Persistent Pesticides Research Articles

Air contamination by legacy and current-use pesticides in Brazilian mountains: An overview of national regulations by monitoring pollutant presence in pristine areas

In the last decades, research regarding the dynamics of pesticides has grown, even in remote regions. Due to long-range atmospheric transport, environmental persistence and toxicological potential of organochlorine pesticides (OCPs), similar characteristics of current-use pesticides (CUPs) and their massive use in Brazil, these contaminants have become a major concern for environmental and human life. Thus, this study aimed to evaluate subgroups or individual chemicals of OCPs and CUPs, which could have travelled over two Conservation Unit sites in the Rio de Janeiro state. The study was carried out for 24 months, (2013–2015), in Itatiaia National Park (INP) and in the Serra dos Órgãos National Park (SONP), at ∼2400 and ∼2200 meters above sea level, respectively. The study was based on atmospheric passive sampling (polyurethane foam disks). Target pesticides were detected by means of gas chromatography device coupled with mass spectrometry (GC-MS). Significantly higher concentrations were measured in SONP when compared to INP. However, in broad terms, the contamination profile was quite similar for both national parks: The highest concentrations of endosulfan (INP - 1275 pg m−3 and SONP - 3202 pg m−3) were followed by cypermethrin (INP - 148 pg m−3 and SONP - 881 pg m−3) and chlorpyrifos (INP - 67 pg m−3 and SONP - 270 pg m−3). In agreement with previous studies, the atmospheric concentrations of legacy OCPs showed background air levels. The decrease of endosulfan over the years was highlighted with a parallel increase of chlorpyrifos, suggesting a collateral effect of the national bias of permissive and massive use of agrochemicals. CUPs seemed to behave like pseudo-persistent pollutants (pseudo-POPs). This is the first report of atmospheric concentrations of pyrethroids in Brazilian mountain regions, and possibly the first to investigate them in the air in South America or in any mountain region in the world.

Evaluating the environmental parameters that determine aerobic biodegradation half-lives of pesticides in soil with a multivariable approach

Aerobic biodegradation half-lives (half-lives) are key parameters used to evaluate pesticide persistence in soil. However, half-life estimates for individual pesticides often span several orders of magnitude, reflecting the impact that various environmental or experimental parameters have on half-lives in soil. In this work, we collected literature-reported half-lives for eleven pesticides along with associated metadata describing the environmental or experimental conditions under which they were derived. We then developed a multivariable framework to discover relationships between the half-lives and associated metadata. We first compared data for the herbicide atrazine collected from 95 laboratory and 65 field studies. We discovered that atrazine application history and soil texture were the parameters that have the largest influence on the observed half-lives in both types of studies. We then extended the analysis to include ten additional pesticides with data collected exclusively from laboratory studies. We found that, when data were available, pesticide application history and biomass concentrations were always positively associated with half-lives. The relevance of other parameters varied among the pesticides, but in some cases the variability could be explained by the physicochemical properties of the pesticides. For example, we found that the relative significance of the organic carbon content of soil for determining half-lives depends on the relative solubility of the pesticide. Altogether, our analyses highlight the reciprocal influence of both environmental parameters and intrinsic physicochemical properties for determining half-lives in soil.

Mulch of plant residues at the soil surface impact the leaching and persistence of pesticides: A modelling study from soil columns

Crop residues left on the soil surface as mulch greatly influence the fate of pesticides in conservation agricultural practices because most of the applied pesticide is intercepted by mulch before passing to the soil. Modelling of pesticide losses from wash-off and leaching will greatly improve our understanding of the environmental consequences of pesticides in these systems. The PASTIS model, which simulates water transfer, mulch decomposition, and pesticide dynamics, was adapted in this new version to model the interactions between pesticides and mulch in order to simulate the impact of mulch on pesticide dynamic. Parameters of mulch dynamics and pesticide degradation and retention processes were estimated using independent incubation experiments. The PASTIS model was tested with experimental laboratory data that were obtained from two pesticides (Glyphosate and s-metolachlor) applied to soil columns where mulch composed of maize and dolichos was placed at the soil surface impacted by two rain intensities (a high and infrequent intensity and a light and frequent intensity). Simulations indicated good agreement between simulated and experimental values. After 1 day, 45–46% of the pesticides leached from the mulch and 54–55% remained in the mulch for both pesticides and both rain intensities. During the experiment, pesticide wash-off was greater for the high and infrequent rain (56–57%) compare to light and frequent rain (39–45%) for both pesticides. A smaller amount of S-metolachlor washed off with the light and frequent rain intensity (39%) than glyphosate (45%) because of its lower desorption rate from mulch residues. Glyphosate was more degraded (37–45%) than s-metolachlor (17–37%), which agrees with preliminary incubation experiments that were used for parameter estimation. A sensitivity analysis indicated that the saturation index of mulch at which pesticides started their diffusion in the rainwater and the time of the first rainfall were the two parameters that influenced the most output variables of our model. This study suggests that the PASTIS model developed for pesticide dissipation in mulch is a useful tool to evaluate the potential risk of pesticide leaching to the groundwater in conservation agriculture systems.

Amendment of soil by biochars and activated carbons to reduce chlordecone bioavailability in piglets

Chlordecone (Kepone or CLD) is a highly persistent pesticide formerly used in French West Indies. Nowadays high levels of this pesticide are still found in soils which represent a subsequent source of contamination for outdoor-reared animals. In that context, sequestering matrices like biochars or activated carbons (ACs) are believed to efficiently decrease the bioavailability of such compounds when added to contaminated soils. The present study intends to test the respective efficiency of soil amendment strategies using commercial ACs or biochars (obtained by a 500 °C or 700 °C pyrolysis of 4 distinct type of wood). This study involved three experimental steps. The first one characterized specific surface areas of biochars and ACs. The second one assessed CLD-availability of contaminated artificial soils (50 μg g−1 of Dry Matter) amended with 5% of biochar or AC (mass basis). The third one assessed CLD bioavailability of those artificial soils through an in vivo assay. To limit ethically the number of animals, selections of the most promising media were performed between each experimental steps. Forty four castrated male 40-day-old piglets were exposed during 10 day by amended artificial soils according to their group (n = 4). Only treatment groups exposed through amended soil with AC presented a significant decrease of concentrations of CLD in liver and adipose tissue in comparison with the control group (p < 0.001). A non-significant decrease was obtained by amending artificial soil with biochars. This decrease was particularly high for a coconut shell activated carbon were relative bioavailability was found lower than 3.2% for both tissues. This study leads to conclude that AC introduced in CLD contaminated soil should strongly reduce CLD bioavailability.

Preparation, characterization and trifluralin degradation of laccase-modified cellulose nanofibers

Laccase, an oxidoreductase enzyme, can biodegrade persistent pesticides and other xenobiotics to less toxic monomers. The present work involves immobilization of laccase onto activated nanocellulose fibers (CNFs) extracted from bagasse. The laccase grafted CNFs were characterized by different techniques. %Immobilization and the activity, stability and reusability of the immobilized laccase was studied using 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) as substrate. The %immobilization was calculated to be 85% with a maximum activity of 0.38 U/mg. 60.5% activity was retained even after 15 repeated uses of the immobilized enzyme. Moreover the immobilized enzyme was found to be stable with 75% relative activity after a period of 45 days. The laccase grafted CNFs were evaluated in degradation of trifluralin, a toxic pesticide resistant to natural transformation or degradation processes, in the presence of humic monomers, guiacol and catechol. Results show 100% degradation of trifluralin in 24 h in the presence of guiacol as mediator.

Removal of alachlor, diuron and isoproturon in water in a falling film dielectric barrier discharge (DBD) reactor combined with adsorption on activated carbon textile: Reaction mechanisms and oxidation by-products

A falling film dielectric barrier discharge (DBD) plasma reactor combined with adsorption on activated carbon textile material was optimized to minimize the formation of hazardous oxidation by-products from the treatment of persistent pesticides (alachlor, diuron and isoproturon) in water. The formation of by-products and the reaction mechanism was investigated by HPLC-TOF-MS. The maximum concentration of each by-product was at least two orders of magnitude below the initial pesticide concentration, during the first 10 min of treatment. After 30 min of treatment, the individual by-product concentrations had decreased to values of at least three orders of magnitude below the initial pesticide concentration. The proposed oxidation pathways revealed five main oxidation steps: dechlorination, dealkylation, hydroxylation, addition of a double-bonded oxygen and nitrification. The latter is one of the main oxidation mechanisms of diuron and isoproturon for air plasma treatment. To our knowledge, this is the first time that the formation of nitrificated intermediates is reported for the plasma treatment of non-phenolic compounds.

An Efficient Extraction Method of Persistent Organic Pesticides in Soil Samples for Their Chromatographic Determination

ABSTRACTIn order to determine persistent organic pesticides (OPs) and their metabolites in soil samples, an analytical procedure was developed, optimized and validated. It possesses advantages like suitable limits of detection, low solvent volume and time consume, and requires a chromatography detector commonly used in routine laboratories. The method allows the determination of Methoxychlor, p,p’-DDT, Endosulfan sulfate, Endrin aldehyde, p,p’-DDD, Endosulfan II, Endrin, Dieldrin, p,p’-DDE, Endosulfan I, Heptachlor epoxide, Aldrin, Heptachlor, δ-HCH, γ-HCH, β-HCH, α-HCH, Etridiazole, Trifluralin, Hexachlorobencene, Chlorothalonil, Chlorpyrifos, DCPA, γ-Chlordane, α-Chlordane, Clorbenzilate, trans-Permethrin, cis-Permethrin. Linearity is evaluated and the analytical parameters are presented. The average recoveries obtained for each pesticide (28 OPs) by using 3, 15 and 22.5 µg kg−1 spiked samples ranged between 50 and 97.3%, 57 and 103% and from 60 to 100% for each case. The limits of detection and quantification vary from 0.18 to 1.28 μg kg−1 and from 0.60 to 4.22 μg kg−1. The reproducibility obtained as relative standard deviation percentages is less than 7.5, 5.3 and 4.2% for low, middle and high level of concentrations, respectively. The procedure is statistically validated for its application to soil samples and compared with other published methods.

The fate of DDT in soils treated with hydroxypropyl-β-cyclodextrin (HPβCD)

ABSTRACTPoint Pelee National Park (PPNP) is highly contaminated with dichlorodiphenyltrichloroethane (DDT) due to the historical use of this persistent organochlorine pesticide. Hydroxypropyl-β-cyclodextrin (HPβCD) has previously been investigated for its role in the remediation of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). In the present study, HPβCD's ability to promote DDT microbial degradation, enhance DDT phytoextraction by two native grasses (Schizachyrium scoparium and Panicum virgatum), and increase DDT bioavailability to redworms (Eisenia fetida) was investigated. Using a range of HPβCD concentrations (2.5% to 10%), it was determined that it did not promote DDT microbial degradation in PPNP soils, however, it was able enhance the DDT phytoextraction ability of S. scoparium plants due to the increased water solubility of DDT. Although HPβCD application to PPNP soil did not increase DDT bioavailability to redworms, its enhanced solubility allowed it to move through the soil column, and hence groundwater contamination is a possibility. Due to this important issue, in situ use of HPβCD to remediate DDT contamination is not recommended unless measures are in place to mitigate movement into groundwater.

Presence of DDT and Lindane in a Karstic Groundwater Aquifer in Yucatan, Mexico

AbstractPollution caused by pesticides is becoming relevant because of their harmful environmental effects. The persistence, bioaccumulation and toxicity of some organochloride pesticides have resulted in their restricted use since 1970 and a requirement to monitor them in many countries. Pesticides have endocrine, immunological, reproductive and carcinogenic effects in both humans and animals. The facilitated infiltration of substances results in the pollution of hydric underground resources in karstic limestone such as that found in the state of Yucatan. Observing the north occidental region of the state of Yucatan is particularly important as it is characterized by agricultural activities (wide use of pesticides), significant human settlements and underground water flows oriented towards the north coast. In this study, the underground water quality of a karstic aquifer was evaluated by quantifying the presence of organochlorine pesticides in 29 wells located throughout the Mérida‐Progreso transect, Yucatan, Mexico. The presence of DDT, lindane and their metabolites was detected at concentrations above the permissible limits stated by Mexican regulatory standards (NOM‐127‐SSA1‐1994 2010) in the majority of wells studied. Continuous monitoring of the underground hydric resources in this region is therefore essential to raising awareness of pollution risks and the vulnerability of the coastal north to the contamination of the underground water flows.

Isotope Fractionation Pinpoints Membrane Permeability as a Barrier to Atrazine Biodegradation in Gram-negative Polaromonas sp. Nea-C.

Biodegradation of persistent pesticides like atrazine often stalls at low concentrations in the environment. While mass transfer does not limit atrazine degradation by the Gram-positive Arthrobacter aurescens TC1 at high concentrations (>1 mg/L), evidence of bioavailability limitations is emerging at trace concentrations (<0.1 mg/L). To assess the bioavailability constraints on biodegradation, the roles of cell wall physiology and transporters remain imperfectly understood. Here, compound-specific isotope analysis (CSIA) demonstrates that cell wall physiology (i.e., the difference between Gram-negative and Gram-positive bacteria) imposes mass transfer limitations in atrazine biodegradation even at high concentrations. Atrazine biodegradation by Gram-negative Polaromonas sp. Nea-C caused significantly less isotope fractionation (ε(C) = −3.5 ‰) than expected for hydrolysis by the enzyme TrzN (ε(C) = −5.0 ‰) and observed in Gram-positive Arthrobacter aurescens TC1 (ε(C) = −5.4 ‰). Isotope fractionation was recovered in cell-free extracts (ε(C) = −5.3 ‰) where no cell envelope restricted pollutant uptake. When active transport was inhibited with cyanide, atrazine degradation rates remained constant demonstrating that atrazine mass transfer across the cell envelope does not depend on active transport but is a consequence of passive cell wall permeation. Taken together, our results identify the cell envelope of the Gram-negative bacterium Polaromonas sp. Nea-C as a relevant barrier for atrazine biodegradation.

Nicotinamide-Modified poly(HEMA-GMA)-Nic Cryogels for Removal of Pesticides

Chlordane is only one of the persistent pesticides used in some countries despite the ban. Removal of chlordane, a severe threat to all living things, was performed using nicotinamide-modified poly (2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA)-Nic, polymeric cryogels in this study. Pesticides are practically insoluble in water. For that reason, ethanol is used as a solvent which is not chemically dangerous and easily accessible in every laboratory. As an adsorbent, poly (HEMA-GMA) polymeric cryogels previously synthesized in the literature have been modified using nicotinamide. The modification of poly(HEMA-GMA) with nicotinamide is the first in the literature. Removal of chlordane in alcohol medium has been accomplished exploiting the alcoho-phobic interaction, which was the first indication in our previous study. Structural analysis of poly(HEMA-GMA)-Nic was performed using Fourier transform infrared spectroscopy (FT-IR) and elemental analysis methods. Scanning electron microscopy (SEM) was used to understand the surface morphology of cryogels. Surface area and cavity volume calculations were determined by applying N2 adsorption method and swelling test. The interaction time and maximum adsorption capacity were identified as 5 minutes and 64.61 mg chlordane/g cryogel for 300 mg/L chlordane concentration and 108.818 mg chlordane/g cryogel for 800 mg/L chlordane concentration during the adsorption experiments. Cyclohexane, toluene, chloroform, dichloromethane, acetone, and acetonitrile were used as solvent to observe the solvent effect on adsorption of chlordane onto the polymeric material. As expected, the removal of chlordane was performed with the highest adsorption performance in cyclohexane with the lowest dielectric constant.

Current status, challenges, and prospects of biopesticide utilization in Nigeria

Abstract The toxicity, persistence, and non-biodegradability of chemical pesticides have increased calls for the adoption of sustainable and cost-effective pest control measures. Biopesticides present a sustainable alternative to synthetic pesticides. However, the biopesticide utilization in agrarian countries like Nigeria remains low, resulting in increased chemical pesticide utilization. Therefore, this paper seeks to examine the current status, challenges, and prospects of biopesticides in Nigeria. The findings revealed that biopesticide utilization in Nigeria is low due to high costs, poor infrastructure, skilled manpower alongside inconsistent field performance and government policies. The solution to these challenges will significantly boost crop protection, food security, and sustainable agriculture in Nigeria.

Long-Term Persistence of Pesticides and TPs in Archived Agricultural Soil Samples and Comparison with Pesticide Application.

For polar and more degradable pesticides, not many data on long-term persistence in soil under field conditions and real application practices exist. To assess the persistence of pesticides in soil, a multiple-compound screening method (log Kow 1.7-5.5) was developed based on pressurized liquid extraction, QuEChERS and LC-HRMS. The method was applied to study 80 polar pesticides and >90 transformation products (TPs) in archived topsoil samples from the Swiss Soil Monitoring Network (NABO) from 1995 to 2008 with known pesticide application patterns. The results reveal large variations between crop type and field sites. For the majority of the sites 10-15 pesticides were identified with a detection rate of 45% at concentrations between 1 and 330 μg/kgdw in soil. Furthermore, TPs were detected in 47% of the cases where the "parent-compound" was applied. Overall, residues of about 80% of all applied pesticides could be detected with half of these found as TPs with a persistence of more than a decade.

Activated carbon, a useful medium to bind chlordecone in soil and limit its transfer to growing goat kids.

Chlordecone (Kepone) (CLD) is a highly persistent pesticide which was extensively used in the French West Indies; high levels of CLD can still currently be found in large agricultural areas. As CLD transfers from soil to animals mainly via involuntary ingestion, the consumption of foodstuffs derived from animals raised in contaminated areas may significantly contribute to exposure of humans to CLD. The present study was designed to test the efficacy of two different activated carbons (ACs) sources in limiting CLD transfer from soil to animal. Three soils (ASs) were prepared according to the OECD guideline 207. One standard soil (SS) lacking AC, and two modified preparations of SS supplemented with 2% coconut-based activated carbon (ORBO), SSO or with 2% lignite-based one (DARCO), SSD. All three soils were spiked with 10 μg of kepone per g of dry matter and aged for three weeks. This study involved 15 goat kids randomly assigned to the 3 experimental groups (n = 5/group), which were fed the experimental matrices at an exposure dose of 10 μg CLD per kg of body weight per day. After 21 d of oral exposure, CLD in adipose tissue and liver were analysed by LC-MS-MS. A significant decrease of 63.7% and 74.7% of CLD concentrations in adipose tissue and liver, respectively, were obtained from animals exposed using SS containing DARCO as compared to those receiving only SS. Decreases in CLD levels of 98.2% (adipose tissue) and 98.7% (liver) were obtained for animals exposed using SS containing ORBO. This study leads us to conclude that (i) the presence of AC in CLD-contaminated soil strongly reduces CLD bioavailability, and (ii) the efficacy depends on the nature and characteristics of the AC used.

Associations between persistent organic pollutants, type 2 diabetes, diabetic nephropathy and mortality

ObjectiveRelationships were examined between persistent organic pollutants (POPs) and incident type 2 diabetes, end-stage renal disease (ESRD) and mortality.MethodsIn a nested case–control study, 300 persons without diabetes had baseline examinations...

Removal of several pesticides in a falling water film DBD reactor with activated carbon textile: Energy efficiency

Bio-recalcitrant micropollutants are often insufficiently removed by modern wastewater treatment plants to meet the future demands worldwide. Therefore, several advanced oxidation techniques, including cold plasma technology, are being investigated as effective complementary water treatment methods. In order to permit industrial implementation, energy demand of these techniques needs to be minimized. To this end, we have developed an electrical discharge reactor where water treatment by dielectric barrier discharge (DBD) is combined with adsorption on activated carbon textile and additional ozonation. The reactor consists of a DBD plasma chamber, including the adsorptive textile, and an ozonation chamber, where the DBD generated plasma gas is bubbled. In the present paper, this reactor is further characterized and optimized in terms of its energy efficiency for removal of the five pesticides α-HCH, pentachlorobenzene, alachlor, diuron and isoproturon, with initial concentrations ranging between 22 and 430 μg/L. Energy efficiency of the reactor is found to increase significantly when initial micropollutant concentration is decreased, when duty cycle is decreased and when oxygen is used as feed gas as compared to air and argon. Overall reactor performance is improved as well by making it work in single-pass operation, where water is flowing through the system only once. The results are explained with insights found in literature and practical implications are discussed. For the used operational conditions and settings, α-HCH is the most persistent pesticide in the reactor, with a minimal achieved electrical energy per order of 8 kWh/m3, while a most efficient removal of 3 kWh/m3 or lower was reached for the four other pesticides.

Richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides in rice paddy fields.

The objective of this study was to verify the richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides of the rice paddy fields. In the crop seasons of 2012/13 and 2013/14, field experiments were performed, which consisted of single-dose applications of the fungicides trifloxystrobin + tebuconazole and tricyclazole, and the insecticides lambda-cyhalothrin + thiamethoxam and diflubenzuron, in 10 m2 experimental plots, over rice plants in the R3 stage. Control plots with and without rice plants were maintained in order to simulate a natural environment. Soil samples were collected during rice cultivation for assessment of the macroinvertebrate fauna. Chemical-physical parameters assessed in the experiments included temperature, pH and oxygen dissolved in the water and pesticide persistence in the water and in the soil. The application of a single dose of the pesticides and fungicides in the recommended period does not cause significant negative effects over the richness and density of the macroinvertebrates. Tebuconazole, tricyclazole and thiamethoxam showed high persistence in the irrigation water of rice paddy fields. Thus, the doses and number of applications of these products in crops should be carefully handled in order to avoid contamination of the environment.

Environmental chemicals and preterm birth: Biological mechanisms and the state of the science.

Preterm birth is a significant worldwide health problem of uncertain origins. The extant body of literature examining environmental contaminant exposures in relation to preterm birth is extensive but results remain ambiguous for most organic pollutants, metals and metalloids, and air pollutants. In the present review we examine recent epidemiologic studies investigating these associations, and identify recent advances and the state of the science. Additionally, we highlight biological mechanisms of action in the pathway between chemical exposures and preterm birth, including inflammation, oxidative stress, and endocrine disruption, that deserve more attention in this context. Important advances have been made in the study of the environment and preterm birth, particularly in regard to exposure assessment methods, exploration of effect modification by co-morbidities and exposures, and in identification of windows of vulnerability during gestation. There is strong evidence for an association between maternal exposure to some persistent pesticides, lead, and fine particulate matter, but data on other contaminants is sparse and only suggestive trends can be noted with the current data. Beyond replicating current findings, further work must be done to improve understanding of mechanisms underlying the associations observed between environmental chemical exposures and preterm birth. By examining windows of vulnerability, disaggregating preterm birth by phenotypes, and measuring biomarkers of mechanistic pathways in these epidemiologic studies we can improve our ability to detect associations with exposure, provide additional evidence for causality in an observational setting, and identify opportunities for intervention.

Nanoparticle silver coexposure reduces the accumulation of weathered persistent pesticides by earthworms.

Although the use of engineered nanomaterials continues to increase, how these materials interact with coexisting contaminants in the environment is largely unknown. The effect of silver (Ag) in bulk, ionic, and nanoparticle (NP; bare and polyvinyl pyrrolidone-coated) forms at 3 concentrations (0 mg/kg, 500 mg/kg, 1000 mg/kg, 2000 mg/kg; ion at 69 mg/kg, 138 mg/kg, 276 mg/kg) on the accumulation of field-weathered chlordane and dichlorodiphenyldichloroethylene + metabolites (DDX) by Eisenia fetida (earthworm) was investigated. Earthworm biomass and survival were unaffected by treatment. At the 500 mg/kg and 1000 mg/kg exposure levels, NP-exposed earthworms contained significantly greater Ag (194-245%) than did the bulk exposed organisms; NP size or coating had no impact on element content. Generally, exposure to Ag of any type or at any concentration significantly reduced pesticide accumulation, although reductions for DDX (35.1%; 8.9-47.0%) were more modest than those for chlordane (79.0%; 17.4-92.9%). For DDX, the reduction in pesticide accumulation was not significantly affected by Ag type or concentration. For chlordane, the 3 NP exposures suppressed chlordane accumulation significantly more than did bulk exposure; earthworms exposed to bulk Ag contained 1170 ng/g chlordane, but levels in the NP-exposed earthworms were 279 ng/g. At the 500 mg/kg exposure, the smallest coated NPs exerted the greatest suppression in chlordane accumulation; at the 2 higher concentrations, chlordane uptake was unaffected by NP size or coating. The findings show that in exposed earthworms Ag particle size does significantly impact accumulation of the element itself, as well as that of coexisting weathered pesticides. The implications of these findings with regard to NP exposure and risk are unknown but are the topic of current investigation. Environ Toxicol Chem 2017;36:1864-1871. © 2016 SETAC.

Persistent organochlorine and organophosphorus pesticides in water and sediments from the Cuitzmala River, Jalisco, Mexico

Persistent organochlorine and organophosphorus pesticides in water and sediments from the Cuitzmala River, Jalisco, Mexico