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As an important type of typical synthetic azo dyes, the use of sudan I-IV dyes has been of concern worldwide because of their wide applications and illegal addition into various foodstuffs, potentially resulting in water and soil pollution and having adverse effects on human health and ecosystems. However, to date, little has been reported regarding the environmental levels of these dyes and the risks that they pose to human health and ecosystems. Understanding the responses of soil enzymes, functional groups of bacteria and microbial communities to sudan dyes is of great importance to reveal their effect on the soil environment. In this study, we performed a toxicological study on the specific and overall effects of sudan I-IV dyes on the activity of soil enzymes including catalase, urease, and alkaline phosphatase after a 2- and 7-day exposure, functional groups of soil bacteria including nitrogen-fixing, ammonia-oxidizing, and denitrifying bacteria on day 14, and the structure and diversity of soil microbial community compositions on day 30. The results showed that sudan I-IV affected the activity of the soil enzymes, the abundance of the bacterium functional groups, and the structure and diversity of microbial community compositions, and the effects varied by sudan dyes I-IV, the exposure concentration, and the exposure time.

Combined toxicity is a critical issue in risk assessment of contaminants. However, very little is known about the joint effects of graphene oxide (GO, a crucial 2-dimensional carbon material) and hexavalent chromium (Cr6+, a widespread heavy metal), particularly with respect to the critical period of embryogenesis. In this study, the combined toxicity of GO and Cr6+ was evaluated through embryo-larval toxicity test in Danio rerio (zebrafish). Results indicated that the co-exposure of Cr6+ (1 mg/L) and GO (0.01 mg/L) inhibited hatching and spontaneous movement of embryos, but no significant changes were found in the single Cr6+ or GO group. Compared with the single GO or Cr6+ exposure, their co-exposure (GO+Cr6+) significantly enhanced the teratogenicity in a concentration-dependent pattern, and the spinal curvature was observed as the main deformity. GO+Cr6+ changed the protein secondary structures of embryos result of the generation of ROS and oxidative stress. The degradations of vertical myosepta and cartilages were observed in co-exposure group, suggesting that GO+Cr6+ disrupted the development of musculoskeletal system. The genes col11a1a, col2a1a and postnb were down-regulated but the genes acta1b and mmp9 were up-regulated by GO+Cr6+. The interactions between Cr6+ and GO demonstrated that the morphology, structure, and surface properties of GO were modified by Cr6+. The enhanced defects and O-containing groups of GO could trap more β-sheets, induced oxidative stress, disturbed the development of skeletal muscles and cartilages in zebrafish. These data suggested that GO+Cr6+ enhanced their joint toxicity due to the variation of nanoparticle properties. This finding is important for assessing the ecological risk of graphene family nanomaterials in the natural environment.

Effects of sewage sludge biochars (SSBCs) on the growth of wheat and the specific toxicological mechanisms were investigated from a metabolic perspective for better ecological risk assessment. We observed that conversion of sludge to biochar remarkably changed the properties, and also caused a significant (p 0.05) reduction of the toxicity towards wheat. Wheat growth under exposure to SSBCs was influenced by the pyrolysis temperature (300 °C, 500 °C and 700 °C), with root length being promoted by SSBCs prepared at higher temperatures (500 °C and 700 °C). In addition to the contaminants, including polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) detected in SSBCs, the morphological characteristics of biochars contributed substantially to the wheat growth. Metabolomics analysis revealed the remarkable differences in the metabolic profiles among the control (CK), SS300- and SS700-treated samples. The toxicological mechanisms involved were found to be associated with the regulation of metabolisms pathways of protein, fatty acids and carbohydrates, among which protein metabolism was most affected by SSBCs. This work presents an innovative concept that SSBCs produced at a proper temperature may minimize the toxic effects on plant growth by regulating the metabolic fluxes in vivo.

Pot experiments were conducted to evaluate the phytoremediation of B[a]P contaminated soil using two ornamental plants (Tagetes patula and Mirabilis jalapa). The results showed that the dry biomass of two plants was increased at low B[a]P contaminated soil and then inhibited with increasing B[a]P concentrations. It exhibited a significantly positive linear relationship between B[a]P absorption in roots, stems, leaves and shoots of the tested plants and the concentration of B[a]P in soils (P

The environmental release of graphene oxide (GO) will certainly induce the GO exposure to plants. To date, the influence of GO on the intracellular structures and the endophytic bacterial ecology of plants have been rarely reported. In the present study, the rice seedlings were exposed to GO (5 mg/L) under hydroponic condition for fifteen days with periodic stir. The cellular structures damage, GO deposition and oxidative stress were found in rice root after GO exposure. A Illumina analysis based on the bacterial 16 S rRNA gene showed that the richness, evenness and diversity of endophytic bacterial communities of rice root decreased due to GO exposure. The relative abundance of beneficial endophytic bacterial populations decreased after GO exposure. Out of potential phenotypes predicted by BugBase, the relative abundance of Gram negative, stress-tolerant and biofilm-forming phenotypes, presented an increase trend after GO exposure.

The effects of graphene oxide (GO) carbon nanomaterials on ecosystems have been well characterized, but the toxicity of GO at predicted environmental concentrations to living organisms at the protein level remain largely unknown. In the present work, the adverse effects and mechanisms of GO at predicted environmental concentrations were evaluated by integrating proteomics and standard analyses for the first time. The abundances of 243 proteins, including proteins involved in endocytosis (e.g., cltcb, arf6, capzb and dnm1a), oxidative stress (e.g., gpx4b, sod2, and prdx1), cytoskeleton assembly (e.g., krt8, krt94, lmna and vim), mitochondrial function (e.g., ndufa10, ndufa8, cox5aa, and cox6b1), Ca2+ handling (e.g., atp1b2a, atp1b1a, atp6v0a1b and ncx4a) and cardiac function (e.g., tpm4a, tpm2, tnni2a.1 and tnnt3b), were found to be notably altered in response to exposure 100 μg/L GO. The results revealed that GO caused malformation and mortality, likely through the downregulation of proteins related to actin filaments and formation of the cytoskeleton, and induced oxidative stress and mitochondrial disorders by altering the levels of antioxidant enzymes and proteins associated with the mitochondrial membrane respiratory chain. Exposure to GO also increased the heart rate of zebrafish larvae and induced pericardial edema, likely by changing the expression of proteins related to Ca2+ balance and cardiac function. This study provides new proteomic-level insights into GO toxicity against aquatic organisms, which will greatly benefit our understanding of the bio-safety of GO and its toxicity at predicted environmental concentrations.

It was observed in this work that joint effects of chlorimuron-ethyl and copper on chlorophyll content, the peroxidases (POD) activity, superoxide dismutases (SOD) activity and soluble protein content in leaves and roots of wheat were markedly significant. The chlorophyll content and the SOD activity in wheat under joint stress of chlorimuron-ethyl and copper were obviously higher than that under single stress of chlorimuron-ethyl. However, joint effect of chlorimuron-ethyl and copper on the decrease of soluble protein content in roots was more serious than that under single stress of chlorimuron-ethyl. The effect of copper dominated the change of POD activity and soluble content in leaves and roots of wheat under joint stress of chlorimuron-ethyl and copper. It was suggested that the change of enzyme activity was related to the change of soluble protein content in roots under single and joint stress of chlorimuron-ethyl and copper.

Responses of the polychaete Perinereis aibuhitensis Grube to single and joint stress of copper (Cu) and petroleum hydrocarbons (PHCs) at biochemical levels (including superoxide dismutases, SOD; peroxidases, POD; and the content of total soluble protein, TSP) were investigated under controlled laboratorial conditions. Significant decreases in SOD activity in the first 3 days of single exposure to Cu or PHCs were observed. Although SOD activity increased and returned to the level of the control on day 6 after having decreased on day 3 under single stress of Cu or PHCs, Cu and PHCs had complicated interactive influences on SOD activity in P. aibuhitensis. Their joint effects on SOD activity depended on concentration combinations and exposure time, called double-dose dependent effects. The POD activity and the content of TSP remained generally constant under both single and joint stress of Cu and/or PHCs, compared with the control. The beef-witted responses of investigated biochemical parameters in this study might suggest that toxic effects of pollutants with emphasis on the action of abiotic parameters and the time factor on the antioxidant enzymes in the polychaete should be addressed in the future work.

Triclosan is an antimicrobial agent widely used in many contemporary consumer and health care products. This study assayed phytotoxicity of triclosan using plant growth tests, soil microbial activity using soil respiration and phosphatase activity tests and soil microbial functional diversity using the Biolog ECO plates. The results showed that triclosan inhibited plant growth in soil, with rice seeds being more sensitive than cucumber seeds with EC50 values of 57 and 108 mg/kg. Soil respiration was significantly inhibited in the treatments with triclosan at concentrations more than 10 mg/kg (dry soil) during the first 4 days of incubation, but recovered later on after longer incubation. Phosphatase activity was also inhibited for all the soils treated with triclosan (from 0.1 to 50 mg/kg dry soil), but a declining inhibition was observed after 2 days of incubation. Biolog analysis found that triclosan treatment increased the utilization of carbon sources and exerted no adverse effects on the functional diversity of soil microbial community.

Changes in the activity of antioxidant enzymes including superoxide dismutase (SOD) and peroxidase (POD) and in the content of soluble protein (SP) in Nereis diversicolor exposed to cadmium (Cd) and petroleum hydrocarbons (PHCs) were investigated under a laboratory condition. The results indicated that SOD activity in N. diversicolor exposed to Cd and PHCs significantly (P

Changes in the activity of antioxidant enzymes including peroxidases (POD) and superoxide dismutases (SOD) and in the contents of chlorophyll (CHL), malondialdehyde (MDA), and soluble proteins (SP) in wheat (Triticum aestivum) under the stress of chlorimuron-ethyl in soil were examined. Chlorimuron-ethyl induced oxidative stress that was indicated by elevated MDA content in leaves and roots after a 1-day exposure. The 300-microg/kg chlorimuron-ethyl treatment caused significant damage to CHL accumulation. The higher POD activity in roots than in leaves may be the result of the tissue-specific gene expression in the roots. Our data could suggest that the plant has the capacity to counteract the oxidative stress caused by 5-150 microg/kg chlorimuron-ethyl exposure at the first stage, but the capacity would be lost with exposure time. It is indicated that the increase of POD activity in the leaves may have been caused by H(2)O(2) produced from sources other than SOD. The damage to the antioxidative defensive systems in plants is affected by the concentration of chlorimuron-ethyl and exposure time, and the defensive effect of antioxidative enzymes is completely lost with prolonged exposure. When treated with 300 microg/kg of chlorimuron-ethyl, a significant decrease of SP content and SOD activity in the leaves and roots indicated that the decrease of SP content and the activity of SOD can be considered biomarkers of the serious stress of chlorimuron-ethyl in soil. The increase of SP content in leaves after 3-4 days of exposure to 5-150 microg/kg chlorimuron-ethyl suggests that the enhanced POD activity was due to true induction of de novo synthesis rather than reactivation of preexisting apoprotein. It can also be concluded that dose-response relationships exist only between the SP content in roots and leaves and the concentration of chlorimuron-ethyl.

To study the sublethal effects induced by ethylbenzene and the capability of a freshwater gastropod Bellamya aeruginosa to take up and depurate ethylbenzene, the snail was subjected to two treatments, a 23-day exposure period followed by a 17-day depuration period. Behavioral alteration, namely retraction response, was observed during the exposure period, and the proportion of retracted snails increased under each treatment as the exposure time prolonged but there was no linear relationship between the retracted proportion and the exposure dose. Such behavioral alteration was probably due to the disturbance of membrane permeability stressed by ethylbenzene. Ethylbenzene uptake in unretracted snails was greater than in retracted snails, while the depuration abilities in the two different responses of snails had no significant difference from each other. Because of the limited capability of snails to detoxify ethylbenzene, the depuration was mainly through a slow excretion process and therefore ethylbenzene was still present in the tissue of snail after 17-day depuration. DNA damage was induced significantly in snails exposed to ethylbenzene, and the levels of DNA damage showed positive time-response and dose-response relationships, and moreover the levels of DNA damage had no difference between the two different responses of snails. There was no linear relationship between the level of DNA damage and the amount of residual ethylbenzene in tissue, which may be related to the adaptation mechanism in snail. Overall, the results suggest that the snail has high capability to take up ethylbenzene and low ability to depurate it, and ethylbenzene has potential genotoxicity to snail.

Investigation of the toxicological effects of some agricultural pollutants on germination rate and on shoot and root elongation of wheat (Triticum aestivum) was carried out. Seeds of wheat were exposed to various concentrations of chlorimuron-ethyl with or without cadmium and copper addition. The inhibitory rates of seed germination and shoot and root elongation of wheat were calculated. Significant linear relationships between the root and shoot elongation and the concentration of chlorimuron-ethyl with or without copper or cadmium addition were observed. The interactive effects of the three pollutants on seed germination were not significant (P0.05), but on shoot and root elongation they were markedly significant (P0.01). When concentrations of added Cd2+ or Cu2+ reached the concentration under which the inhibitory rate of wheat root elongation was about 20%, cadmium (or copper) and chlorimuron-ethyl had an antagonistic effect on the inhibition of shoot and root elongation, although the interactive effects of copper were not significant (P0.05). However, cadmium (or copper) and chlorimuron-ethyl had significantly synergic effects on the inhibition of shoot and root elongation (P0.05) when concentrations of added Cd2+ and Cu2+ reached the concentrations under which the inhibitory rate of root elongation was about 70%. At the high concentration of added cadmium or copper, joint toxicity of chlorimuron-ethyl and the heavy metals was more dependent on the concentrations of the latter. The sensitivity of wheat to the toxicity of the three pollutants was in the following sequence: root elongationshoot elongationgermination rate.