The sulfate input and the occurrence of dryout and rewetting may promote the production of toxic methylmercury (MeHg) in a constructed wetland, Stormwater Treatment Area 2 (STA-2) in South Florida. Therefore, the aim of this study was to investigate the influences of inflow water quality, especially inflow sulfate, and the dryout and rewetting cycle on the mercury (Hg) methylation in three independent cells of STA-2 from 2000 to 2007. Because the majority of the total Hg (THg) bioaccumulated in fish is in MeHg form, THg concentration in mosquitofish was used to present the MeHg production in STA-2. Mosquitofish THg in Cells 1 and 2 (with median values of 0.101 and 0.02 mg/kg, respectively) were significantly higher than in Cell 3 and inflow (both with a median value of 0.01 mg/kg). The difference in mosquitofish THg among the three cells was likely a result of the drying and rewetting cycles occurred in Cells 1 and 2, which promoted the Hg methylation. Inflow sulfate, inorganic Hg, and chloride exhibited a significant correlation with mosquitofish THg in cells, suggesting that these inflow variables played important roles on the Hg methylation. The results indicate that inflow sulfate may likely stimulate sulfate-reducing bacteria and subsequently lead to produce MeHg in the three cells. Our findings in this study indicate that preventing the occurrence of dryout in wetland will help to decline the Hg methylation, and sulfate input is a key factor to influence the Hg methylation in wetland.

Ecotoxicological impacts (survivorship, growth) of two detergents, the linear alkylbenzene sulfonates (LAS) and the nonionic surfactants, nonylphenol ethoxylate (NPE), were examined on two branching coral species (Stylophora pistillata and Pocillopora damicornis). Nubbins assays (n = 1,890, 24-h exposures, 203-day monitoring) revealed high mortality in 1 and 5 mg/l detergents concentrations (for both species combined, LAS LC₅₀ = 1.99 mg/l; NPE LC₅₀ = 2.16 mg/l). Assays further showed detergent as species-specific mortalities (Stylophora LAS LC₅₀ = 1.00 mg/l; NPE = 3.03 mg/l; Pocillopora LAS LC₅₀ = 2.21 mg/l; NPE = 2.26 mg/l), also influenced by genotype-specific mortalities, phenomena which could downgrade genetic diversity of corals in the field, leaving frequently or chronically affected areas with detergent-resistant genotypes. Results revealed that LAS detergents were significantly more detrimental to coral nubbins than NPE detergents, resulting in high mortality and reduced tissue growth on substrates. Surprisingly, nubbins exposed to second and third LAS treatments exhibited significant higher survivorship levels than after the first exposure, whereas in all NPE treatments, nubbins’ survivorship did not significantly differ in the repeated exposures as compared to the first set of assays. This outcome, while adding to our knowledge for the toxicity of various detergents, highlights the need to reduce repeated sewage spills. Furthermore, it is recommended that reef managers should emphasize disparate detergents’ ecotoxicity on corals when establishing environmental policies.

Preindustrial (1850s) and future (2060) streamwater chemistry of an anthropogenically acidified small catchment was estimated using the MAGIC model for three different scenarios for dissolved organic carbon (DOC) concentrations and sources. The highest modeled pH = 5.7 for 1850s as well as for 2060 (pH = 4.4) was simulated given the assumption that streamwater DOC concentration was constant at the 1993 level. A scenario accounting for an increase of DOC as an inverse function of ionic strength (IS) of soilwater and streamwater resulted in much lower preindustrial (pH = 4.9) and future recovery to (pH = 4.1) if the stream riparian zone was assumed to be the only DOC source. If upland soilwater (where significant DOC increase was observed at −5 and −15 cm) was also included, DOC was partly neutralized within the soil and higher preindustrial pH = 5.3 and future pH = 4.2 were estimated. The observed DOC stream flux was 2–4 times higher than the potential carbon production of the riparian zone, implying that this is unlikely to be the sole DOC source. Modeling based on the assumption that stream DOC changes are solely attributable to changes in the riparian zone appears likely to underestimate preindustrial pH.

In the present study, we investigate the effects of a possible protective role of vitamin E (vit E) or selenium (Se) on glucose metabolism disruption induced by static magnetic field (SMF) in rats. Rats have been exposed to SMF (128 mT, 1 h/day during 5 days). Our results showed that SMF failed to alter body weight and relative liver weight. Our data demonstrated that exposure to SMF increased (+21 %) blood glucose level and caused a decrease (−15 %) in liver glycogen content. Moreover, the same treatment induced a reduction of pancreatic islet area. Interestingly, supplementation with vit E (DL α-tocopherol acetate, 150 mg/kg per os during 5 days) prevented alterations induced by SMF on glucose metabolism and liver glycogen content, whereas supplementation with Se (Na₂SeO₃, 0.20 mg/l, in drinking water for 4 weeks) restored only hepatic glycogen contents. By contrast, both vit E and Se failed to correct the area of pancreatic islets.

Fugitive greenhouse gas emissions from unconventional gas extraction processes (e.g. shale gas, tight gas and coal bed methane/coal seam gas) are poorly understood due in part to the extensive area over which these emissions may occur. We apply a rapid qualitative approach for source assessment at the scale of a large gas field. A mobile cavity ring down spectrometer (Picarro G2201-i) was used to provide real-time, high-precision methane and carbon dioxide concentration and carbon isotope ratios (δ¹³C), allowing for “on the fly” decision making and therefore an efficient and dynamic surveying approach. The system was used to map the atmosphere of a production coal seam gas (CSG) field (Tara region, Australia), an area containing pre-production “exploration” CSG wells (Casino, Australia), and various other potential CO₂and CH₄sources (i.e. wetlands, sewage treatment plants, landfills, urban areas and bushfires). Results showed a widespread enrichment of both CH₄(up to 6.89 ppm) and CO₂(up to 541 ppm) within the production gas field, compared to outside. The CH₄and CO₂δ¹³C source values showed distinct differences within and outside the production field, indicating a CH₄source within the production field that has a δ¹³C signature comparable to the regional CSG. While this study demonstrates how the method can be used to qualitatively assess the location and source of emissions, integration with atmospheric models may allow for quantitative assessment of emissions. The distinct patterns observed within the CSG field demonstrates the need to fully quantify the atmospheric flux of natural and anthropogenic, point and diffuse sources of greenhouse gases from individual Australian gas fields before and after production commences.

Research was conducted to assess metal contamination of soils and fruits and evaluate potential human health risks. Heavy metal concentrations (Fe, Mn, Cu, Zn, Cd and Pb) in plum orchard soils were below maximum permissible concentration. Igₑₒshowed that soils were uncontaminated (Igₑₒ<0 for Fe and Mn) and uncontaminated to moderately contaminated (I gₑₒ for Cu, Zn, Pb and Cd ranged from 1.20–0.57, 1.32–0.98, 2.97–0.88 and 1.26–0.58, respectively). Fruit Zn, Cu, Mn, Pb and Cd concentrations were within maximum permissible concentration in foods in Serbia. Only Fe levels were above maximum permissible concentration at most locations. The soil-to-fruit transfer factor (TF) showed large differences between metals. TF for Cd and Pb was 0.0, for Mn 0.007–0.030 and for Zn 0.04–0.09, indicating no potential risk to human health, whereas TF for Fe and Cu was high, i.e. 0.30–1.51 and 0.33–1.69, respectively, suggesting that plum can accumulate Fe and Cu.

Mussel (Mytilus galloprovincialis (Lamarck, 1819)) is directly exposed to sea water contamination that elicits significant physiological and cellular response, although its extent mounted in aquaculture-reared in comparison to wild bivalve populations is scarcely known. Therefore, we have compared contamination biomarkers in mussels from reared (Marina farm) and wild, anthropogenically affected site (Vranjic Bay). While predictably, the levels of metals (Cu, Cd, Pb, Zn, Fe, and Hg) in whole bivalve tissues determined by atomic absorption spectrophotometry resulted in significantly higher concentrations in wild mussels, accompanied by elevated number of apoptotic cells in gills, the activity of multixenobiotic resistance defense mechanism (MXR), measured as the accumulation rate of model substrate rhodamine B (RB) gave contrasting results. The functional RB assay evidenced a lower MXR efflux activity in the gill tissue of wild mussels, indicating two possible scenarios that will need further focus: (1) persisting sea water pollution increased cell damage of bivalve gill cells and consequently led to leakage of the RB into cytoplasm and dysfunctional MXR efflux in wild mussels; or/and (2) a mixture of different toxic compounds present in Vranjic Bay sea water induced oversaturation of MXR efflux, inducing elevated accumulation of the dye. Consequently, it seems that an efficient physiological functioning of MXR in wild mussels is strongly hampered by existence of an unknown quantity of sea water pollutants that may endanger intrinsic organismal defense system and lead toward the enhancement of toxicity.

A photodegradation technology based on the combination of ultraviolet radiation with ozone (UV/O₃) for degrading tri(chloropropyl) phosphate (TCPP) was developed in the present study. Parameters affecting the degradation of TCPP were optimized, and the developed technology was successfully applied to degrade TCPP in two real wastewater samples. The results showed that reaction time, ozone concentration, the initial acidity of reaction solution, and the initial concentration of TCPP in aqueous solution contributed to the degradation efficiency of TCPP. Under the optimized disposal conditions, 100 mg/L of TCPP aqueous solution with a pH value of 7 can be degraded effectively in 60 min with an ozone concentration of 66.2 mg/L. In detail, the yield rates of Cl⁻and PO₄³⁻was high up to 98.9 and 98.2 %, respectively; and total organic carbon (TOC) removal rate was high up to 94.3 %. Method application demonstrated that TCPP can be degraded effectively in pond water. However, only 83.2 and 61.9 % of Cl⁻and PO₄³⁻were produced, and the TOC removal rate was only 81.3 % after 60 min exposure in the effluent discharged from a wastewater treatment plant. Therefore, the presence of interferences may hinder the degradation of TCPP in real wastewater, but its potential application for real wastewater is promising in the future after appropriate domestication and evaluation.

Effects of the combined application of ferrihydrite-modified diatomite (FHMD) and gypsum on phosphorus control were investigated in a laboratory-scale artificial aquarium under anoxic and agitation conditions over 120 days. Daily oscillation of a metal grid to simulate agitating effects by wind did not yield the sediment resuspension in the 120-day treatment aquarium (120-day aquarium) due to the gypsum stabilization, while significant sediment resuspension was observed in the control aquarium. The combined application of FHMD and gypsum did not affect the total kjeldahl nitrogen (TKN) concentrations in both the control aquarium and the 120-day aquarium. Under anoxic conditions and sediment resuspension conditions, a large increase in total phosphorus (TP) concentrations was observed in the control aquarium. However, the TP concentrations in the 120-day aquarium stayed relatively stable, within a range of 9.1–13.3 μg/L. After the 120 days’ incubation, translocation from mobile labile-P and organic-P to P adsorbed by FHMD occurred. The combined application of FHMD and gypsum effectively maintained TP levels within the oligotrophic range under anoxic and agitation conditions in the laboratory-scale artificial aquarium by removing phosphorus from lake water and reducing sedimentary phosphorus release via gypsum sediment stabilization and FHMD phosphorus immobilization.

Phytoremediation can be assisted by microorganisms, which promote plant growth and increase heavy metal availability in soil. In this study, we aimed at evaluating the effect of two plant growth-promoting bacteria (PGPB) on phytoextraction of copper (Cu) by maize. We chose the strains based on their ability to synthesize indole compounds, produce siderophores, solubilize phosphorus, and increase soil conductivity and extractable Cu in soil. Then, in glasshouse experiments, we assessed their ability to increase biomass, chlorophyll content, and Cu extraction by maize. Results showed that Acinetobacter sp. RG30 and Pseudomonas putida GN04 were overall the most active strains to synthesize indole, produce siderophores, and solubilize phosphorus, and hence selected for further studies. Also, both were able to significantly increase soil conductivity and release Cu from soil compared to control. Glasshouse experiments showed that Cu had a negative effect on plant growth, but inoculation with bacteria promoted plant growth and chlorophyll content in its presence (p < 0.05). Notably, the effect of inoculation on plant growth was larger on contaminated than on uncontaminated soil, which suggests an overall bacterial effect for alleviation of stress caused by Cu. Inoculation with RG30 or GN04 improved Cu extraction by maize (p < 0.05); interestingly, co-inoculation led to the highest accumulation (200 μg Cu/g plant dry weight). We conclude, therefore, that inoculation with RG30 and GN04 improves metal extraction by increasing plant growth, fitness, and availability of minerals in soil, which represents an important tool for the improvement of phytoextraction processes in polluted environments.