Developmental Impacts

Cimino et al., 2017

Andria M. Cimino, Abee L. Boyles, Kristina A. Thayer, and Melissa J. Perry, “Effects of Neonicotinoid Pesticide Exposure on Human Health: A Systematic Review,” Environmental Health Perspectives, 2017, 125:2, DOI: 10.1289/EHP515.

ABSTRACT:

BACKGROUND: Numerous studies have identified detectable levels of neonicotinoids (neonics) in the environment, adverse effects of neonics in many species, including mammals, and pathways through which human exposure to neonics could occur, yet little is known about the human health effects of neonic exposure.

OBJECTIVE: In this systematic review, we sought to identify human population studies on the health effects of neonics.

METHODS: Studies published in English between 2005 and 2015 were searched using PubMed, Scopus, and Web of Science databases. No restrictions were placed on the type of health outcome assessed. Risk of bias was assessed using guidance developed by the National Toxicology Program’s Office of Health Assessment and Translation.

RESULTS: Eight studies investigating the human health effects of exposure to neonics were identified. Four examined acute exposure: Three neonic poisoning studies reported two fatalities (n = 1,280 cases) and an occupational exposure study of 19 forestry workers reported no adverse effects. Four general population studies reported associations between chronic neonic exposure and adverse developmental or neurological outcomes, including tetralogy of Fallot (AOR 2.4, 95% CI: 1.1, 5.4), anencephaly (AOR 2.9, 95% CI: 1.0, 8.2), autism spectrum disorder [AOR 1.3, 95% credible interval (CrI): 0.78, 2.2], and a symptom cluster including memory loss and finger tremor (OR 14, 95% CI: 3.5, 57). Reported odds ratios were based on exposed compared to unexposed groups.

CONCLUSIONS: The studies conducted to date were limited in number with suggestive but methodologically weak findings related to chronic exposure. Given the wide-scale use of neonics, more studies are needed to fully understand their effects on human health.  FULL TEXT

Colborn and Carroll, 2007

Colborn, Theo, Lynn Carroll,  “Pesticides, Sexual Development, Reproduction,and Fertility: Current Perspective and Future Direction,” Human and Ecological Risk Assessment, 2007, 13:5.

ABSTRACT: Improvements in chemical analytical technology and non-invasive sampling protocols have made it easier to detect pesticides and their metabolites at very low concentrations in human tissues. Monitoring has revealed that pesticides penetrate both maternal and paternal reproductive tissues and organs, thus providing a pathway for initiating harm to their offspring starting before fertilization throughout gestation and lactation. This article explores the literature that addresses the parental pathway of exposure to pesticides. We use DDT/DDE as a model for chemicals that oftentimes upon exposure have no apparent, immediate health impacts, or cause no obvious birth defects, and are seldom linked with cancer. Their health effects are overlooked because they are invisible and not life threatening—but might have significant health, social, and economic impacts at the individual and population levels. The purpose of this article is to demonstrate the necessity to develop new approaches for determining the safety of pesticides and the need for innovative regulatory policy to protect human and environmental health.

Donauer et al., 2016

Donauer, Stephanie, Mekibib Altaye, Yingying Xu, Heidi Sucharew, Paul Succop, Antonia M. Calafat, Jane C. Khoury, Bruce Lanphear, Kimberly Yolton, “An Observational Study to Evaluate Associations Between Low-Level Gestational Exposure to Organophosphate Pesticides and Cognition During Early Childhood,” American Journal of Epidemiology, 2016, 184:5.

ABSTRACT:

Prenatal exposure to organophosphate pesticides, which is ubiquitous, may be detrimental to neurological development. We examined 327 mother/infant pairs in Cincinnati, Ohio, between 2003 and 2006 to determine associations between prenatal exposure to organophosphate pesticides and neurodevelopment. Twice during pregnancy urinary concentrations of 6 common dialkylphosphates, nonspecific metabolites of organophosphate pesticides, were measured. Aggregate concentrations of diethylphosphates, dimethylphosphates, and total dialkylphosphates were calculated. Bayley Scales of Infant Development, Second Edition-Mental and Psychomotor Developmental indices were administered at ages 1, 2, and 3 years, the Clinical Evaluation of Language Fundamentals-Preschool, Second Edition, at age 4, and the Wechsler Preschool and Primary Scale of Intelligence, Third Edition, at age 5. Mothers with higher urinary total dialkylphosphate concentrations reported higher levels of socioeconomic status and increased fresh fruit and vegetable intake. We found no associations between prenatal exposure to organophosphate pesticides and cognition at 1-5 years of age. In our cohort, exposure to organophosphate pesticides during pregnancy was not associated with cognition during early childhood. It is possible that a higher socioeconomic status and healthier diet may protect the fetus from potential adverse associations with gestational organophosphate pesticide exposure, or that dietary exposure to the metabolites is innocuous and not an ideal measure of exposure to the parent compound.

English et al., 2012

René Glynnis English, Melissa Perry, Mary M. Lee, Elaine Hoffman, Steven Delport, Mohamed Aqiel Dalvie, “Farm residence and reproductive health among boys in rural South Africa,” Environment International, 2012, 47, DOI: 10.1016/J.Envint.2012.06.006.

ABSTRACT:

Few studies have investigated reproductive health effects of contemporary agricultural pesticides in boys. To determine the association between pesticide exposure and reproductive health of boys. We conducted a cross-sectional study in rural South Africa of boys living on and off farms. The study included a questionnaire (demographics, general and reproductive health, phyto-estrogen intake, residential history, pesticide exposures, exposures during pregnancy); and a physical examination that included sexual maturity development ratings; testicular volume; height, weight, body mass index; and sex hormone concentrations. Among the 269 boys recruited into the study, 177 (65.8%) were categorized as farm (high pesticide exposures) and 98 (34.2%) as non-farm residents (lower pesticide exposures). Median ages of the two groups were 11.3 vs 12.0 years, respectively (p<0.05). After controlling for confounders that included socioeconomic status, farm boys were shorter (regression coefficient (RC)=-3.42 cm; 95% confidence interval (CI): -6.38 to -0.45 cm) and weighed less (RC=-2.26 kg; CI: -4.44 to -0.75 kg). The farm boys also had lower serum lutenizing hormone (RC=-0.28 IU/L; CI: -0.48 to -0.08 IU/L), but higher serum oestradiol (RC=8.07 pmol/L; CI: 2.34-13.81 pmol/L) and follicle stimulating hormone (RC=0.63 IU/L; CI: 0.19-1.08 U/L). Our study provides evidence that farm residence is associated with adverse growth and reproductive health of pubertal boys which may be due to environmental exposures to hormonally active contemporary agricultural pesticides.   FULL TEXT

Herzine et al., 2016

Ameziane Herzine, Anthony Laugeray, Justyne Feat, Arnaud Menuet, Valérie Quesniaux, Olivier Richard, Jacques Pichon, Céline Montécot-Dubourg, Olivier Perche, and Stéphane Mortaud,”Perinatal Exposure to Glufosinate Ammonium Herbicide Impairs Neurogenesis and Neuroblast Migration through Cytoskeleton Destabilization,” Frontiers in Cellular Neuroscience, 2016, 10:191, DOI: 10.3389/FNCEL.2016.00191.

ABSTRACT:

Neurogenesis, a process of generating functional neurons from neural precursors, occurs throughout life in restricted brain regions such as the subventricular zone (SVZ). During this process, newly generated neurons migrate along the rostral migratory stream to the olfactory bulb to replace granule cells and periglomerular neurons. This neuronal migration is pivotal not only for neuronal plasticity but also for adapted olfactory based behaviors. Perturbation of this highly controlled system by exogenous chemicals has been associated with neurodevelopmental disorders. We reported recently that perinatal exposure to low dose herbicide glufosinate ammonium (GLA), leads to long lasting behavioral defects reminiscent of Autism Spectrum Disorder-like phenotype in the offspring (Laugeray et al., 2014). Herein, we demonstrate that perinatal exposure to low dose GLA induces alterations in neuroblast proliferation within the SVZ and abnormal migration from the SVZ to the olfactory bulbs. These disturbances are not only concomitant to changes in cell morphology, proliferation and apoptosis, but are also associated with transcriptomic changes. Therefore, we demonstrate for the first time that perinatal exposure to low dose GLA alters SVZ neurogenesis. Jointly with our previous work, the present results provide new evidence on the link between molecular and cellular consequences of early life exposure to the herbicide GLA and the onset of ASD-like phenotype later in life.  FULL TEXT

Lanphear, 2015

Lanphear, Bruce, “The Impact of Toxins on the Developing Brain,” Annual Review of Public Health, 2015, 36:1, DOI: 10.1146/ANNUREV-PUBLHEALTH-031912-114413.

ABSTRACT:

The impact of toxins on the developing brain is usually subtle for an individual child, but the damage can be substantial at the population level. Numerous challenges must be addressed to definitively test the impact of toxins on brain development in children: We must quantify exposure using a biologic marker or pollutant; account for an ever-expanding set of potential confounders; identify critical windows of vulnerability; and repeatedly examine the association of biologic markers of toxins with intellectual abilities, behaviors, and brain function in distinct cohorts. Despite these challenges, numerous toxins have been implicated in the development of intellectual deficits and mental disorders in children. Yet, too little has been done to protect children from these ubiquitous but insidious toxins. The objective of this review is to provide an overview on the population impact of toxins on the developing brain and describe implications for public health.  FULL TEXT

Marc et al., 2004

Julie Marc, Robert Belle, Julia Morales, Patrick Cormier, and Odile Mulner-Lorillon, “Formulated Glyphosate Activates the DNA-Response Checkpoint of the Cell Cycle Leading to the Prevention of G2/M Transition,” Toxicological Sciences, 2004, 82, DOI:10.1093/TOXSCI/KFH281.

ABSTRACT:

A glyphosate containing pesticide impedes at 10 mM glyphosate the G2/M transition as judged from analysis of the first cell cycle of sea urchin development. We show that formulated glyphosate prevented dephosphorylation of Tyr 15 of the cell cycle regulator CDK1/cyclin B in vivo, the end point target of the G2/M cell cycle checkpoint. Formulated glyphosate had no direct effect on the dual specific cdc25 phosphatase activity responsible for Tyr 15 dephosphorylation. At a concentration that efficiently impeded the cell cycle, formulated glyphosate inhibited the synthesis of DNA occurring in S phase of the cell cycle. The extent of the inhibition of DNA synthesis by formulated glyphosate was correlated with the effect on the cell cycle. We conclude that formulated glyphosate’s effect on the cell cycle is exerted at the level of the DNA-response checkpoint of S phase. The resulting inhibition of CDK1/cyclin B Tyr 15 dephosphorylationleads to prevention of the G2/M transition and cell cycle progression.  FULL TEXT

National Research Council, 1993

National Research Council, Committee on Pesticides in the Diets of Infants and Children,  “Pesticides in the Diets of Infants and Children,” 1993, National Academies Press, Washington DC., DOI: 10.17226/2126.  Available at: https://www.nap.edu/read/2126/chapter/1.

Paganelli et al., 2010

Alejandra Paganelli, Victoria Gnazzo, Helena Acosta, Silvia L. López, and Andrés E. Carrasco, “Glyphosate-Based Herbicides Produce Teratogenic Effects on Vertebrates by Impairing Retinoic Acid Signaling,” Chemical Research in Toxicology, 2010, 23:10, DOI: 10.1021/TX1001749.

ABSTRACT:

The broad spectrum herbicide glyphosate is widely used in agriculture worldwide. There has been ongoing controversy regarding the possible adverse effects of glyphosate on the environment and on human health. Reports of neural defects and craniofacial malformations from regions where glyphosate-based herbicides (GBH) are used led us to undertake an embryological approach to explore the effects of low doses of glyphosate in development. Xenopus laevis embryos were incubated with 1/5000 dilutions of a commercial GBH. The treated embryos were highly abnormal with marked alterations in cephalic and neural crest development and shortening of the anterior−posterior (A-P) axis. Alterations on neural crest markers were later correlated with deformities in the cranial cartilages at tadpole stages. Embryos injected with pure glyphosate showed very similar phenotypes. Moreover, GBH produced similar effects in chicken embryos, showing a gradual loss of rhombomere domains, reduction of the optic vesicles, and microcephaly. This suggests that glyphosate itself was responsible for the phenotypes observed, rather than a surfactant or other component of the commercial formulation. A reporter gene assay revealed that GBH treatment increased endogenous retinoic acid (RA) activity in Xenopus embryos and cotreatment with a RA antagonist rescued the teratogenic effects of the GBH. Therefore, we conclude that the phenotypes produced by GBH are mainly a consequence of the increase of endogenous retinoid activity. This is consistent with the decrease of Sonic hedgehog (Shh) signaling from the embryonic dorsal midline, with the inhibition of otx2 expression and with the disruption of cephalic neural crest development. The direct effect of glyphosate on early mechanisms of morphogenesis in vertebrate embryos opens concerns about the clinical findings from human offspring in populations exposed to GBH in agricultural fields.  FULL TEXT

 

Roberts and Karr, 2012

Roberts JR, Karr CJ,  “Pesticide exposure in children,” 2012, Pediatrics,  130:6.

ABSTRACT: This statement presents the position of the American Academy of Pediatrics on pesticides. Pesticides are a collective term for chemicals intended to kill unwanted insects, plants, molds, and rodents. Children encounter pesticides daily and have unique susceptibilities to their potential toxicity. Acute poisoning risks are clear, and understanding of chronic health implications from both acute and chronic exposure are emerging. Epidemiologic evidence demonstrates associations between early life exposure to pesticides and pediatric cancers, decreased cognitive function, and behavioral problems. Related animal toxicology studies provide supportive biological plausibility for these findings. Recognizing and reducing problematic exposures will require attention to current inadequacies in medical training, public health tracking, and regulatory action on pesticides. Ongoing research describing toxicologic vulnerabilities and exposure factors across the life span are needed to inform regulatory needs and appropriate interventions. Policies that promote integrated pest management, comprehensive pesticide labeling, and marketing practices that incorporate child health considerations will enhance safe use.  FULL TEXT