Persistence of two neonicotinoid insecticides in wastewater, and in aqueous solutions of surfactants and dissolved organic matter

Wastewater treatment plants receive organic contaminants, such as pesticides, which reach the sewage system from domestic, industrial or agricultural activities. In wastewater, which is a complex mixture of organic and inorganic compounds, biotic or abiotic degradation of contaminants can be affected by the presence of co-solutes. The photodecomposition in natural sunlight of two neonicotinoid insecticides, thiamethoxam and thiacloprid, was investigated in wastewater, aqueous extracts of sewage sludge and in aqueous surfactant solutions, which are abundant in wastewater. Dissipation in the dark was also studied in wastewater, due to reduction of transmitted sunlight in wastewater ponds. With regard to photolysis, thiamethoxam degraded rapidly in all the aqueous solutions. Among them sewage sludge extracts slightly modified (average half-life 17.6 h), wastewater increased (13.7 h) and non-ionic surfactants led, as a family, to the highest dissipation rates (average 6.2 h), with respect to control water (18.7 h). Additionally this pesticide also underwent a slower biodegradation process in wastewater in the dark under anaerobic conditions (around 25 d). A metabolite of thiamethoxam from the biological decomposition in wastewater was identified by HPLC/MS. On the other hand thiacloprid was found to be resistant to photo- and biodecomposition and remained almost unchanged during the experimental periods in all the tested media.     

Carbon dioxide capture from combustion flue gases with a calcium oxide chemical loop. Experimental results and process development

Post-combustion carbonate looping processes are based on the capture of carbon dioxide from the flue gases of an existing power plant in a circulating fluidized bed reactor (CFB) of calcium oxide (the carbonator) particles. The calcination of calcium carbonate in a new oxy-fired CFBC power plant regenerates the sorbent (calcium oxide particles) and obtains high purity carbon dioxide. This communication presents experimental results from a small test facility (30 kWt) operated in continuous mode using two interconnected CFB reactors as carbonator and calciner. Capture efficiencies between 70 and 97% have been obtained under realistic flue gas conditions in the carbonator reactor (temperatures around 650 °C). The similarity between process conditions and those existing in CFBC power plants should allow a rapid scaling up of this technology. The next steps for this process development are also outlined.     

Assessment of water quality in the Alqueva Reservoir (Portugal) using bioassays

Background, aim, and scope  

Alqueva Reservoir is the biggest artificial freshwater reservoir in Europe and is an important water supply for human and agricultural consumption in the Alentejo region (Portugal). Pollution can impair environmental and human health status, and to assure water quality and ecological balance, it is crucial to frequently monitor water supplies. In this study, we used an ecotoxicological test battery to identify the potential toxicity of water from this reservoir.     

High-impact conservation: invasive mammal eradications from the islands of western México

Islands harbor a disproportionate amount of the earth's biodiversity, but a significant portion has been lost due in large part to the impacts of invasive mammals. Fortunately, invasive mammals can be routinely removed from islands, providing a powerful tool to prevent extinctions and restore ecosystems. Given that invasive mammals are still present on more than 80% of the world's major islands groups and remain a premier threat to the earth's biodiversity, it is important to disseminate replicable, scaleable models to eradicate invasive mammals from islands. We report on a successful model from western México during the past decade. A collaborative effort between nongovernmental organizations, academic biologists, Mexican government agencies, and local individuals has resulted in major restoration efforts in three island archipelagos. Forty-two populations of invasive mammals have been eradicated from 26 islands. For a cost of USD 21,615 per colony and USD 49,370 per taxon, 201 seabird colonies and 88 endemic terrestrial taxa have been protected, respectively. These conservation successes are a result of an operational model with three main components: i) a tri-national collaboration that integrates research, prioritization, financing, public education, policy work, capacity building, conservation action, monitoring, and evaluation; ii) proactive and dedicated natural resource management agencies; and iii) effective partnerships with academic researchers in Mexico and the United States. What is now needed is a detailed plan to eradicate invasive mammals from the remaining islands in the region that integrates the needed additional financing, capacity, technical advances, and policy issues. Island conservation in western Mexico provides an effective approach that can be readily applied to other archipelagos where conservation efforts have been limited.     

Influence of resorcinol chemical oxidation on the removal of resulting organic carbon by activated carbon adsorption

Activated carbon adsorption and chemical oxidation followed by activated carbon adsorption of resorcinol in water has been studied. Three chemical oxidants have been used: hypochlorite, permanganate and Fenton's reagent. The influence of concentrations of resorcinol and activated carbon on adsorption removal rates has been investigated. Both isotherm and adsorption kinetics have been studied. Results are fit well by Freundlich isotherms and adsorption rates of resorcinol were found to follow a pseudo-second-order kinetic model. However, pyrogallol, an intermediate of resorcinol oxidation with permanganate and Fenton's reagent, showed an unfavourable isotherm type. At the conditions investigated, chemical oxidation allows slight reductions of TOC and intermediates formed were found to inhibit the adsorption rate of TOC in the case of permanganate and Fenton's reagent oxidation, likely due to formation of some polymer pyrogallol product. The adsorption process was found to be controlled by pore internal diffusion, which justifies the poor affinity of oxidation intermediates toward activated carbon since molecules of larger size should diffuse rapidly for the adsorption to be effective.     

Combining TiO2-photocatalysis and wetland reactors for the efficient treatment of pesticides

In the present work the photocatalytic and biological degradation of two commercial mixtures of pesticides (Folimat and Ronstar) and two fungicides (pyrimethanil and triadimenol) has been studied. The evolution of some components of these commercial products (dicofol, tetradifon and oxadiazon) and that of the two fungicides has been monitored by means of HPLC, GC-MS, TOC and toxicity (Lemna minor toxicity test) measurements. The photocatalytic method was able to degrade dicofol, tetradifon, pyrimethanil, triadimenol and the components of Ronstar with the exception of oxadiazon. In addition to this, the photocatalytic method eliminated pyrimethanil toxicity and reduced that of triadimenol by a 90%, Ronstar by a 78% and Folimat by an 87%. Nevertheless, the wetland reactors alone could reduce the toxicity of only the former. Finally, the proper dosage of the water containing the pesticides to a photocatalytic reactor followed by a wetland reactor resulted to be the most successful strategy for the detoxification of the studied compounds and their mixtures.     

Evaluation of Cu-PPHs as active catalysts for the SCR process to control NOx emissions from heavy duty diesel vehicles

Copper based catalysts supported on mesoporous materials, which were in turn based on a surfactant expanded zirconium phosphate for the formation of silica galleries in the interlayer space, were prepared by the impregnation method. They were then characterised and tested in the selective catalytic reduction of NO with ammonia as active catalysts for the control of the NOx emissions from heavy duty vehicles. Copper catalysts displayed a high catalytic performance, even in the presence of 14% (v/v) of H2O and 100 ppm of SO2. They also displayed improved catalytic behaviour when compared to a CuZSM5 catalyst.     

Evaluation of carbon degradation during co-composting of exhausted grape marc with different biowastes

In this work the carbon biodegradation of exhausted grape marc (EGM) combined with other organic wastes using the turned pile composting system was studied. Four different piles were made of EGM in Pile 1, EGM mixed with cow manure and straw (CMS) in Pile 2, EGM mixed with municipal solid waste (MSW) in Pile 3 and EGM mixed with grape stalks (GS) in Pile 4. The results obtained were modelled to determine the main kinetic and stoichiometric parameters. Regarding to the rate constants of the composting processes they were increased from 0.033d(-1), the value obtained when EGM was composted alone, to 0.040 and 0.044d(-1) when MSW and GS were added, respectively as co-substrates. However, the addition of CMS reduced the rate constant. About the biodegradable carbon fractions, it was observed that the co-composting reduced significantly the remanent carbon concentration after composting in all the piles whilst increased the readily biodegradable carbon fractions from 35, the value obtained when EGM was composted alone, to 50 and 60%, respectively when MSW or GS were added. As regards the temperature profiles, only Piles 1 and 4 achieved thermal hygienization values and about the nitrogen losses, the lowest percentage of nitrogen loss took place when GS were added, because of its optimum pH and C/N initial ratio. Thus, though any of these wastes could be used for co-composting with EGM, the use of GS as co-substrate and bulking agent for the co-composting process of EGM was recommended.     

Exposure assessment of French women and their newborns to tetrabromobisphenol-A: occurrence measurements in maternal adipose tissue, serum, breast milk and cord serum

A French monitoring study was initiated to evaluate the exposure of fetus and newborn to brominated flame retardants (BFR). A previously developed multi-residue analytical method was used for measuring the main classes of BFR (tetrabromobisphenol-A, and tri- to decabomodiphenyl ethers) in various human biological matrices. Analyzed samples (maternal and cord serum, adipose tissue and breast milk) were collected from 93 volunteer women during caesarean deliveries. TBBPA was detected in 44% of the analyzed breast milk samples, at levels varying from 0.06 to 37.34 ng g(-1) lipid weight, but was not detected in adipose tissue. This compound was also detected in 30% of the analyzed serum samples, with similar average values in maternal and cord serum (154 pg g(-1) fresh weight versus 199 pg g(-1) fresh weight, respectively). The interpretation of the collected data permitted the demonstration of (1) a significant exposure to TBBPA both for mothers and fetuses and (2) a possible risk of overexposure of newborns through breastfeeding.