PURPOSE: Dechlorination with tetravalent sulfur is widely used in wastewater treatment processes after chlorination. Dechlorination can remove certain genotoxic disinfection by-products (DBPs). However, the reactions occurring during dechlorination of chlorinated secondary effluent and their genotoxic chemicals are still very complex, and the related genotoxicity changes remain unknown. Therefore, the effects of dechlorination on genotoxicity in secondary effluent and its fractions and typical genotoxic chemical after chlorination were evaluated. METHODS: The dissolved organic matter in the secondary effluent sample was separated into four fractions with XAD-8 resin. Genotoxicity of secondary effluent and its fractions was evaluated by SOS/umu test, an ISO standard method. The concentration of typical genotoxic chemical named ofloxacin was determined by liquid chromatography with a mass spectrometer and a fluorescence detector. RESULTS: Dechlorination with the addition of Na2SO3 notably decreased the genotoxicity in the chlorinated secondary effluent, especially in the presence of high ammonia nitrogen concentration in the sample before chlorination. The Na2SO3 addition significantly decreased the genotoxicity of the secondary effluent and its genotoxic ofloxacin prior to chlorination. The genotoxicity in the fractions containing hydrophobic acids (HOA) increased after chlorination, while addition of Na2SO3 decreased the genotoxicity induced by chlorination. Tryptophan found in HOA exhibited genotoxicity after chlorination, while dechlorination decreased the genotoxicity in chlorinated tryptophan induced by DBPs. CONCLUSIONS: Dechlorination was found to decrease the genotoxicity of chlorinated secondary effluent. The decrease was associated with the reduction of genotoxicity in genotoxic chemicals in secondary effluent prior to chlorination and DBPs.

INTRODUCTION: While the literature is replete with studies of the toxic potency of pentachlorophenol (PCP), site-specific criteria for native aquatic species that can be used in ecological risk assessments has been lacking and application of toxicity information for non-native species is controversial. MATERIALS AND METHODS: In the present study, acute and chronic toxicities of PCP to six aquatic species native to the Yangtze River were determined. The HC5 and HC50 (hazardous concentration for 5% and 50% of species) were derived from dose–response curves for these native aquatic species and were then compared with those derived for non-native species. RESULTS: The acute toxicity values for the native species ranged from 8.8 × 10−2 mg l−1 (Plagiognathops microlepis) to 1.1 mg l−1 (Soirodela polyrhiza), while chronic toxicity values based on no observed effect concentrations (NOECs) ranged from 0.01 mg l−1 (Macrobrachium superbum) to 0.25 mg l−1 (Soirodela polyrhiza). Native aquatic benthos was more sensitive to acute PCP exposure than non-native species. There was no significant difference in NOECs derived from native fish species and those based on non-native fish species. The median acute HC5 and HC50 derived from the toxicity data of native taxa were both less than those derived from non-native taxa. There was no significant difference between chronic HC5s derived from the two sets of taxa. However, the median chronic HC50 derived from native taxa was less than that derived from non-native taxa. CONCLUSION: The study upon which we report here provides site-specific toxicity information developed for native species which can be used for the protection of local aquatic life from a common contaminant, PCP.

The aim of this study was to demonstrate that zebrafish embryos subjected to a priming exposure provided by one environmental stressor (low-dose alpha particles) can induce an adaptive response against a subsequent challenging exposure provided by another environmental stressor (heavy metal Cd). The effect thus identified would be an antagonistic multiple stressor effect. The effects of alpha particle radiation and/or Cd on whole embryos were studied through quantification of apoptotic signals at 24 h post-fertilization (hpf). Embryos were stained with the vital dye acridine orange, followed by counting the stained cells. For each set of experiments, 30 dechorionated embryos were divided into three groups, each having ten embryos. The three groups of embryos were referred to as (A) the control group, which received no more further treatments after dechorionation, (B) Cd-treated group, which did not receive any priming exposure and would receive a challenging exposure at 10 hpf and (C) (alpha + Cd)-treated group, which would receive both priming and challenging exposures. We defined the normalized net number of apoptotic signals in the (alpha + Cd)-treated group as N C * = [(apoptotic signals for (alpha + Cd)-treated group − average apoptotic signals for the corresponding control group)/average apoptotic signals for the corresponding control group] and that in the Cd-treated group as N B* = [(apoptotic signals for Cd-treated group − average apoptotic signals for the corresponding control group)/ average apoptotic signals for the corresponding control group]. By using the non-parametric Mann–Whitney U statistic, we were able to show that N C * was significantly smaller than N B *(p = 0.006). These demonstrated an antagonistic multiple stressor effect between ionizing radiation and Cd through the induction of an adaptive response by the ionizing radiation against subsequent exposures to Cd.

PURPOSE: To examine (1) the effect of organic (poultry manure) and inorganic (residue mud and phosphogypsum) amendments on nutrient leaching losses from residue sand and (2) whether amendments improve the growth of plants in residue sand. METHODS: Leaching columns were established using residue sand. The phosphogypsum-treated surface layer (0–15 cm) was amended with poultry manure and/or bauxite residue mud and the subsurface layer (15–45 cm) was either left untreated or amended with phosphogypsum. RESULTS: Much of the Na+, K+, Cl− and SO 4 2− was lost during the first four leachings. Additions of phosphogypsum to both surface and subsurface layers resulted in partial neutralization of soluble alkalinity. Mean pH of leachates ranged from 8.0 to 8.4, the major cation leached was Na+ and the major balancing anion was SO 4 2− . Where gypsum was not applied to the subsurface, mean pH of leachates was 10.0–10.9, the main cation leached was still Na+ and the main balancing anions were a combination of SO 4 2− and HCO 3 − /CO 3 2− . At the end of the experiment, concentrations of exchangeable Na+ in the subsurface layers were similar regardless of whether gypsum had been applied to that layer or not. Yields of Acacia saligna were promoted by additions of poultry manure to the surface layer but unaffected by gypsum incorporation into the subsurface layer. CONCLUSIONS: Lack of reaction of phosphogypsum with the subsurface layer is unlikely to be a major factor limiting revegetation of residue sand since in the absence of phosphogypsum the excess Na+ leaches with the residual alkalinity (HCO 3 − /CO 3 2− ) rather than SO 4 2− .

INTRODUCTION: The removal of azo Reactive Red 31(RR31) from synthetic dye solution using tannery sludge-developed activated carbon (TSC) was investigated. METHODS: TSC was prepared from a combination of physical and chemical activation. The developed TSC was characterized by FT-IR, SEM, TG–DTA, specific surface area and zero point charge of pH (pHzpc). The isotherm models, kinetic models and thermodynamic parameters were also analysed to describe the adsorptive behaviour of TSC. The effect of contact time, initial dye concentration, carbon dosage, agitation speed, initial pH and temperature were carried out for batch adsorption studies. The isotherm plot of the dye RR31 on TSC fitted better with the Langmuir adsorption isotherm than the Freundlich model. RESULTS: The maximum monolayer adsorption capacity of TSC in the removal of RR31 ranged from 23.15 to 39.37 mg/g. The thermodynamic parameters showed the endothermic and physical nature of the Reactive Red 31 adsorption on TSC. The entropy and enthalpy values were 181.515 J/Kmol and 5.285 kJ/mol, respectively. CONCLUSION: The developed cationic tannery sludge carbon was found to be an effective adsorbent in the removal of the anionic azo reactive dye RR31.

BACKGROUND, AIM, AND SCOPE: Olive oil mill wastewater (OMW), a by-product of the olive oil extraction process, is annually produced in huge amounts in olive-growing areas and represents a significant environmental problem in Mediterranean areas. We studied the impact of OMW dilutions (1:20 and 1:10) on spinach plants in order to evaluate OMW dilutions as a low-cost alternative method for the disposal of this waste. MATERIALS AND METHODS: The effects of OMW dilutions were evaluated on seed germination, shoot and root elongation, biomass production, nutrient uptake and translocation, ascorbic acid content, polyphenols, photosynthetic pigments, and photosynthetic performance of spinach. RESULTS: Plant biomass was more affected than plant height and total chlorophyll; carotenoid and ascorbic acid content progressively decreased with decreasing OMW dilution. Exposure to both OMW dilutions resulted in overaccumulation of total polyphenols, which were negatively correlated to plant biomass and nutrients. Nutrient (Fe, Ca, and Mg) content was insufficient leading to reduced growth. Water use efficiency decreased mainly due to decreased CO2 assimilation rate rather than to a decline of transpiration rate. Disturbances in photosystem II (PSII) photochemical efficiency could be better envisaged by the ratio between variable fluorescence and initial fluorescence (Fv/Fo), which showed much greater amplitude than the maximal photochemical efficiency of PSII photochemistry (Fv/Fm). CONCLUSIONS: From the data obtained, it is suggested that 1:20 OMW dilutions are still phytotoxic and that higher OMW dilutions should be used in order to use this waste for the irrigation of spinach plants.

INTRODUCTION: Over the last few decades, the chromium-based tanning industry has shown rapid growth in Pakistan. However, the rules and regulations promulgated by the government are not strictly followed for processing the effluent discharge from the tanneries. Consequently, tannery effluents have become a great source of water pollution in surrounding areas. MATERIALS AND METHODS: In this case study, characterization of tannery effluent wastewater (TW), shallow groundwater (SW), and deep groundwater (DW) samples was carried out to determine the source of water pollution in the district of Kasur, Pakistan. RESULTS: The concentrations of calcium (Ca), chlorine (Cl), chromium (Cr), iron (Fe), potassium (K), Mg, sulfur (S), silicon (Si), and Sr in TW were significantly higher than SW and DW, which also exceeded the international limits. In addition, increased concentrations of major toxic elements (Cl, Cr, Fe, K, Ni, and Si) were also observed in SW, which were higher in comparison to DW. Strikingly, the concentrations of Cr and Si in various DW samples were also beyond World Health Organization (WHO) safe limit, which reinforced the trend that water pollution in the area is directly linked to the distance from the source (TW). The particle-induced X-ray emission (PIXE) indices also suggested that TW is a main contributory source of water-based pollution in the area, which is imposing great threat to local inhabitants due to known hazardous and carcinogenic potential of these elements. CONCLUSION: Protecting the water resources will be a formidable challenge in the study area, which requires modernization of tannery industry, thereby improving the recovery and recycling of TW. Moreover, PIXE analysis presented here as a successful tool, could serve as landmark for the contemporary research in environmental toxicology.

INTRODUCTION: On August 2006, a cargo ship illegally dumped 500 t of toxic waste containing high concentrations of hydrogen sulphide in numerous sites across Abidjan. Thousands of people became ill. Seventeen deaths were associated with toxic waste exposure. MATERIALS AND METHODS: This study reports on environmental and health problems associated with the incident. A cross-sectional transect study was conducted in five waste dumping site areas. RESULTS: Of the households, 62.1% (n = 502) were exposed to the effects of the pollutants and 51.1% of the interviewed people (n = 2,368) in these households showed signs of poisoning. Most important symptoms were cough (37.1%), asthenia (33.1%), pruritus (29.9%) and nausea (29.1%). DISCUSSION: The health effects showed different frequencies in the five waste impact sites. Among the poisoned persons, 21.1% (n = 532) presented symptoms on the survey day (i.e., 4 months after incident). Transect sampling allowed to determine a radius of vulnerability to exposure of up to 3 km from the point of toxic waste disposal. CONCLUSION: The area of higher vulnerability is influenced by various environmental factors, such as size and severity of pollution site, duration of toxic waste pollution on the impact site and locally climatic conditions. The surveillance of effects on environment and human health is warranted to monitor the development.

BACKGROUND, AIM, AND SCOPE: Assessment of environmental impacts from pesticide utilization should include genotoxicity studies, where the possible effects of mutagenic/genotoxic substances on individuals are assessed. In this study, the genotoxicity profile of the new formicide Macex® was evaluated with two genotoxicity tests, namely, the micronucleus test with mouse bone marrow and Vicia faba, and a mutagenicity test using the Ames Salmonella assay. MATERIALS AND METHODS: The bacterial reverse mutation test (Salmonella typhimurium strains TA97, TA98, TA100, TA102, and TA1535), the Vicia root tip and mouse micronucleus tests were conducted according to published protocols. RESULTS: In the range of the formicide Macex® concentrations tested from 0.06 to 1.0 g L−1 (or mgkg−1 in the mouse test), no genotoxicity was observed in the prokaryotic or eukaryotic test organisms. However, at Macex® concentrations of 0.5 g L−1 and above a significant decrease in the mitotic index (P ≤ 0.05) in the V. faba was observed. Micronucleus formation was likewise increased in the test organism at concentrations starting at 2.0 g L−1. CONCLUSIONS: These data allow us to classify this natural formicide preparation as a product with no geno-environmental-impact when applied at recommended concentrations.

PURPOSE: The purpose of the research is to investigate the application of bagasse fly ash, a sugar industry solid waste for the synthesis of zeolites and their behavior for the sorption of p-nitrophenol (p-NP). METHODS: Zeolitic materials were prepared from bagasse fly ash using alkaline hydrothermal (CZBFA) and fusion (FZBFA) treatment. Comparative batch sorption studies of prepared zeolitic material and virgin material were undertaken to determine their capacities for removal of p-nitrophenol. RESULTS: PXRD patterns revealed that zeolite P and analcime were the dominant contents of synthesized zeolitic material. Chemical composition, morphology, and crystalline nature of CZBFA and FZBFA were characterized by XRF, FTIR, and SEM. The Langmuir, Freundlich, Dubinin Redushkwich, and Temkin sorption isotherms were applied to compare the sorption nature and capacity of synthesized CZBFA and FZBFA with virgin BFA. For each sorbent-p-NP system, a pseudo-second-order kinetic model described the sorption kinetics accurately. The thermodynamics of the p-NP-sorbent systems exhibit an exothermic sorption process. Intraparticle diffusion model shows that the sorption rate was controlled by film diffusion followed by pore diffusion. Regeneration of sorbents was carried out by desorption studies with HCl, NaOH, and SDS detergent. The column studies were performed for the practical utility of sorbents, and breakthrough curve were obtained, which exhibit higher sorption capacity than batch method. CONCLUSION: The sorption capacities of the synthesized zeolites had improved sorption capacities for the sequestration of p-NP and can be utilized as low-cost sorbents for treatment of p-nitrophenolic wastewater.