residues of TCPY, 3-PBA and 2,4-D were analysed in children's urine as indicators for current exposures. Results Life-time indices were highest for the organophosphates chlorpyrifos (median 114 h (min 2; max 1584), 19.2 kg ai (min 0.37; max 548)) and methamidophos (84 h (6; 1964), 12.2 kg ai (0.30; 780)). The P50 values of children's urinary residues were 3.7 mu g/g creatinine for TCPY, 2.8 for 3-PBA and 0.9 for 2,4-D; TCPY values are comparable with those in other countries, but 3-PBA and 2,4-D are considerably higher. The maximum levels for all three pesticides are the highest reported for children. Residues increased on days after application, but most high residue levels were unrelated to parental pesticide applications. Conclusion Urinary pesticide residues reveal high environmental exposure among children in rural Nicaragua. The quantitative parental pesticide use indices as proxies for children's exposures during different periods may be useful for the evaluation of developmental health effects.

Objective: This study examined cognitive and behavioral performance among school-age children in Nicaragua in relation with long-term and recent organophosphate exposures.

Methods: Long-term organophosphate was assessed in 110 children aged 7-9 through a parental use index of kg of organophosphate during de pregnancy, first year of life and from 1 year old to the present. Recent exposure was determined in a subset of 74 children by urinary 3,5,6-trichloro-2-pyridinol (TCPY) levels. Cognitive function was evaluated with Wechsler Intelligence Scale for Children (WISC IV), total IQ and subtests grouped into indices for perceptual reasoning, verbal comprehension, working memory, and processing speed. Behavior at school was measured with the Conners’ Teacher Rating Scale-Revised:Short (CTRS-R:S). Multivariate linear regression models assessed adjusted associations.

Results: For each 10-fold increase in prenatal indices for total OP use, children’s performance on working memory significantly decreased with 3.5 points, and similarly for chlorpyrifos and methamidophos. Prenatal methamidophos use was, in addition, significantly associated with poorer verbal comprehension and decrease in total IQ, a 10-fold use increase decreasing scores with 3.8 and 3.3 points respectively. Urinary TCPY (mg/g of creatinine) also affected, not significantly, working memory with a 3.2 point decrease for each 10-fold increase. This study did not find associations between postnatal organophosphate use indices and cognitive performance, or pre or postnatal use indices with behavior.

Conclusion: Prenatal exposure to organophosphates decreased the cognitive abilities in Nicaraguan children, particularly in working memory. Methamidophos was also associated with poor verbal comprehension and total IQ.

Objective: This cross-sectional study explored whether pre or postnatal pyrethroid exposure impaired cognitive performance and behavior in school-aged children from a rural area in Nicaragua.

Methods: Pyrethroid exposure was assessed in 110 children age 7-9, attending grade 1-3, with cumulative parental pyrethroid use indices of hours of spraying, during pregnancy, the first year of life, and older than age one. Cypermethrin accounted for most of the pyrethroid use. Cognitive performance of the children was evaluated with 12 sub-tests and total IQ of Wechsler Intelligence Scale for Children (WISC IV), grouped into indices for perceptual reasoning, verbal comprehension, working memory, and processing speed. Behavior at school was measured with the oppositional, cognitive problem/inattention, hyperactivity and ADHD index subscales of the Conners’ Teacher Rating Scale-Revised:Short form (CTRS-R:S). One year later, the pyrethroid metabolite 3-PBA was measured in 211 urine samples from 74 children (median 3.3 µg/g creatinine, max. 547) and the effect of recent exposure on cognitive and behavior was assessed with a shortened battery. 

Results:

Pyrethroid exposure indices during the first year of life significantly decreased performance of perceptual reasoning in children aged 7-9. For each 10-fold increasein hours of pyrethroid application , children’s performance on the Perceptual Reasoning Index decreased on average with 1.1 point.  Postnatal exposures, during the first year and after age 1, associated with hyperactivity and attention problem. Urinary 3-PBA levels were negatively associated with a number of cognitive functions and, noteworthy, with increased scores for ADHD in girls but not in boys.

Conclusion:

Pyrethroid exposure in the first year of life was associated with decreased perceptual reasoning in rural children and with hyperactivity and ADHD predominantly in girls.