We observed substantially higher odds of low neurobehavioral scores , among children living within 100m of a plantation compared to children living at >500m; the odds ratios were weaker among participants living within 101m to 500m of a plantation. Finally, we inspected GAM plots for the relationship between continuous distance and neurobehavior scores for the three subdomains with the largest effect sizes . These are qualitatively similar to the results of analyses of distance by category , exhibiting a decrease in Attention & Inhibitory Control and Language scores at close proximity but do not provide strong evidence of nonlinear effects. Only 12% of the study population lived within 100m of a plantation , which limited the power of our analyses of associations within very close distances to plantations. All results from linear regression analyses comparing growing area within 100m of participant residences to those living further than 100m from floricultural crops were null . In logistic regression analyses, children with the most growing area within 100m of their residence had higher odds of low scores in the Language domain , compared to children without any plantation land within 100m of their residence .We observed that close residential proximity to floricultural crops was associated with poorer neurobehavioral outcomes in the domains of Attention & Inhibitory Control, Language and Memory & Learning. Associations were strongest among children living within 50m of a flower crop and present to some extent among children living between 51 and 100m. These findings were partially corroborated by sensitivity analyses using areas of floricultural crops near homes as a related construct of pesticide drift from flower crops. Unlike short-lived biomarkers of exposure, proximity of a child’s home to agricultural crops may approximate the child’s ongoing and historical low dose exposure to pesticides through off-target drift or direct access to pesticide-treated areas. In the ESPINA study,black plastic nursery pots we previously described positive associations between AChE activity and the domains of Attention & Inhibitory Control, Memory & Learning, and borderline associations with the Language domain affecting boys more than girls .

Alterations in the same domains were observed in the present study, which is consistent with previous findings. Epidemiologic studies provide increasing evidence that pesticide exposure during key developmental periods may be a risk factor for a range of neurocognitive deficits later in life, including attention deficit and hyperactivity disorder, autism spectrum disorder, developmental delay, slowed reaction time, and slowed motor control, poor verbal comprehension People living closest to agricultural crops are at increased risk of pesticide exposure. In our analyses, children living within 100m of a flower crop, and especially within 50m, had lower neurobehavioral scores compared to children living farther than 500m. These findings suggest that the amount of pesticide drift from crops onto nearby homes can especially affect the neurobehavioral performance of children living within 100m. However, alterations in neurobehavioral performance may also be present at greater distances but the limited statistical power of our study to detect smaller differences precluded us from assessing this further. In previous analyses of the ESPINA study, we observed positive associations between residential distances to flower crops and AChE activity, with the lowest AChE levels observed among children living within 232m of a greenhouse floricultural crop . This supports the construct of residential distance to flower plantations as a pathway of exposure to pesticides Furthermore, we previously observed that children living closer to flower crops had higher systolic blood pressures, which indicates that additional physiologic processes may be affected among children living near pesticide spray sites . Multiple investigations have studied the association between proximity of homes to agricultural crops and pesticide exposure . While maximal exposure attributable to pesticide drift, among these studies, varied from 60 to 750 meters, this collection of studies rather consistently indicates that homes residing closer to pesticide treated fields tend to have higher pesticide levels and that children residing closer to pesticide treated fields tend to reflect higher pesticide exposure levels using bio-monitoring studies. In this study, exposure was modeled as distance to the nearest plantation in the primary analyses, based on the assumption that increased distance reflects lower exposures. An alternative measure, area of plantations within varying buffer areas, which is likely a better proxy for exposure to pesticide drift, was also explored.

As expected, results showed consistent associations between these two related but different constructs of pesticide exposure, which strengthens our findings. Several studies have utilized residential proximity to agriculture as a metric of exposure to pesticides when studying its associations with neurodevelopment . A number of these studies used data from California State’s Pesticide Use Reporting System, finding positive correlations between proximity of prenatal residence to areas of agricultural pesticide applications and neurodevelopmental outcomes in early childhood, specifically ASD . In our analyses the observed effect size in the logistics models were small, but the magnitude may have been attenuated by the non-linear dose-response relationship shown in Figure 3. Furthermore, the linear regression models indicated that a difference of 100m in residential proximity to floricultural crops is associated with a greater likelihood of the child scoring in the sub-clinical ranges for the Language and the Memory and Learning domains by 9% and 24% respectively. In the context of measurable outcomes, this is clinically significant in that identifying children with delayed development warrants early intervention by clinicians as well as educators. The expected distance of pesticide drift from flower crops to nearby homes was smaller in our study population compared to those of other studies likely because rose production is enclosed within greenhouses. Greenhouses in Pedro Moncayo County have air circulation vents or windows, which could allow the escape of fumigated pesticides during and after spraying. However, these analyses suggest that pesticide drift, even in this setting, could still be problematic in the context of pesticide exposure affecting the neurodevelopment of children living nearby. This body of evidence coupled with the growing number of studies describing neurobehavioral alterations associated with pesticide exposures suggests that extending buffer zones or protective areas that separate the industry from the neighboring communities, could be an effective way to protect developing children from the adverse effects of pesticide exposure. The present study was subject to several limitations. Though a crude exposure assessment, the use of this exposure metric is supported by the existing literature and validated within our study population . Prevailing winds were not accounted for in the present analyses. This provides potential for non-differential misclassification of the amount of pesticide drift from plantations to homes and may have biased our findings towards the null . Also, while the vast majority of the floricultural production in Pedro Moncayo County includes roses, which are grown inside greenhouses, a small amount of production of other flowers also occurs in nonenclosed fields typically located near the greenhouses. For this reason, it is plausible that some of the pesticide drift from crops, and hence the associations observed in this study, may be a result of both greenhouse and open field floricultural production. Nonetheless, residential proximity to crops is a useful construct of exposure as it is an indicator of chronic pesticide exposure, and provides practical information about the distances in which populations may have an increased risk of pesticide exposure and/or adverse health. While it does not allow us to determine which specific chemicals are influencing this association,greenhouse pot it indirectly accounts for a mixture of the various agrochemicals used in floriculture. The floricultural industry in Pedro Moncayo frequently uses various pesticides including insecticides , many classes of fungicides and to lesser extent, herbicides .

Many of the studies assessing neurodevelopment and pesticide exposure, including the ESPINA Study, are limited in that they study bio-monitoring of few pesticides, even though it is unusual for one pesticide to be used without multiple others. It is plausible that pesticides or other neurotoxicant agrochemical exposures explain the neurobehavioral deficits seen among participants living near the flower crops. Determining the quantity and types of agrochemicals used over time and by location would improve precision but would be very difficult to ascertain in this agricultural setting. Another limitation related to exposure assessment is that we were not able to account for all potential routes of exposure to pesticides, including dietary intake. We did not have information on time-activity patterns, which would have provided better insight into participants’ outdoor exposures . There is also some uncertainty associated with using home location only to estimate exposure to environmental pesticides. Some children in the cohort went to school during the day, while younger children attended daycare or stayed home with a relative. Modeling exposure experienced across all daily activities and locations is beyond the scope of this current study; we choose to focus on exposures at the children’s home locations. Another limitation of this study is that neurobehavioral outcomes were assessed at only one point in time, and thus we are unable to assess if the neurodevelopmental effects are permanent. Additionally, the NEPSY-2 is based on a US normative sample. Although this does not affect the internal validity of our findings, it is unclear how accurately the cut-off values for “low performance” apply to this study population. This study has several strengths and thus contributes to our understanding of the effects of pesticide use in floricultural communities. This study is unique in that there was a wide distribution of participants’ residential distance to crops, and we had a considerable number of children living in close proximity to flower crops, which allowed us to estimate effect sizes at short distances. Additionally, all participants were examined during a period of relatively homogeneous flower production and pesticide use. Children in this study were examined during a period of lower flower production and pesticide use compared to other times of the year. In theory, this would reduce the off-target pesticide drift potential from crops, with resulting lower exposures to children living nearby. Considering that pesticide spray seasons may also have short-term neurobehavioral alterations in children , it is plausible that these observed associations would be stronger during peak exposure periods. Lastly the existing studies have focused on residential distance to agricultural open fields. To our knowledge, the present study is the first to characterize the associations of neurobehavior in relation to greenhouse agricultural production, which is generally though to result in reduced pesticide drift from crops. Many types of crops involve the use of greenhouses such as flowers, tomatoes, cucumber, a variety of herbs, lettuce, bell peppers, and eggplants. The present study findings may be applicable to such agricultural production. High rates of ecosystem modification and subsequent consequences for biota, climate and geochemical natural cycles characterize the Anthropocene . To date, agriculture has modified nearly 40% of terrestrial ecosystems and drives biodiversity depletion via multiple direct and indirect effects associated with wildlife decline . These mechanisms include intensive use of agrochemicals, conversion of natural areas to simplified monocultures, fragmentation associated with land use change, soil erosion and sediment runoff, and greenhouse gas emissions, among others . These negative effects of agriculture consequently impact on species, habitat loss, and lack of connectivity, generating synergic detrimental effects on biodiversity, ecosystem functionality and provision of ecosystem services . Reconciling agricultural production and biodiversity conservation goals is a global priority in light of future scenarios pertaining to food consumption and land use change . However, agricultural management is not homogenous and may differentially influence wildlife. Agricultural intensification which entails a shift from diversified small farming practice to large monoculture production relies on the use of agrochemicals and has taken a toll on biodiversity . Adoption of agroecological principles and wildlife friendly farming can favor habitat suitability for wildlife and maintain sustainable crop yields . Strategies to balance agricultural food production and wildlife conservation include land sharing and land sparing strategies . Land sparing proponents have focused efforts on increasing food productivity per land area often requiring high levels of agrochemical input, and argue that with high production in target crop areas, natural areas can be spared from conversion to crop production . One impact that this approach does not address is the agrochemical spill over and its negative impacts on non-target wildlife species leading – another detrimental externality resulting from agrochemicals .