Persistent Pesticides Research Articles

Degradation of Triazine-2-(14)C Metsulfuron-Methyl in Soil from an Oil Palm Plantation.

Triazine-2-14C metsulfuron–methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-14C metsulfuron–methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP–1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT50 and DT90 values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT50 and DT90 were 31 and 70 days, respectively. The principal degradation product after 60 days was CO2. The higher cumulative amount of 14CO2 in 14C- triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine “ring-opened.”

Effects of Pollution on Freshwater Organisms.

This review includes works published in the general scientific literature during 2014 on the effects of anthropogenic pollutants on freshwater organisms. It begins with two broad sections: research reviews and broad field studies and surveys. This is followed by reviews of research categorized in sections to reflect the pollutant class. These sections include wastewater, stormwater and non-point source pollution, nutrients, sediment cap materials and suspended clays, botanical extracts, surfactants, metals, persistent organic pollutants, pharmaceuticals, endocrine disruptors, pesticides, petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), ionic liquids, and nanomaterials. The final section includes works describing innovations in the field of freshwater pollution research.

Residues of endosulfan in surface and subsurface agricultural soil and its bioremediation

The persistence of many hydrophobic pesticides has been reported by various workers in various soil environments and its bioremediation is a major concern due to less bioavailability. In the present study, the pesticide residues in the surface and subsurface soil in an area of intense agricultural activity in Pakkam Village of Thiruvallur District, Tamilnadu, India, and its bioremediation using a novel bacterial consortium was investigated. Surface (0–15 cm) and subsurface soils (15–30 cm and 30–40 cm) were sampled, and pesticides in different layers of the soil were analyzed. Alpha endosulfan and beta endosulfan concentrations ranged from 1.42 to 3.4 mg/g and 1.28–3.1 mg/g in the surface soil, 0.6–1.4 mg/g and 0.3–0.6 mg/g in the subsurface soil (15–30 cm), and 0.9–1.5 mg/g and 0.34–1.3 mg/g in the subsurface soil (30–40 cm) respectively. Residues of other persistent pesticides were also detected in minor concentrations. These soil layers were subjected to bioremediation using a novel bacterial consortium under a simulated soil profile condition in a soil reactor. The complete removal of alpha and beta endosulfan was observed over 25 days. Residues of endosulfate were also detected during bioremediation, which was subsequently degraded on the 30th day. This study revealed the existence of endosulfan in the surface and subsurface soils and also proved that the removal of such a ubiquitous pesticide in the surface and subsurface environment can be achieved in the field by bioaugumenting a biosurfactant-producing bacterial consortium that degrades pesticides.

Studies of pesticide residues in tomatoes and cucumbers from Kazakhstan and the associated health risks.

The aim of the present study was to assess the level of pesticide residues in vegetables in the Almaty Region of Kazakhstan and to determine the potential health risks associated with the exposures to these pesticides. A total of 82 samples of cucumbers and tomatoes from top agro-based market and greenhouses were analysed using a gas chromatography–micro electron capture detector/nitrogen–phosphorous detector (GC-μECD/NPD), a multiresidue method to analyse 184 different pesticide types. The results indicated that more than half of samples (59 %) contained 29 pesticides, in which 10 are not registered in Kazakhstan, ranging from 0.01 to 0.88 mg kg−1, and 28 % contained pesticide residues above maximum residue levels (MRLs). The estimated daily intakes (EDIs) ranged from 0.01 % of the acceptable daily intake (ADI) for pyrimethanil to 12.05 % of the ADI for lambda-cyhalothrin. The most critical commodity is triazophos and flusilazole in tomatoes, contributing 70.8 and 42.5 % to the acute hazard index (aHI). The results provided important information on the current pesticide contamination status of two commonly consumed vegetables and pointed an urgent need to control the use of plant protection products applied, especially potentially persistent pesticides, such as endosulfan and dicofol. These results also show that the detected pesticides may be considered a public health problem.Electronic supplementary materialThe online version of this article (doi:10.1007/s10661-015-4818-6) contains supplementary material, which is available to authorized users.

Does mechanistic modeling of filter strip pesticide mass balance and degradation processes affect environmental exposure assessments?

Vegetative filter strips (VFS) are a widely adopted practice for limiting pesticide transport from adjacent fields to receiving waterbodies. The efficacy of VFS depends on site-specific input factors. To elucidate the complex and non-linear relationships among these factors requires a process-based modeling framework. Previous research proposed linking existing higher-tier environmental exposure models with a well-tested VFS model (VFSMOD). However, the framework assumed pesticide mass stored in the VFS was not available for transport in subsequent storm events. A new pesticide mass balance component was developed to estimate surface pesticide residue trapped in the VFS and its degradation between consecutive runoff events. The influence and necessity of the updated framework on acute and chronic estimated environmental concentrations (EECs) and percent reductions in EECs were investigated across three, 30-year U.S. EPA scenarios: Illinois corn, California tomato, and Oregon wheat. The updated framework with degradation predicted higher EECs than the existing framework without degradation for scenarios with greater sediment transport, longer VFS lengths, and highly sorbing and persistent pesticides. Global sensitivity analysis (GSA) assessed the relative importance of mass balance and degradation processes in the context of other input factors like VFS length (VL), organic-carbon sorption coefficient (Koc), and soil and water half-lives. Considering VFS pesticide residue and degradation was not important if single, large runoff events controlled transport, as is typical for higher percentiles considered in exposure assessments. Degradation processes become more important when considering percent reductions in acute or chronic EECs, especially under scenarios with lower pesticide losses.

Persistent organochlorine pesticides in internal organs of coypu, Myocastor coypus

A highly selective and sensitive method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) to identify and quantify persistent organochlorine pesticides, (18 compounds including primary compounds and metabolites), in animal internal organs (kidneys, liver, and brain) has been developed. Tandem mass spectrometric conditions were individually optimized for each target compound in Multiple Reaction Monitoring (MRM) mode to obtain maximum sensitivity. Prior to instrumental analysis, a sample preparation method based on matrix solid phase dispersion (MSPD) followed by acidic digestion with sulfuric acid to reduce matrix co-extractives was employed. Analyses of real samples were carried out on coypus (Myocastor coypus) from the autumn slaughter of 19 animals. In the analyzed samples, three of the target compounds, namely DDE-pp′ (DDT metabolite), HCB and lindane, were detected. Their concentration levels fell in the ranges of 0.003–0.007, 0.003–0.025, and 0.003–0.021 mg kg−1 (0.005, 0.010, and 0.010 mg kg−1 on average) in the case of DDE-pp′, HCB and lindane, respectively. Although low quantities of organochlorine pesticides do not pose an immediate danger to consumers' health, they should be of public health concern considering long-term, low-dose exposure.

The key microorganisms for anaerobic degradation of pentachlorophenol in paddy soil as revealed by stable isotope probing

Pentachlorophenol (PCP) is a common residual persistent pesticide in paddy soil and has resulted in harmful effect on soil ecosystem. The anaerobic microbial transformation of PCP, therefore, has been received much attentions, especially the functional microbial communities for the reductive transformation. However, the key functional microorganisms for PCP mineralization in the paddy soil still remain unknown. In this work, DNA-based stable isotope probing (SIP) was applied to explore the key microorganisms responsible for PCP mineralization in paddy soil. The SIP results indicated that the dominant bacteria responsible for PCP biodegradation belonged to the genus Dechloromonas of the class β-Proteobacteria. In addition, the increased production of 13CH4 and 13CO2 indicated that the addition of lactate enhanced the rate of biodegradation and mineralization of PCP. Two archaea classified as the genera of Methanosaeta and Methanocella of class Methanobacteria were enriched in the heavy fraction when with lactate, whereas no archaea was detected in the absence of lactate. These findings provide direct evidence for the species of bacteria and archaea responsible for anaerobic PCP or its breakdown products mineralization and reveal a new insight into the microorganisms linked with PCP degradation in paddy soil.

Biodegradation of commercial Ortiva fungicide by isolated actinomycetes from the activated sludge

Wastewater can be defined as water degraded mainly by human activities. This water must be treated before being reintroduced into the supply circuits. Wastewater from the agricultural sector can be difficult to process because of the presence of many persistent pesticides. The Ortiva fungicide has been used for several years worldwide since 1996. It is very toxic for aquatic organisms and can lead to long-term adverse effects in aquatic environments. Different biological treatment techniques are necessary to overcome the devastating effects of this pollutant. The micro-organisms present in the wastewater sludge are the major players in the suppression of these effects. In this study, we isolated nine actinomycetes strains which are able to degrade the fungicide Ortiva at a concentration of 500 mg/L and at a temperature of 30°C within 21 d of incubation when supplied as a sole carbon source. The molecular identification by 16S rRNA was possible for only seven actinomycetes under laboratory conditions. These isolates showed a homology to Nocardia sp. and Streptomyces sp. The biodegradation ability of these strains reveals its potential for further study as a biological agent for the remediation water contaminated with Ortiva.

Photocatalytic degradation of p,p′-DDT under UV and visible light using interstitial N-doped TiO2

1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (or p,p′-DDT) is one of the most persistent pesticides. It is resistant to breakdown in nature and cause the water contamination problem. In this work, a major objective was to demonstrate the application of N-doped TiO2 in degradation and mineralization of the p,p′-DDT under UV and visible light in aqueous solution. The N-doped TiO2 nanopowders were prepared by a simple modified sol–gel procedure using diethanolamine (DEA) as a nitrogen source. The catalyst characteristics were investigated using XRD, SEM, TEM, and XPS. The adsorption and photocatalytic oxidation of p,p′-DDT using the synthesized N-doped TiO2 under UV and visible light were conducted in a batch photocatalytic experiment. The kinetics and p,p′-DDT degradation performance of the N-doped TiO2 were evaluated. Results show that the N-doped TiO2 can degrade p,p′-DDT effectively under both UV and visible lights. The rate constant of the p,p′-DDT degradation under UV light was only 0.0121 min−1, whereas the rate constant of the p,p′-DDT degradation under visible light was 0.1282 min−1. Under visible light, the 100% degradation of p,p′-DDT were obtained from N-doped TiO2 catalyst. The reaction rate of p,p′-DDT degradation using N-doped TiO2 under visible light was sixfold higher than that under UV light. According to Langmuir-Hinshelwood model, the adsorption equilibrium constant (K) for the N-doped TiO2 under visible light was 0.03078 L mg−1, and the apparent reaction rate constant (k) was 1.3941 mg L−1-min. Major intermediates detected during the p,p′-DDT degradation were p,p′-DDE, o,p′-DDE, p,p′-DDD and p,p′-DDD. Results from this work can be applied further for the breakdown of p,p′-DDT molecule in the real contaminated water using this technology.

Development of a screening tool to assess the temporal risk of pesticides leaching to groundwater using the source, target, vector approach. An Irish case study for shallow groundwater.

During this study, a groundwater screening tool was developed to assess the temporal risk of groundwater contamination from the use of pesticides. It is based on a source, vector, target approach. The method utilised in this study uses a semi-quantitative probabilistic risk assessment where the input parameters were classified and assigned a relative score from 1 to 5 (i.e. 1 = no risk and 5 = high risk). The model was parameterised by using national data and calibrated with 2 years of national pesticide groundwater monitoring data. After calibration, two specific sites were selected for model validation. Based on the presence of the source, vector and target, the evaluation indicated that the temporal risk is site specific (i.e. May to December for the country model, June to September for the Oak Park site and September for the Castledockrell site). A sensitivity analysis performed on the national scale revealed that the groundwater vulnerability category (gv), the clay content (cc%), the persistence of pesticides in soil (DT50) and the rainfall represented by wet day (wd) were the most important parameters that affected model predictions (correlation coefficients of 0.54, -0.39, 0.35 and 0.31, respectively), highlighting the importance of soil hydrogeological conditions, soil type and rainfall in influencing water model predictions. The model developed can help to identify the temporal risk from pesticides to groundwater and guide regulators in highlighting at-risk periods, therefore allowing more focused monitoring programmes.

Evaluation of organochlorine pesticide residues in soil and plants from East Europe and Central Asia

Agriculture products such as cereals, fruit, and vegetables are often found to be contaminated with residues of persistent pesticides and other toxic substances. The major source of entry of these compounds to food chain is the contaminated soil. Therefore, the status of the residue level of most persistent organochlorinated pesticides (OCP) in soil and agricultural crops should be monitored regularly. The frequency of occurrence and contamination levels of OCP residues in samples of soils, cereals, fruit and vegetables from different geographical regions such as Central Asia and East Europe were determined. The samples of soil, fruit (black currant), vegetables (beans, carrots, celery, cucumbers, lupine, parsley, and tomatoes) and cereals collected from Kazakhstan and Poland contained residues of different OCPs like aldrine, dieldrine, hexachlorocyclohexane isomers and dichlorodiphenyltrichloroethane (DDT) complex. Endosulfan and dicofol were also found in some samples in the concentration ranging from 0.008 to 0.8 mg/kg, particularly in samples of tomatoes from Kazakhstan. In the samples of the soil taken from Polish and Kazakhs farms, DDT and metabolites were detected. In the case of DDT complex, i.e. DDD, DDE, and DDT, the concentration ranged between 0.005 and 0.542 mg/kg and the pp′ isomers were more frequently encountered than their op′ counterparts.

Índice para a avaliação do risco de contaminação da água por pesticidas: desenvolvimento e validação

Since surface and ground water are strategic and vulnerable environmental compartments, their contamination by pesticides can cause significant damage to man and ecosystems. The objective of the present paper was to develop a simple and robust index to estimate the risk of water contamination by pesticides, in different agronomic and environmental settings, and to validate it at the field level. The risk of contamination (R) was defined as the product of the environmental vulnerability of the site (V) and the contamination potential of the pesticides (Pc). The vulnerability is calculated using the clay content of the soil, the distance to the nearest stream, and the type of soil management. The contamination potential is the product of the pesticide mobility, persistence, and toxicity to man and fish. A validation experiment was carried out in a soybean field in the Distrito Federal, Brazil. In that study, the glyphosate concentration on the runoff of the slope was compared with the behavior predicted by the index. Furthermore, the glyphosate concentrations in the river downstreamr were compared with the risk calculated by the index. In both cases, the ARCA index correctly predicted the values and trends obtained in the field study. However, considering the limited scope of the experiment, it is recommended that further studies be performed to better assess model validity

Biosurfactant Facilitated Biodegradation of Quinalphos at High Concentrations by Pseudomonas aeruginosa Q10

Previous studies indicate that high concentration of pesticides and their associated toxic effects are high at their point source of application. Use of pesticide-degrading bacteria at point sources could augment degradation and thereby reduce toxic effects associated with pesticide persistence in soil. Quinalphos, an organophosphorus insecticide, though ranked “moderately hazardous” in the WHO's acute hazard ranking, still continues to be used extensively in developing countries. The presence of a chloride radical usually makes this pesticide sparingly soluble in water and hence difficult to degrade. The present study aimed to isolate autochthonous bacterial strains capable of utilizing quinalphos as a carbon source. Primary screening of pesticide-contaminated soil by enrichment culture and degradation analysis by UV-VIS spectrophotometry led to the isolation of 12 different bacterial isolates, of which three efficient isolates of Pseudomonas sp, Serratia sp, and Pseudomonas aeruginosa with degradation rate 86%, 82%, 94%, respectively, were selected. GC-MS studies with P.aeruginosa confirmed the formation of 2-hydroxy quinoxaline and phosphorothioic acid as a result of biodegradation. The present study succeeded in isolating autochthonous bacterial strains capable of utilizing high concentrations of quinalphos as a carbon source in a shorter incubation period. This strain also possessed biosurfactant-production ability, which makes quinalphos available to cells at higher concentrations.

Chemical characterization of commercial organic fertilizers

A wide range of commercial organic fertilizers is currently available to organic farmers. Their use has numerous agronomic implications, including the supply of plant macro- and micronutrients, organic matter, but also pollutants such as toxic elements (metals (often referred to heavy metals), metalloids, and non-metals), persistent organic pollutants, pesticides, and antibiotic residues. For many organic fertilizers, the database concerning all these characteristics is weak. Therefore, in the frame of collections carried out throughout Germany, 77 samples of commercial organic fertilizers were analyzed for their nutrient and pollutant contents. Commercial organic fertilizers differ widely in nutrient concentration as well as in nutrient spectrum, meaning large differences among the fertilizers in their suitability to complement the nutrient supply by base organic fertilizers like composts, livestock manures, or digestates. The sampled commercial organic fertilizers show stable values for few characteristics (e.g. concentration of organic matter, carbon, and nitrogen), and high variation in the composition of the most other macro- and micronutrients as well as toxic metals. Consequently, the use of default values in budget calculation sheets can result in considerable errors of estimation. The concentrations of toxic elements, pesticides, and persistent organic pollutants are low, indicating the low risk of pollution related to their use.

Persistent organochlorine pesticide residue in tissues and blood of goat

The production commensurate with the demand for animal products including meat is increasing due to urbanization and increase in per capita income. However, meat and meat products meant for human consumption should also be safe and free from toxic contaminants. Presence of any xenobiotics in human food web is undesirable and unacceptable particularly in the wake of sanitary and phytosanitary (SPS) measures and strict regulations imposed by many countries on the ground of safety of health of the consumers. In the present study, certain organochlorinated pesticide (OCP) residues in tissues and in blood samples of goat were determined. All samples were analysed for residues of hexachlorocyclohexane (HCH) isomers, dichlorodiphenyltrichloroethane (DDT) isomers and metabolites, endosulfan isomers and metabolite, aldrin, heptachlor and dicofol. The tissue samples were extracted in soxhlet with hexane-acetone (1:1) and cleaned up by florisil column chromatography. The analysis was performed in capillary gas chromatograph equipped with electron capture detector (GC-ECD). The result indicated that 40% tissue samples were contaminated with HCH residues, while DDT and endosulfan were present in 32% samples. In blood samples, no HCH residue could be detected, but DDT and endosulfan were present in 10% and 30% samples, respectively.

Penicillium sp. as an organism that degrades endosulfan and reduces its genotoxic effects

Endosulfan is an organochloride and persistent pesticide that has caused concern because of its impact in the environment and its toxicity to and bioaccumulation in living organisms. In this study, we isolated an endosulfan-degrading fungus from the activated sludge from an industrial wastewater treatment plant. Through repetitive enrichment and successive subculture in media containing endosulfan as the sole carbon source, a fungus designated CHE 23 was isolated. Based on a phylogenetic analysis, strain CHE 23 was assigned to the genus Penicillium sp. In a mineral salt medium with 50 mg/l endosulfan as the sole source carbon, CHE 23 removed the added endosulfan in a period of six days. To verify the decrease in endosulfan toxicity due to the activity of the fungus, we performed genotoxicity tests trough the single cell gel electrophoresis assay or comet assay, with Eisenia fetida as the bioindicator species. This organism was exposed to the supernatants of the culture of the fungus and endosulfan. Our results indicated that the genotoxicity of endosulfan was completely reduced due the activity of this fungus. These results suggest that the Penicillium sp. CHE 23 strain can be used to degrade endosulfan residues and/or for water and soil bioremediation processes without causing toxicity problems, which are probably due to the generation of no-toxic metabolites during biodegradation.

Method for the quantification of current use and persistent pesticides in cow milk, human milk and baby formula using gas chromatography tandem mass spectrometry.

The aim of this study was to develop an analytical method for the quantification of organochlorine (OC), organophosphate (OP), carbamate, and pyrethroid insecticide residues in cow milk, human milk, and baby formula. A total of 25 compounds were included in this method. Sample extraction procedures combined liquid-liquid extraction, freezing-lipid filtration, dispersive primary-secondary amine cleanup, and solid-phase extraction together for effective extraction and elimination of matrix interferences. Target compounds were analyzed using gas chromatography with electron impact ionization-tandem mass spectrometry (GC-EI-MS/MS) in the multiple reaction monitoring (MRM) mode. Average extraction recoveries obtained from cow milk samples fortified at two different concentrations (10 ng/mL and 25 ng/mL), ranged from 34% to 102%, with recoveries for the majority of target compounds falling between 60% and 80%. Similar ranges were found for formula fortified at 25 ng/mL. The estimated limits of detection for most target analytes were in the low pg/mL level (range 3-1600 pg/mL). The accuracies and precisions were within the range of 80-120% and less than 15%, respectively. This method was tested for its viability by analyzing 10 human milk samples collected from anonymous donors, 10 cow milk samples and 10 baby formula samples purchased from local grocery stores in the United States. Hexachlorobenzene, p,p-dicofol, o,p-DDE, p,p-DDE, and chlorpyrifos were found in all samples analyzed. We found detectable levels of permethrin, cyfluthrin, and fenvalerate in some of the cow milk samples but not in human milk or baby formula samples. Some of the pesticides, such as azinphos-methyl, heptachlor epoxide, and the pesticide synergist piperonyl butoxide, were detected in some of the cow milk and human milk samples but not in baby formula samples.

Performance and storage integrity of dried blood spots for PCB, BFR and pesticide measurements

Dried blood spots (DBSs) can provide accurate and valuable estimates of exposure to environmental toxicants, and the use of information derived from archived newborn DBSs has enormous potential to open up new research on the impacts of early chemical exposure on disease. Broad application of DBS for the purpose of quantitative exposure estimation requires robust and validated methods. This study investigates the suitability of DBS analyses for population studies of exposure to three chemical groups: polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs), and chlorinated pesticides. It examines background (matrix) contamination, recovery and extraction variability, sensitivity, and storage stability. DBS samples prepared using 50μL of adult blood were analyzed by GC/MS, and method performance was confirmed by using certified materials and paired DBS-blood samples from six volunteers. Several of the target compounds and their degradation products have not been previously measured in DBSs. All target compounds were detected in DBS samples collected from the volunteers. Sample DBS cards showed background contamination of several compounds. When stored at room temperature, target compounds, excluding PBDEs, were stable for up to one month. When refrigerated or frozen, stability was acceptable for all compounds up to one year, and multiyear storage appears acceptable at colder (e.g., −80°C) temperatures. Multicompartment models may be used to estimate or correct for storage losses. Considering concentrations of contaminants for adults and children reported in the literature, and experimental values of detection limits and background contamination, DBS samples are suitable for quantifying exposures to many PCBs, BFRs and persistent pesticides.

Effect of rainfall regimes and mulch decomposition on the dissipation and leaching of S-metolachlor and glyphosate: a soil column experiment.

Interception by plant residues is a major process affecting pesticide persistence and leaching in conservation agriculture. Dissipation and leaching of S-metolachlor and glyphosate was studied in repacked soil columns covered with a mulch of maize and lablab residues. The columns were submitted to two contrasting simulated rainfall regimes: one with light but frequent rain (LF) and one with less frequent but more intense rain (HI). In both treatments, columns received the same amount of rainwater by the end of the experiment. Decomposing crop residues on the soil surface retained more than 50% of the applied amount of pesticide. S-metolachlor dissipation in mulch residues was faster under the LF rainfall regime. This was attributed to more humid surface conditions, under which mulch decomposition was also faster. The formation of metabolites of both molecules was higher under the LF rainfall regime. However, leaching of S-metolachlor and its metabolites to deeper soil layers was greater under the HI rainfall regime, whereas they accumulated in the surface layer under the LF rainfall regime. Glyphosate remained in the surface soil layer because of its strong adsorption capacity, whereas aminomethylphosphonic acid leached down in small amounts without any difference between the two rainfall regimes. The impact of mulch residues on herbicide dissipation was strongly dependent on molecule type and rainfall regime. © 2014 Society of Chemical Industry.

Adherence to reporting guidelines in observational studies concerning exposure to persistent organic pollutants and effects on semen parameters

Are studies on semen quality in men exposed to persistent pesticides reported according to the 'strengthening the reporting of observational studies in epidemiology' (STROBE) recommendations and the guidelines for the appraisal of semen quality studies (SEMQUA)? Most studies of the impact of pesticides on semen quality do not follow the STROBE and SEMQUA guidelines, thus adherence is low, especially in methodological aspects. Much of the controversy about reduced semen quality in recent decades arises from a lack of standardization in the methodology applied, despite the existence of several validated instruments for evaluating the quality of reporting. Indeed, SEMQUA was purpose-designed for the particular characteristics of semen quality studies. A structured literature search identified eligible articles reporting on persistent pesticides and human semen quality, published in English before 1 September 2012. Opinion articles and reviews were excluded. We assessed the adherence to reporting guidelines of the articles, using and comparing the STROBE statement and the SEMQUA guidelines, in both cases with indicators relevant to observational studies of semen quality. A comprehensive bibliographic search in various electronic literature databases using the key words 'sperm' and 'pesticide' obtained 1179 papers, of which 46 were valid for our purposes. The papers examined occupational (26) and environmental exposure (20). Two of the present authors independently piloted the data extraction form for this review. The articles were then evaluated by two researchers using the STROBE and SEMQUA checklists. Although no significant differences were found between the overall degree of compliance with STROBE and SEMQUA (47.0 ± 18.5% versus 43.1 ± 11.6%), there were significant differences when only methodological aspects were considered (48.4 ± 21.0% versus 39.5 ± 17.4%; P < 0.001). We observed an increase over time in the degree of compliance, for SEMQUA (r = 0.61 and P < 0.001) and STROBE (r = 0.45 and P < 0.01). The papers that reported a negative effect of exposure to persistent pesticides on sperm concentration presented a lower level of compliance to SEMQUA (42.1 ± 18.3% versus 57.6 ± 14.2%; P < 0.01) and STROBE (40.2 ± 10.3% versus 49.5 ± 11.6%; P < 0.05) than those which recorded no such influence. The year of publication and the observed effect on sperm concentration were the only candidate variables included in the model of stepwise multiple regression model for the 'degree of compliance' variables of SEMQUA and STROBE. Other characteristics of reporting quality, such as legibility, were not evaluated. The low degree of compliance observed is consistent with that observed in other studies of reproductive medicine and highlights the need to improve the design of studies of semen quality. SEMQUA proved to be a more specific tool than STROBE for the field of semen quality. Editors, reviewers and authors should be aware of SEMQUA and apply it when assessing papers on semen quality. No research funding was received and none of the authors have any conflict of interests.