Ameliorative effects of corn silk extract on acetaminophen-induced renal toxicity in rats

Environmental Science and Pollution Research - The current study aimed to investigate the protective effect of corn silk methanolic extract (CSME) against acetaminophen (APAP)-induced...     

Ameliorative effect of zinc oxide nanoparticles against potassium bromate-mediated toxicity in Swiss albino rats

Environmental Science and Pollution Research - Potassium bromate (PB) is a commonly used food additive, a prominent water disinfection by-product, and a class IIB carcinogen. It exerts a various...     

Histopathological effects of carbaryl on testes of snake-eyed lizard, Ophisops elegans

Background, aim and scope  

Due to their ecological niche and insectivore nature, lizards are of increased risk of exposure to pesticides in agricultural areas. In addition to their potential direct effects on non-target species, insecticides can also result in indirect impacts on lizard population by reducing their food source. Carbaryl is a common insecticide that is widely used in areas of Turkey that are home to a variety of reptiles. However, to date, little is known about the potential effects of the exposure of reptiles such as lizards or snakes to this pesticide. The aim of the study was to investigate toxic effects of carbaryl on the testes of snake-eyed lizard, Ophisops elegans that is common to regions in Turkey where Carbaryl is applied and that it can be easily cultured in the laboratory.     

Fate and effects of heavy metals in salt marsh sediments

The fate and effects of selected heavy metals were examined in sediment from a restored salt marsh. Sediment cores densely covered with Spartina patens were collected and kept either un-amended or artificially amended with nickel (Ni) under standardized greenhouse conditions. Ni-amendment had no significant effect on the fate of other metals in sediments, however, it increased root uptake of the metals. Metal translocation into the shoots was small for all metals. Higher Ni concentrations in plants from amended cores were accompanied by seasonal reductions in plant biomass, photosynthetic capacity and transfer efficiency of open photosystem II reaction centers; these effects, however, were no longer significant at the end of the growing season. Root colonization by arbuscular mycorrhizal fungi (AMF) resembled that of natural salt marshes with up to 20% root length colonized. Although Ni-amendment increased AMF colonization, especially during vegetative growth, in general AMF were largely unaffected.     

Comparative toxicity of acrylic acid to marine and freshwater microalgae and the significance for environmental effects assessments.

In this study, we compared the sensitivity of freshwater and marine organisms to two structurally similar substances, acrylic acid and methacrylic acid. Reported acute toxicity data (L(E)C50-values) for freshwater organisms range from 0.1 to 222 mg/l and 85 to >130 mg/l for acrylic acid and methacrylic acid, respectively. The large variation in toxicity data for acrylic acid is due to a specific toxicity to certain species of freshwater microalgae, with algae EC50-values being two to three orders of magnitude lower than L(E)C50-values reported for fish and invertebrates. To evaluate the sensitivity of marine organisms, ecotoxicity data was generated for ten species of microalgae, one invertebrate species and one fish species. For methacrylic acid, we found a marine acute toxicity that ranged from 110 to >1260 mg/l, which is comparable to reported data on freshwater organisms. In strong contrast, the resulting L(E)C50-values for acrylic acid ranged from 50 to >1000 mg/l, and there was no specific sensitivity of marine algae when compared to marine invertebrates and fish. For acrylic acid, therefore, use of the available freshwater toxicity data for an effects assessment for the marine environment is likely to overestimate the hazard and risk from this substance. Overall, the results of the study suggest that ecotoxicity data generated on freshwater species may not always be appropriate for the effects assessments of organic chemicals in the marine environment, thus emphasising the importance of using ecologically relevant data to assess environmental risk.     

Selenium for the mitigation of toxicity induced by lead in chicken testes through regulating mRNA expressions of HSPs and selenoproteins

Lead (Pb) is a toxic element and environmental pollutant. Pb toxicity and antagonistic effect of selenium (Se) on Pb have been deeply studied in mammals. The testis is one of the target organs of Pb in birds. The aim of this study was to investigate the mitigating effect of Se on Pb toxicity in chicken testes by determining messenger RNA (mRNA) expressions of 5 heat shock proteins (HSPs) and 25 selenoproteins. Sixty male chickens (7-day-old) were randomly divided into the control group, the Se group, the Pb group, and the Pb + Se group, and were fed for 90 days. The feeding methods of chickens were as follows: The control group was fed drinking water and commercial diet (0.49 mg/kg Se). Lead acetate was added into the drinking water (350 mg/L Pb). Sodium selenite was added into the commercial diet (1 mg/kg Se). Multivariate correlation analysis and principal component analysis (PCA) were used to define the relationships among all the measured factors and the most important parameters that could be used as key factors, respectively. The results indicated that Se decreased the increase of mRNA expressions of all the HSPs and increased the decrease of mRNA expressions of all the selenoproteins induced by Pb in the chicken testes. HSP70 may be a biomarker of Pb poisoning in the chicken testes. Se alleviated Pb-induced toxicity in the chicken testes through regulating mRNA expressions of HSPs and selenoproteins.

     

Studies on thallium toxicity, its tissue distribution and histopathological effects in rats

The distribution of thallium (Tl) in the body and its toxic effect on the histology and function of the liver and kidney of rats after Tl administration were investigated using biochemical and histopathological assays. Male albino rats exhibited a markedly dose-dependent increase in the serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) at 16 h after an intraperitoneal injection of 30, 60 or 120 mg/kg Tl. The serum level of creatinine in the rats injected with 30 mg/kg Tl, elevated significantly after 4 days of administration. The distribution of Tl in the tissues of intoxicated rats was uneven. The content of Tl was found to be highest in the kidney, followed by ileum, stomach and liver. Histological examination demonstrated frequent occurrence of hepatocyte necrosis and vacuolation in the liver and pathological changes of renal tubules in the treated rats.     

Fate and effects of nutrients and heavy metals in experimental salt marsh ecosystems

Fate and effects of the macro nutrients nitrogen and phosphorus, and the heavy metals zinc, copper and cadmium, brought into experimental salt marsh ecosystems via sediment supply, were studied over a three-year period. The supply of sediment from the Marsdiep (at a low and high rate) and from the harbour of Delfzijl (at a high rate) led to an increase of the macro nutrients and heavy metals in the top soil. The growth of the salt marsh plants Aster tripolium, Puccinellia maritima and Spartina anglica and the uptake of the macro nutrients and heavy metals by the plants was only slightly affected by the addition of sediment. A high load of sediment led to an increase in growth or in the concentrations of the macro nutrients or heavy metals in the plants at a number of sampling dates, but only minor differences between treatments were found. From a mass balance constructed over a three-year study period it could be concluded that about 50% of the macro nutrients and heavy metals were retained in the salt marsh sediment. This was equal to the retained amount of organic matter, indicating that retention of the elements was closely related to retention of organic matter. The 50% loss of the macro nutrients and heavy metals probably occurred via ebb tides after resuspension of sediment and organic matter.     

Influence of Suwannee River humic acid on particle properties and toxicity of silver nanoparticles

Adsorption of natural organic matter (NOM) on nanoparticles can have dramatic impacts on particle dispersion resulting in altered fate and transport as well as bioavailability and toxicity. In this study, the adsorption of Suwannee River humic acid (SRHA) on silver nanoparticles (nano-Ag) was determined and showed a Langmuir adsorption at pH 7 with an adsorption maximum of 28.6 mg g⁻¹ nano-Ag. It was also revealed that addition of <10 mg L⁻¹ total organic carbon (TOC) increased the total Ag content suspended in the aquatic system, likely due to increased dispersion. Total silver content decreased with concentrations of NOM greater than 10 mg TOC L⁻¹ indicating an increase in nanoparticle agglomeration and settling above this concentration. However, SRHA did not have any significant effect on the equilibrium concentration of ionic Ag dissolved in solution. Exposure of Daphnia to nano-Ag particles (50 μg L⁻¹ and pH 7) produced a linear decrease in toxicity with increasing NOM. These results clearly indicate the importance of water chemistry on the fate and toxicity of nanoparticulates.     

Protective effects of thymoquinone and diallyl sulphide against malathion-induced toxicity in rats

Environmental Science and Pollution Research - Malathion is a potent organophosphate insecticide that inhibits acetylcholinesterase (AChE) enzyme. Our experimental objective was to investigate the...     

镁盐改性活性炭对普拉红B的吸附性能研究

运用化学沉淀-原位复合法制得氢氧化镁/活性炭复合材料(Mg(OH)2/AC),对其比表面积和XRD谱进行了表征,考察了该复合材料对普拉红B的脱色性能.结果表明,在293～313 K下,Langmuir模型和Freundlich模型都能很好地描述Mg(OH)2/AC对普拉红B的等温吸附过程,而Langmuir模型更为合适...     

Mechanistic insights to lactic and formic acid toxicity on benthic oligochaete worm Tubifex tubifex

Environmental Science and Pollution Research - Lactic and formic acid are two commonly found monocarboxylic organic acids. Lactic acid is discharged into the water bodies as acidic industrial...     

Field and laboratory investigations on the effects of road salt (NaCl) on stream macroinvertebrate communities

Field and laboratory experiments were conducted to examine the effects of road salt (NaCI) on stream macroinvertebrates. Field studies investigated leaf litter processing rates and functional feeding group composition at locations upstream and downstream from point source salt inputs in two Michigan, USA streams. Laboratory studies determined the effects of increasing NaCl concentrations on aquatic invertebrate drift, behavior, and survival. Field studies revealed that leaves were processed faster at upstream reference sites than at locations downstream from road salt point source inputs. However, it was sediment loading that resulted in partial or complete burial of leaf packs, that affected invertebrate activity and confounded normal leaf pack colonization. There were no significant differences that could be attributed to road salt between upstream and downstream locations in the diversity and composition of invertebrate functional feeding groups. Laboratory drift and acute exposure studies demonstrated that drift of Gammarus (Amphipoda) may be affected by NaCl at concentrations greater than 5000 mg/l for a 24-h period. This amphipod and two species of limnephilid caddisflies exhibited a dose response to salt treatments with 96-h LC50 values of 7700 and 3526 mg NaCl/l, respectively. Most other invertebrate species and individuals were unaffected by NaCl concentrations up to 10,000 mg/l for 24 and 96 h, respectively.     

Potential protective effects of Spirulina platensis on liver,kidney, and brain acrylamide toxicity in rats

Environmental Science and Pollution Research - Acrylamide (AA) is a hazardous chemical that is widely used in industrial practices. Spirulina platensis (SP) is a blue green alga that is rich in...     

酸碱盐改性对活性炭吸附油气特征的影响

采用酸碱盐溶液浸渍方法对活性炭进行改性,探究了其吸附油气的特征,考察了改性后的活性炭对油气吸附量和穿透时间的影响,采用BET、SEM、XRD及FT-IR等方法对活性炭进行了表征。结果表明：改性后的活性炭孔结构和表面化学性质发生了明显的变化,2^#样品(醋酸改性)比表面积最大为1 264.33 m²·g⁻¹,碱改性活性炭对油气的吸附性能优于其他改性方法,3^#样品(氨水改性)吸附容量最高为0.279 g·g⁻¹,拟合动力学速率常数k′值是0.096 3,5^#样品(氢氧化钾改性)穿透时间最长为130 min;改性处理后,增加了活性炭表面的—OH与C=C含量,正丁烷主要以—CH₂基团吸附在吸附剂表面。在综合酸碱盐溶液改性的基础上,利用Yoon-Nelson动力学方程对吸附曲线进行拟合,评价改性活性炭对油气的吸附性能。以上研究结果可为活性炭吸附油气的工业应用提供参考。     

Solubility of organic acids in various methanol and salt concentrations: the implication on organic acid sorption in a cosolvent system

The well-known cosolvency-induced sorption model is not applicable to predict the sorption of carboxylic acids in cosolvent system. To investigate the phenomenon, sorption and solubility of chlorinated phenols (2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP)) and carboxylic acids (benzoic acid and 2,4-dichlorophenoxyacetic acid (2,4-D)) were measured in soil-methanol mixture with various ionic strengths. The sorption (K_m) of chlorinated phenols was explained by a cosolvency-induced sorption model; the inverse log-linear relationship between the K_m and methanol volume fraction (f_c). However, the K_m of carboxylic acids increased with increasing f_c. This discrepancy was attributed to the effect of the carboxylic moiety. To explain the effect, solubility was measured for benzoic acid and 2,4,6-TCP from various liquid conditions. For both solutes, the cosolvency power (σ) increased with CaCl₂ concentrations and the salting constant (K^s) became smaller as f_c increased. However, the σ value at a given salt concentration and the K^s value at a given f_c were greater for 2,4,6-TCP than for benzoic acid, both of which were due to the greater hydrophobicity of the former. Overall, the solubility profiles of the both solutes on combination of f_c and CaCl₂ concentration evidenced no specific role of the carboxylic moiety. Therefore, it can be reasonably concluded that the positive relationship between K_m and f_c for carboxylic organic acid can be attributed to the modification of the activity coefficient occurred in the solid phase, which cannot be traceable by cosolvency-based model.     

异喹啉季铵盐在盐酸中对A3钢的吸附及其缓蚀作用

采用失重、电化学法研究了异喹啉季铵盐在 1mol/L盐酸溶液中对A3钢的缓蚀行为及吸附规律。实验表明 ,异喹啉季铵盐是一种阴、阳极混合型缓蚀剂 ,其缓蚀性能优良 ,在A3钢表面产生化学吸附 ,吸附过程为放热反应。     

Tidal salt marsh sediment in California, USA: part 3. Current and historic toxicity potential of contaminants and their bioaccumulation

To assess potential health risks to benthic organisms from exposure to toxic contaminants, sediment chemistry data from five salt marshes along the coast of California were compared with threshold effects levels (TELs) and probable effects levels (PELs). As an integrated estimate of toxicity potential of multiple contaminants, mean PEL quotients (mPELQs) were used to categorize sampling stations into three groups: high (>0.5), medium (0.1–0.5) and low (<0.1). In all sediments from Stege Marsh located in San Francisco Bay, at least one contaminant exceeded PELs by up to 18-fold and mPELQs were higher than 0.7. Mean PELQs in two core sediments from eastern Stege Marsh ranged from 0.7 to 2.1, indicating that benthic organisms in Stege Marsh may have been adversely affected for several decades. To investigate bioavailability and bioaccumulation of contaminants in sediments, longjaw mudsuckers (Gillichthys mirabilis) were transplanted to six Stege Marsh stations for 60 days. Body burdens of organic contaminants clearly showed that they were readily available for benthic organisms. Measured concentrations of organic contaminants in mudsuckers were similar to estimated levels computed using a theoretical bioaccumulation potential model. Levels of PCBs and arsenic in mudsuckers were higher than screening values set as guidelines for the protection of humans and levels of PCBs and DDTs were higher than criteria for wildlife. The results of this study indicate that the levels of contaminants in Stege Marsh sediments may not fully support the well-being of benthic organisms and also may provoke adverse effects on fish-eating animals and humans through trophic transfer.     

Increasing UV-B radiation at the earth's surface and potential effects on aqueous mercury cycling and toxicity

In the past two decades, a great deal of attention has been paid to the environmental fate of mercury (Hg), and this is exemplified by the growing number of international conferences devoted uniquely to Hg cycling and its impacts on ecosystem functions and life. This interest in the biogeochemistry of Hg has resulted in a significant improvement of our understanding of its impact on the environment and human health. However, both past and current research, have been primarily oriented toward the study of direct impact of anthropogenic activities on Hg cycling. Besides a few indirect effects such as the increase in Hg methylation observed in acid-rain impacted aquatic systems or the reported enhanced Hg bioaccumulation in newly flooded water reservoirs; changes in Hg transformations/fluxes that may be related to global change have received little attention. A case in point is the depletion of stratospheric ozone and the resulting increase in solar UV-radiation reaching the Earth. This review and critical discussion suggest that increasing UV-B radiation at earth's surface could have a significant and complex impact on Hg cycling including effects on Hg volatilization (photo-reduction), solubilization (photo-oxidation), methyl-Hg demethylation, and Hg methylation. Therefore, this paper is written to provoke discussions, and more importantly, to stimulate research on potential impacts of incoming solar UV-radiation on global Hg fluxes and any toxicity aspects of Hg that may become exacerbated by UV-radiation.     

The effects of ethylene chlorohydrin on fatty acid synthesis

Male chicks weighing 700 to 900 g. received an acute or eight doses IG of 60 or 40 mg/kg ethylene chlorohydrin (ECH) respectively and were sacrificed eighteen hours after the last dose. Mitochondrial elongation of fatty acids was decreased significantly while fatty acid synthetase activity was not significantly affected by ECH treatment. Cytochrome c oxidase activity in fresh whole liver homogenate was significantly higher in chicks subjected to acute exposure with ECH when compared to the controls. Upon freezing and thawing of homogenates, cytochrome c oxidase activity increased significantly in the control group but was unchanged in the ECH group which suggests that the mitochondrial membrane integrity is compromised by the ECH treatment. Serum and liver triglyceride levels were significantly elevated in both the single and multiple ECH dose groups. Liver to body weight ratios were significantly higher in both treatment groups when compared to their controls. Histological examination of the liver of ECH-treated chicks showed cytoplasmic clearing of the cells but no vacuolization or centrilobular necrosis. Serum isocitrate dehydrogenase levels were significantly higher in the multiple treatment ECH group than in the control group.