PURPOSE: Persistent organic pollutants (POPs) are of global concern due to their ubiquitous presence and toxicity. The occurence of polychlorinated dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs), co-planar biphenyls (PCBs), hexachlorocyclohexanes (HCH), dichlorodiphenyltrichloroethanes (DDT), and organochlorine pesticides (OCPs) in forest soil collected from Taurus mountains may have adverse effects on the environment and health. The aim of the study was to investigate the outcome and distribution of POPs in the environment and the possible grasshopper effect along an altitude transect from sea level up to nearly 2,000 m a.s.l at a spatial distance of about 60 km in the southeastern Turkish Mediterranean Sea. METHODS: The samples were collected at a height of 121, 408, 981, 1,225, 1,373, 1,639, and 1,881 m above sea level from Taurus Mountains, Turkey. The results were confirmed using high-resolution gas chromatography–high-resolution mass spectrometry. RESULTS: The levels of the PCDD in forest soil from Taurus Mountains varied from nearly 4 to 12 pg g−1 dry weight (dw). PCDF concentrations ranged from 2 to 7 pg g−1 dw. Considerably high DDT levels detected in five stations indicated (3,223–24,564 pg g−1) its extensive local application or atmospheric transport. PCB levels were determined between 80 and 288 pg g−1 dw. HCH concentrations ranged from 141 to 1,513 pg g−1 dw. The other OCP was between 102 and 731 pg g−1. CONCLUSION: Although the use of POPs has been banned, our results show that they could still be found in Turkey. Their presence may be attributed to the degradation of pesticides which are newly banned and, as well as to the atmospheric migration and deposition. The lattitude of sampling sites, the chemical, and physical parameters of soil have observed no effect on the fate of POPs in the environment.

The purpose of this study was to link toxicokinetics/toxicodynamics (TK/TD) and bioavailability-based metal uptake kinetics to assess arsenic (As) uptake and bioaccumulation in three common farmed species of tilapia (Oreochromis mossambicus), milkfish (Chanos chanos), and freshwater clam (Corbicula fluminea). We developed a mechanistic framework by linking damage assessment model (DAM) and bioavailability-based Michaelis–Menten model for describing TK/TD and As uptake mechanisms. The proposed model was verified with published acute toxicity data. The estimated TK/TD parameters were used to simulate the relationship between bioavailable As uptake and susceptibility probability. The As toxicity was also evaluated based on a constructed elimination–recovery scheme. Absorption rate constants were estimated to be 0.025, 0.016, and 0.175 mL g−1 h−1 and As uptake rate constant estimates were 22.875, 63.125, and 788.318 ng g−1 h−1 for tilapia, milkfish, and freshwater clam, respectively. Here we showed that a potential trade-off between capacities of As elimination and damage recovery was found among three farmed species. Moreover, the susceptibility probability can also be estimated by the elimination–recovery relations. This study suggested that bioavailability-based uptake kinetics and TK/TD-based DAM could be integrated for assessing metal uptake and toxicity in aquatic organisms. This study is useful to quantitatively assess the complex environmental behavior of metal uptake and implicate to risk assessment of metals in aquaculture systems.

INTRODUCTION: Mercury is a high-priority regulatory concern because of its persistence and bioaccumulation in the environment and evidence of its having serious adverse effects on the neurological development of children. DISCUSSION: Mercury is released into the atmosphere from both natural and anthropogenic sources. Coal-fired utilities are considered to be one of the largest anthropogenic mercury emission sources. The period since the late 1990s has been marked by increasing concern over mercury emissions from combustion systems to the extent that a number of national governments have either already implemented or are in the process of implementing, legislation aimed at enforcing tighter control over mercury emissions and a reduction in mercury consumption. CONCLUSION: This review examines the most important national and international policies and agreements for controlling mercury emissions from coal-fired combustion systems. To provide a global perspective, this study lists the countries with the largest estimated mercury emissions and regulatory efforts to reduce them.

INTRODUCTION: The unhairing step, a part of the beamhouse process, is particularly polluting, generating an alkaline wastewater with high concentrations of organic and inorganic matter. The aim of this study was to evaluate the treatment of this industrial wastewater using a combination of biological and microfiltration processes. MATERIALS AND METHODS: The performance of the activated sludge system (AS) was evaluated under varying organic loading rate (OLR) from 0.9 to 3.4 kg chemical oxygen demand (COD) m−3 day−1 and decreasing hydraulic retention time (HRT) from 3 to 1.6 days. RESULTS: For an HRT of 3 days, the increase of OLR significantly affected the removal of organic matter. Therefore, the biological organic matter removal of unhairing wastewater decreased from 92% to 66% for COD and from 87 to 53% for biological oxygen demand (BOD5). GC-MS analyses showed that biological treatment of unhairing wastewater contributed to the removal of long chain fatty acids and their degradation products. Microfiltration of unhairing wastewater was performed using 0.2 μm pore-size membranes in tangential filtration. The highest removal efficiencies were obtained for bacteria (100%) and turbidity (98.4%) which confirmed the importance of the microfiltration step in treatment of unhairing wastewater. The result showed that the flux decay rate was greatest at the start of the microfiltration assay (90 L h−1 m2), becoming 60.7 L h−1 m2 after 32 min. CONCLUSION: This change indicated that fouling occurred rapidly once the membrane module was put into operation.

PURPOSE: Heavy metals have been detected in water and sediments from the Embalse La Florida, an artificial lake in the arid region of San Luis province, Argentina, representing one of the few sources of permanent water for reproduction of native anuran species. This study assesses lead (Pb) and cadmium (Cd) concentrations in the anuran species found in this water reservoir as well as differences between compounds, species and sites of collection. METHODS: Adult anuran amphibians were collected on the north and south shores of the Embalse La Florida and Pb and Cd concentrations were measured in whole body homogenates digested using wet ashing techniques. RESULTS: All individuals of the six species assayed had detectable levels of Pb and Cd that ranged from 1.19 to 5.57 μg/g dry mass and from 1.09 to 6.86 μg/g dry mass, respectively. Anuran amphibians collected in the more contaminated south shore accumulated 21% more Cd and 40% more Pb than individuals from the less altered north shore. Cd and Pb accumulation was not significantly correlated with the concentration in water at the site of collection. CONCLUSIONS: Amphibians of the Embalse La Florida accumulate Cd and Pb. Between and within species, differences were detected in Cd and Pb concentrations. Differences in metal concentrations between species, metals, and individuals collected on shores of the Embalse La Florida with different contamination, were detected. Therefore, it is crucial to implement adequate policies to protect amphibians from the accelerated urban development experienced in this location.

BACKGROUND, AIM, AND SCOPE: Okadaic acid (OA) and analogues of dinophysistoxin (DTX) are key diarrheic shellfish poisoning (DSP) toxins, which possibly arouse DSP symptoms by consuming the contaminated shellfish. Because of the stable toxicity in high temperature and the long-term carcinogenicity, the outbreaks of DSP related to consumption of bivalve mollusks contaminated by DSP toxins pose a hazard to public health. Therefore, it is worth developing a fast and reliable analytical method for the detection of OA and analogues in shellfish. In this paper, an indirect competitive enzyme-linked immunosorbent assay (ELISA) (icELISA) for detecting OA and DTX-1 in seafood was developed based on monoclonal antibody (McAb). METHODS: The OA was conjugated to human immunoglobulin G (IgG) and bovine serum albumin (BSA) by the active ester method as the immune antigen and the detective antigen. The spleen cells from BALB/c mice immunized with OA-IgG were fused with SP2/0 myeloma cells. A hybridoma cell line, which secreted McAb against OA, was selected by “limiting dilution” cloning. An icELISA was developed based on immobilized conjugate (OA-BSA) competing the McAb with the free OA in seafood sample. RESULTS: A hybridoma cell line, which secreted IgG1 subclass monoclonal antibody (McAb) against OA, was selected. The IC₅₀ of the McAb for OA and dinophytoxin-1 (DTX-1) were 4.40 and 3.89 ng/mL, respectively. Based on the McAb, an indirect competitive ELISA for detection of OA and DTX-1 in seafood was developed. The regression equation was y = 54.713x − 25.879 with a coefficient correlation of R ² = 0.9729. The linear range and the limit of detection were 0.4–12.5 and 0.45 ng/mL, respectively. The average recovery of OA and DTX-1 spiked shellfish was 82.29% with the coefficient of variation of 7.67%. CONCLUSION: The developed icELISA is a fast, sensitive, and convenient assay for detecting of total amount of OA and DTX-1 in seafood.

PURPOSE: The major aromatic constituents of petroleum products viz. benzene, toluene, and mixture of xylenes (BTX) are responsible for environmental pollution and inflict serious public concern. Therefore, BTX biodegradation potential of individual as well as formulated bacterial consortium was evaluated. This study highlighted the role of hydrogen peroxide (H2O2), nitrate, and phosphate in stimulating the biodegradation of BTX compounds under hypoxic condition. MATERIALS AND METHODS: The individual bacterium viz. Bacillus subtilis DM-04 and Pseudomonas aeruginosa M and NM strains and a consortium comprising of the above bacteria were inoculated to BTX-containing liquid medium and in soil. The bioremediation experiment was carried out for 120 h in BTX-containing liquid culture and for 90 days in BTX-contaminated soil. The kinetics of BTX degradation either in presence or absence of H2O2, nitrate, and phosphate was analyzed using biochemical and gas chromatographic (GC) technique. RESULTS: Bacterial consortium was found to be superior in degrading BTX either in soil or in liquid medium as compared to degradation of same compounds by individual strains of the consortium. The rate of BTX biodegradation was further enhanced when the liquid medium/soil was exogenously supplemented with 0.01 % (v/v) H2O2, phosphate, and nitrate. The GC analysis of BTX biodegradation (90 days post-inoculation) in soil by bacterial consortium confirmed the preferential degradation of benzene compared to m-xylene and toluene. CONCLUSIONS: It may be concluded that the bacterial consortium in the present study can degrade BTX compounds at a significantly higher rate as compared to the degradation of the same compounds by individual members of the consortium. Further, addition of H2O2 in the culture medium as an additional source of oxygen, and nitrate and phosphate as an alternative electron acceptor and macronutrient, respectively, significantly enhanced the rate of BTX biodegradation under oxygen-limited condition.

PURPOSE AND AIM: The present study provides an optimization of electrocoagulation process for the simultaneous removal of heavy metals such as mercury, lead, and nickel from water. In doing so, the thermodynamic, adsorption isotherm and kinetic studies were also carried out. MATERIALS AND METHODS: Magnesium alloy, magnesium, aluminum, and mild steel sheet of size 2 dm² were used as anode and galvanized iron as cathode. To optimize the maximum removal efficiency, different parameters like effect of initial concentration, effect of temperature, pH, and effect of current density were studied. Mercury-, lead-, and nickel-adsorbed magnesium hydroxide coagulant was characterized by SEM and EDAX. RESULTS: The results showed that the maximum removal efficiency was achieved for mercury, lead, and nickel with magnesium alloy as anode and galvanized iron as cathode at a current density of 0.15 Å/dm² and pH of 7.0. The adsorption of mercury, lead, and nickel are preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. The adsorption process follows second-order kinetics. Temperature studies showed that adsorption was endothermic and spontaneous in nature. CONCLUSIONS: The magnesium hydroxide generated in the cell removes the heavy metals present in the water and reduces to a permissible level, making it drinkable.

Concentrations of air pollutants, nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), particulate matter (PM2.5 and PM10), trace metals, and polycyclic aromatic hydrocarbons (PAHs) were measured in 2008 and 2009 in the city of Eskişehir, central Turkey. Spatial distributions of NO2, SO2, and ozone were determined by passive sampling campaigns carried out during two different seasons with fairly large spatial coverage. A basic population exposure assessment was carried out employing Geographical Information System techniques by combining population density maps with pollutant distribution maps of NO2 and SO2. It was found that 95 % of the population is exposed to NO2 levels close to the World Health Organization guideline value. Regarding SO2, a large proportion of the population (83 %) is exposed to levels above the WHO second interim target value. Concentrations of all the pollutants showed a seasonal pattern increasing in winter period, except for ozone having higher concentrations in summer season. Daily PM10 and PM2.5 concentrations exceeded European Union limit values almost every sampling day. Toxic fractions of the measured PAHs were calculated and approximately fourfold increase was observed in winter period. Copper, Pb, Sn, As, Cd, Zn, Sb, and Se were found to be moderately to highly enriched in PM10 fraction, indicating anthropogenic input to those elements measured. Exposure assessment results indicate the need for action to reduce pollutant emissions especially in the city center. Passive sampling turns out to be a practical and economical tool for air quality assessment with large spatial coverage.

PURPOSE: The disinfection efficiency of water and secondary treated wastewater by means of photoelectrocatalytic oxidation (PEC) using reference strains of Enterococcus faecalis and Escherichia coli as faecal indicators was evaluated. Operating parameters such as applied potential (2–10 V), initial bacterial concentration (103–107 CFU/mL), treatment time (up to 90 min) and aqueous matrix (pure water and treated effluent) were assessed concerning their impact on disinfection. METHODS: PEC experiments were carried out using a TiO2/Ti film anode and a zirconium cathode in the presence of simulated solar radiation. Bacterial inactivation was monitored by the culture method and real-time SYBR green PCR. RESULTS: A 6.2 log reduction in E. faecalis population was achieved after 15 min of PEC treatment in water at 10 V of applied potential and an initial concentration of 107 CFU/mL; pure photocatalysis (PC) led to only about 4.3 log reduction, whilst negligible inactivation was recorded when the respective electrochemical oxidation process was applied (i.e. without radiation). PEC efficiency was generally improved increasing the applied potential and decreasing initial bacterial concentration. Regarding real wastewater, E. coli was more susceptible than E. faecalis during treatment at a potential of 5 V. Wastewater disinfection was affected by its complex composition and the contained mixed bacterial populations, yielding lower inactivation rates compared to water treatment. Screening the results obtained from both applied techniques (culture method and real-time PCR), there was a discrepancy regarding the recorded time periods of total bacterial inactivation, with qPCR revealing longer periods for complete bacterial reduction. CONCLUSIONS: PEC is superior to PC in terms of E. faecalis inactivation presumably due to a more efficient separation and utilization of the photogenerated charge carriers, and it is mainly affected by the applied potential, initial bacterial concentration and the aqueous matrix.