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Complex mixtures of Pesticides in Midwest U.S. streams indicated by POCIS time-integrating samplers
2017
Van Metre, Peter C. | Alvarez, David A. | Mahler, Barbara J. | Nowell, Lisa | Sandstrom, Mark | Moran, Patrick
The Midwest United States is an intensely agricultural region where pesticides in streams pose risks to aquatic biota, but temporal variability in pesticide concentrations makes characterization of their exposure to organisms challenging. To compensate for the effects of temporal variability, we deployed polar organic chemical integrative samplers (POCIS) in 100 small streams across the Midwest for about 5 weeks during summer 2013 and analyzed the extracts for 227 pesticide compounds. Analysis of water samples collected weekly for pesticides during POCIS deployment allowed for comparison of POCIS results with periodic water-sampling results. The median number of pesticides detected in POCIS extracts was 62, and 141 compounds were detected at least once, indicating a high level of pesticide contamination of streams in the region. Sixty-five of the 141 compounds detected were pesticide degradates. Mean water concentrations estimated using published POCIS sampling rates strongly correlated with means of weekly water samples collected concurrently, however, the POCIS-estimated concentrations generally were lower than the measured water concentrations. Summed herbicide concentrations (units of ng/POCIS) were greater at agricultural sites than at urban sites but summed concentrations of insecticides and fungicides were greater at urban sites. Consistent with these differences, summed concentrations of herbicides correlate to percent cultivated crops in the watersheds and summed concentrations of insecticides and fungicides correlate to percent urban land use. With the exception of malathion concentrations at nine sites, POCIS-estimated water concentrations of pesticides were lower than aquatic-life benchmarks. The POCIS provide an alternative approach to traditional water sampling for characterizing chronic exposure to pesticides in streams across the Midwest region.
Show more [+] Less [-]Evaluation of cytotoxic and genotoxic activity of fungicide formulation Tango® Super in bovine lymphocytes
2017
Schwarzbacherová, Viera | Wnuk, Maciej | Lewinska, Anna | Potocki, Leszek | Żebrowski, Jacek | Koziorowski, Marek | Holečková, Beáta | Šiviková, Katarína | Dianovský, Ján
Tango® Super is a two-compound fungicide formulation widely employed in grain protection. However, details of Tango® Super effects on cell cultures have not been fully investigated. In this study, bovine lymphocytes were exposed to a concentration range 0.5; 1.5; 3; 6; and 15 μg mL⁻¹ for 4 h to assess the cytotoxicity and genotoxicity of the fungicide. Our experiments revealed that this fungicide treatment reduced cell viability, decreased cell proliferation and provoked apoptotic cell death. Cell cycle analysis showed predominant accumulation of cells in the G0/G1 phase of the cell cycle. The fungicide was able to induce mitochondrial superoxide production accompanied by elevated levels of carbonylated proteins and changes in the lipid membrane composition. The fungicide did not induce micronuclei production, but stimulated both DNA double-strand breaks and the formation of p53 binding protein, which is accumulated during the DNA repair process at the site of double-strand breaks. Based on the obtained data we suppose that the fungicide-induced DNA damage is the result of oxidative stress, which may contribute to higher occurrence of apoptotic cell death. Because ergosterol biosynthesis-inhibiting fungicides are widely used in agriculture to ensure higher crop yields and may cause health impairment of animals and humans, there is a need for further testing to elucidate their potential genotoxic effects using in vivo and/or in vitro systems.
Show more [+] Less [-]The use of buccal swabs as a minimal-invasive method for detecting effects of pesticide exposure on enzymatic activity in common wall lizards
2017
Mingo, Valentin | Lötters, Stefan | Wagner, Norman
Habitat loss and environmental pollution are among the main causes responsible for worldwide biodiversity loss. The resulting species and population declines affect all vertebrates including reptiles. Especially in industrialized countries, pollution by agrochemicals is of remarkable importance. Here, habitat loss has historically been associated with expansion of agriculture. Species persisting in such environments do not only need to cope with habitat loss, but more recently, also with chemical intensification, namely pesticide exposure. In this study, we examined effects of different fungicide and herbicide applications on the common wall lizard (Podarcis muralis) in grape-growing areas. We used three enzymatic biomarkers (GST, GR, AChE) and for the first time saliva from buccal swabs as a minimal-invasive sampling method for detection. Our results demonstrate absorption of substances by lizards and effects of pesticide exposure on enzymatic activities. Our findings are in accordance with those of previous laboratory studies, although samples were retrieved from natural habitats. We conclude that buccal swabs could become a useful tool for the detection of pesticide exposure in reptiles and have the potential to replace more invasive methods, such as organ extraction or cardiac puncture. This is an important finding, as reptiles are non-target organisms of pesticide applications, and there is a strong need to integrate them into pesticide risk assessments.
Show more [+] Less [-]Does long-term fungicide exposure affect the reproductive performance of leaf-shredders? A partial life-cycle study using Hyalella azteca
2017
Baudy, Patrick | Zubrod, Jochen P. | Konschak, Marco | Weil, Mirco | Schulz, Ralf | Bundschuh, Mirco
Leaf-shredding amphipods play a critical role in the ecosystem function of leaf litter breakdown, a key process in many low order streams. Fungicides, however, may adversely influence shredders' behavior and the functions they provide, while there is only limited knowledge concerning effects on their reproductive performance. To assess the latter, a semi-static 56-day partial life-cycle bioassay using the model shredder Hyalella azteca (n = 30) was performed applying two environmentally relevant concentrations of a model fungicide mixture (i.e., 5 and 25 μg/L) composed of five fungicides with different modes of toxic action. Variables related to the food processing (leaf consumption and feces production), growth (body length and dry weight), energy reserves (lipid content), and reproduction (amplexus pairs, number and length of offspring) were determined to understand potential implications in the organisms' energy budget. While the fungicides did not affect leaf consumption, both fungicide treatments significantly reduced amphipods' feces production (∼20%) compared to the control. This observation suggests an increased food utilization to counteract the elevated and stress-related energy demand: although growth as well as energy reserves were unaffected, amplexus pairs were less frequently observed in both fungicide treatments (∼50–100%) suggesting a tradeoff regarding energy allocation favoring the maintenance of fundamental functions at the organism level over reproduction. As a result, the time to release of first offspring was delayed in both fungicide treatments (7 and 14 days) and the median number of offspring was significantly lower in the 25-μg/L treatment (100%), whereas offspring length remained unaffected. The results of this study thus indicate that chronic fungicide exposures can negatively impact shredders' reproductive performance. This may translate into lower abundances and thus a reduced contribution to leaf litter breakdown in fungicide-impacted streams with potentially far-reaching consequences for detritus-based food webs.
Show more [+] Less [-]Quantifying exposure of wild bumblebees to mixtures of agrochemicals in agricultural and urban landscapes
2017
Botías, Cristina | David, Arthur | Hill, Elizabeth M. | Goulson, Dave
The increased use of pesticides has caused concern over the possible direct association of exposure to combinations of these compounds with bee health problems. There is growing proof that bees are regularly exposed to mixtures of agrochemicals, but most research has been focused on managed bees living in farmland, whereas little is known about exposure of wild bees, both in farmland and urban habitats. To determine exposure of wild bumblebees to pesticides in agricultural and urban environments through the season, specimens of five different species were collected from farms and ornamental urban gardens in three sampling periods. Five neonicotinoid insecticides, thirteen fungicides and a pesticide synergist were analysed in each of the specimens collected. In total, 61% of the 150 individuals tested had detectable levels of at least one of the compounds, with boscalid being the most frequently detected (35%), followed by tebuconazole (27%), spiroxamine (19%), carbendazim (11%), epoxiconazole (8%), imidacloprid (7%), metconazole (7%) and thiamethoxam (6%). Quantifiable concentrations ranged from 0.17 to 54.4 ng/g (bee body weight) for individual pesticides. From all the bees where pesticides were detected, the majority (71%) had more than one compound, with a maximum of seven pesticides detected in one specimen. Concentrations and detection frequencies were higher in bees collected from farmland compared to urban sites, and pesticide concentrations decreased through the season. Overall, our results show that wild bumblebees are exposed to multiple pesticides when foraging in agricultural and urban landscapes. Such mixtures are detected in bee tissues not just during the crop flowering period, but also later in the season. Therefore, contact with these combinations of active compounds might be more prolonged in time and widespread in the environment than previously assumed. These findings may help to direct future research and pesticide regulation strategies to promote the conservation of wild bee populations.
Show more [+] Less [-]Enantioselective bioaccumulation following exposure of adult zebrafish (Danio rerio) to epoxiconazole and its effects on metabolomic profile as well as genes expression
2017
Wang, Yao | Teng, Miaomiao | Wang, Dezhen | Yan, Jin | Miao, Jiyan | Zhou, Zhiqiang | Zhu, Wentao
Although epoxiconazole is the worldwidely used fungicide, limited information is known about its toxic effects and bioaccumulation behavior in freshwater ecosystems. In this study, zebrafish were exposed to epoxiconazole at concentrations of 100 and 1000 μg L−1 for 21 d. 1H NMR-based metabolomics analysis showed that low- and high-dose epoxiconazole exposure resulted in two similar but not identical patterns for the change of endogenous metabolites related to energy, lipid and amino acid metabolism. The expression of genes associated with mitochondrial respiratory chain, ATP synthesis and fatty acid β-oxidation were further measured to explore the reason for the disturbed energy metabolism, finding epoxiconazole had an inhibition effect on the genes expression of the above ways. Significant enantioselectivity was observed with (+)-epoxiconazole enrichment in the bioaccumulation process. These results will be of great importance in understanding the toxic effects induced by epoxiconazole and provide important basis for its comprehensive environmental assessment.
Show more [+] Less [-]Heavy Metal Uptake by Herbs. V. Metal Accumulation and Physiological Effects Induced by Thiuram in Ocimum basilicum L
2017
Adamczyk-Szabela, Dorota | Romanowska-Duda, Zdzisława | Lisowska, Katarzyna | Wolf, WojciechM.
Basil (Ocimum basilicum L.) is extensively cultivated as either an important spice and food additive or a source of essential oil crucial for the production of natural phenylpropanoids and terpenoids. It is frequently attacked by fungal diseases. The aim of the study was to estimate the impact of thiuram contact time on the uptake of manganese, cobalt, nickel, copper, zinc, cadmium, and lead by Ocimum basilicum L. The relevant plant physiological parameters were also investigated. Two farmland soils typical for the Polish rural environment were used. Studies involved soil analyses, bioavailable, and total forms for all investigated metals, chlorophyll content, and gas exchange. Atomic absorption spectrometry was used to determine concentration of all elements. Analysis of variance proved hypothesis that thiuram treatment of basil significantly influences metal transfer from soil and their concentration in roots and aboveground parts. This effect is mostly visible on the 14th day after the fungicide administration. Thiuram modifies mycoflora in the rhizosphere zone and subsequently affects either metal uptake from the soil environment or their further migration within the basil plant. Notable, those changes are more evident for basil planted in mineral soil as compared to organic soil with higher buffering capacity.
Show more [+] Less [-]Sorption of thiabendazole in sub-tropical Brazilian soils
2017
de Oliveira Neto, Odilon França | Arenas, Alejandro Yopasa | Fostier, Anne Hélène
Thiabendazole (TBZ) is an ionizable anthelmintic agent that belongs to the class of benzimidazoles. It is widely used in veterinary medicine and as a fungicide in agriculture. Sorption and desorption are important processes influencing transport, transformation, and bioavailability of xenobiotic compounds in soils; data related to sorption capacity are therefore needed for environmental risk assessments. The aim of this work was to assess the sorption potential of TBZ in four Brazilians soils (sandy, sandy-clay, and clay soils), using batch equilibrium experiments at three pH ranges (2.3–3.0, 3.8–4.2, and 5.5–5.7). The Freundlich sorption coefficient (K F) ranged from 9.0 to 58 μg¹–¹/ⁿ (mL) ¹/ⁿ g⁻¹, with higher values generally observed at the lower pH ranges (2.3–3.0 and 3.8–4.2) and for clay soils. The highest organic carbon-normalized sorption coefficients (KOC) obtained at pH 3.8–5.7 (around the natural pH range of 4.1–5.0) for both clay soils and sandy-clay soil were 3255 and 2015 mL g⁻¹, respectively. The highest correlations K F vs SOM (r = 0.70) and K F vs clay content (r = 0.91) were observed at pH 3.8–4.2. Our results suggest that TBZ sorption/desorption is strongly pH dependent and that its mobility could be higher in the studied soils than previously reported in soils from temperate regions.
Show more [+] Less [-]Changes of soil bacterial activities and functions after different N additions in a temperate forest
2017
Guo, Peng | Han, Tiwen | Zhang, Li | Li, Shushan | Ma, Dongzhu | Du, Yuhan
It has been shown that different nitrogen (N) addition led to various influences on soil microbial activities in forest ecosystems; however, the changes of bacteria were still unclear. In this work, inorganic N (NH₄NO₃) and organic N (urea and glycine) were fertilized with different ratios (5:0, 1:4, 3:2, 2:3, and 1:4) on temperate forest soils, while fungicide (cycloheximide) was simultaneously added on half of each treatment to inhibit fungal activities (leaving only bacteria). After a 3-year field experiment, soil samples were harvested, then microbial enzymatic activities involved in carbon (C), and N and phosphorus (P) cycles were determined. Under laboratory conditions, four purified bacteria which were isolated from sample site had been inoculated in sterilized soils under different N types and enzymatic activities were assayed after 90-day incubation. The results showed that cellulase and polyphenol oxidase activities of non-fungicide-added treatments increased after N addition and greater organic N accelerated the increases. However, these enzymatic activities of fungicide-added treatments were not significantly influenced by N addition and N types. It may be due to the insufficient ability of bacteria to synthesize enough enzymes to decompose complex organic C (such as cellulose and lignin) into available compound, although N-limitation was alleviated. Alkaline phosphatase activities increased after N addition in both non-fungicide-added and fungicide-added treatments, and the acceleration on bacterial alkaline phosphatase activities was even greater. Furthermore, organic N showed at least 2.5 times promotion on bacteria alkaline phosphatase than those of inorganic N, which indicated greater alleviation of bacterial P-limitation after the addition of organic N. All the results indicated that soil bacteria may be seriously limited by soil available C but become the dominant decomposer of the complex P compounds after N addition, particularly greater organic N.
Show more [+] Less [-]Environmental risk assessment of blight-resistant potato: use of a crop model to quantify nitrogen cycling at scales of the field and cropping system
2017
Young, MarkW. | Mullins, Ewen | Squire, GeoffreyR.
Environmental risk assessment of GM crops in Europe proceeds by step-wise estimation of effect, first in the plant, then the field plot (e.g. 10–100 m⁻²), field (1000–10,000 m⁻²) and lastly in the environment in which the crop would be grown (100–10,000 km²). Processes that operate at large scales, such as cycling of carbon (C) and nitrogen (N), are difficult to predict from plot scales. Here, a procedure is illustrated in which plot scale data on yield (offtake) and N inputs for blight resistant (both GM and non-GM) and blight-susceptible potato are upscaled by a model of crop resource use to give a set of indicators and metrics defining N uptake and release in realistic crop sequences. The greatest potential damage to environment is due to loss of N from the field after potato harvest, mainly because of the large quantity of mineral and plant matter, high in N, that may die or be left in the field. Blight infection intensifies this loss, since less fertiliser N is taken up by plants and more (as a proportion of plant mass) is returned to the soil. In a simulation based on actual crop sequences, N returns at harvest of potato were raised from 100 kg ha⁻¹ in resistant to 150 kg ha⁻¹ in susceptible varieties subject to a 40% yield loss. Based on estimates that blight-resistant types would require ~20% of the fungicide applied to susceptible types, introduction of resistant types into a realistic 6-year cropping sequence would reduce overall fungicide use to between 72 and 54% depending on the inputs to other crops in the sequence.
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