On the rumors about the silent spring. Review of the scientific evidence linking occupational and environmental pesticide exposure to endocrine disruption health effects

An updated status of currently used pesticides in India: Human dietary exposure from an Indian food basket

Currently used pesticides (CUPs) were introduced to have lower persistence and bioaccumulation, and lesser bioavailability towards non-target species. Nevertheless, CUPs still represent a concern for both human health and the environment. India is an important agricultural country experiencing a conversion from the use of obsolete organochlorine pesticides to a newer generation of phytosanitary products. As for other developing countries, very little is known about the transfer of CUPs to the human diet in India, where systematic monitoring is not in place. In this study, we analyzed ninety four CUPs and detected thirty CUPs in several food products belonging to five types: cereals and pulses, vegetables, fruits, animal-based foods, and water. Samples were taken from markets in Delhi (aggregating food produced all over India) and in the periurban area of Dehradun (northern India) (representing food produced locally and through more traditional practices). Overall, chlorpyrifos and chlorpropham were the most detected CUPs with a detection frequency of 33% and 25%, respectively. Except for vegetables and fruits, the levels of CUPs in all other food types were significantly higher in samples from Delhi (p < 0.05). Exposure dosage of CUPs through different food matrices was calculated, and chlorpropham detected in potatoes had the maximum exposure dosage to humans (2.46 × 10-6 mg/kg/day). Risk analysis based on the hazard quotient technique indicated that chlorpyrifos in rice (2.76 × 10-2) can be a concern.

The Association between Long-Term DDT or DDE Exposures and an Altered Sperm Epigenome-a Cross-Sectional Study of Greenlandic Inuit and South African VhaVenda Men

BACKGROUND

The organochlorine dichlorodiphenyltrichloroethane (DDT) is banned worldwide owing to its negative health effects. It is exceptionally used as an insecticide for malaria control. Exposure occurs in regions where DDT is applied, as well as in the Arctic, where its endocrine disrupting metabolite, p , p ' -dichlorodiphenyldichloroethylene (p , p ' -DDE) accumulates in marine mammals and fish. DDT and p , p ' -DDE exposures are linked to birth defects, infertility, cancer, and neurodevelopmental delays. Of particular concern is the potential of DDT use to impact the health of generations to come via the heritable sperm epigenome.

OBJECTIVES

The objective of this study was to assess the sperm epigenome in relation to p , p ' -DDE serum levels between geographically diverse populations.

METHODS

In the Limpopo Province of South Africa, we recruited 247 VhaVenda South African men and selected 50 paired blood serum and semen samples, and 47 Greenlandic Inuit blood and semen paired samples were selected from a total of 193 samples from the biobank of the INUENDO cohort, an EU Fifth Framework Programme Research and Development project. Sample selection was based on obtaining a range of p , p ' -DDE serum levels (mean = 870.734 ± 134.030  ng / mL ). We assessed the sperm epigenome in relation to serum p , p ' -DDE levels using MethylC-Capture-sequencing (MCC-seq) and chromatin immunoprecipitation followed by sequencing (ChIP-seq). We identified genomic regions with altered DNA methylation (DNAme) and differential enrichment of histone H3 lysine 4 trimethylation (H3K4me3) in sperm.

RESULTS

Differences in DNAme and H3K4me3 enrichment were identified at transposable elements and regulatory regions involved in fertility, disease, development, and neurofunction. A subset of regions with sperm DNAme and H3K4me3 that differed between exposure groups was predicted to persist in the preimplantation embryo and to be associated with embryonic gene expression.

DISCUSSION

These findings suggest that DDT and p , p ' -DDE exposure impacts the sperm epigenome in a dose-response-like manner and may negatively impact the health of future generations through epigenetic mechanisms. Confounding factors, such as other environmental exposures, genetic diversity, and selection bias, cannot be ruled out. https://doi.org/10.1289/EHP12013.

Production of Escovopsis weberi (Ascomycota: Hypocreales) Mycelial Pellets and Their Effects on Leaf-Cutting Ant Fungal Gardens

The maintenance of the symbiosis between leaf-cutting ants and their mutualistic fungus Leucoagaricus gongylophorus Singer (Moller) is vital for the survival of both species. The specialist fungal parasite Escovopsis weberi Muchovej & Della Lucia is a threat to this symbiosis, causing severe damage to the fungal garden. Mycelial pellets are resistant fungal structures that can be produced under laboratory conditions. These structures were studied for use in biological pest control, but the production of mycelial pellets has not previously been documented in Escovopsis. One of the aims of this study was to induce Escovopsis weberi to produce mycelial pellets and investigate the potential of these pellets for the control of leaf-cutting ants. We compared the pathogenicity of Escovopsis weberi mycelial pellets and conidia against mini-colonies of Acromyrmex subterraneus subterraneus Forel when applied in the form of baits. Worker ants were able to distinguish mycelial pellets from conidia, as baits with mycelial pellets were more attractive to workers than those with conidia, causing a greater negative impact on colony health. All types of baits containing Escovopsis weberi influenced the foraging activity but only treatments with viable fungal propagules resulted in an increase in the quantity of waste material, with a significant negative impact on the fungal garden biomass. The results provided novel information regarding Escovopsis recognition by worker ants and differences between conidia and mycelial pellet dynamics in leaf-cutting ant colonies, with new perspectives for the biological control of these important pests.

Dietary pattern interfered with the impacts of pesticide exposure by regulating the bioavailability and gut microbiota

Dietary intake is an essential way for pesticides to enter the human body. The effects of dietary pattern on the risks of pesticides and what diet can reduce the damage are largely unknown. Here, it is found that Mediterranean diet and Vegetarian diet could alleviate insulin resistance and obesity induced by chlorpyrifos, while Western diet could aggravate that. Gut microbiota and chlorpyrifos bioavailability mediated by the diets were involved in these effects. Both the dietary pattern and chlorpyrifos could change the composition of gut microbiota. Chlorpyrifos caused gut dysbacteriosis which was an important reason for the induced metabolic syndrome. Mediterranean diet and Vegetarian diet could maintain gut microbiota homeostasis and increase intestinal bacteria producing short-chain fatty acids, repair the gut microbiota and intestinal barrier damaged by chlorpyrifos. High dietary fat intake increased the bioavailability of chlorpyrifos, which aggravated the gut dysbacteriosis and destruction of intestinal integrity. Thus, the amount of endotoxin entering the blood increased and caused low-grade inflammation, which was also an important pathway of metabolic syndrome. The results suggested that although it was almost impossible to avoid the exposure to pesticides in modern life, healthy diets could regulate beneficial gut microbiota and alleviate the risk of pesticide exposure.

Bacillus thuringiensis affects reproductive capacity of adult rat offspring

We investigated the effects of B. thuringiensis-based biological insecticides, XenTari and Dipel, and deltamethrin on the reproductive development of pups of pregnant rats. Twenty 90-day-old pregnant rats were divided randomly onto four equal groups: control group (GC) administered only water; XenTari group (GX) administered 1 mg XenTari (containing Cry1Ac toxin of B. thuringiensis)/100 g body weight; Dipel group (GDi) administered 1 mg Dipel (containing Cry1Aa, Cry1Ab and Cry1Ac toxins of B. thuringiensis)/100 g body weight; and a deltamethrin group (GDe) administered 2 mg deltamethrin (0.08 ml Keshet 25EC)/kg body weight as a positive control. Insecticides were administered by gavage at doses of 1 mg/100 g/day (GX and GDi), and 2 mg/kg/day (GDe) during pregnancy and lactation. Treatment with both biologic and synthetic insecticides reduced the weight gain of the mothers. The biological insecticides reduced the number, weight and length, and increased malformation and mortality of the offspring. In female offspring for all three groups administered insecticides, opening of the vagina was delayed, metestrus was increased and estrogen and progesterone levels were reduced compared to proestrus, estrus and metestrus of the cycle. The ovaries of female offspring of all three groups administered insecticides contained numerous tertiary and atretic follicles, few corpora lutea, primary and secondary follicles, and reduced estrogen receptors compared to controls. In male offspring, all three groups exposed to insecticides exhibited reduced testosterone levels. Histopathological changes in the testes including vacuolation and desquamation of the seminiferous epithelium were observed only in the GX and GDi groups. The number of androgen receptors was reduced significantly in the testes and testicular morphometry revealed reduced tubule diameter, height of the seminiferous epithelium and total tubule length compared to the control. The biological insecticides, XenTari and Dipel, administered in sublethal doses to pregnant rats, caused reproductive changes in the offspring similar to those of the insecticide, deltamethrin.

Azole pesticide products and their hepatic metabolites cause endocrine disrupting potential by suppressing the homo-dimerization of human estrogen receptor alpha

We selected azole pesticides products that are managed by setting maximum residue limits (MRLs) in the Republic of Korea and describe the estrogen receptor (ER) α-related negative effect to endocrine system using in vitro Organization for Economic Cooperation and Development performance-based test guideline. No azoles were found to be an ERα agonist. Conversely, three azoles (bitertanol, cafenstrole, and tebufenpyrad) were determined to be ERα antagonists. In addition, the ERα antagonistic activities of bitertanol, cafenstrole, and tebufenpyrad were not significantly perturbed in the existence of phase I (hydroxylation, dealkylation, oxidation or reduction) and phase II (conjugation). Regarding the mechanism underlying their ERα-mediated endocrine disrupting potentials, ERα proteins cannot be translocated to the nucleus by suppressing the dimerization of ERα in the cytoplasm by bitertanol, cafenstrole, and tebufenpyrad. These data indicated that azole pesticide products show the capability to interfere the ERα-related human endocrine system. Furthermore, we identified the mechanism of ERα-mediated endocrine disrupting by azole insecticide products through this study.

Endocrine disrupting potential of selected azole and organophosphorus pesticide products through suppressing the dimerization of human androgen receptor in genomic pathway

Several pesticides widely used in agriculture have been considered to be endocrine disrupting chemicals through their binding affinities to estrogen or androgen receptors. This study was conducted to clarify the human androgen receptor (hAR)-mediated genomic endocrine disrupting mechanism of eight selected pesticide products by in vitro assay providing the Organization for Economic Co-operation and Development Test Guideline No. 458, 22Rv1/MMTV_GR-KO AR transcriptional activation assay and a homo-dimerization confirmation assay. None of the tested pesticide products showed an AR agonistic effect, whereas they were all determined to be AR antagonists at non-toxic concentrations. Also, the eight pesticide products were verified as true AR antagonists through a specificity control test. In the Bioluminescence Resonance Energy Transfer-based AR homo-dimerization confirmation assay, the eight pesticide products did not induce AR homo-dimerization. Additionally, western blotting revealed that none of the eight pesticide products induced AR translocation from the cytoplasm to the nucleus. In conclusion, we found for the first-time evidence to understand the AR-mediated endocrine disrupting mechanisms induced by selected azole and organophosphorus pesticide products.

Non-occupational exposure to pesticides and health markers in general population in Northern Finland: Differences between sexes

BACKGROUND

Occupational exposure to pesticides has been reported among general population worldwide. However, little is known about the associations between non-occupational exposure to pesticides, and biological markers of health and their response by sex.

OBJECTIVES

We aimed to assess the associations between non-occupational overall pesticide exposure, length of exposure and specific pesticides reported with 35 biological markers of health representing cardiometabolic, haematological, lung function, sex hormones, liver and kidney function profiles, and vitamin D in Finnish cohort.

METHODS

31-year cross-sectional examination of the Northern Finland Birth Cohort 1966 provided blood samples for biomarker measurements in 1997-1998. Number of subjects varied between 2361 and 5037 for given exposures and certain outcome associations. Multivariable regression analyses were performed to examine associations between overall pesticide exposure (OPE), length of pesticide exposure in months (PEM), in years (PEY), and specific pesticides use (PEU) or not with cardiometabolic [SBP, DBP, TC, LDL, HDL, triglycerides, fasting glucose, insulin, HOMA-IR, HOMA-B, HOMA-S, hs-CRP], hematological [WBC, RBC, Hb, HCT, MCV, MCH, MCHC, platelets], lung function (FVC, FEV1), sex hormones [luteinizing hormone (LH), testosterone (TT), sex-hormone binding globulin (SHBG)], liver and kidney function profiles [total protein, albumin, globulin, ALP, ALT, GGT, urea, creatinine], and vitamin D adjusting for sex, BMI, socioeconomic position (SEP) and season of pesticide use.

RESULTS

This cohort study on up to 5037 adults with non-occupational OPE, PEM, PEY and PEU differed by sex and SEP. In regression analyses, all the exposures were positively associated with total cholesterol and low-density lipoprotein cholesterol, and PEU was negatively associated with high-density lipoprotein cholesterol in females. OPE and PEM were positively associated with haematocrit in females and PEU with platelets in males. PEU was negatively associated with mean corpuscular haemoglobin. OPE and PEM were positively associated with LH in males. OPE was negatively associated with total protein and albumin in males.

DISCUSSION

In Finnish young adults, non-occupational overall pesticide exposure, length of exposure and specific pesticides were associated with multiple biological markers of health. The biological markers seem to be indicative of adverse effects of pesticides and warrant for further studies to replicate the findings and determine the underlying mechanisms.

The effects of diazinon on the cell types and gene expression of the olfactory epithelium and whole-body hormone concentrations in the Persian sturgeon (Acipenser persicus)

The olfactory function and imprinting of odorant information of the native stream play a critical role during the homing migration in fish. Pesticides may impair olfactory imprinting by altering olfaction and hormone functions. The present study aimed to determine how diazinon impacts olfactory epithelium morphology and cell composition, as well as hormone concentrations in Persian sturgeon (Acipenser persicus) during their lifetime in freshwater and, also during diazinon-free saltwater acclimation. Fingerlings were exposed to 0, 150, 300, and 450 μg·L^-1 of diazinon in freshwater for 7 days and then were transferred to diazinon-free saltwater by gradually increasing salinity up to 12 ppt. After diazinon exposure, the number of olfactory receptor cells (ORCs) and goblet cells (GCs) decreased and increased, respectively, and the expression of G-protein αolf (GPαolf) and calmodulin-dependent kinase II delta (CAMKIId) was down-regulated and up-regulated, respectively. Transferring the fish to diazinon-free saltwater (8 and 12 ppt) raised the number of ORCs, supporting cells (SCs), GCs, and GPαolf expression, and down-regulated CAMKIId without any significant differences among treatments. Exposure to diazinon increased whole-body cortisol at the high concentration, while decreased whole-body thyroxin (T4) and triiodothyronine (T3) in a dose-dependent manner. Although whole-body T4 and T3 increased in all the treatments after saltwater acclimation (8 and 12 ppt), the level of these hormones was lower in fish that had been exposed to diazinon than in the control. These results showed that diazinon can disrupt olfactory epithelium morphology and cell composition as well as hormone concentrations, which in turn may affect the olfactory imprinting in Persian sturgeon fingerlings.

Exposure to Spectracide® causes behavioral deficits in Drosophila melanogaster: Insights from locomotor analysis and molecular modeling

This study was focused on gaining insights into the mechanism by which the herbicide- Spectracide®, induces oxidative stress and alters behavior in Drosophila melanogaster. Exposure to Spectracide® (50%) significantly (p < 0.05) reduced the negative geotaxis response, jumping behavior and dampened locomotor activity rhythm in adult flies compared to non-exposed flies. Protein carbonyl levels indicative of oxidative damage increased significantly coupled with down-regulation of Sniffer gene expression encoding carbonyl reductase (CR) and its activity in Spectracide®-exposed flies. In silico modeling analysis revealed that the active ingredients of Spectracide® (atrazine, diquat dibromide, fluazifop-p-butyl, and dicamba) have significant binding affinity to the active site of CR enzyme, with atrazine having comparatively greater affinity. Our results suggest a mechanism by which ingredients in Spectracide® induce oxidative damage by competitive binding to the active site of a protective enzyme and impair its ability to prevent damage to proteins thereby leading to deficits in locomotor behavior in Drosophila.

Associations between organohalogen exposure and thyroid- and steroid-related gene responses in St. Lawrence Estuary belugas and minke whales

Elevated concentrations of persistent organic pollutants (POPs) and emerging halogenated flame retardants (HFRs) have been reported in tissues of the endangered St. Lawrence Estuary (Canada) beluga population as well as in minke whales visiting that same feeding area. This study examined the linkages between blubber concentrations of POPs and emerging HFRs, and transcription in skin of genes involved in the regulation of thyroid and steroid axes in belugas and minke whales from the St. Lawrence Estuary. In belugas, concentrations of PCBs, OCs and hexabromobenzene (HBB) were positively correlated with the transcription of thyroid- and/or steroid-related genes, while Dec-604 CB concentrations were negatively associated with the transcription of glucocorticoid and thyroid genes. In minke whales, PBDE concentrations changed positively with Esrβ transcript levels and HBB concentrations negatively with Nr3c1 transcripts. Present results suggest that several biological functions including reproduction and energetic metabolism may represent potential targets for organohalogens in these whales.

Intergenerational reproductive toxicity of chlordecone in male Caenorhabditis elegans

Chlordecone (CLD), also named Kepone, is a synthetic organochlorine pesticide. As one of the common persistent organic pollutants (POPs) in nature, CLD has a profound impact on the environment and human health. The study aims to investigate the reproductive toxicity effects of CLD on male Caenorhabditis elegans and on progeny. L1-stage male nematodes were exposed to the control group (M9 solution) and four dose groups (0.02, 0.2, 2, and 20 μg/L). After exposure for 48 h, the male nematodes were picked to mating experiment and progeny experiment that the number of progeny and the time of observation in male parent and in F1 generation were counted; the number of germ cells and the number of sperm in the meiotic division of male nematodes were counted by staining with dimercaptophenyl hydrazine (DAPI), and the nematode gland area was observed under the bright field of the microscope. In male nematodes, the results showed that a number of progeny were 351.20 ± 31.40, 321.60 ± 24.70, 307.30 ± 19.30, 240.10 ± 27.60, and 227.90 ± 22.70 (P < 0.05); the generation times were 55.80 ± 1.95 h, 56.40 ± 1.60 h, 56.70 ± 0.92 h, 60.80 ± 0.95 h, and 69.60 ± 1.97 h (P < 0.05); relative areas of gonad were (99.80 ± 6.27)%, (93.00 ± 1.70)%, (85.00 ± 1.70)%, (70.70 ± 9.81)%, and (60.00 ± 5.23)% (P < 0.05); DAPI staining results showed the number of germ cells in meiosis area were 191.00 ± 10.97, 181.10 ± 15.56, 177.00 ± 9.20, 147.50 ± 10.56, and 139.30 ± 23.79 (P < 0.05); the sperm numbers were 335.60 ± 21.31, 308.60 ± 19.60, 306.00 ± 11.23, 260.10 ± 27.41, and 255.00 ± 3.72 (P < 0.05). In the F1 generation, the progeny numbers were 328.10 ± 22.28, 167.50 ± 15.30, 150.00 ± 13.65, 131.30 ± 18.40, and 130.20 ± 16.17 (P < 0.05); the generation times were 55.50 ± 2.36, 71.10 ± 0.97, 70.90 ± 0.52, 74.10 ± 2.07, and 73.90 ± 1.35 h (P < 0.05). The groups are grouped in order as M9 solution, 0.02, 0.2, 2, and 20 μg/L. The results revealed that CLD caused decrease in progeny number, relative area of gonad, number of germ cells, and sperm number and prolonged the generation time in the male nematode. In offspring grown up without CLD, the effect of CLD on generation time and sperm number can still be observed on offspring. In conclusion, CLD induces male nematode reproductive toxicity and causes defects in offspring.

Prenatal exposure to organochlorine pesticides and early childhood communication development in British girls

BACKGROUND

The developing brain is susceptible to exposure to neurodevelopmental toxicants such as pesticides.

AIMS

We explored associations of prenatal serum concentrations of hexachlorobenzene (HCB), beta-Hexachlorocyclohexane (β-HCH), 2,2-Bis(4-chlorophenyl)-1,1-dichloroethene (p,p'-DDE) and 2,2-Bis(4-chlorophenyl-1,1,1-trichloroethane (p,p'-DDT) with maternal-reported measures of verbal and non-verbal communication in young girls.

STUDY DESIGN AND METHODS

We studied a sample of 400 singleton girls and their mothers participating in the Avon Longitudinal Study of Parents and Children (ALSPAC) using multivariable linear regression models adjusting for parity, Home Observation Measurement of the Environment (HOME) score, maternal age and education status, and maternal tobacco use during the first trimester of pregnancy.

EXPOSURE AND OUTCOME MEASURES

Maternal serum samples (collected at median 15 wks. gestation [IQR 10, 28]) were assessed for selected organochlorine pesticide levels. Communication was assessed at 15 and 38 months, using adapted versions of the MacArthur Bates Communicative Development Inventories for Infants and Toddlers (MCDI).

RESULTS

At 15 months, girls born to mothers with prenatal concentrations of HCB in the highest tertile had vocabulary comprehension and production scores approximately 16% (p = 0.007) lower than girls born to mothers with concentrations in the lowest tertile. This association varied by maternal parity in that the evidence was stronger for daughters of nulliparous mothers. At 38 months, girls born to mothers with prenatal concentrations of HCB in the highest tertile had mean adjusted intelligibility scores that were 3% (p = 0.03) lower than those born to mothers with concentrations in the lowest tertile; however, results did not vary significantly by parity. Maternal concentrations of β-HCH and p,p'-DDE were not significantly associated with MCDI scores at 15 or 36 months. p,p'-DDT had an inconsistent pattern of association; a significant positive association was observed between p,p'-DDT with verbal comprehension scores at 15 months; however, at 38 months a significant inverse association was observed for p,p'-DDT with communicative scores. This inverse association for p,p'-DDT among older girls tended to be stronger among daughters of mothers who had lower depression scores.

CONCLUSIONS

Organochlorine pesticide exposure in utero may affect communication development.

Hazardous effects of chemical pesticides on human health-Cancer and other associated disorders

Poisoning from pesticides is a global public health problem and accounts for nearly 300,000 deaths worldwide every year. Exposure to pesticides is inevitable; there are different modes through which humans get exposed to pesticides. The mode of exposure is an important factor as it also signifies the concentration of pesticides exposure. Pesticides are used extensively in agricultural and domestic settings. These chemicals are believed to cause many disorders in humans and wildlife. Research from past few decades has tried to answer the associated mechanism of action of pesticides in conjunction with their harmful effects. This perspective considers the past and present research in the field of pesticides and associated disorders. We have reviewed the most common diseases including cancer which are associated with pesticides. Pesticides have shown to be involved in the pathogenesis of Parkinson's and Alzheimer's diseases as well as various disorders of the respiratory and reproductive tracts. Oxidative stress caused by pesticides is an important mechanism through which many of the pesticides exert their harmful effects. Oxidative stress is known to cause DNA damage which in turn may cause malignancies and other disorders. Many pesticides have shown to modulate the gene expression at the level of non-coding RNAs, histone deacetylases, DNA methylation patterns suggesting their role in epigenetics.

Determination of Spatial Distribution of Children Treated in Children Oncology Clinic with the Aid of Geographic Information Systems

The main objective of this research is to examine child cancer cases in Zonguldak/Turkey descriptively in epidemiological aspect with the help of GIS. Universe of the study is composed of 60 children between 1 and 19 years old who were treated in Children Oncology Clinic with a diagnosis of cancer. Whole universe was reached without selecting a sample in the study. Data were collected by using a form prepared by obtaining expert advice and they were applied to children and their parents at study dates. Results were expressed as percentages. Chi-Square test was used in intergroup comparisons, results were assessed within 95 % confidence interval and p < 0.05 was considered as statistically significant. Variables that were used in the study were assessed, recorded in prepared data collection form and distribution maps were produced. When disease diagnosis of the children participated in the study were evaluated, the most observed three types are ALL with 33.3 % (n = 20), Medullablastoma with 13.3 % (n = 8) and Hodgkin-nonHodgkin Lymphoma with 11.7 % (n = 7). Kdz. Eregli with 31.7 % (n = 19), Center with 31.7 % (n = 19), and Caycuma with 18.3 % (n = 11) are the first-three counties where the cases were mostly observed. Statistically significant difference was found (p = 0.016) comparing disease diagnosis with living place, and distribution maps of the number of cancer cases were produced.

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

Low-dose exposures to common environmental chemicals that are deemed safe individually may be combining to instigate carcinogenesis, thereby contributing to the incidence of cancer. This risk may be overlooked by current regulatory practices and needs to be vigorously investigated.

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety ‘Mode of Action’ framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology.

Impact of Sediment on Agrichemical Fate and Bioavailability to Adult Female Fathead Minnows: A Field Study

Precipitation induced runoff is an important pathway for agrichemicals to enter surface water systems and expose aquatic organisms to endocrine-disrupting compounds such as pesticides and steroid hormones. The objectives of this study were to investigate the distribution of agrichemicals between dissolved and sediment-bound phases during spring pulses of agrichemicals and to evaluate the role of suspended sediment in agrichemical bioavailability to aquatic organisms. To accomplish these objectives, suspended sediment and water samples were collected every 3 days from a field site along the Elkhorn River, located at the downstream end of a heavily agricultural watershed, and were screened for 21 pesticides and 21 steroids. Adult female fathead minnows (Pimephales promelas) were exposed in field mesocosms to river water containing varying sediment loads. Changes in organism hepatic gene expression of two estrogen-responsive genes, vitellogenin (VTG) and estrogen receptor alpha (ERα), as well as the androgen receptor (AR) were analyzed during periods of both low and high river discharge. Trends in agrichemical concentrations of both the dissolved and sediment phases as a function of time show that, while sediment may act as both a source and a sink for agrichemicals following precipitation events, the overall driver for molecular defeminization in this system is direct exposure to the sediment-associated compounds. This study suggests that endocrine disrupting effects observed in organisms in turbid water could be attributed to direct exposure of contaminated sediment.

Male fertility following occupational exposure to dichlorodiphenyltrichloroethane (DDT)

BACKGROUND

The inconsistent epidemiological results of the endocrine disrupting effects of DDT fuel a harsh debate on its global ban.

OBJECTIVES

We tested the hypothesis that occupational exposure to dichloro-diphenyl-trichloroethane (DDT) causes impairment in male fertility in a cohort of DDT exposed workers, in Sardinia, Italy.

METHODS

We accessed official records on date of marriage and date of birth of the first child to estimate time to pregnancy (TTP) in the spouses of 1223 workers employed in a 1946-1950 anti-malarial campaign. The TTP calculation was censored at the 13th month after date of marriage. We used a modified Cox's proportional hazard model to calculate the fecundability ratio (FR) by job, by cumulative exposure to DDT, and by time window in relation to the anti-malarial operations, adjusting by paternal age at marriage.

RESULTS

Among the spouses of DDT applicators, fecundability did not vary during DDT use (FR=1.22, 95% CI 0.84-1.77) nor in the following decade (FR=1.01, 95% CI 0.67-1.50) with reference to the prior years. A significant increase occurred among the unexposed and the less exposed sub-cohorts, which generated a non-significantly reduced FR among the DDT applicator sub-cohort with reference to the unexposed following exposure.

CONCLUSION

We did not find evidence of an impairment in male fertility following heavy occupational exposure to DDT. However, although fecundability was highest among the spouses of the DDT applicators in the years prior to the anti-malarial campaign, we cannot exclude that DDT exposure prevented an increase parallel to that observed among the unexposed and the less exposed sub-cohorts.

Hematological and hepatic alterations in Brazilian population heavily exposed to organochlorine pesticides

The aim of this study was to investigate the frequency of hematological and hepatic alterations and possible association with serum levels of beta-hexachlorocyclohexane (beta-HCH), p,p'-DDE, and hexachlorobenzene (HCB) among residents in an area heavily contaminated with organochlorine (OC) pesticides. A cross-sectional study was conducted in 415 male and 432 female residents aged >14 years. Serum samples were collected and analyzed for OC pesticides concentrations and biochemical parameters. Frequencies of hematological and hepatic alterations were calculated for each gender. Association between beta-HCH, p,p'-DDE (1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene), and HCB levels and presence of alterations was determined by logistic regression stratified by gender and controlling for confounders. Highest frequencies were observed for eosinophilia (23% men and 18% women), low hemoglobin (12% men and 15% women), and low erythrocyte count (12% men). High levels of bilirubin, glutamic-oxaloacetic transaminase (GOT), and glutamic-pyruvic transaminase (GPT) were observed, respectively, in 10, 11, and 12% of men and <10% of women. Gamma-glutamyl transferase (GGT) was elevated in 26 and 25% of males and females, respectively. Multivariate analysis revealed associations between eosinophilia and beta-HCH in men (OR = 1.06, 95%CI = 1.01-1.12) and women (OR = 1.05, 96%CI = 0.99-1.11), p,p'-DDE in men (OR = 1.03, 95%CI = 0.99-1.06) and women (OR = 1.02, 95%CI = 0.99-1.06), and HCB in women (OR = 1.54, 95%IC = 0.85-4.45). Beta-HCH was found to be associated with increased risk of elevated bilirubin in females (OR = 1.18, 95%CI = 1.07-1.29) and males (OR = 4.21, 95%CI = 1.87-9.47 for fourth vs. first quintile). Thus, OC pesticides may exert adverse effects on hematopoietic tissue and liver in populations chronically exposed to high levels of these compounds.

Vigilância aos agrotóxicos: quantificação do uso e previsão de impactos na saúde-trabalho-ambiente para os municípios brasileiros

Como estratégia da vigilância em saúde do trabalhador, população e ambiente, foram analisadas as quantidades, os tipos e a toxicidade de agrotóxicos usados por hectare nas lavouras mato-grossenses para servir de apoio às vigilâncias dos municípios brasileiros. O Brasil cultivou 95 milhões de hectares de lavouras em 2012 e Mato Grosso foi o maior consumidor de agrotóxicos. Utilizaram-se dados do banco informatizado do Instituto de Defesa Agropecuário que registra nas notas fiscais de venda e local de uso e os dados dos receituários agronômicos. Os resultados mostraram que em média um hectare de soja consumiu 12 litros de agrotóxicos, o de milho 6 litros, o de cana 4,8 litros e o de algodão 24 litros. Verificaram-se também os tipos e classes toxicológicas usadas por hectare de cada lavoura. Também, verificou-se, através de uma matriz de produção agropecuária e consumo de pesticidas, que alguns agravos à saúde estão correlacionados com as regiões mais produtoras. A partir dos dados de consumo de agrotóxicos, pela produção agrícola e da toxicidade desses venenos, podem-se inferir seus agravos e danos nos municípios brasileiros e estabelecer estratégias de prevenção e de vigilância à saúde dos trabalhadores, do ambiente e das populações expostas.

Experimental approaches to test pesticide-treated seed avoidance by birds under a simulated diversification of food sources

Pesticide coated seeds are known to be potentially toxic for birds, but the risk of poisoning will depend on how likely the individuals are to consume them. To refine the risk assessment of coated seed consumption by birds we studied the consumption and avoidance of seeds treated with imidacloprid, thiram, maneb or rhodamine B under different scenarios of food unpredictability (diversity or changes in food sources). In a first set of experiments, we examined during four days the amount of ingested food by red-legged partridges (Alectoris rufa) when offered untreated seeds, treated seeds or both. In the latter case, we also assessed the effect of a daily interchange in the position of feeders containing treated and untreated food. A second experiment, conducted with imidacloprid only, consisted of offering, during 27 h, fixed overall amounts of treated and untreated food, equally distributed in a different number of feeders per pen (1, 2, 4 or 8 feeders of each type of food) in order to diversify food sources. All the tested pesticide-treated seeds were avoided in two-choice experiments, and imidacloprid and thiram were also avoided in one-choice experiments. We found that imidacloprid treated seeds were avoided, probably as a consequence of a conditioned aversion effect due to the post-ingestion distress. However, under a diversification of two-choice food sources with multiple feeders, imidacloprid-treated seeds were ingested by partridges at increasing amounts that can produce sublethal effects or even death. Thiram treated seeds were also initially avoided in one-choice experiment, but probably mediated by a sensory repellence that progressively decreased with time. Our results reveal that the risk of pesticide exposure in birds may increase by unpredictability of food resources or prolonged availability of coated seeds, so pesticide registration for seed coating should consider worst-case scenarios to avoid negative impacts on farmland birds.

Malformações congênitas em municípios de grande utilização de agrotóxicos em Mato Grosso, Brasil

Mato Grosso é o maior produtor agrícola e também o maior consumidor nacional de agrotóxicos. A exposição materna aos agrotóxicos no período periconcepcional tem sido associada com aumento no risco de malformações congênitas. O objetivo deste artigo é analisar a associação entre o uso de agrotóxicos e as malformações congênitas em municípios com maior exposição aos agrotóxicos em Mato Grosso. Estudo de caso-controle realizado com 219 nascidos vivos com malformação congênita e 862 nascidos vivos sadios. Estimou-se a média de utilização dos agrotóxicos nos trimestres anterior e posterior à data da fecundação e durante todo o período periconcepecional segundo município e mês e ano de sua utilização. Posteriormente, estas medidas foram quartilizadas e transformadas em variáveis do tipo indicadoras (dummy ), atribuindo-se um nível de exposição para cada intervalo interquartil. Foi realizada análise bivariada e regressão logística. Foram observadas associações significantes (p < 0,05) no terceiro (OR=1,66, IC95% 0,98 - 2,79) e quarto quartil (OR=1,88, IC95% 1,09 - 3,24) do período pós-fecundação e no quarto quartil (OR=2,04, IC95%1,17-3,56) durante todo o período periconcepecional. A exposição materna aos agrotóxicos foi associada à maior ocorrência de malformações congênitas.

Environmental toxins

This review comprehensively summarizes the effects of more than 15 mostly used pesticides on male reproductive physiology, as recent experimental and epidemiological research have indicated their alarming impact on overall human health. Mechanisms have described that pesticide exposure damages spermatozoa, alter Sertoli or Leydig cell function, both in vitro and in vivo and thus affects semen quality. But, the literature suggests a need for more intricate research in those pesticides that are defined as mutagens or carcinogens and directly affect the hypothalamic–pituitary–gonadal axis. This literature review also proposes specific solutions to overcome these health effects.

Pesticide-induced gene mutations and Parkinson disease risk: a meta-analysis

AIMS

Increasing scientific evidence suggests that pesticide-induced gene mutations may contribute to increasing susceptibility to Parkinson disease (PD), but many existing studies have yielded inconclusive results. This meta-analysis aims at assessing the exact roles of pesticide-induced gene mutations in the development of PD.

METHODS

An extensive literature search for relevant studies was conducted on PubMed, Embase, Web of Science, Cochrane Library, and CBM databases from their inception through May 1st, 2013. This meta-analysis was performed using the STATA 12.0 software. The crude odds ratio with 95% confidence interval was calculated.

RESULTS

Ten case-control studies were included with a total of 1248 PD patients and 1831 healthy controls. Our meta-analysis revealed that PD patients with pesticide exposure had higher gene mutation rates than those of healthy controls. Subgroup analysis by gene type indicated that the mutation rates in the GSTP1, SLC6A3, and MDR1 genes of PD patients with pesticide exposure were higher than those of healthy controls. No publication bias was detected in this meta-analysis.

CONCLUSION

The current meta-analysis indicates that pesticide-induced gene mutations may contribute to increasing susceptibility to PD, especially in the GSTP1, SLC6A3, and MDR1 genes.

Dissecting Major Signaling Pathways throughout the Development of Prostate Cancer

Prostate cancer (PCa) is one of the most common malignancies found in males. The development of PCa involves several mutations in prostate epithelial cells, usually linked to developmental changes, such as enhanced resistance to apoptotic death, constitutive proliferation, and, in some cases, to differentiation into an androgen deprivation-resistant phenotype, leading to the appearance of castration-resistant PCa (CRPCa), which leads to a poor prognosis in patients. In this review, we summarize recent findings concerning the main deregulations into signaling pathways that will lead to the development of PCa and/or CRPCa. Key mutations in some pathway molecules are often linked to a higher prevalence of PCa, by directly affecting the respective cascade and, in some cases, by deregulating a cross-talk node or junction along the pathways. We also discuss the possible environmental and nonenvironmental inducers for these mutations, as well as the potential therapeutic strategies targeting these signaling pathways. A better understanding of how some risk factors induce deregulation of these signaling pathways, as well as how these deregulated pathways affect the development of PCa and CRPCa, will further help in the development of new treatments and prevention strategies for this disease.

Pesticides and human chronic diseases: evidences, mechanisms, and perspectives

Along with the wide use of pesticides in the world, the concerns over their health impacts are rapidly growing. There is a huge body of evidence on the relation between exposure to pesticides and elevated rate of chronic diseases such as different types of cancers, diabetes, neurodegenerative disorders like Parkinson, Alzheimer, and amyotrophic lateral sclerosis (ALS), birth defects, and reproductive disorders. There is also circumstantial evidence on the association of exposure to pesticides with some other chronic diseases like respiratory problems, particularly asthma and chronic obstructive pulmonary disease (COPD), cardiovascular disease such as atherosclerosis and coronary artery disease, chronic nephropathies, autoimmune diseases like systemic lupus erythematous and rheumatoid arthritis, chronic fatigue syndrome, and aging. The common feature of chronic disorders is a disturbance in cellular homeostasis, which can be induced via pesticides' primary action like perturbation of ion channels, enzymes, receptors, etc., or can as well be mediated via pathways other than the main mechanism. In this review, we present the highlighted evidence on the association of pesticide's exposure with the incidence of chronic diseases and introduce genetic damages, epigenetic modifications, endocrine disruption, mitochondrial dysfunction, oxidative stress, endoplasmic reticulum stress and unfolded protein response (UPR), impairment of ubiquitin proteasome system, and defective autophagy as the effective mechanisms of action.

Health risk assessment of exposure to chlorpyrifos and dichlorvos in children at childcare facilities

The present study evaluated 168 childcare facilities from 6 cities in South Korea to assess exposure to organophosphorus pesticides (OPs) in children through 4 major pathways (indoor air, indoor dust, surface wipe of indoor objects, and hand wash water of children). The Excess Cancer Risk (ECR) was calculated based on the Cancer Potency Factor (CPF) and Age Dependent Adjustment Factor (ADAF) in adults. Dichlorvos residues were detected in the indoor air, indoor dust, surface wipes of indoor objects, and the hand wash water of children at frequencies of 47.4, 90, 100, and 100%, respectively. After revision based on the ADAF, total cancer risk in the 50th percentile was 3.99×10(-3) for inhalation, oral intake, and dermal contact in children ages 3 to 4 and 4.63×10(-4) in kindergarteners ages 5 to 6. Inhalation was the primary pathway of pesticide exposure in children in childcare facilities. Children ages 3 to 4 in daycare centers had a Hazard Quotient (HQ) of 0.5 for dichlorvos, which was 50% lower than the risk criterion level of 1 but was higher than the 95% percentile with a HQ of 1.9. This study postulates that children in childcare facilities may be exposed to specific OPs.

Effect of endocrine disruptor pesticides: a review

Endocrine disrupting chemicals (EDC) are compounds that alter the normal functioning of the endocrine system of both wildlife and humans. A huge number of chemicals have been identified as endocrine disruptors, among them several pesticides. Pesticides are used to kill unwanted organisms in crops, public areas, homes and gardens, and parasites in medicine. Human are exposed to pesticides due to their occupations or through dietary and environmental exposure (water, soil, air). For several years, there have been enquiries about the impact of environmental factors on the occurrence of human pathologies. This paper reviews the current knowledge of the potential impacts of endocrine disruptor pesticides on human health.

Ergonomics contribution to chemical risks prevention: An ergotoxicological investigation of the effectiveness of coverall against plant pest risk in viticulture

The purpose of this article is to present the contribution of a trans-disciplinary approach focused on ergonomics and chemical risk control. We shall more precisely discuss how such an approach carried out in the field of agricultural work has made it possible to highlight serious shortcomings in the effectiveness of the coveralls that are supposed to protect vineyard workers from pesticides. The study results, as well as the whistle-blow that followed have questioned the control and prevention measures used until then. The aforementioned trans-disciplinary approach gathers knowledge and methods from epidemiology, industrial hygiene, occupational health and safety and ergonomics. Ergonomics were central in the development of the approach as it connected task and activity analysis with contamination measurements. Lastly, the first results that were obtained have been confirmed and reused by the AFSSET (Agence Française de Sécurité Sanitaire Environnement et Travail, the French governmental agency in charge of environmental health and occupational health and safety issues) regarding the agricultural sector but also for all other situations in which workers use coveralls as protection against chemical risks.

Xeno-oestrogens and phyto-oestrogens are alternative ligands for the androgen receptor

The androgen receptor (AR) plays a critical role in prostate cancer development and progression. This study aimed to use a computerized docking approach to examine the interactions between the human AR and phyto-oestrogens (genistein, daidzein, and flavone) and xeno-oestrogens (bisphenol A, 4-nonylphenol, dichlorodiphenyl trichloroethane [DDT], diethylstilbestrol [DES]). The predicted three-dimensional structure of AR and androgens was established using X-ray diffraction. The binding of four xeno-oestrogens and three phyto-oestrogens to AR was analysed. The steroids estradiol and dihydrotestosterone (DHT) were used as positive controls and thyroxine as negative control. All the ligands shared the same binding site except for thyroxine. The endogenous hormones DHT and 17beta-oestradiol showed the strongest binding with the lowest affinity energy (< -10 kcal mol(-1)). All three phyto-oestrogens and two xeno-oestrogens (bisphenol A and DES) showed strong binding to AR. The affinities of flavone, genistein, and daidzein were between -8.8 and -8.5 kcal mol(-1), while that of bisphenol A was -8.1 kcal mol(-1) and DES -8.3 kcal mol(-1). Another two xeno-oestrogens, 4-nonylphenol and DDT, although they fit within the binding domain of AR, showed weak affinity (-6.4 and -6.7 kcal mol(-1), respectively). The phyto-oestrogens genistein, daidzein and flavone, and the xeno-oestrogens bisphenol A and DES can be regarded as androgenic effectors. The xeno-oestrogens DDT and 4-nonylphenol bind only weakly to AR.

Biodegradation of epoxyconazole and piraclostrobin fungicides by Klebsiella sp. from soil

Three bacterial strains have been isolated from soil in which soybean had been continuously cropped and treated with Opera(®), a fungicide containing epoxyconazole and pyraclostrobin. The three strains (1,805, 2,801 and 3,803), obtained from soil at 80-100 cm depth, were selected on medium containing 0.03% Opera(®). Morphological examination revealed that the strains were Gram-negative, and two of them (1,805 and 2,801) exhibited polymorphism. The growth profiles demonstrated that 1,805 and 3,803 were more efficient growing in the presence of Opera(®) than 2,801. Maximum growth was reached between 24 and 48 h, however, 2,801 was not able to survive after this period. The total protein content produced by 1,805, 2,801 and 3,803 in liquid selective medium containing Opera(®) were 111.0 ± 0.02, 80.0 ± 0.05 and 130.5 ± 0.07 μg/ml, respectively. According to its biochemical and molecular features, strain 1,805 was identified as Klebsiella sp. On the basis of the characteristics presented (facultative anaerobic nature, polymorphic character and capacity of growing in the presence of Opera(®)) strain 1,805 seems to be able to degrade the epoxyconazole and pyraclostrobin.

Changes of thyroid hormone levels and related gene expression in Chinese rare minnow (Gobiocypris rarus) during 3-amino-1,2,4-triazole exposure and recovery

Thyroid hormones (THs) play an important role in the development and metabolism of fish through their influences on genetic transcription and are targets for endocrine disruptive agents in the aquatic environment. Amitrole is a pesticide potentially interfering with thyroid hormone regulation. In this study, the rare minnow (Gobiocypris rarus) was exposed to different levels of 3-amino-1,2,4-triazole (amitrole) and allowed to recover in clean water. Plasma TH levels and the expression of TH-related genes, including transthyretin (ttr), deiodinases (d1 and d2), and the thyroid hormone receptor (tralpha) from the livers and brains were evaluated. After exposure, the plasma TH levels did not change. Histopathological observations showed that livers were degenerated at 10,000 ng/l and these damages could be recovered by the withdrawal of amitrole. However, the ttr, d1, and d2 mRNA levels in the livers of males were significantly up-regulated in all exposure groups (p<0.05). The ttr and d2 mRNA levels were significantly up-regulated at 10,000 ng/l and 10, 100, and 1000 ng/l in the livers of females, respectively (p<0.05). In the brains of males, a twofold increase of d2 mRNA levels at > or = 100 ng/l and a fivefold decrease of tralpha mRNA levels at > or = 10 ng/l were observed (p<0.05), whereas no significant differences were observed in the expression of d2 and tralpha in the brains of females. After a recovery period, the ttr, d1, and d2 mRNA levels in the livers of males returned to control levels, but the tralpha mRNA levels were irreversibly decreased at all treatments (p<0.05). In addition, the d2 mRNA levels in the livers of females were significantly induced at > or = 100 ng/l. Moreover, the d2 mRNA levels in the brains of males and females were up-regulated at 10,000 ng/l. These results indicated that amitrole exposure could result in alternations of ttr, d1, d2, and tralpha gene expression in different tissues of the rare minnow. The expression of these TH-related genes in males was more sensitive to amitrole than those of females. Recovery in clean water was associated with the selective regulation of TH-related gene transcription in the rare minnow. Therefore, these TH-related genes can serve as biomarkers to screen the effects of thyroid disruption chemicals in rare minnow.

[Is there any relationship between rural environmental factors and reproductive health in the Pampa Humeda in Argentina?]

The relationship between environmental factors and health is well known. Rural environmental influences on reproductive health have been properly proved, both in animals and humans. In Latin America, few studies have been conducted in this area. The current project is based on the description of relationships between reproductive health and environmental factors in rural populations, characterized by specific environmental characteristics. Three variables were evaluated: male-to-female birth ratio, male urogenital malformations (cryptorchidism and hypospadias), and endocrine-related cancer incidence. Five rural communities in the Pampa Humeda in Argentina were selected, and the data were compared to the national mean. Biomedical data and environmental risk factors were correlated through a geographic information system. The ratio of male to female births did not show any differences. Malformations showed very significant differences. Endocrine-related cancers showed higher incidence rates compared to the national mean, particularly in some communities. In conclusion, there is a relationship between environmental factors and reproductive health conditions in this region.

Agrotóxicos e saúde humana: contribuição dos profissionais do campo da saúde

Focaliza a produção científica dos profissionais da saúde, em especial das enfermeiras, sobre o tema agrotóxico e saúde humana. O ensaio reúne e apresenta informações por meio de pesquisa bibliográfica, procurando reconhecer a contribuição de cada autor e sua utilidade para o campo da saúde humana. Foram localizados 32 artigos de pesquisa publicados em periódicos brasileiros. A análise dos artigos destaca que a contribuição dos profissionais de saúde é focada na saúde humana - especialmente na saúde do trabalhador e na qualidade dos alimentos. No intuito de minimizar os efeitos dos agrotóxicos para a saúde ambiental e humana, os autores expõem sugestões de ação, tanto para os profissionais da saúde como para os órgãos competentes.

DDT reintroduction for malaria control: the cost-benefit debate for public health

DDT is a persistent insecticide that was widely used in the world from the 1940s until the 70s, when it was banned in the United States and other countries. Most of its toxic effects are not observed in the acute forms, but particularly after chronic exposure. These long-term issues include reproductive effects, varying according to the time of life in which the individuals were exposed. The aims of the current study were to review the principal toxicological effects of DDT on reproduction, stratifying by physiological periods of exposure, and based on the magnitude of these effects, to discuss the cost-benefit relationship of reintroducing DDT with the specifically defined vector control criteria.

Reductive dechlorination of methoxychlor and DDT by human intestinal bacterium Eubacterium limosum under anaerobic conditions

Methoxychlor [1,1,1-trichloro-2,2-bis(p-methoxyphenyl)ethane], a substitute for 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), is a compound of environmental concern because of potential long-term health risks related to its endocrine-disrupting and carcinogenic potency. In order to determine the metabolic fate of methoxychlor and DDT in the human intestinal gut, Eubacterium limosum (ATCC 8486), a strict anaerobe isolated from the human intestine that is capable of O-demethylation toward O-methylated isoflavones, was used as a model intestinal microbial organism. Under anaerobic incubation conditions, E. limosum completely transformed methoxychlor and DDT in 16 days. Based on gas chromatography-mass chromatography analyses, the metabolites produced from methoxychlor and DDT by E. limosum were confirmed to be 1,1-dichloro-2,2-bis(p-methoxyphenyl)ethane (methoxydichlor) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), respectively. This study suggests that E. limosum in the human intestinal gut might be a participant in the reductive dechlorination of methoxychlor to the more antiandrogenic active methoxydichlor.

Endocrine disrupting pesticides: implications for risk assessment

Endocrine disrupting (ED) chemicals are compounds that alter the normal functioning of the endocrine system, potentially causing disease or deformity in organisms and their offspring. Pesticides are used widely to kill unwanted organisms in crops, public areas, homes and gardens and medicinally to kill parasites. Many are proven or suspected to be EDs. Ancient physiological similarities between different vertebrate groups suggest that disorders observed in wildlife may indicate risks to humans. This makes accurate risk assessment and effective legislation difficult. In this paper, the hazardous properties of pesticides which are known to have ED properties are reviewed in order to assess the implications for risk assessment. As well as data on sources of exposure in the United Kingdom (UK) an assessment of the evidence on the health effects of ED pesticides is also included. In total, 127 have been identified from the literature and their effects and modes of action are listed in this paper. Using the UK as a case study, the types and quantities of pesticides used, and their methods of application are assessed, along with their potential pathways to humans. In the UK reliable data are available only for agricultural use, so non-agricultural routes of pesticide exposure have been poorly quantified. The exposure of people resident in or visiting rural areas could also have been grossly under-estimated. Material links between ED pesticide use and specific illnesses or deformities are complicated by the multifactorial nature of disease, which can be affected by factors such as diet. Despite these difficulties, a large body of evidence has accumulated linking specific conditions to ED pesticides in wildlife and humans. A more precautionary approach to the use of ED pesticides, especially for non-essential purposes is proposed.

Acetamiprid, carbendazim, diuron and thiamethoxam sorption in two Brazilian tropical soils

Sorption of acetamiprid ((E)-N1-[(6-chloro-3-pyridyl)methyl]-N2-cyano-N1-methylacetamidine), carbendazim (methyl benzimidazol-2-ylcarbamate), diuron (N-(3,4-dichlorophenyl)-N, N-dimethyl urea) and thiamethoxam (3-(2-chloro-thiazol-5-ylmethyl)-5-methyl-[1,3,5]oxadiazinan-4-ylidene-N-nitroamine) was evaluated in two Brazilian tropical soils, Oxisol and Entisol, from Primavera do Leste region, Mato Grosso State, Brazil. To describe the sorption process, batch experiments were carried out. Linear and Freundlich isotherm models were used to calculate the K(d) and K(f) coefficients from experimental data. The K(d) values were utilized to calculate the partition coefficient normalized to soil organic carbon (K(oc)). For the pesticides acetamiprid, carbendazim, diuron and thiamenthoxan the K(oc) (mL g(- 1)) values ranged in both soils from 98 - 3235, 1024 - 2644, 145 - 2631 and 104 - 2877, respectively. From the studied pesticides, only carbendazim presented correlation (r(2) = 0.82 and p < 0.01) with soil organic carbon (OC) content. Acetamiprid and thiamethoxam showed low sorption coefficients, representing a high risk of surface and ground water contamination.

The menace of endocrine disruptors on thyroid hormone physiology and their impact on intrauterine development

The delivery of the appropriate thyroid hormones quantity to target tissues in euthyroidism is the result of unopposed synthesis, transport, metabolism, and excretion of these hormones. Thyroid hormones homeostasis depends on the maintenance of the circulating 'free' thyroid hormone reserves and on the development of a dynamic balance between the 'free' hormones reserves and those of the 'bound' hormones with the transport proteins. Disturbance of this hormone system, which is in constant interaction with other hormone systems, leads to an adaptational counter-response targeting to re-establish a new homeostatic equilibrium. An excessive disturbance is likely to result, however, in hypo- or hyper- thyroid clinical states. Endocrine disruptors are chemical substances forming part of 'natural' contaminating agents found in most ecosystems. There is abundant evidence that several key components of the thyroid hormones homeostasis are susceptible to the action of endocrine disruptors. These chemicals include some chlorinated organic compounds, polycyclic aromatic hydrocarbons, herbicides, and pharmaceutical agents. Intrauterine exposure to endocrine disruptors that either mimic or antagonize thyroid hormones can produce permanent developmental disorders in the structure and functioning of the brain, leading to behavioral changes. Steroid receptors are important determinants of the consequences of endocrine disruptors. Their interaction with thyroid hormones complicates the effect of endocrine disruptors. The aim of this review is to present the effect of endocrine disruptors on thyroid hormones physiology and their potential impact on intrauterine development.

Atividade agrícola e externalidade ambiental: uma análise a partir do uso de agrotóxicos no cerrado brasileiro

Esse artigo tem como objetivo discutir as externalidades negativas associadas ao uso intensivo de agrotóxicos nos municípios do cerrado brasileiro, área em franca expansão da atividade agrícola. Tais externalidades estão relacionadas principalmente aos danos ambientais e à saúde humana (de trabalhadores, famílias rurais e consumidores,) cujos custos acabam sendo socializados. O presente estudo analisa como externalidade a contaminação do solo e da água por esses produtos a partir de dados obtidos por meio da Pesquisa de Informações Básicas Municipais (IBGE), que em 2003 aplicou um questionário suplementar com questões ambientais. Mapas foram construídos procurando associar áreas contaminadas e o grau de atividade agrícola dos municípios, captado na Pesquisa Agrícola Municipal (IBGE, 2003). Por meio de uma regressão logística, foi possível encontrar fatores de risco da contaminação no solo e na água por agrotóxicos e fertilizantes, tais como área de lavoura temporária, poluição no ar por queimadas e proliferação de pragas. Conclui-se que o artigo pode contribuir para a formulação de políticas no sentido de auxiliar o desenho dos instrumentos de regulação e o diagnóstico das áreas prioritárias em que essas ações preventivas deveriam ser implementadas.

Systematic review and meta-analysis of cyclodiene insecticides and breast cancer

Cyclodienes are a group of organochlorine pesticides that have been the focus of increasing numbers of breast cancer etiology studies in recent years. The aim of this systematic review and meta-analysis was to summarize and pool the results of breast cancer and cyclodiene insecticide contamination studies. We used databases from 1966 to 7/2006 and included 21 case-control studies. Pooled odds ratios or differences in means as geometric means ratios were calculated. Meta-analysis of the chemicals did not reveal any statistically significant association except for heptachlor. The heterogeneity among the different studies and the methodology limitations are discussed.