Pesticide genotoxicity in cotton picking women in Pakistan evaluated using comet assay

To control agricultural pests and meet the increasing food demands, pesticides use has been increased substantially over time. Although pesticides are relatively specific to their targets, they can affect non-target organisms and are hazardous for the population around the application areas particularly to the individuals engaged in different types of agricultural activities. This situation is worse in developing and under-developed countries where personal protective equipment is merely used and regulatory guidelines are hardly practiced. In the present study, DNA damage in women exposed to pesticides while picking cotton with bare hands was assessed using single cell gel electrophoresis assay or comet assay. The presence of pesticides in blood serum of exposed individuals was also analyzed using high-performance liquid chromatography. Blood samples were collected from 138 (69 exposed and 69 control) randomly selected females from a major cotton growing area (Bahawalpur District) of the Punjab province of Pakistan. DNA damage, as determined by the mean comet tail length, was significantly higher (p?pesticides, cyhalothrin, endosulfan, and deltamethrin found significantly higher (p?pesticides in their serum samples indicating a positive association of DNA damage and pesticide exposure. The present study suggests that exposure to pesticides leads to DNA damage.     

Literature review: dermal monitoring data for pesticide exposure assessment of farm workers

Objective: To conduct a literature review to determine the types of information that existing dermal pesticide monitoring data could provide for future pesticide exposure assessment in occupational epidemiology.

Methods: A systematic literature search was performed on eight online databases. Two screening phases with predetermined criteria identified the qualifying literature. Standard information and dermal pesticide monitoring data were recorded and summarized from each qualifying study to assess its usefulness for future pesticide exposure assessment.

Results: A total of 31 farm studies qualified for review; task information was used to standardize all farm job(s) evaluated into 5 job groups: operators, applicators, mixer-loaders, field workers, and flaggers. When attempting to compare dermal exposure levels between studies, two types of variation were identified: (1) variation in study focus and reporting and 2) variation in exposure levels. The former variation type prevented exposure level comparisons between studies. Within studies, exposure levels were compared across body parts to identify that which had the highest measured exposure and to determine if results were similar in other studies that evaluated the same farm job. Using studies that measured exposure for multiple farm jobs, within study comparisons of total body exposure were performed to evaluate work factors.

Conclusion: Future dermal pesticide exposure monitoring studies should standardize reporting procedures, as suggested in this review, to allow for more extensive dermal data comparisons. Body parts with highest measured levels of dermal exposure were identified by farm job, along with work factors to be further investigated as potential dermal pesticide exposure determinants for farm workers.     

Oral Treatment of Organophosphate Poisoning in Mice

OBJECTIVE: Organophosphates are used as pesticides, herbicides, and chemical warfare agents. Treatment of organophosphate poisoning is with intravenous atropine and pralidoxime in addition to supportive care. This study determined the efficacy of oral agents in preventing death from organophosphate poisoning. METHODS: The organophosphate paraoxon (8 mg/kg) was used in a murine model with lethality at four and 24 hours as an end point. For oral treatment, 15 male Balbc mice were given either atropine sulfate (4 mg/kg), or a combination of atropine sulfate (4 mg/kg) with pralidoxime (100 mg/kg), by oral gavage. A control group of 22 mice received water by oral gavage. Chi-square analysis was used to compare results in the different groups. RESULTS: Of the control group, six of 22 survived to four hours after paraoxon exposure. Of the exposed animals treated with oral atropine, eight of 15 survived to four hours. Of the exposed animals treated with a combination of atropine and pralidoxime, 13 of 15 survived to four hours. All animals surviving to four hours survived to 24 hours. The increased survival of animals in the atropine group relative to the control group was not significant (p = 0.09). Survival was significant in the group treated with atropine and pralidoxime relative to atropine alone (p = 0.02) and to the control group (p = 0.0002). All treated mice surviving at four hours were alive at 24 hours. CONCLUSIONS: Both oral atropine and a combination of oral atropine and pralidoxime improved survival, and combination therapy achieved statistical significance. Generalization of this result to other organophosphate pesticides, other doses of paraoxon, and other species cannot be made without further investigations.     

The organochlorine p,p′-dichlorodiphenyltrichloroethane induces colorectal cancer growth through Wnt/β-catenin signaling

Dichlorodiphenyltrichloroethane (DDT), an organochlorine pollutant, is associated with several types of cancer. However, the relationship between DDT and colorectal cancer is uncertain. In this study, the impact of p,p′-DDT on colorectal cancer growth was evaluated using both in vitro and in vivo models. Our results indicated that the proliferation of human colorectal adenocarcinoma DLD1 cells was significantly promoted after exposed to low concentrations of p,p′-DDT ranging from 10⁻¹² to 10⁻⁷ M for 96 h. Exposure to p,p′-DDT from 10⁻¹⁰ to 10⁻⁸ M led to upregulation of phospho-GSK3β (Ser9), β-catenin, c-Myc and cyclin D1 in DLD1 cells. RNA interference of β-catenin inhibited the proliferation of DLD1 cells stimulated by p,p′-DDT. Inhibiting of estrogen receptors (ERs) had no significant effect on the action of p,p′-DDT. Treatment with p,p′-DDT induced production of intracellular reactive oxygen species (ROS) and inhibited superoxide dismutase (SOD) activity in DLD1 cells. Treatment with N-acetyl-L-cysteine (NAC), a ROS inhibitor, suppressed the induction of Wnt/β-catenin signaling and DLD1 cell proliferation by p,p′-DDT. Moreover, in a mouse xenograft model, 5 nmol/kg p,p′-DDT resulted in increased tumor size, oxidative stress and Wnt/β-catenin signaling. These results indicated that low concentrations of p,p′-DDT promoted colorectal cancer growth through Wnt/β-catenin signaling, which was mediated by oxidative stress. The finding suggests an association between low concentrations of p,p′-DDT exposure and colorectal cancer progression.     

黄芩中有机氯类农药残留检测方法研究

目的建立黄芩中农药多残留量的新检测方法,考察陕西不同地区黄芩药材中12种农药残留情况。方法采用DB-17MS毛细管柱(30m×0.25mm×0.25μm),用气相色谱-质谱串联技术(GC-MS)进行目标成分的定量测定。结果建立了气相色谱-质谱串联法测定黄芩中农药多残留的方法,通过对陕西省不同地区黄芩药材中农药进行检测,发现尚无超标的农药。结论该方法严谨可靠,操作简便,能较准确地反映测定结果,与国家现有标准的方法相比,实验时间短,灵敏度高,减少了人为因素的影响。     

Organophosphate Pesticide Exposure in School-Aged Children Living in Rice and Aquacultural Farming Regions of Thailand

Organophosphate pesticides (OPs) are widely used in agricultural sectors in Thailand. Previous studies have documented that children residing in agricultural areas have higher exposure to OPs than children living in other residential areas. The objective of this study was to quantify urinary biomarkers of OP exposure and determine the environmental conditions and activities that predict their levels among children living in Central Thailand farming regions. In October 2011, 53 6–8-year-old participants were recruited from Pathum Thani Province, Thailand. Twenty-four lived in rice farming communities at Khlong Luang District where OPs are the pesticides used frequently. Twenty-nine participants, living in aquacultural farming communities at Lum Luk Ka District where OPs are not used, were recruited to serve as controls for pathways of exposure (e.g., residential, dietary) other than occupational/paraoccupational exposures encountered in rice farming. Household environments and participants’ activities were assessed using a parental structured interview. Urine samples (first morning voids) were collected from participants for OP urinary metabolite (i.e., dialkylphosphates [DAPs] and 3,5,6-trichloro-2-pyridinol [TCPy]) measurements. The levels of most urinary OP metabolites were significantly higher in participants who lived in a rice farming community than those who lived in an aquacultural farming community (P < .05). The results from linear regression analysis revealed that the frequency of OP application on rice farms (∑DAP: P = .001; TCPy: P = .001) and living in a rice farming community (∑DAP: P = .009; TCPy: P < .001) were significant predictors of urinary DAP metabolite levels in participants. Increasing TCPy levels were significantly related to proximity to rice farm (P = .03), being with parent while working on a farm (P = .02), playing on a farm (P = .03), and the presence of observable dirt accumulated on the child’s body (P = .02). In conclusion, OP metabolite levels among children who live in rice farming communities were strongly influenced by farming activity, household environments, and child behaviors, suggesting that these are the primary pathways in which children living in these agricultural communities in Thailand were exposed to OPs.     

Agricultural Pesticide Usage and Prioritization in South Korea

This study aims to review agricultural pesticide usage and trends and to identify hazardous pesticides for regulation, in terms of public health, in South Korea. The authors collected data on usage and trends of agricultural pesticides through agriculture-related databases. Criteria from the US Environmental Protection Agency classification for carcinogenicity, World Health Organization classification for acute toxicity, and European Union prioritization list for endocrine-disrupting chemicals were used for the hazard categorization of identified individual active ingredients. Pesticides to be prioritized among all pesticides used in South Korea between 2007 and 2011 were selected by taking into account the volume of usage, toxicity, and epidemiological evidence. Annual agricultural use of pesticides has increased rapidly from the 1970s to 1990s in South Korea, but has declined since 2001. The quantity of pesticides used in 2011 was reported as 19,131 tons, and was comprised of 34.7% insecticides, 28.0% fungicides, and 27.1% herbicides. The 50 pesticides with the greatest volume of usage accounted for 82.6% of the total volume of pesticides used between 2007 and 2011, with the most-used active ingredient being machine oil, followed by mancozeb and then paraquat. Organophosphates were the most used among the top 50 pesticides. A total of 24 pesticides were selected for recommendation of intensive regulation in South Korea. In conclusion, the authors described the usage and trends of overall agricultural pesticides, which would serve as a fundamental step forward in managing pesticide in terms of public health. Intensive efforts are required for the prevention of potential health effects from the 24 identified pesticides.     

长期接触有机磷农药对机体血液指标的影响

目的观察分析南京市某有机磷农药生产企业人员外周血象（包括WBC、PLT、RBC和Hb）、丙氨酸转氨酶（ALT）和胆碱酯酶（CHE）结果的变化情况,探讨不同工种、不同工龄、不同性别与研究指标之间的关系,为减少职业危害提供科学依据。方法对2013年某有机磷农药生产企业1 138名人员和某外厂692名未接触有机磷农药的工人进行外周血象、ALT和CHE检测分析。结果有机磷组的WBC为（6.0±1.47）×10^9/L,PLT为（158.2±52.29）×10^9/L,RBC为（4.59±0.49）×10^12/L,Hb为（137.3±15.93）g/L,ALT为（24.9±19.78）U/L,CHE为（248.3±85.43）U/L,均在正常参考范围内;但WBC、PLT、RBC、Hb和CHE均低于对照组,差异有统计学意义（均P〈0.01）。不同工种间,PLT、Hb、RBC、ALT和CHE的差异有统计学意义（P〈0.01）,操作工的WBC为（5.97±1.47）×10^9/L,PLT为（155.7±51.55）×10^9/L,RBC为（4.58±0.49）×10^12/L,Hb为（137.1±16.0）g/L,ALT为（24.1±17.33）U/L,CHE为（236.3±86.06）U/L,均低于管理人员,差异均有统计学意义。随着接害工龄的增加,血液检查的各项指标有逐渐降低的趋势,其中,5-15 a组的CHE为（213.6±83.85）U/L,RBC（4.49±0.52）×10^12/L,Hb为（133.9±16.99）g/L,显著低于〈5 a组,差异有统计学意义。CHE的异常率在性别间差异有统计学意义。结论长期接触有机磷农药对生产工人的外周血象,ALT和CHE有一定的负面影响,对工龄5-15年的影响尤为明显。