The performance of the electrochemical oxidation process for efficient treatment of domestic wastewater loaded with organic matter was studied. The process was firstly evaluated in terms of its capability of producing an oxidant agent (H₂O₂) using amorphous carbon (or carbon felt) as cathode, whereas Ti/BDD electrode was used as anode. Relatively high concentrations of H₂O₂(0.064 mM) was produced after 90 min of electrolysis time, at 4.0 A of current intensity and using amorphous carbon at the cathode. Factorial design and central composite design methodologies were successively used to define the optimal operating conditions to reach maximum removal of chemical oxygen demand (COD) and color. Current intensity and electrolysis time were found to influence the removal of COD and color. The contribution of current intensity on the removal of COD and color was around 59.1 and 58.8 %, respectively, whereas the contribution of treatment time on the removal of COD and color was around 23.2 and 22.9 %, respectively. The electrochemical treatment applied under 3.0 A of current intensity, during 120 min of electrolysis time and using Ti/BDD as anode, was found to be the optimal operating condition in terms of cost/effectiveness. Under these optimal conditions, the average removal rates of COD and color were 78.9 ± 2 and 85.5 ± 2 %, whereas 70 % of total organic carbon removal was achieved.

Concentrations of inorganic tin (Snᵢₙₒᵣg), tributyltin (TBT) and its degradation products dibutyltin (DBT) and monobutyltin (MBT) were measured in surface sediments and in two cores from the Toulon Bay, hosting the major French military harbour. Anticipating planned dredging, the aim of the present work is to map and evaluate for the first time the recent and historic contamination of these sediments by inorganic and organic Sn species derived from antifouling paints used for various naval domains including military, trade, tourism and leisure. Tin and butyl-Sn concentrations in the bay varied strongly (4 orders of magnitude), depending on the site, showing maximum values near the shipyards. The concentrations of total Sn (1.3–112 μg g⁻¹), TBT (<0.5–2,700 ng g⁻¹), DBT (<0.5–1,800 ng g⁻¹) and MBT (0.5–1,000 ng g⁻¹) generally decreased towards the open sea, i.e. as a function of both distance from the presumed main source and bottom currents. Progressive degradation state of the butyl-Sn species according to the same spatial scheme and the enrichment factors support the scenario of a strongly polluted bay with exportation of polluted sediment to the open Mediterranean. Low degradation and the historical records of butyl-Sn species in two²¹⁰Pb-dated sediment cores, representative of the Northern Bay, are consistent with the relatively recent use of TBT by military shipyards and confirm maximum pollution during the 1970s, which will persist in the anoxic sediments for several centuries. The results show that (a) degradation kinetics of butyl-Sn species depend on environmental conditions, (b) the final degradation product SnᵢₙₒᵣgBTis by far the dominant species after 10–12 half-life periods and (c) using recent data to reliably assess former TBT contamination requires the use of a modified butyl-Sn degradation index BDIₘₒd. Resuspension of extremely contaminated subsurface sediments by the scheduled dredging will probably result in mobilization of important amounts of butyl-Sn species.

Smoked meat is widely consumed in many areas, particularly in rural southwest China. High concentrations of polycyclic aromatic hydrocarbons (PAHs) in smoked meat could lead to adverse dietary exposure and health risks. In this study, 27 parent PAHs (pPAHs), 12 nitrated PAHs (nPAHs), and 4 oxygenated PAHs (oPAHs) were measured in coal- and wood-smoked meats. The median concentrations of pPAHs, nPAHs, and oPAHs were as high as 1.66 × 10³, 4.29, and 20.5 ng/g in the coal-smoked meat and 2.54 × 10³, 7.32, and 9.26 ng/g in the wood-smoked meat, respectively. Based on the relative potency factors of individual PAHs, the calculated toxic equivalent (TEQ) values of all pPAHs were 22.1 and 75.1 ng TEQ/g for the wood- and coal-smoked meats, respectively. The highest concentrations of PAHs can be found in the surface layer of skin and decrease exponentially with depth. Surface PAH concentrations correlated with concentrations of PAHs in household air and with the concentration in emission exhaust. Migration of PAHs from surface to interior portions of meat is faster in lean than in fat or skin, and oPAHs and pPAHs can penetrate deeper than pPAHs. The penetration ability of PAHs is negatively correlated with the molecular weight.

To collect a complete dataset regarding the occurrence of organic substances in groundwater, this study presents the examination of 66 organic contaminants in the groundwater of overseas departments, including pesticides, pharmaceutical compounds, hormones and some industrial substances. The selective and sensitive analytical methods are described. These techniques begin with solid-phase extraction (SPE) followed by analysis using liquid chromatography–tandem mass spectrometry (LC-MS/MS) and gas chromatography–mass spectrometry (GC-ToF-MS). The paper summarises the analytical results from 40 sampling points collected during two campaigns in Guadeloupe, Martinique, Reunion, Mayotte and Guiana, representing 80 samples. Of the 66 target substances, 36 were determined at least once. Among the most frequently detected are bisphenol A (frequency, 96 %; max., 7,400 ng/L), caffeine (frequency, 91 %; max., 1,240 ng/L), pentachlorophenol (frequency, 55 %; max., 418 ng/L), and carbamazepine (frequency, 56 %; max., 22 ng/L). The results do not put in evidence that the origin of the sample or climatic characteristics of these regions influence the dilution and release of micropollutants.

Lake Al-Asfar (Al-Hassa, Saudi Arabia) is under threat from contaminants released through human activities such as agriculture and urban and industrial developments. In the present study, histopathologic and ultrastructural changes in liver of tilapia Oreochromis niloticus were analyzed to monitor the possible impact of pollution in Al-Asfar estuary. Heavy metals such as Ni, Fe, Zn, Co, Ba, Pb, and Cd were predominant in the lake water and far exceeded the international permissible limits. In fish samples, high prevalences of preneoplastic changes (50 %) and one case of cholangiocarcinoma were revealed in liver tissues. Cytological damage in fish hepatocytes included glycogen exhaustion, deformation of nuclear envelope, heterochromatin condensation, mitochondrial degeneration, vesiculation of rough endoplasmic reticulum, augmentation of smooth endoplasmic reticulum, and lysosomal proliferation. In conclusion, the observed biomarker responses were potential indicators of health impairment or disease in field fish populations, although there was no direct proof of a simple cause–effect relationship. This is the first biological effect assessment in Lake Al-Asfar using tilapia as suitable target species.

Struvite precipitate obtained from yeast industry anaerobic effluent with high ammonium nitrogen (NH₄–N) was investigated for fertilizer effect on plant growth and nutrition according to applications of N, nitrogen/phosphorus/potassium (NPK), and control. Optimum struvite formation conditions were determined via Box–Behnken design. Optimum condition was obtained at pH 9.0 and Mg/N/P molar ratio of 1.5:1:1. Under these conditions, heavy metal concentrations in the obtained struvite precipitate (except Cu) were below the detection limits. In addition to high N, P, and Mg content, energy-dispersive X-ray (EDX) analysis showed that the struvite also included the nutritional elements Ca, K, Na, and Fe. X-ray diffraction (XRD) analysis revealed the complex structures of NaAl(SO₄)₂(H₂O)₁₂, NaMn²⁺Fe₂(PO₄)₃, and (Na₂,Ca)O₂(Fe,Mn)O.P₂O₅in the precipitate. High Na⁺and Ca²⁺concentrations in the anaerobic effluent reacted with phosphate during struvite precipitation. Different applications and struvite dosages significantly affected fresh and dry weights and nutrient element uptakes by plants (P < 0.05). N, P, and Mg uptakes of plants were significantly higher at struvite ×2, ×3, and ×4 dosages compared with NPK application. For adequate nutrition and supply of optimum dry weight, struvite ×2 dosage (5.71 g struvite/kg soil) was found appropriate for both maize and tomato plants.

The anatase/schorl composites were prepared and employed for the photocatalytic discoloration of an azo dye, Methyl Orange (MO). X-ray diffraction results indicated that TiO₂existed in the form of anatase phase and no diffraction peaks of schorl could be observed for all the composite samples. Scanning electron micrographs showed that the particles of anatase were well deposited and dispersed on the surface of schorl. Photocatalytic experiments revealed that the anatase/schorl composites exhibited higher photocatalytic activity for MO discoloration than pure TiO₂and more than 90 % discoloration ratio could be obtained within 60 min UV irradiation when the sample containing 3 wt.% of schorl as TiO₂support was used. Then, the central composite design (CCD) under the response surface methodology (RSM) was employed for the experiment design and process optimization. The significance of a second-order polynomial model for predicting the optimal values of MO discoloration was evaluated by the analysis of variance (ANOVA) and 3D response surface plots for the interactions between two variables were constructed. Based on the model prediction, the optimum conditions for the photocatalytic discoloration of MO by TiO₂/schorl composite were determined to be 15 × 10⁻³ mM MO initial concentration, 2.7 g/l photocatalyst dosage, solution pH 6.6 and 43 min reaction time, with a maximum MO discoloration ratio of 98.6 %. Finally, a discoloration ratio of 94.3 % was achieved for the real sample under the optimum conditions, which was very close to the predicted value, implying that RSM is a powerful and satisfactory strategy for the process optimization.

Ionic liquids (ILs) are called "green" solvents, which are due to their unique physicochemical properties and potential applications in various areas. However, the toxicity of ILs has attracted increasing attention from scientific researchers. The present paper studied the toxic effects of 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈mim]PF₆) on wheat seedlings at 0, 1, 2, 4, 6, and 8 mg l⁻¹on days 7, 10 and 13. The present results showed that the growth of wheat seedlings was seriously inhibited when the concentration was higher than 2 mg l⁻¹and the inhibitory effect enhanced with increasing concentration and time. The EC₅₀values for germination, shoot length, root length and dry weight were 11.104, 5.187, 4.380 and 6.292 mg l⁻¹, respectively. [C₈mim]PF₆could cause an increase in the production of ROS, which led to the oxidative damage and lipid peroxidation. Furthermore, these toxic effects on wheat seedlings were irreversible.

The Australian and New Zealand Guidelines for Fresh and Marine Water Quality are a key document in the Australian National Water Quality Management Strategy. These guidelines released in 2000 are currently being reviewed and updated. The revision is being co-ordinated by the Australian Department of Sustainability, Environment, Water, Population and Communities, while technical matters are dealt with by a series of Working Groups. The revision will be evolutionary in nature reflecting the latest scientific developments and a range of stakeholder desires. Key changes will be: increasing the types and sources of data that can be used; working collaboratively with industry to permit the use of commercial-in-confidence data; increasing the minimum data requirements; including a measure of the uncertainty of the trigger value; improving the software used to calculate trigger values; increasing the rigour of site-specific trigger values; improving the method for assessing the reliability of the trigger values; and providing guidance of measures of toxicity and toxicological endpoints that may, in the near future, be appropriate for trigger value derivation. These changes will markedly improve the number and quality of the trigger values that can be derived and will increase end-users’ ability to understand and implement the guidelines in a scientifically rigorous manner.

Many jurisdictions around the globe have well-developed regulatory frameworks for the derivation and implementation of water quality guidelines (WQGs) or their equivalent (e.g. environmental quality standards, criteria, objectives or limits). However, a great many more still do not have such frameworks and are looking to introduce practical methods to manage chemical exposures in aquatic ecosystems. There is a potential opportunity for learning and sharing of data and information between experts from different jurisdictions in order to deliver efficient and effective methods to manage potential aquatic risks, including the considerable reduction in the need for aquatic toxicity testing and the rapid identification of common challenges. This paper reports the outputs of an international workshop with representatives from 14 countries held in Hong Kong in December 2011. The aim of the workshop and this paper was to identify ‘good practice’ in the development of WQGs to deliver to a range of environmental management goals. However, it is important to broaden this consideration to cover often overlooked facets of implementable WQGs, such as demonstrable field validation (i.e. does the WQG protect what it is supposed to?), fit for purpose of monitoring frameworks (often an on-going cost) and finally how are these monitoring data used to support management decisions in a manner that is transparent and understandable to stakeholders. It is clear that regulators and the regulated community have numerous pressures and constraints on their resources. Therefore, the final section of this paper addresses potential areas of collaboration and harmonisation. Such approaches could deliver a consistent foundation from which to assess potential chemical aquatic risks, including, for example, the adoption of bioavailability-based approaches for metals, whilst reducing administrative and technical burdens in jurisdictions.