The flux of metals at the tidal limits of major rivers are an important metric of freshwater contaminant transfer to marine habitats, reported in Northeast Atlantic bordering countries under the 1992 Oslo-Paris (OSPAR) Convention. This paper presents an assessment of long-term OSPAR data for four trace metals (Cd, Cu, Pb, and Zn) using a range of spatial datasets to assess the broad distribution of metal flux and yield across England and Wales. Mine site records and geological and land use data are used to classify river basins into six classes. The bulk of metal flux to seas around England and Wales occurs from catchments containing extensive mineralization and a legacy of metal mining (52 % of the total Zn flux, 47 % of Pb, 39 % of Cu, and 48 % of Cd were associated with mined catchments). Catchment area, metal flux from point mine discharges at source, and extent of mineralization typically accounted most for variation in catchment outlet metal flux in stepwise multiple linear regression (SMLR). There are a number of small mining-impacted rural catchments contributing significant fluxes of metals to coastal waters. Of particular prominence are Restronguet Creek (drainage area 87 km²) in southwest England that discharges 176 t Zn/year and 18 t Cu/year and the Afon Goch Dulas (27 km²) in north Wales, which releases 20 t Zn/year and 9 t Cu/year. Although such exercises cannot directly determine the provenance of metals, comparison with metal release data and a review of catchment-scale studies suggest a critical role of mining-related contaminants in contributing to catchment metal export.

A new analytical methodology based on ultra high performance liquid chromatography (UHPLC) after microwave assisted extraction, followed by a clean-up and preconcentration step with solid phase extraction (MAE-SPE) has been developed for the simultaneous determination of 11 endocrine-disrupting compounds (EDCs), including alkylphenolic compounds, bisphenol A, and various synthetic and natural steroidal hormones, in sewage sludge samples. The effects of different variables on MAE-SPE were studied and optimised. The recoveries obtained were higher than 77 %, whereas the relative standard deviations were less than 9 %. The detection limits ranged between 0.1 and 0.7 ng g -1. The developed methodology was successfully applied to the assessment of the presence of EDCs to sewage sludge samples that were collected bimonthly during 1 year and a half from two wastewater treatment plants (WWTPs) located in Las Palmas de Gran Canaria (Canary Islands, Spain). All compounds were consistently found in all the samples under study. © 2013 Springer Science+Business Media Dordrecht.

The aims of the present study were to identify the halophilic Archaea that can degrade aromatic hydrocarbons (namely, p-hydroxybenzoic acid, naphthalene, phenanthrene, and pyrene) and to determine their catabolic pathways in the process of degrading the hydrocarbons. It was determined nine archaeal isolates used p-hydroxybenzoic acid, naphthalene, phenanthrene, and pyrene as sole carbon and energy sources. The isolates were identified as Halobacterium piscisalsi, Halorubrum ezzemoulense, Halobacterium salinarium, Haloarcula hispanica, Haloferax sp., Halorubrum sp., and Haloarcula sp. by 16S rRNA gene sequences. Activity of catechol 1,2 dioxygenase and protocatechuate 3,4 dioxygenase enzyme of the ortho cleavage pathway were detected. Determination of the genes of these dioxygenases was also shown. This study clearly demonstrated for the first time that Halorubrum sp. and H. ezzemoulense among the isolates were able to grow at 20 % (w/v) NaCl, utilizing p-hydroxy-benzoic acid, naphthalene, phenanthrene, and pyrene as the sole carbon sources.

Land use in east China tends to change from paddy rice to vegetables or other high-value cash crops, resulting in high input rates of organic manures and increased risk of contamination with both heavy metals (HMs) and antibiotics. This investigation was conducted to determine the accumulation, distribution and risks of HMs and tetracyclines (TCs) in surface soils and profiles receiving different amounts of farmyard manure. Soil samples collected from suburbs of Hangzhou city, Zhejiang province were introduced to represent three types of land use change from paddy rice to asparagus production, vineyards and field mustard cultivation, and divided into two portions, one of which was air-dried and sieved through 2-, 0.3- and 0.149-mm nylon mesh for determination of pH and heavy metals. The other portion was frozen at -20 °C, freeze-dried and sieved through a 0.3-mm nylon mesh for tetracyline determination. HM and TC concentrations in surface soils of 14-year-old mustard fields were the highest with total Cu, Zn, Cd and ∑TCs of 50.5, 196, 1.03 mg kg(-1) and 22.9 μg kg(-1), respectively, on average. The total Cu sequence was field mustard > vineyards > asparagus when duration of land use change was considered; oxytetracycline (OTC) and doxycycline were dominant in soils used for asparagus production; OTC was dominant in vineyards and chlortetracycline (CTC) was dominant in mustard soils. There were positive pollution relationships among Cu, Zn and ∑TCs, especially between Cu and Zn or Cu and ∑TCs. Repeated and excessive application of manures from intensive farming systems may produce combined contamination with HMs and TCs which were found in the top 20 cm of the arable soil profiles and also extended to 20-40 cm depth. Increasing manure application rate and cultivation time led to continuing increases in residue concentrations and movement down the soil profile.

In this study, the effectiveness of subcritical water extraction (SCWE) was assessed by extracting four pesticides, namely diazinon, parathion, phenthoat, and EPN, from contaminated soil. The extraction efficiencies of different temperatures (25, 75, 100, 125, and 150 C); times (10, 20, 30, and 40 min); pressures (1, 2, and 3 MPa); and water flow rates (0.5, 0.7, 1.0, and 1.5 mL/min) were investigated. The optimum temperature, time, pressure, and flow rate were found to be 150 C, 20 min, 2 MPa, and 0.5 mL/min, respectively, in lab-scale. At this operating condition, the residual concentration of pesticide was less than 0.5 mg/kg, corresponding to an extraction efficiency of 99.9 %. The aim of this study was to also evaluate the removal efficiency on 30- and 167-fold scale-up extraction at optimum extraction condition obtained from lab-scale studies. The scale-up method considering constant ratio of the volume of water to soil mass was a feasible procedure. The results of our study suggest that SCWE is a promising option for effective disposal of pesticide- contaminated soil. © 2013 Springer Science+Business Media Dordrecht.

The objectives of this study were to assess susceptibility to acidification and nitrogen (N) saturation caused by atmospheric deposition to northeastern US forests, evaluate the benefits and shortcomings of making critical load assessments using regional data, and assess the relationship between expected risk (exceedance) and forest health. We calculated the critical loads of nutrient N and of sulfur (S) + N using the steady-state mass balance method at >4,000 regional and national vegetation and soil monitoring network plots in the northeastern USA. Regional calculations of critical loads necessitate use of soil maps which provide a range for each soil characteristic resulting in a broad range of critical load of S + N and exceedance values. For the scenario most representative of regional conditions, over 80 % of the critical loads fell into the range of 850–2050 eq ha⁻¹ yr⁻¹; at 45 % of the plots, deposition exceeded the critical load. In contrast, the critical load for nutrient N, 200–300 eq ha⁻¹ yr⁻¹, was lower. Site measurements, especially to estimate soil weathering, would increase the certainty of the critical load. We observed significant negative correlations between critical load exceedance and growth (17 species) and crown density (4 species); we observed significant positive correlations of exceedance with declining vigor (four species), with crown dieback (six species) and crown transparency (seven species). Among the species which demonstrate the most significant detrimental responses to atmospheric deposition are balsam fir, red spruce, quaking aspen, and paper birch. These results indicate that significant detrimental responses to atmospheric deposition are being observed across the northeastern USA.

The speciation of mercury (Hg) is a major determinant of its methylation rate by sulfate-reducing bacteria (SRB), considered the primary methylators. Under anoxic conditions, sulfur (S) cycling may have a significant influence on Hg complexation and methylation, by influencing both SRB activity and the pool of available reduced S ligands, as the presence of zero-valent sulfur (S(0)) in sulfidic water results in the formation of polysulfides. While SRB frequently coexist with S-oxidizing bacteria in natural environments, the effect that these organisms may have on methylation by SRB is not understood. In this study, we investigate the role of S(0) in methylation by SRB monocultures and cocultures with phototrophic green or purple S-oxidizing bacteria. In the coculture experiments, the presence of S-oxidizers was found to increase Hg methylation rates, apparently by maintaining favorable chemical speciation in the environment. The measured Hg methylation rates were in accord with predictions based on geochemical modeling of speciation. In SRB monoculture experiments conducted in the presence and absence of S(0), the data showed that at limited total Hg, the presence of polysulfides resulted in decreased Hg methylation, presumably by causing a decrease in the most bioavailable Hg–sulfide complexes. These results indicate that models of Hg speciation and methylation in the environment should include a detailed investigation of S redox speciation.

Emissions of volatile organic compounds (VOCs) were studied from three heavily polluted rivers (Huijiang, Nancun, and Zengbian Rivers) in Guangzhou, South China. A total of 49 species of VOCs were identified. Nancun River had the highest concentration of total VOCs (TVOCs), which ranged from 1,467 to 5,522 μg m⁻³. Trichloroethene, benzene, toluene, ethylbenzene, m/p-xylene, o-xylene, styrene, and 1,3,5-trimethylbenzene were the main pollutants. The levels of VOCs evaporated from the three rivers exhibited different patterns. Correlations between the concentrations of major VOCs were established and found to be statistically significant, except for o-xylene. The ratios of toluene/benzene, ethylbenzene/benzene, and xylene/benzene were estimated and found to be higher than widely reported in the literature. TVOC fluxes in the three rivers were calculated to be the range from 24.8 to 765 μg m⁻² h⁻¹. This study provides a regional background for the emission inventories of VOCs from heavily polluted rivers in southern China and provides resource managers with important information to guide remediation and policy concerning VOC emissions to the environment.

Hydrogels based on p(4-VP) of different dimensions were prepared and, after chemical modification, were used in the removal of one of the most potent toxic materials, cyanide. Macro and micron p(4-VP) hydrogel swelling behavior was evaluated in various aquatic environments. HCl, bromoethane, 1-bromobutane, 1-bromohexane, and 2-bromoethylamine were used as quaternizing agents to generate positive charges on both p(4-VP) macrogels and microgels. The modified p(4-VP) macrogels and microgels were used in cyanide ion removal for the first time from aqueous environments. The p(4-VP)-HCl at macro and micro sizes removed almost 49 and 61 mg cyanide ions per gram hydrogel in deionized water after modification, respectively. Moreover, the absorption capacity of the modified p(4-VP) hydrogel did not change significantly in tap, drinking, and creek waters. Parameters that affect the absorption process, such as cyanide concentration, contact time, hydrogel amount, and contaminated water source, were investigated. Additionally, magnetic field responsive macro and micro p(4-VP) hydrogel composites provided many advantages, such as easy handling after cyanide absorption, e.g., ready removal of cyanide-loaded p(4-VP) composites with an externally applied magnetic field. Langmuir and Freundlich adsorption isotherms were applied to the data obtained for cyanide uptake from aqueous environments.

The decolorization and degradation of anionic sulphonated azo dye (Reactive orange 16 (RO16)), which is suspected to be carcinogenic, were investigated using ozone. The decolorization process of the reactive dye was carried out by bubbling ozone at the bottom of a bubble column reactor containing the dye solution. The effect of pH, reaction time, dye concentration, ozone concentration, and decolorization time was studied. Also, degradation products and possible degradation mechanism were investigated. The results showed that ozonation was a highly effective way to remove color from wastewater. The color of a synthetic waste solution containing water-soluble reactive dye was reduced to 69.69 % under the basic condition (pH 12), with complete RO16 degradation occurring in 8 min. Ozone consumption continued for a further 16 min after which time most of the degradation reactions were complete. Kinetic studies showed that direct ozonation of the aqueous dyes represented a pseudo-first-order reaction with respect to the dye. The apparent rate constant increased with both the applied ozone dose and higher pH values and declined logarithmically with the initial dye concentration. Intermediates such as 6-acetylamino-3-aminonaphthalene-2-sulfonic acid, 2-(4-nitrosophenyl) sulfonylethyl hydrogen sulfate, and 6-acetamido-4-hydroxy-3-nitroso naphthalene-2-sulfonic acid were detected by gas chromatograph coupled with mass spectrometry in the absence of pH buffer, while nitrate and sulfate ions and formic, acetic, and oxalic acids were detected by ion chromatography.