Environmental Toxicology and Chemistry
1552-8618
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Cơ quản chủ quản: Wiley-Blackwell , WILEY
Lĩnh vực:
Environmental ChemistryHealth, Toxicology and Mutagenesis
Các bài báo tiêu biểu
Comparison of element concentrations in fir and rhododendron leaves and twigs along an altitudinal gradient Abstract Concentrations of 23 elements (Ca, K, Mg, P, Al, Cu, Fe, Mn, Mo, Na, Ni, Zn, Ag, Ba, Be, Cd, Co, Cr, Pb, Sb, Th, Tl, and V) in leaf and twig samples of a fir (Abies fabri ) and a rhododendron (Rhododendron williamsianum ) collected along an altitudinal gradient on Mount Gongga, China, are reported in the present study. Most of the macronutrients (K and P), micronutrients (Fe, Zn, Cu, Na, Ni, Mo, and Al), and trace elements (Pb, Tl, Ag, Cd, Ba, Co, V, Be, and Cr) are significantly enriched in fir when compared to rhododendron; however, Ca, Mg, Mn, Ba, and Cd are more enriched in rhododendron than in fir. Most of the elements in both plants are more significantly enriched in twigs than in leaves. The relationship between element concentration in plants and altitudinal gradient is nonlinear. Altitudes of 3,200 and 3,400 m are turning points for fir and rhododendron growth, respectively. Concentrations of all trace elements in the two plants along the altitudinal gradient are well below the toxic level in plants. No known industrial sources of the elements investigated exist in the Mount Gongga area, China. Element concentrations in the present study are higher than those found in mosses collected from the same area, indicating that the area is not contaminated. The element concentrations that we observed in plant samples were due to soil uptake. The pronounced differences between the two species are due to the different uptake characteristics of fir and rhododendron. Environ. Toxicol. Chem. 2011;30:2608–2619. © 2011 SETAC
Tập 30 Số 11 - Trang 2608-2619 - 2011
Field‐scale examination of neonicotinoid insecticide persistence in soil as a result of seed treatment use in commercial maize (corn) fields in southwestern Ontario Abstract Neonicotinoid insecticides, especially as seed treatments, have raised concerns about environmental loading and impacts on pollinators, biodiversity, and ecosystems. The authors measured concentrations of neonicotinoid residues in the top 5 cm of soil before planting of maize (corn) in 18 commercial fields with a history of neonicotinoid seed treatment use in southwestern Ontario in 2013 and 2014 using liquid chromatography–tandem mass spectrometry with electrospray ionization. A simple calculator based on first‐order kinetics, incorporating crop rotation, planting date, and seed treatment history from the subject fields, was used to estimate dissipation rate from the seed zone. The estimated half‐life (the time taken for 50% of the insecticide to have dissipated by all mechanisms) based on 8 yr of crop history was 0.64 (range, 0.25–1.59) yr and 0.57 (range, 0.24–2.12) yr for 2013 and 2014, respectively. In fields where neonicotinoid residues were measured in both years, the estimated mean half‐life between 2013 and 2014 was 0.4 (range, 0.27–0.6) yr. If clothianidin and thiamethoxam were used annually as a seed treatment in a typical crop rotation of maize, soybean, and winter wheat over several years, residues would plateau rather than continue to accumulate. Residues of neonicotinoid insecticides after 3 yr to 4 yr of repeated annual use tend to plateau to a mean concentration of less than 6 ng/g in agricultural soils in southwestern Ontario. Environ Toxicol Chem 2016;35:295–302. © 2015 SETAC
Tập 35 Số 2 - Trang 295-302 - 2016
Characteristics of imidacloprid toxicity in two <i>Apis mellifera</i> subspecies Abstract Imidacloprid (1‐(6‐chloro‐3‐pyridylmethyl)‐N‐nitroimidazolidin‐2‐ylideneamine) belongs to a new chemical family of chloronicotinyl compounds whose mode of action on the insect nervous system differs from that of traditional neurotoxic products. Imidacloprid, a strong systemic compound, is effective against several sucking and mining pests. The acute toxicity of contact and oral applications on two Apis mellifera subspecies, Apis mellifera mellifera and Apis mellifera caucasica , was investigated. In all toxicological studies, each dose included three cages of 20 individuals and each study was replicated three times. The dose‐mortality relation revealed some unusual characteristics. At low imidacloprid concentrations, a biphasic mortality appeared, particularly with the contact exposure route. At moderate doses, mortality profiles at 24 and 48 h were different only after oral application. Response kinetics showed that mortality was delayed at the higher doses of imidacloprid. After oral intoxication, the LD50 values of imidacloprid at 24 and 48 h were about 5 ng/bee for both A. m. mellifera and A. m. caucasica. After contact application, the LD50 values at 24 and 48 h were approximately 24 ng/bee for A. m. mellifera and 14 ng/bee for A. m. caucasica. Imidacloprid ranks among the more potent contact insecticides in this important pollinator species.
Tập 19 Số 7 - Trang 1901-1905 - 2000
The stingless bee species, <i>Scaptotrigona</i> aff. <i>depilis</i>, as a potential indicator of environmental pesticide contamination Abstract Neonicotinoids have the potential to enter the diet of pollinators that collect resources from contaminated plants. The species Scaptotrigona aff. depilis (Moure, 1942) can be a useful indicator of the prevalence of these chemicals in the environment. Using high‐performance liquid chromatography–mass spectrometry, the authors devised a protocol for neonicotinoid residue extraction and detected the presence of neonicotinoids in the bee bodies. Thus, the authors consider this species to be a potential indicator of environmental contamination. Environ Toxicol Chem 2015;34:1851–1853. © 2015 SETAC
Tập 34 Số 8 - Trang 1851-1853 - 2015
The Effect of Microplastic Ingestion on Survival of the Grass Shrimp <i>Palaemonetes pugio</i> (Holthuis, 1949) Challenged with <i>Vibrio campbellii</i> Abstract Recent research indicates that microplastic (<5 mm) ingestion may impact the immune function of marine and aquatic organisms at the tissue and cellular levels; however, their susceptibility to disease following exposure has not been directly investigated. The objective of the present study was to directly evaluate the impact of microplastic ingestion on the susceptibility of the grass shrimp Palaemonetes pugio to bacterial infection with Vibrio campbellii. Grass shrimp were exposed to one of several particle treatments (natural sediment, polyethylene spheres, polypropylene fragments, tire fragments, and polyester fibers) or particle‐free water for 96 h at a nominal concentration of 50 000 particles/L prior to a bacterial challenge with V. campbellii . No significant mortality was observed among any of the particle types during the 96‐h particle exposure. The survival of grass shrimp following V. campbellii challenge did not vary significantly among shrimp exposed to particle‐free water, sediment, polyethylene spheres, polypropylene fragments, tire fragments, and polyester fibers. Grass shrimp cleared the majority of ingested particles and all the ventilated particles within 48 h. The present study shows that microplastic ingestion did not alter the susceptibility of grass shrimp to bacterial infection, and also provides depuration rates for a variety of microplastic shapes and polymer types that were previously lacking. This information increases our understanding of the size‐ and shape‐dependent effects of microplastic ingestion. Environ Toxicol Chem 2019;38:2233–2242. © 2019 SETAC.
Tập 38 Số 10 - Trang 2233-2242 - 2019
Bioaccumulation and trophic transfer of some brominated flame retardants in a Lake Winnipeg (Canada) food web Abstract The extent of bioaccumulation and trophic transfer of brominated diphenyl ether (BDE) congeners, hexabromocyclododecane (HBCD) diastereoisomers (α, β, and γ), decabromodiphenylethane (DBDPE), and bis(2,4,6‐tribromophenoxy)ethane (BTBPE) was examined in a Lake Winnipeg (Canada) food web. Six species of fish, zooplankton, mussels, sediment, and water from the south basin of the lake were selected for study. Significant positive correlations were found between concentrations of total (Σ) polybrominated diphenylethers (PBDEs; p < 0.005), ΣHBCDs (p < 0.0001), BTBPE (p < 0.0001), and lipid content in fish. Strong positive linear relationships also were observed from individual plots of BDE 47, BDE 209, and DBDPE concentrations (lipid wt) and trophic level (based on δ15 N), suggesting that these compounds biomagnify in the Lake Winnipeg food web. Biomagnification factors varied for the chemicals studied. Plots of log bioaccumulation factors for mussel and zooplankton versus log octanol–water partition coefficient (K ow ) were similar and suggest that neither mussels nor zooplankton are in equilibrium with the water. Fifteen BDE congeners were consistently detected in water (dissolved phase, n = 3), with BDE 47 having the greatest concentration (17 pg/L). The rank order of compounds in water (arithmetic mean ± standard error) were ΣPBDEs (49 ± 12 pg/L) > α‐HBCD (11 ± 2 pg/L) > BTBPE (1.9 ± 0.6 pg/L). Concentrations of DPDPE, BDE 209, and β‐ and γ‐HBCD isomers were below their respective method detection limits (MDLs) in water. Total PBDE concentrations in sediment (n = 4) were greater than any other brominated flame retardant examined in the present study and ranged from 1,160 to 1,610 ng/g (dry wt), with BDE 209 contributing roughly 50% of the total. The γ‐HBCD isomer was detected at concentrations of 50 ± 20 pg/g (dry wt) in sediment, whereas BTBPE and DBDPE were consistently below their respective MDLs in sediment.
Tập 25 Số 8 - Trang 2177-2186 - 2006
Analysis of glutathione endpoints for measuring copper stress in <i>Chlamydomonas reinhardth</i> Abstract Glutathione (GSH) is the most abundant nonprotein thiol in eukaryotic cells and it protects cells by functioning as an antioxidant and a metal‐binding ligand. Because glutathione readily undergoes oxidation‐reduction reactions to combat oxidative stress, intracellular ratios of the reduced (GSH) to the oxidized (GSSG) forms of glutathione may serve as an important biomarker of exposure and effect of trace metals in eukaryotic cells. We compared sensitivity of glutathione ratios in the freshwater alga Chlamydomonas reinhardtii to the traditional endpoints of cell growth rates and chlorophyll a following exposure to Cu for periods of 6 and 24 h. A response of the GSH:GSSG ratio to Cu concentration was observed at Cu levels of 40 and 80 nM after exposure for both 6 and 24 h. The concentration of total GSH at 24 h was roughly half the value at 6 h after exposure to either 40 or 80 nM Cu. A response for cell growth rate was observed only at 24 h, whereby the average specific growth rate decreased from about 1.1 to 0.4 d−1 . The total Cu concentrations eliciting a cell response of 50%, effect concentrations (EC50s), after 24 h of exposure were similar (49.2, 49.8, and 38.2 nM Cu) and not significantly different for GSH:GSSG ratio, GSH levels, and specific growth, respectively. Total cell‐associated Cu concentrations after exposure for 24 h were calculated from the EC50 endpoints and ranged from 13.3 to 17.0 fg/cell. Overall, thiol ratios were indicative of toxicity resulting from exposure to Cu, but precision may be greater for the cell growth rate endpoints.
Tập 26 Số 8 - Trang 1563-1571 - 2007
Effect assessment of the herbicide paraquat on a green alga using differential gene expression and biochemical biomarkers Abstract Effects of the herbicide paraquat were assessed on the green freshwater alga Chlamydomonas reinhardtii using different endpoints of toxicity. Cell concentration and growth rate were monitored, whereas flow cytometry was applied to determine changes in chlorophyll content, viability and presence of reactive oxygen species. Furthermore, a transcriptomics approach using microarray hybridizations was applied to elucidate the mechanisms of toxicity. The results reveal that paraquat concentrations above 0.25 µM induce toxic effects in C. reinhardtii , reflected in a significantly reduced growth rate and cell concentration with a corresponding median effective concentration (EC50) value of 0.26 µM. With increasing paraquat concentrations, an increase in cell volume was registered with a particle counter as well as in the forward scattering signal of flow cytometric measurements, which is a measure of cell size. Flow cytometry, moreover, showed an increase in reactive oxygen species with increasing exposure concentration, corroborating the general knowledge that this herbicide exerts its toxicity through the generation of oxidative stress. At the same time, several genes involved in oxidative stress defense mechanisms, such as L‐ascorbate peroxidase, glutaredoxin, and a possible glutathione‐S ‐transferase were differentially expressed, demonstrating the value of microarrays for elucidating possible mechanisms of toxicity. The fact that several genes were differentially expressed at paraquat concentrations that caused no adverse effects on higher levels of biological organization indicates that a transcriptomics approach allows for the detection of early effects, even before they become manifest at higher levels. Environ. Toxicol. Chem. 2010;29:893–901. © 2009 SETAC
Tập 29 Số 4 - Trang 893-901 - 2010
Effect of tributyltin on testicular development in <i>Sebastiscus marmoratus</i> and the mechanism involved Abstract Organotin compounds, such as tributyltin (TBT), that have been used as antifouling biocides can induce masculinization in female mollusks. However, few studies addressing the effects of TBT on fishes have been reported. The present study was conducted to investigate the effects of TBT at environmentally relevant concentrations (1,10, and 100 ng/L) on testicular development in Sebastiscus marmoratus and to gain insight into its mechanism of action. After exposure for 48 d, the gonadosomatic index had decreased in a dose‐dependent manner. Although the testosterone levels in the testes were elevated and the 17β‐estradiol levels were decreased, spermatogenesis was suppressed. Moreover, γ‐glutamyl transpeptidase activity (which is used as a Sertoli cell marker) was decreased in a dose‐dependent manner after TBT exposure, and serious interstitial fibrosis was observed in the interlobular septa of the testes in the 100 ng/L TBT test group. Increases in the retinoid × receptors and peroxisome proliferator activated receptor γ expression and the progressive enlargement of lipid droplets in the testes were observed after TBT exposure. Estrogen receptor α levels in the testes of the fish exposed to TBT decreased in a dose‐dependent manner. The reduction of estrogen receptor α mRNA resulted from the decrease of 17β‐estradiol levels, and the progressive enlargement of lipid droplets may have contributed to the dysfunction of the Sertoli cells, which then disrupted spermatogenesis.
Tập 28 Số 7 - Trang 1528-1535 - 2009
17α‐Ethinylestradiol alters reproductive behaviors, circulating hormones, and sexual morphology in male fathead minnows (<i>Pimephales promelas)</i> Abstract Ecologically relevant indicators of endocrine disruption in fish must be linked with measures of reproductive success. The ability of male fathead minnows (Pimephales promelas ) to compete for, maintain, and defend a spawning substrateis paramount to reproductive success. The present study quantified alterations in male fathead minnow reproductive behaviors after exposure to environmentally relevant concentrations (0, 10, 20, or 40 ng/L) of 17α‐ethinylestradiol (EE2 ) for 21 d. A video‐based behavioral quantification system examined changes in male‐male competitive behaviors (chasing and head‐butting) and ability of males to maintain spawning substrates (nibbling and scrubbing). Behaviors analyzed included time under the spawning substrate, frequency of substrate cleaning, and conspecific aggression. Plasma hormone levels (11‐ketotestosterone [11‐KT], testosterone, and estradiol [E2 ]), vitellogenin (VTG), secondary male characteristics (tubercle count and dorsal nape pad rank), gonadosomatic index (GSI), and gonad histology also were evaluated. Exposure to 40 ng/L of EE2 decreased the ability of exposed males to compete with control males for spawning substrates (p = 0.09). Furthermore, exposed males displayed reduced frequency of substrate cleaning activities as well as chasing male competitors (p ≤ 0.05). 11‐Ketotestosterone, testosterone, and E2 were lower, and VTG was notably higher, in EE2 ‐exposed males compared with control males (p ≤ 0.03). 17α‐Ethinylestradiol exposure in males also was associated with reductions in tubercles; lower GSI, gonadal maturity ranks, and number of resorbed tubercles; and presence of an ovipositor (p ≤ 0.001). These data reveal alterations in male reproductive behavior that coincide with decreased hormone levels and secondary sex characteristics. Behavioral endpoints to discern potential ecological consequences in fish exposed to low concentrations of endocrine‐disrupting chemicals may provide sensitive and functional indices of effect.
Tập 28 Số 5 - Trang 953-961 - 2009