Separating the effects of organic matter-mineral interactions and organic matter chemistry on the sorption of diuron and phenanthrene

Even though it is well established that soil C content is the primary determinant of the sorption affinity of soils for non-ionic compounds, it is also clear that organic carbon-normalized sorption coefficients (K(OC)) vary considerably between soils. Two factors that may contribute to K(OC) variability are variations in organic matter chemistry between soils and interactions between organic matter and soil minerals. Here, we quantify these effects for two non-ionic sorbates-diuron and phenanthrene. The effect of organic matter-mineral interactions were evaluated by comparing K(OC) for demineralized (HF-treated) soils, with K(OC) for the corresponding whole soils. For diuron and phenanthrene, average ratios of K(OC) of the HF-treated soils to K(OC) of the whole soils were 2.5 and 2.3, respectively, indicating a substantial depression of K(OC) due to the presence of minerals in the whole soils. The effect of organic matter chemistry was determined by correlating K(OC) against distributions of C types determined using solid-state (13)C NMR spectroscopy. For diuron, K(OC) was positively correlated with aryl C and negatively correlated with O-alkyl C, for both whole and HF-treated soils, whereas for phenanthrene, these correlations were only present for the HF-treated soils. We suggest that the lack of a clear effect of organic matter chemistry on whole soil K(OC) for phenanthrene is due to an over-riding influence of organic matter-mineral interactions in this case. This hypothesis is supported by a correlation between the increase in K(OC) on HF-treatment and the soil clay content for phenanthrene, but not for diuron.     

Chloramphenicol influence on antioxidant enzymes with preliminary approach on microsomal CYP1A immunopositive-protein in Chamelea gallina

Chloramphenicol (CA) is a largely used antibiotic and it is an inhibitor of protein synthesis that also induces ROS production. In this work there were investigated activities and expressions in the Adriatic bivalve Chamelea gallina of some antioxidant and detoxification proteins like superoxide dismutase (Mn-SOD, Cu/Zn-SOD), catalase (CAT) and Cytochrome P450 (CYP1A). Clams exposed to 5mgl(-1) of chloramphenicol were sampled 2, 4 and 8 days after treatment (CA2, CA4 and CA8). SODs, CAT, and CYP1A activity and/or expression were detected in pooled digestive glands by Western blotting and by spectrophotometrical analysis. Enzymes activities increase during the entire antibiotic exposure. With respect to the control Cu/Zn-SOD expression increases, while Mn-SOD expression decreases significantly after 4 days. Two CYP1A immunopositive-proteins (57.7 and 59.8kDa) were detected. The lower band significantly decreases in CA8, the upper one also in CA4 condition. High levels of Mn-SOD, CAT activity and Cu/Zn-SOD expression, indicate intense ROS production while Mn-SOD expression inhibition might be ascribable to mitochondrial alterations due to CA and indirectly to ROS. CYP1A1 action determines H(2)O(2) production that would contribute to a CYP1A1 gene promoter down regulation, a response to oxidative stress with the antioxidant enzymes activation as a final result. This study highlights the close association, in C. gallina, in presence of chloramphenicol, between SOD/CAT and CYP system, and it appear particularly interesting to the lack of similar researches on mollusc species.     

Genotoxicity assessment of acute exposure of chlorpyrifos to freshwater fish Channa punctatus (Bloch) using micronucleus assay and alkaline single-cell gel electrophoresis

Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridylphosphorothioate) is one of the organophosphate pesticides widely used in agricultural practices throughout world and irreversible inhibitor of cholinesterase in all animal species. Limited efforts have been made to study acute genotoxic effects of chlorpyrifos (CPF) in different tissues of fish using genotoxic biomarkers. Therefore, the present investigation was aimed to study the induction of DNA damage by CPF in freshwater teleost fish Channapunctatus using micronucleus assay (MN assay) and alkaline single-cell gel electrophoresis (comet assay). The value of LC(50) - 96 h of CPF was determined as 811.98 microgl(-1) for C. punctatus, in a semi-static system and on the basis of LC(50) value three acute concentrations viz., 203, 406 and 609 microgl(-1) were determined. The fishes were exposed to the different concentrations of CPF for 96 h and samplings were done at regular intervals for assessment of the MN frequencies and DNA damage. In general, significant effects (P<0.01) from both concentrations and time of exposure were observed in exposed fishes. It was found that the micronucleus induction was highest on 96 h at all concentrations in the peripheral blood. Similar trend was observed for the DNA damage measured in terms of the percentage of tail DNA in the lymphocyte and gill cells. This study explored the combined use of micronucleus assay and comet assay for in vivo laboratory studies using fresh water fish for screening the genotoxic potential of xenobiotics.     

Haematological and biochemical effects of polyphenolics in animal models

Polyphenols of natural and synthetic origin are exploited in tanning sector to convert putrescible skin/hide to non-putrescible leather. However, only 30-40% of the inputs have been taken up for processing, the remaining is released as unspent. The existing conventional wastewater treatment systems are inefficient in removing or degrading these unspent polyphenols and thus detrimental to ecosystem. The present study demonstrates the evaluation of impact of both synthetic and natural polyphenols on biochemical and haematological properties of blood and serum in animal models. The results reveal that concentrations of polyphenols play a major role. At higher concentrations, irrespective of their nature, there was a marked change in the lipid profile (81% reduction), followed by insignificant change in glucose levels, RBC and WBC counts and other haematological parameters. At lower concentrations, no significant changes in the above said properties were observed.     

Discriminating the pH toxicity to Poecilia reticulata Peters, 1859 in the Dunas Lake (Camaçari, BA, Brazil)

Toxic potential of the pH reduction to fingerlings of Poecilia reticulata, through acute toxicity bioassays, as well as the influence of increased pH on the toxicity were assessed. Acid lake samples (Dunas Lake) were collected during 19 months, and assessed with following treatments: water at local pH (+/-3.0) and samples with modified pH to 3.5, 3.8, 4.0, 4.3, 4.6, 5.0, 5.5, 6.0, and 6.5. Culture water samples with pH reduced to 3.0 were also assessed. Newborn P. reticulata were exposed during 96h, and dead/immobile organisms were counted at various time intervals during exposure (short intervals in the beginning and long towards the end). Mean results of LT(50) and confidence intervals from the Dunas Lake and control water with reduced pH were 1.36 (+/-0.48)h, and 1.03 (+/-0.50)h, respectively, with no statistical difference. Samples with increased pH showed a significant reduction in toxicity, with no toxicity detected at pH 6.0 and higher. Relationship between pH and lethal toxicity for fingerlings of P. reticulata demonstrated that pH exerted a strong effect on the survival of this species at the Dunas Lake, explaining about 80% of the toxicity observed.     

Use of electrochemical technology to increase the quality of the effluents of bio-oxidation processes. A case studied

In this work, it has been studied the use of conductive-diamond electrochemical oxidation (CDEO) as a refining technology to assure the quality of the effluents of door manufacturing processes (DMP). To do this, the raw effluents of these factories have been treated by a combination of physicochemical, biological and CDEO treatments. CDEO was found to be a feasible alternative to the refinement of a wooden DMP waste. It can successfully decrease the organic load of the effluents of the biological oxidation with low energy requirements. In addition, in case of incidents in the biological process, CDEO can treat successfully the effluents of the coagulation process. The effluents of the biological treatment have also been treated by CDEO in order to check the possible use of electrochemical technology to increase the biodegradability of the effluents and their possible recycle to the biological treatment. Unfortunately, electrochemical technology was found to be not adequate to increase the biodegradability of the effluents of a biological treatment. The hard oxidation conditions generated during CDEO do not lead to the accumulation of intermediates but to the almost direct formation of carbon dioxide. Lowering the current density or changing the electrodes can not enhance the biodegradability of the effluents of an electrochemical cell.     

Sorption of copper, zinc and lead on soil mineral phases

Soil mineral phases play a significant role in controlling heavy metal mobility in soils. The effective study of their relation needs the integrated use of several analytical methods. In this study, analytical electron microscopy analyses were combined with sequential chemical extractions on soils spiked with Cu, Zn and Pb. Our aims were to study the metal sorption capacity of soil mineral phases and the effect of presence of iron oxide and carbonate on this property of soil minerals. Copper and Pb were found to be characterized by higher and stronger sorption on the studied samples than Zn. Only the former two metals showed significant differences in their immobilized metal amounts on the studied samples and soil mineral particles. Highest metal amounts were sorbed on the swelling clay mineral particles (smectites and vermiculites), but iron-oxide phases may also have similar lead sorption capacity. Alkaline conditions due to the carbonate content of soils resulted both in increased sorption on the mineral particles for Cu and in enhanced role of precipitation for all the studied metals. On the other hand, the intimate association of phyllosilicates and iron resulted in significant increase in metal sorption capacity of the given particle. The results of sequential extractions could be successfully completed by the analytical electron microscopy analyses for studying the sorption capacity of discrete mineral particles. Their integrated use helps us in better understanding the heavy metal-mineral interactions in soils.     

Photocatalytic and combined anaerobic-photocatalytic treatment of textile dyes

A photocatalytic process based on immobilized titanium dioxide was used to treat crude solutions of azo, anthraquinone and phthalocyanine textile dyes. In addition, the process was applied to the treat autoxidized chemically reduced azo dyes, i.e. representatives of recalcitrant dye residues after biological sequential anaerobic-aerobic treatment. Photocatalysis was able to remove more than 90% color from crude as well as autoxidized chemically reduced dye solutions. UV-absorbance and COD were also removed but to a lower extent (50% in average). The end products of photocatalytic treatment were not toxic toward methanogenic bacteria. The results demonstrate that photocatalysis can be used as a pre- or post-treatment method to biological anaerobic treatment of dye-containing textile wastewater.     

An international survey of decabromodiphenyl ethane (deBDethane) and decabromodiphenyl ether (decaBDE) in sewage sludge samples

Decabromodiphenyl ethane (deBDethane) is an additive flame retardant marketed as a replacement for decabromodiphenyl ether (decaBDE). The structures of the two chemicals are similar, and hence deBDethane may also become an environmental contaminant of concern. Environmental data on deBDethane are scarce. Since sewage sludge is an early indicator of leakage of these chemicals into the environment, an international survey of deBDethane and decaBDE levels in sludge was conducted. Samples were collected from 42 WWTPs in 12 different countries and analyzed with GC/LRMS. DeBDethane was present in sludge from all countries and may therefore be a worldwide concern. The levels of deBDethane in sludge samples from the Ruhr area of Germany were the highest so far reported in the literature (216 ng g⁻¹ d.wt.). The [deBDethane]/[decaBDE] quotient for the whole data set ranged from 0.0018 to 0.83. High ratios were found in and around Germany where deBDethane imports are known to have been high and substitution of decaBDE with deBDethane is likely to have occurred. Low ratios were found in the USA and the UK, countries that have traditionally been large users of decaBDE. An estimate of the flux of deBDEthane from the technosphere via WWTPs to the environment within the European Union gave 1.7 ± 0.34 mg annually per person. The corresponding value for decaBDE was 41 ± 22 mg annually per person.     

Combustion characteristics of Malaysian municipal solid waste and predictions of air flow in a rotary kiln incinerator

Malaysia is in dire need of alternatives to landfilling for solid waste management. Recently, landfills have faced the problems of overfilling, overflowing of leachates leading to pollution of water resources, and uncontrolled dust emissions adversely affecting the local environment. With the rising cost of urbanization coupled with the high rate of waste generation, one possible method of waste treatment that is receiving particular attention by the government is incineration. Incineration of solid waste is rather new in Malaysia, with limited usage in handling small sources of waste generation such as the municipal solid waste (MSW) of resort islands; however, its potential in ameliorating the problems associated with solid waste treatment may make it an attractive alternative to landfill. This article presents the results of test runs conducted to investigate the performance of a locally designed and manufactured rotary kiln incinerator (RKI). The test runs were conducted using MSW collected from the Shah Alam municipality. The combustion efficiency was analyzed by looking at the temperature profiles and chemical species concentrations. To complement the combustion characteristics measurements, predictions of the air flow in the incinerator during the process were also investigated. The overall performance of the RKI suggests that it is suitable for treating MSW.