Low Concentrations Of Pesticides Research Articles

Immunological and physiological responses to predation risk and sublethal concentrations of chlorothalonil and β-endosulfan in Lithobates taylori (Anura: Ranidae) tadpoles

Pesticide exposure and its interaction with other natural stressors can play a role in amphibian population declines because disruptions in stress hormone regulatory mechanisms may inhibit immune responses during metamorphosis. Here, we determined the interactive effects of predation risk and sublethal concentration of two pesticides on immunological and physiological responses in tadpoles of the tropical frog Lithobates taylori. Using mesocosms, we used chronic exposure to three levels of chlorothalonil and β-endosulfan in the presence or absence of Odonate larvae. Our results show that β-endosulfan in high concentrations reduced the weight of the tadpoles and increased the neutrophil count and corticosterone (CORT) levels. Larval development was accelerated by high concentrations of chlorothalonil. Also, this pesticide in low and high concentrations increases the absolute values of lymphocytes. Tadpoles exposed to chlorothalonil increased the numbers of monocytes (in low concentrations), and lymphocytes (in high and low concentrations). The interactions of the low concentrations of both pesticides with and without the predator's presence also increased the number of lymphocytes. A combination of pesticides increases the number of lymphocytes in the blood due to synergistic cytotoxicity. This study proves that β- endosulfan elevates circulating CORT and thus generates physiological stress in tadpoles. Given that both pesticides are widely used within the distribution of L. taylori in Costa Rica, it is likely that tadpoles’ development and immune function are altered by pesticide use. In combination with stressors such as emerging diseases and altered precipitation regimes, widespread agrochemical uses likely caused this species enigmatic decline in recent decades.

Facile Fabrication of SERS Substrates by the Electrodeposition Method to Detect Pesticides with High Enhancement Effect and Long-Term Stability.

In this study, surface-enhanced Raman scattering substrates were investigated by the electrodeposition method to detect low concentrations of pesticides via the electrodeposition method with different agents from silver and gold precursors on APTES-modified ITO glass. A dual-potential method supplied three electrodes and was performed with a nucleation potential of 0.7 V for 2 s and a growth potential of -0.2 V for 500 s. The Ag film produced by the electrodeposition approach has great surface uniformity and good SERS signal amplification for the thiram insecticide at low concentrations. Interestingly, the ITO/APTES/Ag substrate extensively increased the sensitivity than the other investigated ones, thanks to the adequate assistance of amino groups of APTES in the denser and hierarchical deposition of Ag NPs. These observations were additionally elucidated via finite-difference time-domain (FDTD) calculation. For thiram, the detection was set at 10-8 M with an enhancement factor of up to 3.6 × 107 times. Comparing the SERS spectra of thiram at concentrations of 10-3, 10-4, and 10-5 M with a relative standard deviation (RSD) of less than 7.0% demonstrates excellent reproducibility of the ITO/APTES/Ag substrate. In addition, the special selectivity of the ITO/APTES/Ag substrate for thiram demonstrates that these nanostructures can identify pesticides with extreme sensitivity.

Exposure to PFAS contaminated urban wetland water causes similar metabolic alterations to laboratory-based exposures in the freshwater amphipod Austrochiltonia subtenuis

Assessing the harm caused by pollutants in urban ecosystems remains a significant challenge. Traditional ecotoxicological endpoints are often not sensitive enough to detect the effects of toxicants at environmentally relevant concentrations (≤ng/L). A potential solution is using molecular biology methods to look at small biochemical changes caused by exposure to ng/L concentrations of contaminants. This has been tested in the lab but not conclusively demonstrated in the field. We exposed the freshwater amphipod (Austrochiltonia subtenuis) to water from an urban wetland containing known concentrations of per-and polyfluoroalkyl substances (as well as very low concentrations of pesticides) for 14 days and analyzed their metabolite profiles. Mannose, Myo-inositol, and Isopropyl propionate were found to change in PFAS exposed amphipods, a similar response to that previously observed in laboratory exposures to the same PFAS, but not pesticides. The results give a better understanding of PFAS toxicity at environmentally relevant concentrations and conditions.

Surface-Enhanced Raman Spectroscopy Detection for Fenthion Pesticides Based on Gold Molecularly Imprinted Polymer Solid-State Substrates.

Current label-free surface-enhanced Raman spectroscopy (SERS) assay for the detection and analysis of organophosphorus pesticides has achieved initial success, but the application still faces constraints of substrate portability and specificity. To this end, this paper demonstrates a method for portable, rapid, and specific detection of low concentrations of fenthion pesticides based on a solid substrate of gold nanoparticle monolayers combined with molecularly imprinted polymers (MIPs). The nano-monolayers were transferred to the surface of mercapto-silicon wafers by interfacial self-assembly technique to form a stable connection with S-Au bonds and, at the same time, prevent nanoparticles from dropping off during the surfactant removal process. Then, the fenthion MIPs were directly generated on the surface of the monolayer film by spin-coating with a pre-polymerization solution and ultraviolet-induced polymerization. Tests showed that the molecular imprint was able to accurately bind to fenthion, but not other molecules, in a mixture of structural analogs, achieving a low concentration detection of 10-8 mol/L. The composite substrate maintained a signal uniformity of a relative standard deviation (RSD) = 7.05% and a batch-to-batch reproducibility of RSD = 10.40%, making it a potential pathway for the extended application of SERS technology.

Thermal sensitivity of Rhinella arenarum tadpole at low concentrations of dimethoate pesticides

One of the main causes of contamination of aquatic environments, which affects biotic communities, is the use of pesticides in agricultural regions. Amphibians are considered good bio-indicators of aquatic pollution, because they are one of the most susceptible groups to pollution. Several studies suggest that both pollution and climate change produce synergistic effects in amphibians which amplify the toxicity afecting survival, and malformations with an increase in temperature. We studied the sensitivity of sublethal concentrations of dimethoate in Rhinella arenarum tadpoles on two fitness related thermal traits including locomotor swimming performance and thermal tolerance limits (CTmax = critical thermal maximum and CTmin = critical thermal minimum). The locomotor performance of R. arenarum tadpoles decreased with increasing sublethal dimethoate concentrations up to ∼60 % at intermediates dimethoate concentration. The tadpoles showed a tendency to decrease their tolerance to high temperatures (CTmax) with increasing dimethoate concentration around ∼0.5 °C, however no significant differences were found among treatments. Similarly, tadpoles showed decreases in their cold resistance (CTmin) with dimethoate concentrations, around 1 °C the high concentrations of dimethoate. The increase of atypical climatic events, such as heat waves may put R. arenarum tadpoles at greater risk when exposed to dimethoate. Our results show that the sublethal concentrations of the dimethoate pesticide may affect the fitness and survival of the larvae of R. arenarum in natural, and seminatural enviroments.

Pyriproxyfen Contamination in Daphnia magna: Identifying Early Warning Biomarkers.

Pyriproxyfen is an insecticide currently employed in numerous countries for the management of agricultural and indoor pests. Several studies indicate that this insecticide has been detected in multiple rivers, with concentrations reaching as high as 99.59 ng/L in the Júcar River in Spain. Therefore, the determination of some biochemical and genetic effects of this insecticide on aquatic organisms could serve as an early warning mechanism to identify potential disruptions in various biomarkers. Based on this, Daphnia magna organisms were exposed to pyriproxyfen sublethal concentrations for 21 days. Some biochemical parameters, including cholesterol, triglycerides, glucose, lactate, and LDH activity, were determined. Additionally, some genetic biomarkers associated with oxidative stress, heat shock proteins, lipid metabolism, hemoglobin, metallothioneins, and vitellogenin synthesis were evaluated in daphnids exposed to the insecticide for 21 days. LDH activity increased significantly in those daphnids exposed to the highest insecticide concentration (14.02 µg/L), while cholesterol levels decreased significantly. In contrast, glucose, total proteins, and triglycerides remained unaffected in D. magna exposed to pyriproxyfen. On the other hand, exposure to the insecticide led to notable alterations in gene expression among individuals. Specifically, genes associated with lipid metabolism and reproduction exhibited a significant reduction in gene expression. Fabd expression was decreased by approximately 20% in exposed daphnids, while vtg expression was suppressed as much as 80% when compared to control values. Furthermore, it was observed that the hgb1 and hgb2 genes, associated with hemoglobin synthesis, exhibited significant overexpression. Notably, the dysfunction observed in both hemoglobin genes was linked to an increase in pigmentation in Daphnia magna during the course of the experiment. These alterations in gene expression could serve as effective indicators of early contamination even at low pesticide concentrations.

A review of the harm of environmental pollutants to human health: Take microplastic, insecticide, and PFAS as examples

Environmental pollution is a key issue of social concern. Pollutants generated by a variety of human activities are eventually discharged into the atmosphere, water bodies, and soil, and these pollutants have great negative impacts on the human body. Taking Microplastics (MPs), pesticides, Per- and polyfluoroalkyl substances (PFAS) as examples, this paper explores the sources of three new types of pollutants in the environment and the hazards to the human body respectively, and proposes corresponding management measures in the hope of raising people’s awareness of environmental protection. The results show that MPs mainly come from industrial and agricultural applications and poorly managed wastes, with potential reproductive toxicity and immunotoxicity to the human body; pesticides mainly come from agricultural applications, and high concentrations of pesticides can lead to acute toxicity in the human body, while low concentrations of pesticides may have an immunosuppressive effect on the human body; PFAS mainly come from industrial production, and it has been established that non-alcoholic fatty liver disease (NAFLD) is linked to PFAS exposure. Restricting the production and use of related products and strengthening supervision and monitoring can effectively control environmental pollution and reduce harm to human beings.

Exposure to sublethal concentrations of imidacloprid, pyraclostrobin, and glyphosate harm the behavior and fat body cells of the stingless bee Scaptotrigona postica

Pesticide use in agriculture threatens non-target insects such as bees. Considering the ecological and economic relevance of native bees, such as Scaptotrigona postica, and the insufficient studies on the effects of pesticides on their behavior and physiology, improving the current knowledge on this issue is essential. Therefore, this study investigated the sublethal effects of imidacloprid, pyraclostrobin, and glyphosate on the behavior and fat body cells of S. postica. Pesticide ingestion decreased the walking distance and mean velocity of bees compared to the control and solvent control groups. The oenocytes of the control groups were spherical, with central nuclei containing decondensed chromatin, and the trophocytes presented irregular morphology, with cells varying in shape and the cytoplasm filled with vacuoles and granules. However, bees exposed to pesticides showed extensive cytoarchitectural disruption in the fat body, such as vacuolization and shape changes in oenocytes and altered nuclei morphology in trophocytes. Moreover, pesticide exposure increased the number of atypical oenocytes and altered trophocytes, except for the PYR group, which showed a lower number of atypical oenocytes. Caspase-positive labeling significantly increased in all exposed bee groups. Alternatively, TLR4 labeling was significantly decreased in the exposed groups compared to the control groups. There was a significant increase in HSP90 immunolabeling in all exposed groups compared to the control. These findings reinforce the importance of research on the sublethal effects of low pesticide concentrations on key neotropical pollinators and prove that these toxic substances can impair their detoxification and immune defense.

A new voltammetric approach for the determination of the growth retardant paclobutrazol in the presence of difenoconazole in pesticide preparations

Paclobutrazol (PBZ) belongs to the group of triazole pesticides, which act as inhibitors of the synthesis of phytohormones and thereby regulate plant growth. In this study, the electrochemical oxidation of this pesticide was investigated for the first time. PBZ provides on a boron-doped diamond electrode (BDDE) one irreversible anodic peak over a wide pH range of the supporting electrolyte at a significantly positive potential of ca. +1950 mV (vs Ag/AgCl), which is suitable for electroanalytical purposes. Based on the LC-MS analysis of the products of electrolysis, the mechanism of the electrochemical oxidation of PBZ was also proposed. The method developed for the determination of PBZ using differential pulse voltammetry in connection with BDDE in the supporting electrolyte of 0.07 mol L−1 NaOH with 33 % of acetonitrile provided a very low limit of quantification amounted to 2.6 × 10−7 mol L−1. Under optimized conditions, the determination of the studied plant growth regulator is also possible in the presence of the other insecticide difenoconazole, which is usually found in commercial preparations mixed with PBZ. For natural water samples with very low concentrations of pesticides, a method of analyte pre-concentration using strong acid Amberlite® IRC120 H catex was developed. The proposed procedures were successfully applied for the analysis of model solutions, commercially available pesticide preparations, and spiked natural waters.

Cost-Effective and Facile Fabrication of a Tattoo Paper-Based SERS Substrate and Its Application in Pesticide Sensing on Fruit Surfaces.

Surface-enhanced Raman spectroscopy (SERS) has been transformed into a useful analytical technique with significant advantages in relation to sensitive and low-concentration chemical analyses. However, SERS substrates are expensive and the analyte sample preparation is complicated; hence, it is only used in limited areas. We have fabricated a tattoo paper-based SERS substrate by using non-complicated inkjet printing. The sensitivity of the SERS substrate was increased by removing the carbon residues via exposure to ultraviolet light without damaging the substrate. Thus, low concentrations of pesticides (up to 1 μM thiram) were measured. The SERS substrate was attached to the curved surface of an apple to demonstrate its advantages, such as the flexibility and easy attachability of tattoo paper, and its feasibility was verified by measuring 1 μM thiram on the apple's surface. Due to its economic cost, simple usage, and rapid measurement, it will be helpful for the identification of both agricultural adulterants and food adulterants and for water-based pollutant detection. It will also possibly be helpful for medical purposes related to human body surfaces in the future.

Risk assessment of persistent pesticide pollution: Development of an indicator integrating site-specific characteristics

Detection of high pesticide concentrations in sediments and water often leads to prioritizing a site as being ‘at risk’. However, the risk does not depend on pesticide concentration alone, but on other site-specific characteristics also. We developed an indicator that identifies the ‘Level of Concern’ by integrating five such characteristics: (i) pesticide concentrations in surface and groundwater causing risks to ecological health (ii) impacts on human health, (iii) water scarcity, (iv) agricultural production, and (v) biodiversity richness. We applied this framework in an agricultural region of the Lower Ganges Basin in West Bengal, India. We measured concentrations of selected organochlorine pesticides (OCPs) in surface and groundwater within an 8 km2 area in 2019. Of 20 banned and restricted OCPs, 11 were detected as causing high risk to ecological health and 10 at concentrations above the Accepted Carcinogenic Risk Limit (ACRL) for humans. In the pre-monsoon, the mean concentrations of ΣOCPs in groundwater and surface water were 126.9 ng/L and 104 ng/L, in the monsoon they were 144.7 ng/L and 138 ng/L, and in the post-monsoon 122.1 ng/L and 147 ng/L respectively. In groundwater, no significant seasonal difference was observed in most pesticides. In the surface water, 7 pesticides were significantly higher in the monsoon and post-monsoon, which may be attributed to increased runoff as well as post monsoon application of OCPs. In September 2022 we again measured OCP concentrations in surface water and sediment. The mean concentration of 14 of the 20 measured OCPs were found to be significantly lower in the post-pandemic period compared to the pre-pandemic time. These lower pesticide concentrations may indicate a reduced use of OCPs in agricultural practices during the pandemic. This area was identified as being at the highest Level of Concern, even though the OCP concentrations alone conformed to general guidelines.

In Vitro Detection of Biochemical Effect in Human CaCo-2 Cell Line after Exposure to a Low Concentration of a Deltamethrin-Based Pesticide

Pesticide residues are chemicals frequently found in food as contaminants. Pesticides may have adverse health effects, particularly when the digestive tract is concerned, as a consequence of food ingestion. Deltamethrin is a pyrethroid pesticide widely used in various fields, such as agriculture, veterinary and in the household, so the ingestion of a small amount of this chemical may occasionally occur. To assess whether exposure to pesticide residues may have a biological effect at the intestinal level, it is primarily necessary to perform in vitro exposure experiments about cell lines models of the intestinal barrier at low concentrations of the chemical. In the present study, CaCo-2 cells were exposed to different concentrations of a Deltamethrin-based commercial pesticide, which was diluted in the cell medium. An MTT viability test indicated that the cytotoxic concentration value of the pesticide inside 1 mL of medium is between 10−6 and 10−5 mL. However, the analysis of Raman spectra found that biochemical changes occur inside cells exposed to a non-cytotoxic concentration of 10−6 mL of the pesticide inside 1 mL of the medium. Such changes involve mainly an increase in the ratio between the amount of lipid with respect to that of the protein components in the cell cytoplasm. The results obtained by Raman micro-spectroscopy were confirmed by fluorescence images obtained by using a fluorophore staining neutral lipids. Overall, the obtained results suggest that Raman micro-spectroscopy can be successfully used to monitor the cellular modifications due to exposure at low concentrations of pesticides, as those values that can be found inside food are residuals.

A Study on the Diversity of Pesticide-Resistant Bacterial Population from Different Agricultural Fields of Manjoor

The regular usage of pesticides in agricultural fields results in the development of a pesticide-resistant microbial population. Vegetable cultivation is a common practice in the agricultural growing areas of Manjoor, Kerala. The present study was envisaged to understand the resistance of microorganisms to different types and doses of pesticides. The study revealed that heterotrophic bacteria are capable of resisting lower concentrations (0.01 and 0.001%) of the pesticides lindane and methyl parathion while a higher concentration of carbaryl (0.1%) could also be tolerated. In the soil sample where there was no prior addition of pesticides, the heterotrophic bacteria could only tolerate very low concentrations of pesticides The results of mean pesticide-resistant bacterial load when compared to normal Total Heterotrophic Bacteria (THB) of soils indicate that pesticides exhibited an inhibitory effect on the heterotrophic bacteria of soils collected from different agricultural fields and the pesticide-resistant bacterial load was lower than normal THB.

Reproductive toxicity by exposure to low concentrations of pesticides in Caenorhabditis elegans

In view of the recurrent applications of pesticides in agricultural producing countries, the increased presence of these substances in the environment raise a demand for the evaluation of adverse effects on non-target organisms. This study assesses the impact of exposure to five pesticides suspected of being endocrine disruptors (atrazine, 2,4-dichlorophenoxyacetic acid, mancozeb, chlorpyrifos and cypermethrin) on the reproductive development of the nematode Caenorhabditis elegans. To this end, nematodes in the L4 larval stage were exposed to different concentrations of pesticides for 24 h and the consequences on brood size, percentage of gravid nematodes, expression of reproductive-related genes and vitellogenin trafficking and endocytosis were measured. Moreover, 17β-estradiol was used as an estrogenic control for endocrine disrupting compounds throughout the work. The results showed that all the pesticides disturbed to some extent one or more of the evaluated endpoints. Remarkably, we found that atrazine, 2,4-dichlorophenoxyacetic acid and chlorpyrifos produced comparable responses to 17β-estradiol suggesting that these pesticides may have estrogen-like endocrine disrupting activity. Atrazine and 17β-estradiol, as well as 2,4-dichlorophenoxyacetic acid and chlorpyrifos to a lesser extent, decreased the brood size, affected vitellogenin trafficking and endocytosis, and changed the expression of several reproductive-related genes. Conversely, mancozeb and cypermethrin had the least impact on the evaluated endpoint. Cypermethrin affected the brood size at the highest concentration tested and mancozeb altered the distribution of vitellogenin only in approximately 10% of the population. However, both products overexpressed hus-1 and vit-2 genes, indicating that an induction of stress could interfere with the normal development of the nematode. In conclusion, our work proved that C. elegans is a useful biological model to identify the effects of estrogen-like endocrine disruptor compounds, and the sublethal endpoints proposed may serve as an important contribution on evaluating environmental pollutants.

Effects of Diazinon on the Survival, Blood Parameters, Gills, and Liver of Grass Carp (Ctenopharyngodon idella Valenciennes, 1844; Teleostei: Cyprinidae)

Diazinon (DZN) is a widely used pesticide that can affect the vital organs of non-target aquatic animals—mainly fish. This study evaluated the acute toxicity (LC50) of six DZN concentrations (0.5, 0.75, 1.5, 2, 2.5, and 3 mg·L−1) and, based on its evaluation after 24 h, 48 h, 72 h, and 96 h, two sublethal concentrations for chronic toxicity testing (0.01 and 0.05 mg·L−1) for 21 days of exposure to DZN on grass carp fingerlings (Ctenopharyngodon idella Valenciennes, 1844). The median lethal concentrations of DZN at 24, 48, 72, and 96 h were 1.83, 1.57, 1.35, and 1.12 mg·L−1, respectively. Next, histological observations after 96 h LC50 showed oedema of the primary lamellae of the gills at low pesticide concentrations (0.5 to 1 mg·L−1) and extensive necrosis of primary lamellae of the gills at higher concentrations (1.5 to 3 mg·L−1). Moreover, cytoplasmic vacuolation and extensive necrosis were observed in liver tissue. Increased skin mucus, unbalanced swimming on the water surface, and increased gill opercula movements were noted during chronic exposure. Haematological parameters such as haematocrit, red blood cell count, white blood cell count, haemoglobin, and mean corpuscular volume were significantly reduced after 21 days of exposure to 0.05 mg·L−1 of DNZ (p < 0.05). The present study shows that DZN has various toxic effects on grass carp, which may pose a potential risk for other fish species.

The sublethal concentration of Cyflumetofen adversely affect demographic parameters of Tetranychus urticae (Acari: Tetranychidae): Using age-stage, two-sex life tables

ABSTRACT The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) has an extensive host range and is the most important pest mite worldwide. Traditional control measures have on the application of the lethal dose of acaricides, thus underestimating the total effects of acaricides on the population dynamics. Our main objective was to evaluate whether it is possible to rely on sublethal concentrations of the pesticide to control mites without getting meaningful crop. To test this hypothesis, we used sublethal concentrations (including LC10, LC20, LC30) of cyflumetofen to see the impact on population parameters of T. urticae. The experiments were performed under laboratory conditions at 25 ± 2°C, 60 ± 5% relative humidity (RH), and a photoperiod of 16:8 (L: D) hours. Results were based on age-stage, two-sex life table analysis. The data showed that sublethal concentrations of the pesticide suppress fecundity, adult longevity (both female and male individuals), and the intrinsic rate of increase significantly. For example, the fecundity in the LC10, LC20, LC30 and control was 36.55, 42.26,and 57.96 eggs/female, respectively, showing significant differences. Similarly, the intrinsic rate of increase (r) are also significantly different between LC30 (r = 0.20) and the control (0.24). The data presented here raise awareness into mite control since using a lower pesticide concentration not only controls the pest population but also produces lower risk to the environment, consumers, and biocontrol agents. Therefore, one could infer that using sublethal concentrations of pesticides would be more beneficial to both the environment and consumers in the long run.

POSITIVE ASPECTS OF NANOTECHNOLOGY ON AGRICULTURAL SUSTAINABLE DEVELOPMENT: APPLICATION OF NANOPARTICLES AND FIBERS FOR INCREASING AGRICULTURAL YIELD

Recently, nanotechnology is widely used in agriculture with the aim of achieving high agricultural yields. Due to the unique surface and physicochemical properties, nanomaterials can be used to deliver nutrients to plants via nanoparticles, for the synthesis of nanopesticides, nanofungicides, and to design nanosensors for the detection of very low concentrations of pesticides and other contaminants. Excessive use of pesticides and fertilizers causes the loss of soil biodiversity and the development of resistance to pathogens. Nenoencapsulation of fertilizers, pesticides and herbicides is used for slow and specific dosed release of nutrients as well as agrochemicals. This paper discusses the applications of nanotechnology and their positive effect in agriculture in relation to the common methods used so far.

FLEXIBLE SERS-ACTIVE SUBSTRATE BASED ON SILVER NANOSTRUCTURES FOR DETERMINATION OF PESTICIDES

A SERS-active substrate made of a cellulose membrane material coated with a silver film and additionally modified with silver nanostructures has been obtained and characterized. Using the example of malathion, the effectiveness of the SERS-active substrate for determining low concentrations of pesticides is shown.

Efficacy of quaternary ammonium groups based polyelectrolytes for the reduction of various pesticide formulations content from synthetic wastewater

• Cationic polymers were studied for the removal of different commercial pesticides. • Lower optimum polymer dose was found for the samples with higher charge content. • A reduced pesticide removal degree was noticed for lower pesticide concentrations. • Zeta potential results indicate charge neutralization mechanism for pesticide removal. Cationic polyelectrolytes, synthetic (PCA) and dextran derivatives (D40-EtX) have been evaluated, for the first time, as flocculants for the separation of the commercial pesticides Novadim Progress -organophosphoric type (active ingredient Dimethoate), Decis and Karate Zeon - pyrethroid type (active ingredients Deltamethrin and lambda- Cyhalothrin, respectively) from synthetic wastewater. The investigated ionic polymer samples contain different amount of quaternary ammonium salts groups in the chain. The effects of settling time, polymer dose, ionic groups content, pesticides concentration on the separation efficacy have been investigated . The UV–Vis spectroscopy data indicate that the highest removal efficiency of pesticides (between 90 and 94% for Novadim Progress and between 86 and 94% for the pyrethroids insecticides) has been achieved by the polyelectrolytes with the highest charged groups content (higher than 90%). The charge neutralization mechanism had a noteworthy contribution to the pesticide removal as indicated by the zeta potential and particle size measurements. Slightly lower optimum polycation doses were found for lower pesticides concentrations.

Assessing the ecological functionality and integrity of natural ponds, excavated ponds and stormwater basins for conserving amphibian diversity

Wetlands provide ecological functionality by maintaining and promoting regional biodiversity supporting quality habitat for aquatic organisms. Globally, habitat loss, fragmentation and degradation due to increases in agricultural activities and urban development have reduced or altered geographically isolated wetlands, thus reducing biodiversity. The objective of this study was to assess the relative ecological function and integrity of natural ponds, excavated ponds and stormwater basins in the New Jersey Pinelands, located in the northeastern United States by comparing hydrologic conditions, water quality, pesticide concentrations (water, sediment and tissue) and wetland assemblages including amphibians. Twenty-four wetlands were selected based on surrounding land-use and sampled for a variety of abiotic and biotic variables. Abiotic and biotic wetland variables were similar between natural and excavated ponds, with notable differences between the ponds and stormwater basins. Natural and excavated ponds displayed characteristic Pinelands water quality (low pH, high organic carbon, and low pesticide concentrations), exhibited high ecological integrity and supported native ampbibians. Stormwater basins and degraded ponds surrounded by altered land-use exhibited degraded water quality (high pH, high pesticide concentrations) and were dominated by non-native and introduced plants and amphibians. Results from this study can broadly inform resource conservation strategies for amphibians and other communities with a diverse range of habitat requirements, particularly in areas where conservation and development are competing priorities. To conserve biodiversity in changing landscapes, wetlands with similar functionality and land-use characteristics need to be identified and managed to preserve water quality for species of conservation concern.