Two types of hydrogels with different functional groups, trimethylamine on quaternary ammonium and dimethylethoxyamine on quaternary ammonium, were synthesized. Type 1 and type 2 hydrogels were characterized with Fourier transform infrared, X-ray photoelectron spectroscopy and zeta potential analysis. The anion selectivity of these two hydrogels was investigated. The surface charges of the type 2 hydrogel were lower than those of type 1, probably because of the presence of the hydroxyl group in the ethoxy group. The Cr(VI) removal capacity of type 2 hydrogel was, therefore, less than that of type 1 hydrogel, although their adsorption rates were similar. The anion selectivity of the hydrogels was found to have a similar order: Cr(VI) > sulphate > bromide > As(V). Under the co-presence of Cr(VI) and sulphate conditions, type 2 hydrogel shows a higher selectivity towards Cr(VI). The higher hydrophobicity was caused by the presence of the ethoxy group on the quaternary ammonium in type 2 hydrogel and thus increased in selectivity towards monovalent ions (i.e. HCrO 4 − ). In addition, the hydrogels have a high reusability. Compared with type 1 hydrogel, type 2 hydrogel has an advantage for applications in Cr(VI) removal and recovery processes.

Lead is a well-known pollutant with documented toxicity. Lead-containing weights used to balance motor vehicle wheels are regularly lost from vehicles and enter the environment. Lead weights deposited on roadways in the vicinity of Trenton, NJ were gathered and measured from February 2006 to January 2009. Measurements included loss of mass from specific weights exposed to traffic. Extrapolation of the results to the entire state suggests that approximately 12 tons per year of lead in the form of wheel weights are deposited on New Jersey roadways, and that approximately 40 kg of lead enters the environment in the form of small particles formed from the abrasion and grinding action of traffic on weights deposited on roadways. This quantity of small particles is much less than the approximately 60 tons per year of lead estimated by an earlier study to enter New Jersey in precipitation, some of which may result from the combustion of leaded aviation fuel. The quantity is also likely small compared with the fluxes of lead into the environment that still continue from leaded paint and with the residue of finely dispersed lead from historical uses of leaded gas in motor vehicles that remains in the environment. The quantity of lead released to the environment in the form of wheel weights appears likely to decline in the future because of legislation, voluntary phase-outs by manufacturers, and new trends in wheel technology

Tests were conducted to study the influence of non-ionic surfactants Triton X-100 and Tween 80 on the removal of mixed contaminants from a sandy soil using phytoremediation. Cd(II) and Pb(II) were used to form the inorganic contaminant, while used engine oil was selected to form the organic contaminant. The Indian mustard (Brassica juncea) plant was the plant chosen for phytoremediation of the sandy soil that contained the mixed contaminant. Thirty days after the plants were grown in the greenhouse, surfactants were applied to test pots in which the soil had been spiked with 50 mg kg−1 of CdCl2, 500 mg kg−1 of PbCl2 and 500 mg kg−1 of used engine oil. Two control tests were conducted in this study. Planted and unplanted control tests were conducted using soil without surfactants. Following these tests, the tests were completed using the plants and surfactants at different concentrations. Test results showed that Triton X-100 and Tween 80 at concentrations higher than their critical micellar concentration enhanced Cd(II) and Pb(II) accumulation in the plant roots. Further, test data showed that translocation of contaminants to plant shoots occurred for Cd(II) but not for Pb(II). At the same concentrations, Tween 80 was more effective than Triton X-100 in facilitating rhizodegradation of used engine oil. This study demonstrates that simultaneous phytoremediation of Pb(II), Cd(II) and oil can be enhanced by using non-ionic surfactant Tween 80. Leaching test results indicated that the enhanced phytoremediation could remove the mixed contaminants safely from the point of view of limiting groundwater contamination.

An excess of phosphorus (P) is the most common cause of eutrophication of freshwater bodies. Thus, it is imperative to reduce the concentration of P to prevent harmful algal blooms. Moreover, recovery of P has been gaining importance because its natural source will be exhausted in the near future. Therefore, the present work investigated the removal and recovery of phosphate from water using a newly developed hybrid nanocomposite containing aluminium nanoparticles (HPN). The HPN-Pr removes 0.80 ± 0.01 mg P/g in a pH interval between 2.0 and 6.5. The adsorption mechanism was described by a Freundlich adsorption model. The material presented good selectivity for phosphate and can be regenerated using an HCl dilute solution. The factors that contribute most to the attractiveness of HPN-Pr as a phosphate sorbent are its moderate removal capacity, feasible production at industrial scale, reuse after regeneration and recovery of phosphate.

The use of azo dyes is popular in different branches of industry. Discharge of colourants to surface water cause harmful environmental effects. The aim of the present study was evaluation of effectiveness of diazo Evans blue decolourization by two Pseudomonas strains and estimation of process byproducts toxicity. In static conditions, both tested strains removed more than 85 % of dye after 48 h and completely decolorized samples after 120 h. Agitation had negative impact on Evans blue removal (less than 70 % of dye removed after 120 h). Ecotoxicological effects were different for both studied strains beside comparable decolourization effectiveness. Increase of zootoxicity was noticed for strain Sz6 and decrease from IV to III class was noticed for strain SDz3. Optimization of process conditions for the most promising strain SDz3 should be deeply examined.

Temporal depositional rates are important in order to understand the production and occurrence of perchlorate (ClO 4 − ) as limited information exists regarding the impact of anthropogenic production or atmospheric pollution on ClO 4 − deposition. Perchlorate concentrations in discrete ice core samples from the Eclipse Icefield (Yukon Territory, Canada) and Upper Fremont Glacier (Wyoming, USA) were analyzed using ion chromatography tandem mass spectrometry to evaluate temporal changes in the deposition of ClO4 − in North America. The ice core samples cover a time period from 1726 to 1993 and 1970 to 2002 for the Upper Fremont Glacier (UFG) and Eclipse ice cores, respectively. The average ClO4 − concentration in the Eclipse ice core for the time period from 1970 to 1973 was 0.6 ± 0.3 ng L−1, with higher values of 2.3 ± 1.7 and 2.2 ± 2.0 ng L−1 for the periods 1982–1986 and 1999–2002, respectively. All pre-1980 ice core samples from the UFG had ClO4 − concentrations <0.2 ng L−1, and the post-1980 samples ranged from <0.2 ng L−1 to a maximum of 2.6 ng L−1 for the year 1992. A significant positive correlation (R = 0.75, N = 15, p < 0.001) of ClO 4 − with SO 4 2− was found for the annual UFG ice core layers and of ClO4 − with SO 4 2− and NO 3 − in sub-annual Eclipse ice samples (R > 0.3, N = 121, p < 0.002). The estimated yearly ClO 4 − depositional flux for the Eclipse ice core ranged from 0.6 (1970) to 4.7 μg m−2 year−1 (1982) and the UFG from <0.1 (pre-1980) to 1.4 μg m−2 year−1 (1992). There was no consistent seasonal variation in the ClO 4 − depositional flux for the Eclipse ice core, in contrast to a previous study on the Arctic region. The presence of ClO 4 − in these ice cores might correspond to an intermittent source such as volcanic eruptions and/or any anthropogenic forcing that may directly or indirectly aid in atmospheric ClO 4 − formation.

Agricultural runoff containing nitrogen fertilizer is a major contributor to eutrophication in aquatic systems. One method of decreasing amounts of nitrogen entering rivers or lakes is the transport of runoff through vegetated drainage ditches. Vegetated drainage ditches can enhance the mitigation of nutrients from runoff; however, the efficiency of nitrogen removal can vary between plant species. The efficiency of three aquatic macrophytes, cutgrass (Leersia oryzoides), cattail (Typha latifolia), and bur-reed (Sparganium americanum), to mitigate dissolved and total nitrogen from water was investigated. Replicate mesocosms of each plant species were exposed to flowing water enriched with ammonium and nitrate for 6 h, allowed to remain stagnant for 42 h, and then flushed with non-enriched water for an additional 6 h to simulate a second storm event. After termination of the final simulated runoff, all vegetated treatments lowered total nitrogen loads exiting mesocosms by greater than 50%, significantly more than unvegetated controls, which only decreased concentrations by 26.9% (p ≤ 0.0023). L. oryzoides and T. latifolia were more efficient at lowering dissolved nitrogen, decreasing ammonium by 42 ± 9% and 59 ± 4% and nitrate by 67 ± 6% and 64 ± 7%, respectively. All treatments decreased ammonium and nitrate concentrations within mesocosms by more than 86% after 1 week. However, T. latifolia and L. oryzoides absorbed nitrogen more rapidly, lowering concentrations by greater than 98% within 48 h. By determining the nitrogen mitigation efficiency of different vegetative species, plant communities in agricultural drainage ditches can be managed to significantly increase their remediation potential.

The present study evaluated the short-term toxicity of seven selected pesticides: four insecticides (chlorpyrifos, dieldrin, diazinon and pirimiphos-methyl) and three herbicides (diuron, alachlor and atrazine). With this aim, a standard toxicity test with the highly sensitive early life stages (ELS) of a marine fish was used. The turbot, Psetta maxima, is abundant in shallow estuarine and costal habitats and is currently the most commonly cultivated fish species in Galicia, NW Spain. According to the turbot ELS test results, chlorpyrifos was the most toxic pesticide tested for both embryos and larvae and was followed in order of decreasing toxicity by dieldrin, pirimiphos-methyl, diazinon, alachlor, atrazine and diuron. Larvae were more sensitive than embryos to the seven pesticides. The median lethal concentrations of the selected pesticides during a 48- and a 96-h exposure for turbot embryos and larvae were, respectively (in micrograms per litre): chlorpyrifos, 116.6 and 94.65; dieldrin, 146 and 97; pirimiphos-methyl, 560 and 452; diazinon, 1,837 and 1,230; alachlor, 2,177 and 2,233; diuron, 10,076 and 7,826; and atrazine, 11,873 and 9,957. According to their acute toxicity, the insecticides were more toxic than the herbicides. Furthermore, all insecticides and herbicides appear to be teratogenic to turbot ELS.

This study assessed the efficiency of sewage treatment plants (STPs) in removing sterols based on chemical analyses of both influents and effluents. Samples from 3s and three tertiary plants were collected and analyzed by gas chromatography mass spectrometry for 23 individual sterols including mestranol, norethindrone, equol, estrone, equilin, norgestrel, 17α-ethinylestradiol, 17α-estradiol, 17β-estradiol, estriol, dihydrocholesterol (cholestanol), coprostanol, epicoprostanol, cholesterol, desmosterol, campesterol, stigmasterol, β-sitosterol, coprostanone, cholestanone, epicholestanol, stigmastanol, and 24-ethylcoprostanol. The percentage of sterols remaining in effluent samples (compared to influent samples) ranged from 0% to 80% and varied among sterol compounds and with STP location and treatment type. Differences in the efficiency of sterol removal for secondary and tertiary STPs were statistically significant. Although the concentration of sterol compounds differed between influents and effluents, sterol abundances remained the same. The most abundant sterol detected was cholesterol, followed by the fecal sterol coprostanol, and the plant sterols 24-ethylcoprostanol and β-sitosterol. For three STPs, the hormone estrone was detected in effluents at concentrations of 0.03–0.05 μg L−1. Ten sterol ratios specific for human fecal contamination and eight sterol ratios for differentiating among multiple sources of fecal contamination were calculated and showed that 12 ratios for influent and nine ratios for effluent were successful for human fecal source tracking. Based on sterol ratio values in this study, new criteria for identification of human fecal contamination were suggested.