Metals and emerging contaminants in groundwater and human health risk assessment

Environmental Science and Pollution Research - Groundwaters are normally consumed without previous treatment and therefore the monitoring of contaminants in order to guarantee its safety is...     

The ChimERA project: coupling mechanistic exposure and effect models into an integrated platform for ecological risk assessment

Current techniques for the ecological risk assessment of chemical substances are often criticised for their lack of environmental realism, ecological relevance and methodological accuracy. ChimERA is a 3-year project (2013–2016), funded by Cefic’s Long Range Initiative (LRI) that aims to address some of these concerns by developing and testing mechanistic fate and effect models, and coupling of these models into one integrated platform for risk assessment. This paper discusses the backdrop against which this project was initiated and lists its objectives and planned methodology.     

Effects of climate change on surface-water photochemistry: a review

Information concerning the link between surface-water photochemistry and climate is presently very scarce as only a few studies have been dedicated to the subject. On the basis of the limited knowledge that is currently available, the present inferences can be made as follows: (1) Warming can cause enhanced leaching of ionic solutes from the catchments to surface waters, including cations and more biologically labile anions such as sulphate. Preferential sulphate biodegradation followed by removal as organic sulphides in sediment could increase alkalinity, favouring the generation of the carbonate radical, CO₃ ^·?. However, this phenomenon would be easily offset by fluctuations of the dissolved organic carbon (DOC), which is strongly anticorrelated with CO₃ ^·?. Therefore, obtaining insight into DOC evolution is a key issue in understanding the link between photochemistry and climate. (2) Climate change could exacerbate water scarcity in the dry season in some regions. Fluctuations in the water column could deeply alter photochemistry that is usually favoured in shallower waters. However, the way water is lost would strongly affect the prevailing photoinduced processes. Water outflow without important changes in solute concentration would mostly favour reactions induced by the hydroxyl and carbonate radicals (·OH and CO₃ ^·?). In contrast, evaporative concentration would enhance reactions mediated by singlet oxygen (¹O₂) and by the triplet states of chromophoric dissolved organic matter (³CDOM*). (3) In a warmer climate, the summer stratification period of lakes would last longer, thereby enhancing photochemical reactions in the epilimnion but at the same time keeping the hypolimnion water in the dark for longer periods.     

氧化石墨烯/Fe_3O_4磁性纳米材料固定辣根过氧化物酶及其降解酚类物质

以原位沉淀法制备的氧化石墨烯/Fe3O4磁性纳米复合颗粒为固定化载体,1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐为交联剂,成功固载了辣根过氧化物酶。探讨了固定化条件对辣根过氧化酶活性的影响以及固定化酶的理化性质,实验结果表明,固定化最佳pH为6、温度为30℃、时间为11 h、交联剂浓度为1 mg/L。与游离酶相比,固定化酶具有良好的pH稳定性和热稳定性。最后将固定化酶用于降解水中的苯酚和2,4-二氯酚,并考察了固定化酶的重复利用性。     

Sustainable farming practices of the Chinese mitten crab (<Emphasis Type="Italic">Eriocheir sinensis)</Emphasis> around Hongze Lake,lower Yangtze River Basin,China

Results of a survey of 156 Chinese mitten crab (Eriocheir sinensis) grow-out farms around Hongze Lake (118.48–118.72°E; 33.36–33.38°N) are reported. Area farmed has remained relatively unchanged but production (59 932 t in 2012) increased steadily over the last 7 years, indicative of the viability and sustainability of the farming system that has gradually replaced intensive Chinese major carp polyculture around Hongze Lake. Results showed that production range was 135–2400 kg ha⁻¹ cycle⁻¹ (mean 1144 ± 34). Crab yields correlated linearly to stocking density and conformed to a normal distribution curve, with 66.7 % of farms yielding 900 kg ha⁻¹ cycle⁻¹ or more. Yield was negatively correlated to pond size and capture size (p < 0.01), and farms with macrophyte coverage rate lower than 30 % of water surface were significantly (p < 0.05) lower than those exceeding 30 %.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0722-0) contains supplementary material, which is available to authorized users.     

Characterization and application of the enzyme peroxidase to the degradation of the mycotoxin DON

Deoxynivalenol (DON), one of the main mycotoxins found in food matrices, has high level of toxicity. This study aimed to characterize the peroxidase enzyme extracted from rice bran to be applied to the biodegradation of DON in order to evaluate the potential peroxidase (PO) from rice bran (RB) has to degrade DON in optimal conditions. Purification and recovery factors of PO extracted from RB and purified by three-phase partitioning were 5.7% and 50%, respectively. PO had the highest level of activity in the phosphate buffer 5 mM pH 5.5 in both crude and purified forms, whose reaction temperatures were 25°C and 10°C. At the end of production, purification and characterization steps, specific activities of the bran were 115.79 U mg^?1 and 4363 U g^?1. Reduction in the mycotoxin DON in optimal conditions determined for PO from RB was 20.3%, a promising result when the aim is to adequate mycotoxicological levels to foods.     

How certain can we really be that our boss is trustworthy,and does it matter? A metacognitive perspective on employee evaluations of supervisor trustworthiness

This research helps to integrate the metacognitive concept of evaluation certainty into the trust literature by demonstrating that certainty can amplify the effects of trustworthiness evaluations and stabilize trustworthiness evaluations over time. Across an experimental study (Study 1) and a multiwave survey of employees (Study 2), we show that trustworthiness evaluations exert a stronger influence on individuals' trust at higher levels of certainty and that trust transmits the multiplicative effects of trustworthiness evaluations and certainty on key indicators of employee risk-taking including reliance and disclosure behavior. Further, in Study 2, we show that certainty can help predict change in trustworthiness evaluations over time. Finally, in a two-wave field survey (Study 3), we examine factors that influence evaluation certainty and show that relational transparency and leader prototypicality (LP) have interactive effects on employees' certainty such that the influence of relational transparency on certainty will be more positive at higher levels of LP. Theoretical and practical implications are discussed.     

Toxicity assessment of 2,4-D and MCPA herbicides in primary culture of fish hepatic cells

In this study, we used primary cultures of fish hepatic cells as a tool for evaluating the effects of environmental contamination. Primary hepatic cell cultures derived from the subtropical fish Metynnis roosevelti were exposed to different concentrations (0.275, 2.75 and 27.5 μg L^?1) of the herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA). Cellular respiratory activity was evaluated by polarography using three substrates: 0.5 M glucose, 0.5 M succinate and 0.5 M α-ketoglutarate. Significant changes were observed in cellular oxygen consumption with 0.5 M α-ketoglutarate. Even at low concentrations, 2,4-D and MCPA were potent uncouplers of oxidative phosphorylation. Primary cultures of M. roosevelti liver cells may provide a useful tool for the evaluation of environmental contaminant effects. A review of regulations regarding permitted concentrations of these herbicides is needed.     

Effect of coumaphos on cholinesterase activity,hematology, and biochemical blood parameters of bovines in tropical regions of Mexico

To assess the effect of coumaphos [O-(3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl) O,O-diethyl phosphorothioate] exposure on physiological responses during bovine production, acetylcolinesterase (AChE) and butyrylcholinesterase (BuChE) activities were measured in whole blood, erythrocytes, and plasma of healthy male steers (Bos Taurus x Bos indicus) sprayed with coumaphos at a non-lethal dose of 1 mg kg^{? 1} body weight per day once every 14 (in vivo group) or 21 days (southern and central groups). Coumaphos topically administered at 1 mg/kg body weight per day to cattle under normal management practices in tropical areas produced a significant inhibition in erythrocyte (RBC) AChE and BuAChE activities when compared to baseline levels. RBC-AChE activity for the in vivo group decreased 71.3% (P < 0.05) and BuChE activity 59.1% (P < 0.05); RBC-AChE activity decreased 55.1% (P < 0.05) (southern group) and 43.4% (P < 0.05) (central group). Compared to the control specimens, steers from in vivo, southern, and central groups after 150 days of exposure had lower (P < 0.05) leukocyte count, absolute lymphocyte, erythrocyte, and platelet counts. Decreases in RBC-AChE activities correlated with decreased lymphocyte (r = 1.000, p = 0.01), erythrocyte (r = 1.000, p = 0.003), and platelet counts (r = 0.841, p = 0.036). Significantly increased BUN levels (P < 0.05) correlated with the decrease in RBC-AChE activities (r = ? 0.997, p = 0.047) and with the decrease in absolute red blood cell (r = ? 0.883, p = 0.020) and lymphocyte (r = ? 0.825, p = 0.043) counts; increased (P < 0.05) total plasma protein levels correlated with the decrease in RBC-AChE activities (r = ?0.998, p = 0.043), absolute red blood cell (r = ? 0.998, p = 0.040), lymphocyte (r = ? 0.893, p = 0.017), and platelet (r = -0.855, p = 0.030) counts. The physiological responses correlated with the erythrocyte acetylcholinesterase inhibition could be considered as early indicators or warning responses of bovine exposures to organophosphorus pesticides (OPs).