Elimination of pharmaceutical pollutants by solar photoelectro-Fenton process in a pilot plant

Environmental Science and Pollution Research - In this study, the simultaneous degradation of antibiotics (ampicillin, sulfamethazine, and tetracycline; and non-steroidal anti-inflammatories...     

Understanding and Integrating Local Perceptions of Trees and Forests into Incentives for Sustainable Landscape Management

We examine five forested landscapes in Africa (Cameroon, Madagascar, and Tanzania) and Asia (Indonesia and Laos) at different stages of landscape change. In all five areas, forest cover (outside of protected areas) continues to decrease despite local people's recognition of the importance of forest products and services. After forest conversion, agroforestry systems and fallows provide multiple functions and valued products, and retain significant biodiversity. But there are indications that such land use is transitory, with gradual simplification and loss of complex agroforests and fallows as land use becomes increasingly individualistic and profit driven. In Indonesia and Tanzania, farmers favor monocultures (rubber and oil palm, and sugarcane, respectively) for their high financial returns, with these systems replacing existing complex agroforests. In the study sites in Madagascar and Laos, investments in agroforests and new crops remain rare, despite government attempts to eradicate swidden systems and their multifunctional fallows. We discuss approaches to assessing local values related to landscape cover and associated goods and services. We highlight discrepancies between individual and collective responses in characterizing land use tendencies, and discuss the effects of accessibility on land management. We conclude that a combination of social, economic, and spatially explicit assessment methods is necessary to inform land use planning. Furthermore, any efforts to modify current trends will require clear incentives, such as through carbon finance. We speculate on the nature of such incentive schemes and the possibility of rewarding the provision of ecosystem services at a landscape scale and in a socially equitable manner.     

Kinetics and reversibility of micropollutant sorption in sludge

The fate of micropollutants throughout wastewater treatment systems is highly dependent on their sorption interactions with sludge matter. In this study, both the sorption and desorption kinetics of polycyclic aromatic hydrocarbons (PAHs) in activated sludge were shown to be very rapid in comparison to biodegradation kinetics. It was concluded that PAH transfer does not limit their biodegradation and that their fate is governed by the sorption/desorption equilibrium state. The effect of contact time between sludge and PAHs was also investigated. It was shown that aging did not influence the sorption/desorption equilibrium although PAH losses during aging suggest that sequestration phenomena had occurred. This implies that for PAH sorption assessment within treatment processes there is no need to include a contact time dimension. As a consequence, thanks to an innovative approach taking into account sorption equilibria and sequestration, this work has demonstrated that studies in the literature which, in main, deal with micropollutant sorption in sewage sludge with only a short contact time can be extrapolated to real systems in which sorption, desorption and aging occur.     

Economic Analysis of Summer Fallow Management to Reduce Take-All Disease and N Leaching in a Wheat Crop Rotation

This paper addresses the question of summer cover-crop adoption by farmers in presence of a risk of yield loss due to take-all disease and climate variability. To analyze the public incentives needed to encourage farmers to adopt summer cover crops as a means of reducing N leaching, we combine outputs from an economic, an epidemiological and an agronomic model. The economic model is a simple model of choice under risk. The farmer is assumed to choose among a range of summer fallow managements and input uses on the basis of the expected utility criterion (HARA assumption) in presence of both climate and take-all risks. The epidemiological model proposed by Ennaïfar et al. (Eur J Plant Pathol 118:127–143, 2007) is used to determine the impact of take all on yields and N uptake. The crop-soil model (STICS) is used to compute yield developments and N leaching under various management options and climatic conditions. The input parameters are chosen to match the conditions prevailing in Grignon, located in the main wheat-growing area in France. Eight management systems are examined: four summer fallow managements: ‘wheat volunteers’ (WV), ‘bare soil’ (BS), ‘early mustard’, ‘late mustard’, and two input intensities. We show that the optimal systems are BS (WV) when the take-all risk is (not) taken into account by agents. We then compute the minimum payment to each system such that it emerges in the optimum. We thus derive the required amounts of transfer needed to trigger catch-crop adoption. The results of the Monte Carlo sensitivity analysis show that the ranking of management systems is robust over a wide range of input parameters.     

Spatio-temporal variability of solid, total dissolved and labile metal: passive vs. discrete sampling evaluation in river metal monitoring

In order to obtain representative dissolved and solid samples from the aquatic environment, a spectrum of sampling methods are available, each one with different advantages and drawbacks. This article evaluates the use of discrete sampling and time-integrated sampling in illustrating medium-term spatial and temporal variation. Discrete concentration index (CI) calculated as the ratio between dissolved and solid metal concentrations in grab samples are compared with time-integrated concentration index (CI) calculated from suspended particulate matter (SPM) collected in sediment traps and labile metals measured by the diffusive gel in thin films (DGT) method, collected once a month during one year at the Seine River, upstream and downstream of the Greater Paris Region. Discrete CI at Bougival was found to be significantly higher than at Triel for Co, Cu, Mn, Ni and Zn, while discrete metal partitioning at Marnay was found to be similar to Bougival and Triel. However, when using time-integrated CI, not only was Bougival CI significantly higher than Triel CI, CI at Marnay was also found to be significantly higher than CI at Triel which was not observed for discrete CI values. Since values are time-averaged, dramatic fluctuations were smoothed out and significant medium-term trends were enhanced. As a result, time-integrated concentration index (CI) was able to better illustrate urbanization impact between sites when compared to discrete CI. The impact of significant seasonal phenomenon such as winter flood, low flow and redox cycles was also, to a certain extent, visible in time-integrated CI values at the upstream site. The use of time-integrated concentration index may be useful for medium- to long-term metal studies in the aquatic environment.     

Sex pheromone composition and reproductive isolation in two Busseola species (Lepidoptera: Noctuidae) in Kenya

Closely related species provide an interesting and useful model to understand mate communication diversification. Pre-mating isolation is the result of selection processes and is achieved by utilization of different sex pheromones, but also by different ecological and life traits such as geographic distribution, host-plant specialization and allochrony of sexual behavior. Here, we report sex pheromone identifications and pre-mating isolation of two closely related species of stemborers: Busseola segeta and the yet undescribed Busseola nov. sp., developing on different host-plants and in different geographical locations in Kenya. GC–MS analyses showed that the two species produced the same pheromone components, but in slight different ratios. The respective synthetic pheromone mixtures tested in the field were attractive for males of each species. The low inter-specific variation in the pheromone mixture would allow possible interbreeding in case of accidental introduction of both species in the same environment. Under laboratory conditions, allochrony of the mating period is total and might prevent interbreeding if confirmed in natural conditions. This point would ensure the reproductive isolation between the two species in case of modifications of ecological factors. This study and the chemical structures of the identified pheromone components clearly demonstrate that these Busseola species are closely related although they differ in morphology.     

Biosorption of copper from aqueous solutions by date stones and palm-trees waste

The removal of toxic metals from wastewaters by biosorption, based on the metal-binding capacities of various biological materials, has received much interest. However, the success of this approach depends on economic feasibility, which can be obtained by optimization of the environmental conditions. This paper evaluates, for the first time, the use of low-cost biosorbent (date stones (DS) and palm-tree waste (PTW)) to eliminate Cu(II) from aqueous solutions. The effect of some parameters on copper biosorption has been studied using date stones and palm-tree waste as solid sorbents. Results show that the highest percentage of copper adsorption was obtained for the smallest size of the sorbent particles. The biosorption process was found to occur rapidly, i.e. the maximum sorption capacity was reached within 20 min. The process involved pseudo-second-order kinetics with an activation energy value within the normal range considered for processes, where a physical interaction between the sorbate and the sorbent solid predominated. The thermodynamic parameters of the copper ions uptake onto the solid sorbents indicated that, the process was endothermic and proceeds spontaneously from the date stones. However, the thermodynamic studies of the adsorption of copper on palm-tree waste indicated that the process was exothermic and proceeds spontaneously.     

Voltammetric analysis of metallothioneins and copper (II) in fish for water biomonitoring studies

An major research area in environmental chemistry is the development of methods for the analysis of biomarkers. Metallothioneins are used as biomarkers in studies of heavy metals exposure in water, because metallothioneins are synthesized and accumulated when organisms are exposed to toxic concentrations of pollutants. In this work, simple and sensitive voltammetric methods were developed for metallothionein and copper (II) determinations in fish liver Lepomis gibbosus. Both analytical methodologies were optimized and applied to samples extracted from individuals previously submitted to sub-lethal toxicological trials with copper sulphate (CuSO₄) and cadmium chloride (CdCl₂). The obtained results showed that both methods are very precise, sensitive, and involve simple sample preparation processes. Moreover, metallothioneins showed better correlation with the toxic exposure than Cu²⁺. To the best of our knowledge, this is the first time that hepatic metallothioneins and Cu²⁺ contents are voltammetrically determined in order to be compared in their function as heavy metal biological indicators.     

Voltammetric determination of the herbicide Bifenox in drinking and river water using a silver solid amalgam electrode

A new method for the determination of submicromolar and nanomolar concentrations of herbicide Bifenox using differential pulse voltammetry at a mercury meniscus modified silver solid amalgam electrode is described. This new type of working electrode is non-toxic, environmentally friendly, and compatible with principles of green analytical chemistry, and its surface can be easily electrochemically renewed in the case of passivation. The newly developed direct differential pulse voltammetric determination of Bifenox gives limit of determination 6.7·10^?7 and 6.9·10^?7?M in drinking and river water, respectively. Both the selectivity and the sensitivity can be further increased by preliminary separation and preconcentration using solid phase extraction. This combination enables to reach limit of determination 0.9?×?10^?9 and 1.5?×?10^?9?M for drinking and river water, respectively. Because of lower running and investment costs, this electroanalytical method can be used for large scale monitoring of possible water contamination with tested herbicide.     

Occurrence of pharmaceuticals and hormones in drinking water treated from surface waters

The levels of a wide variety of pharmaceuticals and hormones, in source and potable-water supplies of French drinking water treatment plants, were assessed. In surface waters, 27 of the 51 target compounds were determined at least once. Paracetamol, salicylic acid and carbamazepine were quantified in more than 80% of samples. The highest concentration of 71 ng/L was observed for paracetamol. Twelve other substances were widely found in the surface waters studied, contaminating between 33 and 80% of the samples. These compounds include analgesics, psychotropic drugs, antibiotics and beta-blockers consistent with the French consumption, as well as natural hormones (oestrone, progesterone and androgens) and synthetic progestatives. In drinking water supplies, 25 compounds were also present, salicylic acid being the most frequently detected. Carbamazepine and the β-blocker atenolol found at lower levels (maximum 2 ng/L), are also present in more than 30% of the contaminated drinking waters. The pharmaceuticals exhibit different reactivity towards the treatments, while progestagens and androgens seem resistant to most of them. The effectiveness of the treatments is discussed, as well as the consequences of the presence of all these compounds on human health. This is the first time that such a long list of compounds (51) is proposed to assessment, and consequently this study provides the first data on pharmaceuticals and steroids occurrences in French drinking waters and represents a basis for the assessment of risks for humans. Moreover, at the international level, this is the first time that so many substances are quantified in drinking water, due to the very low detection limits, especially in the case of the hormones.