Do environmental and occupational exposure to pyrethroids and organophosphates affect human semen parameters? Results of a systematic review and meta-analysis

Our purpose was to review and analyse the impact of pyrethroids and organophosphates exposure on human semen parameters. A comprehensive literature search was performed through MEDLINE via PubMed, Scopus and Webscience. Only cohort studies examining semen parameters in workers or general populations exposed to pyrethroids or organophosphates were included. Ejaculate volume, sperm count, concentration, motility, viability, normal morphology and seminal pH alterations were pooled using the Cochran–Mantel–Haenszel Method with the random effect model and expressed as weighted mean difference, risk ratios, 95% confidence intervals and p-values. Seven cross-sectional studies regarding pyrethroids were included. Four of them were eligible for meta-analysis. The only parameter affected by pyrethroid exposure was normal sperm morphology (WMD-7,61%, 95%CI –11,92 to −3,30;p = 0,0,005). Nine studies were selected to evaluate the impact of organophosphates on semen parameters with six of them eligible for meta-analysis. A significant reduction was detected for the following: ejaculate volume (WMD −0,47ml, 95%CI −0,69 to −0,25; p < 0,0001), sperm count (WMD-40,03, 95%CI −66,81 to −13,25;p = 0,003), concentration (WMD-13,69 x10⁶/mL, 95%CI −23, 27 to-4,12;p = 0,005) and motility (WMD −5,70%, 95%CI −12,89 to 1,50;p = 0,12). Despite the increase in sperm abnormality, it has been shown that pyrethroids are unrelated to reduced sperm quality. However, the negative association of organophosphates with spermatogenesis is noteworthy.     

A TLC screening program for 170 commonly used pesticides using the corrected Rf value (R f c value)

Summary This article reports TLC data (corrected R_f values; R _f ^c values) of 170 commonly used pesticides which are regularly encountered in toxicological analysis. Silica gel was used as the stationary phase and three binary systems were chosen as solvents.     

Chronic effect of endosulfan on the testicular functions of rat

Aim: To find out the toxic effect of endosulfan on the tesficular function of pubertal rats, Methods: Male rats of pu-bertal age were orally administered endosulfan at a dose of 1.0 mg/kg body weight for 30 days. Twenty-four hours af-ter the last tmagnent, the rats were sacrificed and the testis, epididymis, seminal vesicles and ventral prostate were re-moved and weighed. A 10 % testicular homogenate was prepared for biochemical estimations. Results: In endosul-fan-treated rats, there were a reduction in the body weight and the weights of testis and accessory sex organs, a de-crease in the testicular lactate and pyruvate activities, and in the testicular DNA and RNA concentrations, whereas thetesticular protein concentration was slightly increased; the specific activity of testicular steroidogenic enzyme, 33OH-steroid dehydrogenase and the ascorbic acid level were decreased, which were correlated with a decrease in steroidoge-nesis. The lysosomal enzyme acid phosphatase and brush-border enzyme alkaline phosphatase activities were also de-creased in the testis of treated rats. Conclusion: In puhertal rats, endosulfan treaanent inhibits the testicular functions.(Asian J Androl 1999 Dec; 1 : 203 - 206)     

Neuropsychiatric evaluation in subjects chronically exposed to organophosphate pesticides.

Long-term exposure to low levels of organophosphate pesticides (OP) may produce neuropsychiatric symptoms. We performed clinical, neuropsychiatric, and laboratory evaluations of 37 workers involved in family agriculture of tobacco from southern Brazil who had been exposed to OP for 3 months, and in 25 of these workers, after 3 months without exposure to OP. Plasma acetylcholinesterase activity levels of all subjects were within the normal range (3.2 to 9.0 U/l) and were not different between on- and off-exposure periods (4.7 +/- 0.9 and 4.5 +/- 1.1 U/l, respectively). Clinically significant extrapyramidal symptoms were present in 12 of 25 subjects, which is unexpected in such a population. There was a significant reduction of extrapyramidal symptoms after 3 months without exposure to OP, but 10 subjects still had significant parkinsonism. Mini-mental and word span scores were within the expected range for this population and were not influenced by exposure to OP. Eighteen of the 37 subjects (48%) had current psychiatric diagnoses in the first interview (13 with generalized anxiety disorder and 8 with major depression). Among the 25 subjects who completed both evaluations, the total number of current psychiatric diagnoses, after 3 months without using OP, dropped from 24 to 13 and the number of affected individuals with any psychiatric diagnosis dropped from 11 to 7. In conclusion, this study reinforces the need for parameters other than acetylcholinesterase activity to monitor for chronic consequences of chronic low-dose OP exposure, and it suggests that subjects have not only transient motor and psychiatric consequences while exposed, but may also develop enduring extrapyramidal symptoms.     

瓜蒌中有机氯农药残留量的含量测定

 目的 对中药瓜蒌进行有机氯农药的残留量测定，开展瓜蒌质量标准的规范化研究。方法 采用气相色谱法对六六六（BHC）4种异构体、滴滴涕（DDT）4种异构体和五氯硝基苯(PCNB)进行测定。结果 11个瓜蒌样品中六六六的总含量位于2.86～21.85 μg·kg^-1的范围，滴滴涕的总含量位于2.86～50.04 μg·kg^-1的范围，五氯硝基苯的含量低于4.94 μg·kg^-1。结论 所测瓜蒌中农药残留量低于我国国家相关的规定限量；样品中商品瓜蒌的农药残留量高于非商品瓜蒌的残留量，提示我们在瓜蒌的贮存、运输等过程中应该限制农药的污染。     

Chlorinated pesticides and heavy metals in human semen

The concentration of chlorinated pesticides and heavy metals (lead and cadmium) was measured using gas liquid chromatography and the graphite tube atomizer of atomic absorption spectrophotometer, respectively, in semen samples collected from men in the normal human population. Significant concentrations of lead and cadmium were detected. Significant amounts of hexachlorocyclohexane (HCH) and its isomers alpha, beta, gamma and delta, the dichlorodiphenyl trichloroethane (DDT) metabolite 1,1,1-trichloro-2,2-bis (p chlorophenyl ethane) (pp'-DDE) and low values of 1,1,2-dichloro-2, 2-bis(p chlorophenyl ethane) (pp'-DDD) aldrin or endosulfan were detected. The presence of these xenobiotics in human semen might be related to the extensive use of pesticides, emission of exhaust from motor vehicles, consumption of tobacco and industrial operations.     

农业地区人群膀胱癌死亡率与环境中农药暴露的相关性

分析农业地区人群膀胱癌死亡率与环境中农药暴露是否存在相关关系。方法收集沈阳市六个郊区县的农药资料和膀胱癌死亡资料，用SPSS(10.0)统计软件进行spearsman等级相关及线性回归分析。结果农业用途和杀菌剂及其它种类的农药使用密度与膀胱癌死亡率显著正相关。按性别分析，男性膀胱癌死亡率与农业用途、杀菌剂及其它种类的农药使用密度显著正相关；而女性膀胱癌死亡率只与畜牧业用途的农药使用密度显著相关。线性回归分析显示男性与农业用途和其它种类、女性与畜牧业用途的农药使用密度存在线性依存关系。结论农业地区人群膀胱癌死亡率与环境中农药暴露存在相关关系。     

A Current Review of Cypermethrin-Induced Neurotoxicity and Nigrostriatal Dopaminergic Neurodegeneration

Cypermethrin, a class II pyrethroid pesticide, is used to control insects in the household and agricultural fields. Despite beneficial roles, its uncontrolled and repetitive applications lead to unintended effects in non-target organisms. Cypermethrin crosses the blood-brain barrier and induces neurotoxicity and motor deficits. Cypermethrin prolongs the opening of sodium channel, a major site of its action, leading to hyper-excitation of the central nervous system. In addition to sodium channel, cypermethrin modulates chloride, voltage-gated calcium and potassium channels, alters the activity of glutamate and acetylcholine receptors and adenosine triphosphatases and induces DNA damage and oxidative stress in the neuronal cells. Cypermethrin also modulates the level of neurotransmitters, including gamma-aminobutyric acid and dopamine. It is one of the most commonly used pesticides in neurotoxicology research not only because of its variable responses depending upon the doses, time and routes of exposure and strain, age, gender and species of animals used across multiple studies but also owing to its ability to induce the nigrostriatal dopaminergic neurodegeneration. This article describes the effect of acute, chronic, developmental and adulthood exposures to cypermethrin in experimental animals. The article sheds light on cypermethrin-induced changes in the central nervous system, including its contribution in the onset of specific features, which are associated with the nigrostriatal dopaminergic neurodegeneration. Resemblances and dissimilarities of cypermethrin-induced nigrostriatal dopaminergic neurodegeneration with sporadic and chemicals-induced disease models along with its advantages and pitfalls are also discussed.     

Comparison of Farmers in the Agricultural Health Study to the 1992 and 1997 Censuses of Agriculture

Abstract

Context: The Agricultural Health Study (AHS) is a large, prospective cohort study in the states of Iowa and North Carolina that has been developed to better understand how pesticides and other agricultural exposures relate to the occurrence of cancer and other diseases.

Purpose: This report compares the characteristics of AHS farmers to the Census of Agriculture to evaluate the generalizability of AHS findings.

Methods: We restricted the AHS to private pesticide applicators who enrolled in Iowa (n = 31,065) and in North Carolina (n = 17,239) between 1993 and 1997, and who identified themselves as living or working on a farm. We compared their self-reported data with data from the 1992 and 1997 Censuses of Agriculture.

Findings: AHS farmers in Iowa are younger; live or work on larger farms; more frequently apply herbicides, insecticides, and fungicides; and are more likely to raise beef cattle and swine, and grow corn, soybeans, hay, and oats. AHS farmers in North Carolina are also younger, live or work on larger farms, more frequently reported growing crops commonly seen in the state, and are more frequent pesticide users. However, animals raised are similar to those in the North Carolina Census of Agriculture.

Conclusions: AHS farmers likely represent the higher end of pesticide usage in both states in part because AHS farmers have larger farms. Since the health effects of pesticides are best ascertained among pesticide users with the greatest exposure, the AHS cohort should prove to be a valuable resource for health effects research.     

Pesticides as risk factors for head and neck cancer: A review

Humans may be exposed to pesticides such as fungicides, herbicides, and insecticides, during occupational and non‐occupational activities. Pesticides could be related to cancer development mainly because of their effects on the endocrine and immune systems and their cumulative effect. The present review evaluated in current literature evidence of an association between exposure to pesticides and the occurrence of head and neck cancer (HNC). A literature search for cohort studies was conducted in the PubMed, Web of science, and Cochrane databases. Methodological quality of each study was rated with the Scottish Intercollegiate Guidelines Network (SIGN) checklist. One thousand one hundred and thirty‐two studies were identified. Thirty‐two were included. Most of the studies found addressed occupational exposure to pesticides and were conducted in Europe and North America. Eleven high‐quality studies were found. Most of them found no association between exposure to pesticides and increased risk of HNC. Two studies found some evidence of a positive association between pesticide (malathion and atrazine) exposure and thyroid cancer. The literature review does not support a clear evidence for association between pesticides exposure and HNC. Only limited evidence points to a positive association between exposure to some pesticides and thyroid cancer. Further standardized studies based on appropriate designs are required to clarify the effect of pesticides on the genesis of HNC, considering dose, length of exposure, and type of pesticide.