The effect of repeated chlorothalonil applications on its persistence and soil microbial activities were investigated in planted soil under greenhouse conditions. The results revealed that suppressed dissipation of chlorothalonil and the consequent accumulation of chlorothalonil and its toxic metabolite, 4-hydroxychlorothalonil, resulted from four successive applications at rates of 2, 4, and 10 kg a.i./ha. Soil respiration for 7 h (SR7) was slightly affected by chlorothalonil applications at all three levels, whereas soil respiration for 24 h (SR24) at 10 kg a.i./ha was reduced by 17.6–59.1 %, depending upon the frequency. This harmful effect of chlorothalonil on SR24 persisted throughout the experiment although it gradually weakened with time. A persistent inhibitory effect on soil dehydrogenase activity was also observed with repeated applications of chlorothalonil at 10 kg a.i./ha. This study indicated that repeated chlorothalonil applications may lead to the accumulation of chlorothalonil and its metabolite in soil under greenhouse conditions and thereby alter soil microbial activity.

The biological treatment of ammonia-rich landfill leachates due to an inadequate C to N ratio requires expensive supplementation of carbon from an external carbon source. In an effort to reduce treatment costs, the objective of the study was to determine the feasibility of nitrogen removal via the nitrite pathway during landfill leachate co-treatment with municipal wastewater. Initially, the laboratory-scale sequencing batch reactor (SBR) was inoculated with nitrifying activated sludge and fed only raw municipal wastewater (RWW) during a start-up period of 9 weeks. Then, in the co-treatment period, consisting of the next 17 weeks, the system was fed a mixture of RWW and an increasing quantity of landfill leachates (from 1 to 10 % by volume). The results indicate that landfill leachate addition of up to 10 % (by volume) influenced the effluent quality, except for BOD₅. During the experiment, a positive correlation (r² = 0.908) between ammonia load in the influent and nitrite in the effluent was observed, suggesting that the second step of nitrification was partially inhibited. The partial nitrification (PN) was also confirmed by fluorescence in situ hybridisation (FISH) analysis of nitrifying bacteria. Nitrogen removal via the nitrite pathway was observed when the oxygen concentration ranged from 0.5 to 1.5 mg O₂/dm³and free ammonia (FA) ranged from 2.01 to 35.86 mg N-NH₃/dm³in the aerobic phase. Increasing ammonia load in wastewater influent was also correlated with an increasing amount of total nitrogen (TN) in the effluent, which suggested insufficient amounts of assimilable organic carbon to complete denitrification. Because nitrogen removal via the nitrite pathway is beneficial for carbon-limited and highly ammonia-loaded mixtures, obtaining PN can lead to a reduction in the external carbon source needed to support denitrification.

The photodegradation of indoxacarb, a broad spectrum foliar insecticide and spinosad, a natural insecticide containing two active ingredients, spinosyn A (major component) and spinosyn D (minor component), was studied in aqueous suspensions of binary (ZnO and TiO₂) and ternary (Zn₂TiO₄ and ZnTiO₃) oxides under artificial light (300–460 nm) irradiation. As expected, the influence of the semiconductor materials on the degradation of both was very significant in all cases. Photocatalytic experiments showed that the addition of semiconductors in tandem with Na₂S₂O₈ as electron acceptor strongly improved the removal of indoxacarb and spinosad in water compared with the photolytic tests. The reaction rates significantly increased, especially for the ZnO/Na₂S₂O₈ and TiO₂/Na₂S₂O₈ systems. The first-order equation (monophasic model) satisfactorily explained the disappearance process, although it offered no explanation for the small concentrations remaining in the process.

In the present work, we investigated the use of nano-metallic calcium (Ca) and calcium oxide (CaO) dispersion mixture for the simultaneous remediation of contaminated soils with both heavy metals (As, Cd, Cr, and Pb) and polychlorinated biphenyls (PCBs). Regardless of soil moisture content, nano-metallic Ca/CaO dispersion mixture achieved about 95–99 % of heavy metal immobilization by a simple grinding process. During the same treatment, reasonable PCB hydrodechlorination efficiencies were obtained (up to 97 %), though higher hydrodechlorination efficiency by preliminary drying of soil was observed.

Blood levels of the elements Cu, Zn, Se, As, Cd, Hg, and Pb have been determined in 62 Nigerian women who were occupationally exposed to vehicular pollution. Mercury was determined using a direct mercury analyzer, while all the other elements were determined by an inductively coupled plasma mass spectrometer system. The mean values for all the toxic elements were all within the recommended desirable/tolerable limits, except for Se (0.44 μg/mL, compared with <0.2 μg/mL recommended by the WHO). More than 98 % of the subjects had blood selenium levels higher than this recommended limit. For As, Hg, and Pb, the corresponding figures of subjects with blood levels above the recommended limits were 4, 8, and 19.3 %, respectively. When the subjects were grouped according to their body mass indexes as normal, underweight, overweight, and obese, analysis of variance shows that mean blood levels of Cu, As, and, to some extent Hg were significantly different in the four nutritional status groups. Blood Hg level correlates significantly with blood As in all the groups, except in obese subjects. Also, a significant correlation between age and blood Hg was observed only in normal subjects and between age and blood Pb only in obese subjects. These results suggest that nutritional status could influence both elemental levels and the interactions between trace elements in the blood of female subjects. Nutrition is therefore a factor to consider in efforts to modify human susceptibility to toxic elements.

Modern society grapples with large amounts of household waste. The anaerobic digestion of this waste offers a promising source for energy-rich biogas production but generates high toxic effluents that require treatment before reuse or disposal into the environment. This study aimed to investigate three techniques, namely coagulation/flocculation, electro-coagulation, and activated sludge, in terms of efficiency in the treatment of these effluents. It also aimed to assess their toxicity effects on the germination and growth of durum wheat Triticum aestivum L. seeds before and after 6 days of treatment. Activated sludge was most efficient in reducing chemical oxygen demand, turbidity, and conductivity (95.7 %, 15.8 %, and 37.5 %, respectively). The effluent treated with this technique induced a marked delay in germination (low mean time of germination) and a significant reduction in the percentages of seed germination and root and leaf growths. It was also noted to strongly induce lipid peroxidation in roots and leaves, which presumably explained the germination/growth inhibition of the wheat seeds. The effluent also induced marked lipid peroxidation effects and strongly inhibited the activities of butyrylcholinesterase in mice bone marrows. The effluent shows a high ability to inhibit the growth of three microalgae; these endpoints are useful tools to biomonitor the physico-chemical quality of this wastewater. Overall, while no significant alterations were observed in terms of animal and vegetable toxicities when the effluent was treated by coagulation/flocculation, activated sludge treatment proved efficient in reducing the toxicities induced by the untreated effluents. The results indicate that the application of this technique is promising with regards to attaining efficient, eco-friendly, and cost-effective strategies for the management and treatment of household waste.

Accurate monitoring of degradation levels in soils is essential in order to understand and achieve complete degradation of petroleum hydrocarbons in contaminated soils. We aimed to develop the use of multivariate methods for the monitoring of biodegradation of diesel in soils and to determine if diesel contaminated soils could be remediated to a chemical composition similar to that of an uncontaminated soil. An incubation experiment was set up with three contrasting soil types. Each soil was exposed to diesel at varying stages of degradation and then analysed for key hydrocarbons throughout 161 days of incubation. Hydrocarbon distributions were analysed by Principal Coordinate Analysis and similar samples grouped by cluster analysis. Variation and differences between samples were determined using permutational multivariate analysis of variance. It was found that all soils followed trajectories approaching the chemical composition of the unpolluted soil. Some contaminated soils were no longer significantly different to that of uncontaminated soil after 161 days of incubation. The use of cluster analysis allows the assignment of a percentage chemical similarity of a diesel contaminated soil to an uncontaminated soil sample. This will aid in the monitoring of hydrocarbon contaminated sites and the establishment of potential endpoints for successful remediation.

Global sustainability research requires an integrative research effort underpinned by digital infrastructures (systems) able to harness data and heterogeneous information across disciplines. Digital data and information sharing across systems and applications is achieved by implementing interoperability: a property of a product or system to work with other products or systems, present or future. There are at least three main interoperability challenges a digital infrastructure must address: technological, semantic, and organizational. In recent years, important international programs and initiatives are focusing on such an ambitious objective. This manuscript presents and combines the studies and the experiences carried out by three relevant projects, focusing on the heavy metal domain: Global Mercury Observation System, Global Earth Observation System of Systems (GEOSS), and INSPIRE. This research work recognized a valuable interoperability service bus (i.e., a set of standards models, interfaces, and good practices) proposed to characterize the integrative research cyber-infrastructure of the heavy metal research community. In the paper, the GEOSS common infrastructure is discussed implementing a multidisciplinary and participatory research infrastructure, introducing a possible roadmap for the heavy metal pollution research community to join GEOSS as a new Group on Earth Observation community of practice and develop a research infrastructure for carrying out integrative research in its specific domain.

In recent years, occupational and environmental exposure to toxic pollutants has increasingly contributed to declining sperm quality and increasing morbidity of human male genital diseases. This study explored the effects of electronic waste (e-waste) environmental pollutions on male genital health in Guiyu, one of the largest e-waste recycling centers in the world. We collected outpatient case information from 2001 to 2009 in Guiyu and a control hospital and performed statistical analysis on male genital diseases morbidity (MGDM). The MGDM in Guiyu and the control hospital per thousand from 2004 to 2009 were 1.410/0.403 (2004), 0.539/0.385 (2005), 0.248/0.284 (2006), 0.485/0.195 (2007), 1.107/0.272 (2008), and 0.741/0.586 (2009) while the average total MGDM from 2004 to 2009 were 0.753 and 0.355 per thousand, respectively. Percentage of occurrence of epididymitis, impotence and prospermia, redundant prepuce, gonorrhea, urethritis, sexual function dysfunction, azoospermia, asthenospermia, and unknown etiology male sterility were higher in Guiyu (P < 0.05), whereas the frequency of prostatitis, condyloma accuminatum, and genital herpes were higher in the control (P < 0.05). Morbidity of male genital diseases was higher in Guiyu than in the control area. Male reproductive health may be threatened by e-waste environmental pollution in Guiyu, especially for diseases that could be influenced by environmental factors, and it may influence local population diathesis.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds with carcinogenic and/or mutagenic potential. To address the limitations of individual remediation techniques and to achieve better PAH removal efficiencies, the combination of chemical and biological treatments can be used. The degradation of phenanthrene (chosen as a model of PAH) by persulfate in freshly contaminated soil microcosms was studied to assess its impact on the biodegradation process and on soil properties. Soil microcosms contaminated with 140 mg/kgDRY SOILof phenanthrene were treated with different persulfate (PS) concentrations 0.86–41.7 g/kgDRY SOILand incubated for 28 days. Analyses of phenanthrene and persulfate concentrations and soil pH were performed. Cultivable heterotrophic bacterial count was carried out after 28 days of treatment. Genetic diversity analysis of the soil microcosm bacterial community was performed by PCR amplification of bacterial 16S rDNA fragments followed by denaturing gradient gel electrophoresis (DGGE). The addition of PS in low concentrations could be an interesting biostimulatory strategy that managed to shorten the lag phase of the phenanthrene biological elimination, without negative effects on the physicochemical and biological soil properties, improving the remediation treatment.