Toxicity of contaminated soils cannot be assessed only by chemical analyses, therefore bioassays are increasingly used. Widely accepted ecotoxicological methods include organisms from all levels of the food-chain but plant-based ones are usually restricted to germination and growth tests. In our study the toxicity of heavy metal contaminated soil samples were examined not only by germination and bacterial tests of their extracts but also by the measurement of physiological parameters of two plant species (cucumber and wheat) that were grown directly on the contaminated substrate. Changes in chlorophyll concentration, stomatal conductance, fluorescence characteristics, and malondialdehyde (MDA) level (showing oxidative damage to lipids in leaves) undoubtedly indicated the mobilisation and toxic effect of contaminants. The results showed that the sensitivity of plant physiological parameters was higher than that of the extract-based ecotoxicological tests. Whereas these latter could not reveal the toxic effect of the highly contaminated soils the plants have reacted in a more complex way and their physiological parameters have changed significantly in all cases validating their use in such studies. The applied measurements also allow quicker and more reliable testing even under field conditions (stomatal conductance) or the detection of a more complex response if detailed analyses is needed (MDA, fluorescence imaging) thus underlining the importance of plant-based methods.

Oil spill leaves detrimental effects to environment, living organisms, and economy. As such, it is of considerable interest to find an effective, simple, and inexpensive method to treat this calamity. This work reports the use of banana trunk fibers (BTF) modified with oleic acid, stearic acid, castor oil, and palm oil for oil spill recovery. The maximum sorption capacity, effect of oil to water ratio, effect of light oil fractions, and effect of dissolved organic compounds in weathered oil-contaminated seawater were studied. It is found that BTF treated with oleic acid exhibited the best sorption capacity for engine oil, dissolved organic compounds in weathered oil, and light oil fractions. The equilibrium process was described well by the Freundlich isotherm model, and the kinetic studies show good correlation coefficients for a pseudo-second-order kinetic model.

Exposure to micropollutants can pose a serious risk to both the environment and human health. Although sewage treatment works (STWs) aim to reduce levels of pollutants in municipal wastewater discharges, they have become a significant point source of dangerous substances to the aquatic environment. With increasing regulation on pollution prevention, it has become essential to assess STW source inputs in order to control pollutant discharge into the environment. This paper has therefore focussed on developing calculations to estimate micropollutant levels in STW influents. The analysis was carried out using information from published literature, the Water Industry, and monitored influent data. Results demonstrated that, where monitoring data were available for metals and organic pollutants, STW influent could be adequately estimated and validated, with accuracy between 77% and 100%. In addition, based on these calculations and using data for over 600 STWs in England, our analysis showed that compounds such as di(2-ethylhexyl) phthalate, lead and linear alkylbenzenesulfonate could reach influent levels that could be challenging for conventional wastewater treatment removal.

The Han River, which is the largest river in Korea, is the primary source of drinking water for the 20 million people that live in the Seoul metropolitan and surrounding areas. The sediments in the river are highly polluted due to pollutant inputs from upstream tributaries as well as from partially treated municipal wastewaters. To characterize the contamination of the sediments, disturbed and undisturbed sediment samples were periodically collected from eight locations of the mid-to-lower Han River. They were analyzed for pH, water content, total solids, ignition loss (IL), total phosphorous (TP), total Kjehldahl nitrogen (TKN), and chemical oxygen demand (COD). The mean values of pollutant concentrations in disturbed sediment were determined to be 6.9% for IL, 1,700 mg/kg for TP, 3,350 mg/kg for TKN, and 65,710 mg/kg for COD. Pollutant concentrations of undisturbed samples were found to decrease with sediment depth and time due to the removal mechanism. Monitoring of pre- and post-dredging conditions was also performed, and the results show that the pollutant concentrations decreased from those for the pre-dredging condition to 33-57% for TP, 51-64% for TKN, and 30-62% for COD. It is concluded that dredging was an effective means to reduce the internal pollutant source.

We assessed the impacts of a specific conductance gradient attributable to treated coal-mining discharges on the fish communities of a southwestern Pennsylvania stream. Total dissolved solids concentrations were determined from specific conductance values. A total of 10,940 fish representing seven families and 42 species/hybrids were collected from 17 stations over the entire survey. Species richness, density, and the coefficient of community loss (I) showed marked impairment at the two stations directly below the discharges and the downstream recovery was interrupted at one station by untreated discharges from a mine refuse pile. Species richness declined from 28 at the reference site to 7 at the station directly below the treated effluents. This study suggests that the threshold for in-stream conductivity impairment to fish communities in this region is in the range of 3,000-3,500 µS/cm and 2,000-2,300 mg/l of total dissolved solids, respectively.

We tested the efficacy of matrix-based fertilizers (MBFs) to improve Kentucky bluegrass (Poa pratensis L.) growth while reducing NH, NO3, dissolved reactive phosphorus (DRP), and total phosphorus (TP) compared to commercial slow-release fertilizer (SRF) Polyon®, ESN®, and Avail® in greenhouse column studies. The MBFs covered a range of inorganic N and P in compounds that are relatively loosely bound (MBF6) and more tightly bound compounds (MBF7) with Al(SO4)318H2O and/or Fe2(SO4)33H2O and with high ionic exchange compounds starch, cellulose, and lignin. The total amount of NO3 and NH4 leached was greater from columns receiving Polyon® and ESN® fertilizers than all other treatments. The MBF6+Avail® or MBF7+Avail® fertilizers leached 64–68% less NO3 than Polyon® (43-0-0) and ESN® (46-0-0), and 73–76% less TDP and TP than Avail® (10-34-0). A greater amount of NO3 was leached from the MBF6+Avail® and the MBF7+Avail® treatments than the other MBF fertilizer treatments. Shoot and root biomass were greater when plants received the Avail®, MBF6+Avail®, and MBF7+Avail® fertilizer treatments than the other fertilizer treatments. When combined with small quantities of commercial SRFs, these new MBFs were able to maintain plant growth while reducing N and P leaching. These new MBF formulations do not depend on organic or inorganic coatings to reduce N and P leaching and with further testing and development could be effective commercial fertilizers.

To evaluate adverse impacts of metal pollution originating from smelting activities on the aquatic ecosystem of Deûle river in northern France, water samples were collected from five selected stations along a contaminated region of this river (during two surveys: April-June 2005 and April-May 2007). All samples were analysed using inductively coupled plasma (ICP) atomic emission spectroscopy and/or ICP-mass spectrometry. Both the concentrations of dissolved and particulate elements were determined, and analytical data were compared with national and international water/particle quality guidelines as well as with some values reported in the literature for polluted rivers. For all the metals studied (i.e. Cd, Cr, Cu, Mn, Ni, Pb and Zn), our investigations showed that the effects of the dissolved phase on this aquatic medium were weak, according to water quality status established by US Environmental Protection Agency, USEPA (1994, 1999). Conversely, the levels of metals in suspended particulate matter were found to be much higher than local background contents and natural reference levels in French catchments. These levels were further quantified as “serious” contamination, i.e. above the “red” range that was previously elaborated by most existing metal-contamination scales in French basins of similar geology. The affinity of these metals for the particulate phase in Deûle waters follows the order: Cd >Cr > Pb > Zn = Mn > Cu > Ni. The trace metals released from anthropogenic activities were found to be partly bound to the reactive particulate phase, calcite, which is sensitive to physico-chemical variations occurring in the river ecosystem. To appraise the risk of ecotoxicity by metals, predictions on the ability to release metallic pollutants from calcite into waters were made successfully by testing three equilibrium geochemical speciation models (JCHESS, VISUAL MINTEQ and WINHUMIC) in which soluble organic matter was taken into account. Calculations showed that metal-water-calcite systems in Deûle River are close to thermodynamic equilibrium with generation of solid solutions, MeαCa₁₋αCO₃, by (co)precipitation and/or adsorption reactions. On the basis of results mentioned here, more measurements of river chemistry and assessments of predictive capabilities of chosen water-quality guidelines with time would be developed in aquatic and calcareous areas for controlled dredging operations or other treatment engineering works.

Adsorption to biomass is a key mechanism which results in the elimination of natural estrogens and their conjugates from sewage. Freundlich model showed that the adsorption capacities of estrone and 17β-estradiol to activated sludge were the highest at neutral pH. The lower capacities at pH 2 and 11.5 could be due to the competition of sludge adsorption sites by cations or electrostatic repulsion from particles of similar charges. The lowest adsorption capacity at pH 11.5 was attributable to electrostatic repulsion, and the highest capacity at pH 2 might be due to the increased sulfate adsorbability. For estrogen conjugates such as estrone-3-sulfate and 17β-estradiol-3-sulfate, adsorption performances were similar at pH 5, 7, and 9. It was observed that mean values of log K D were 2.78, 2.61, 1.67, and 1.94 l kg TSS⁻¹; log K OM were 2.96, 2.79, 1.77, and 2.04 l kg VSS⁻¹ and those of log K OC were 3.31, 3.12, 2.21, and 2.46 l kg OC⁻¹ for estrone, 17β-estradiol, estrone-3-sulfate, and 17β-estradiol-3-sulfate, respectively.

The remediation of groundwater contaminated with benzene, toluene, ethylbenzene, and the xylenes (BTEX) typically involves in situ biodegradation. Although the mechanisms of aerobic BTEX biodegradation in laboratory cultures have been well studied, less is known about the microorganisms responsible in mixed culture samples or at contaminated sites. In this study, the microorganisms responsible for in situ degradation within mixed culture samples were investigated using the molecular method stable isotope probing (SIP). For this, m-xylene was utilized as a model BTEX contaminant. Specifically, DNA-based SIP was utilized to identify active m-xylene degraders in microcosms constructed with soil from three sources (a gasoline-contaminated site and two agricultural sites). Replicate microcosms were amended with either labeled (¹³C) or unlabeled m-xylene, and the extracted DNA samples were ultracentrifuged, fractioned, and subjected to terminal restriction fragment length polymorphism (TRFLP). The dominant m-xylene degraders (responsible for ¹³C uptake) were determined by comparing relative abundance of TRFLP phylotypes in heavy fractions of labeled m-xylene (¹³C) amended samples to the controls (from unlabeled m-xylene amended samples). Four phylotypes were identified as the dominant m-xylene degrading species, falling within either the β Proteobacteria or the Bacilli. Of these, two 16S rRNA gene sequences were highly novel, displaying very limited similarity (94% and 90%) to any previously reported 16S rRNA gene sequence. Further, three of these phylotypes fell within genera with limited or no previous links to BTEX degradation, suggesting much information is still to be gained concerning the identity of microorganisms responsible for degradation within mixed culture samples.

A strong base anion exchange resin Amberlite IRA-400 Cl⁻ and its hybrids with Mn(OH)₂ and Cu(OH)₂ are used for the removal of chromium from the synthetic spent tannery bath. The recovery is examined by varying the experimental conditions, viz., resin dosage, stirring speed, and temperature. The rate of chromium removal by Amberlite IRA-400 Cl⁻ increased almost four times when the resin dosage was increased from 0.2 to 1.0 g. Furthermore, the rate of chromium sorption almost doubled when the stirring speed was increased from 100 to 1,000 rpm, suggesting that the sorption is a diffusionally controlled process. The chromium removal capacity also increased with the rise of temperature, showing the endothermic nature of the process. The results are explained with the help of film diffusion, particle diffusion, and Lagergren pseudo-first-order kinetic models. The kinetics results of the Amberlite IRA-400 Cl⁻ are compared with its hybrid anion exchange resins IRA-400 Mn(OH)₂ and IRA-400 Cu(OH)₂. It is found that the hybrid ion exchangers have greater removal ability and fast kinetics as compared to the parent exchanger.