In the course of searching for hepatoprotective agents from natural sources, the protective effect of chemical constituents of the marine red alga Alsidium corallinum (A. corallinum) against potassium bromate (KBrO₃)-induced liver damage in adult mice was investigated. The in vitro antioxidant and antibacterial properties of A. corallinum were firstly investigated. Then, A. corallinum was tested in vivo for its potential protective effects against damage caused by KBrO₃ in mice models divided into four groups: controls, KBrO₃, KBrO₃ + A. corallinum, and A. corallinum. Our results demonstrated the rich composition of A. corallinum in antioxidant compounds like phenolics, flavonoids, anthocyanins, polysaccharides, chlorophyll and carotenoids. Its antioxidant activity was also confirmed using β-carotene bleaching by linoleic acid assay, reducing sugar test and trolox equivalent antioxidant capacity. The ethanolic extract of A. corallinum also showed good inhibition of the tested bacteria. The coadministration of the red alga associated to the KBrO₃ alleviated hepatotoxicity as monitored by the improvement of hepatic oxidative stress biomarkers and plasma biochemical parameters, when compared to the KBrO₃-treated mice. These results were confirmed by the improvement of histological and molecular changes. Treatment with A. corallinum prevented liver damage induced by KBrO₃, thus protecting the body against free radicals and reducing inflammation and hypercholesterolemia risks.

Potential detrimental impacts of neonicotinoids on non-target organisms, especially bees, have been subject to a wide debate and the subsequent ban of three neonicotinoids by the EU. While recent research has fortified concerns regarding the effects of neonicotinoids on ecosystem service (ES) providers, potential impacts have been considered negligible in systems with a relatively small proportion of arable land and thus lower the use of these pesticides. In this paper we argue that there is not sufficient information to assess magnitude and extent of neonicotinoid application, as well as potential non-target impacts on ES providers in grass-dominated systems with frequent land-use change. Using Ireland as an example, we show that the highly dynamic agricultural landscape, in conjunction with estimated persistence times of neonicotinoids in soils, may lead to a much larger area (18.6 ± 0.6 % of the Irish agricultural area) exposed to these pesticides than initially assumed. Furthermore we present a number of important gaps in current research regarding the impacts of neonicotinoids on ES providers in such systems.

Ionic liquids that are not that “green” to many organisms have recently been identified. This study examined the subchronic toxicity of the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate ([omim]PF₆) to earthworms (Eisenia fetida). Earthworms were exposed for a 28-day period (sampled on days 7, 14, 21, and 28) at concentrations of 0, 5, 10, 20, and 40 mg/kg. The levels of reactive oxygen species (ROS), antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD)), detoxifying enzyme (glutathione S-transferase (GST)), lipid peroxidation, and DNA damage were measured. ROS significantly accumulated in all the treatment groups; the maximum ROS content was 51.9 % higher than the control at 40 mg/kg [omim]PF₆ on day 28. Increased SOD activities attenuated over the time of exposure, while the CAT activities of the treatment groups were similar to the controls, except on day 14. Furthermore, the activities of POD and GST were stimulated. Lipid peroxidation in earthworms was not apparent at 5 and 10 mg/kg [omim]PF₆ but was quite obvious at 40 mg/kg [omim]PF₆. In addition, DNA damage was dose- and time-dependent. In conclusion, [omim]PF₆ caused oxidative stress and genotoxicity in earthworms.

Microbial extracellular polymeric substances (EPS) excreted from microorganisms were a complex natural biological polymer mixture of proteins and polysaccharides, which played an important roles in the transport of metals, such as Ag⁺. Electroactive bacteria, is an important class of environmental microorganisms, which can use iron or manganese mineral as terminal electron acceptors to generate energy for biosynthesis and cell maintenance. In this work, the EPS extracted of three electroactive bacteria (Shewanella oneidensis, Aeromonas hydrophila, and Pseudomonas putida) were used for reducing Ag⁺ and forming silver nanoparticles (AgNPs). Results showed that all the three microbial EPS could reduce Ag⁺ to AgNPs. The formed AgNPs were characterized in depth by the UV-visible spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The main components in the EPS from the three electroactive bacteria were analyzed. The presence of cytochrome c in these EPS was confirmed, and they were found to contribute to the reduction of Ag⁺ to AgNPs. The results indicated that the EPS of electroactive bacteria could act as a reductant for AgNPs synthesis and could provide new information to understand the fate of metals and their metal nanoparticles in the natural environments.

Profound understanding of behaviors of organic matter from sources to multistage rivers assists watershed management for improving water quality of river networks in rural areas. Ninety-one water samples were collected from the three orders of receiving rivers in a typical combined polluted subcatchment (diffuse agricultural pollutants and domestic sewage) located in China. Then, the fluorescent dissolved organic matter (FDOM) information for these samples was determined by the excitation–emission matrix coupled with parallel factor analysis (EEM-PARAFAC). Consequently, two typical humic-like (C1 and C2) and other two protein-like (C3 and C4) components were separated. Their fluorescence peaks were located at λ ₑₓ/ₑₘ = 255(360)/455, <250(320)/395, 275/335, and <250/305 nm, which resembled the traditional peaks of A + C, A + M, T, and B, respectively. In addition, C1 and C2 accounted for the dominant contributions to FDOM (>60 %). Principal component analysis (PCA) further demonstrated that, except for the autochthonous produced C4, the allochthonous components (C1 and C2) had the same terrestrial origins, but C3 might possess the separate anthropogenic and biological sources. Moreover, the spatial heterogeneity of contamination levels was noticeable in multistage rivers, and the allochthonous FDOM was gradually homogenized along the migration directions. Interestingly, the average content of the first three PARAFAC components in secondary tributaries and source pollutants had significantly higher levels than that in subsequent receiving rivers, thus suggesting that the supervision and remediation for secondary tributaries would play a prominent role in watershed management works.

In order to better understand air pollution in deve-loping regions, such as China, it is important to investigate the wet deposition behavior of atmospheric trace metals and its sources in the subtropical watershed. This paper studies the seasonal change of trace metal concentrations in precipitation and other potential sources in a typical subtropical watershed (Jiazhuhe watershed) located in the downstream of the Yangtze River of China. The results show that typical crustal elements (Al, Fe) and trace element (Zn) have high seasonal variation patterns and these elements have higher contents in precipitation as compared to other metals in Jiazhuhe watershed. In addition, there is no observed Pb in base flow in this study, and the concentration magnitudes of Al, Ba, Fe, Mn, Sr, and Zn in base flow are significantly higher than that of other metals. During different rainfall events, the dynamic export processes are also different for trace metals. The various trace metals dynamic export processes lead to an inconsistent mass first flush and a significant accumulative variance throughout the rainfall events. It is found that in this region, most of the trace metals in precipitation are from anthropogenic emission and marine aerosols brought by typhoon and monsoon.

For the precise estimation of the risk to human health caused by persistent organic pollutants (POPs), it is important to discuss enantiomer fraction value (EF value) because it is reported that behaviors such as stability and toxicity of enantiomers are quite different in human body. Among POPs, polychlorinated biphenyl (PCB) is known as one of the most persistent compounds in human breast milk samples. The main exposure source of PCB for human body is mostly from food especially in seafood. The contamination of fish and shellfish has been a serious problem for the Japanese, who consume a large amount of fish in their diet. PCBs have 19 congeners which are chlorine-substituted in 3- or 4- ortho positions are known to have enantiomers. In this study, we analyzed PCB 183 (2,2′,3,4,4′,5′,6-hepta CB) in human breast milk and fish samples enantioselectively and revealed the time trends of the EF value. Though EF value of PCB 183 in fish samples sustained close to racemate (EF = 0.5) from 1982 to 2012, that in breast milk increased over time. This fact indicates that (+)-PCB-183 has greater bioaccumulation potential than (-)-PCB-183 in human body; therefore, the toxicity of (+)-PCB-183 should be emphasized.

The removal efficiency of organic matter, the formation potential of trihalomethanes (THMFP), and the formation potential of haloacetic acids (HAAFP) in each unit of three advanced treatment processes were investigated in this paper. The molecular weight distribution and the components of organic matter in water samples were also determined to study the transformation of organic matter during these advanced treatments. Low-molecular-weight matter was the predominant fraction in raw water, and it could not be removed effectively by ultrafiltration and biofiltration. The dominant species of disinfection by-product formation potential (DBPFP) in raw water were chloroform and monochloroacetic acid (MCAA), with average concentrations of 107.3 and 125.9 μg/L, respectively. However, the formation potential of chloroform and MCAA decreased to 36.2 and 11.5 μg/L after ultrafiltration. Similarly, biological pretreatment obtained high removal efficiency for DBPFP. The total THMFP decreased from 173.8 to 81.8 μg/L, and the total HAAFP decreased from 211.9 to 84.2 μg/L. Separate ozonation had an adverse effect on DBPFP, especially for chlorinated HAAFP. Numerous low-molecular-weight compounds such as aldehydes, ketones, and alcohols were generated during the ozonation, which have been proven to be important precursors of HAAs. However, the ozonation/biological activated carbon (BAC) combined process had a better removal efficiency for DBPFP. The total DBPFP decreased remarkably from 338.7 to 113.3 μg/L after the O₃/BAC process, far below the separated BAC of process B (189.1 μg/L).

In this study, magnetic polydivinylbenzene latex particles MPDVB with a core-shell structure were tested for the removal of bisphenol A (BPA), copper Cu(II), lead Pb(II), and zinc Zn(II) from aqueous solutions by a batch-adsorption technique. The effect of different parameters, such as initial concentration of pollutant, contact time, adsorbent dose, and initial pH solution on the adsorption of the different adsorbates considered was investigated. The adsorption of BPA, Cu(II), Pb(II), and Zn(II) was found to be fast, and the equilibrium was achieved within 30 min. The pH 5–5.5 was found to be the most suitable pH for metal removal. The presence of electrolytes and their increasing concentration reduced the metal adsorption capacity of the adsorbent. Whereas, the optimal pH for BPA adsorption was found 7, both hydrogen bonds and π–π interaction were thought responsible for the adsorption of BPA on MPDVB. The adsorption kinetics of BPA, Cu(II), Pb(II), and Zn(II) were found to follow a pseudo-second-order kinetic model. Equilibrium data for BPA, Cu(II), Pb(II), and Zn(II) adsorption were fitted well by the Langmuir isotherm model. Furthermore, the desorption and regeneration studies have proven that MPDVB can be employed repeatedly without impacting its adsorption capacity.