Passive samplers have been used widely as an alternative to the traditional grab water sampling method as they i) allow pre-concentration of micropollutants, ii) integrate average contaminant concentrations over extended sampling periods and ii) minimize the sampling logistic¹. The use of passive samplers is particularly beneficial when environmental concentrations vary strongly over time. In this case, the grab sampling approach can miss important input from short events such e.g. storm-events and bias interpretation of micropollutant transfer. Compound-specific isotope analysis (CSIA) allows teasing apart the contribution of non-degradative (dilution, sorption) and degradative processes both resulting in overall pollutant dissipation². CSIA is widely applied for industrial contaminated sites, with a relatively high concentration of contaminants. However, is less often extended to micropollutants, as herbicides and pharmaceuticals, due to smaller environmental concentrations. Here we developed the application of commercially available polar organic chemical integrative sampling (POCIS) for simultaneous evaluation of concentration and carbon CSIA of herbicides (atrazine, metalaxyl, terbutryn, S-metolachlor, tebuconazole, dimethomorph) in artificial wetlands receiving pesticide runoff from a vineyard catchment (42.7 ha, Alsace, France).

Prior to field deployment, POCIS performance was tested for sorption and subsequent isotope analysis of selected herbicides for different concentrations, matrices (distilled vs. pond water), flow conditions, and hydrogeological events patterns. In parallel, self-made POCIS samplers were prepared and compared to the commercially available passive samplers. Our results show that i) pesticide sorption on POCIS is linear for concentrations below 10 µg/L, ii) extraction from POCIS causes no significant isotopic effect for studied herbicides, iii) commercial and self-made POCIS did not differ in terms of concentration and δ¹³C measured in extracts and iv) POCIS records accurately changes of isotope signatures of pollutants in water. As POCIS techniques are not selective to the molecules of interest, the only limitation arises sporadically from matrix effects for some compounds in complex matrices, a common problem in CSIA from environmental samples. This issue can be solved in the future with a further combination of POCIS with further matrix cleanup techniques.

Finally, POCIS was deployed into the storm-water pond located at the outlet of the vineyard catchment for intervals of 28 days over 3 months. All the compounds detected in the grab water samples (10L) taken in parallel were found in POCIS. In particular, the widely used fungicide dimetomorph was pre-concentrated in POCIS extracts up to 2 mg/L compared to the surrounding water average concentration of 100 ng/L. This high preconcentration factor (x 20’000) makes CSIA of dimetomorph feasible, supporting assessment of degradation in the field. Altogether, we anticipate this study to be a starting point for the application of multi-element CSIA to assess the fate of a variety of micropollutants in surface waters.

Literature:

(1) Alvarez, D. A.; Petty, J. D.; Huckins, J. N.; Jones-Lepp, T. L.; Getting, D. T.; Goddard, J. P.; Manahan, S. E. Development of a Passive, in Situ, Integrative Sampler for Hydrophilic Organic Contaminants in Aquatic Environments. Environ. Toxicol. Chem. 2004. https://doi.org/10.1897/03-603.

(2) Hunkeler, D.; Meckenstock, R. U.; Sherwood Lollar, B.; Schmidt, T. C.; Wilson, J. T. A Guide for Assessing Biodegradation and Source Identification of Organic Ground Water Contaminants Using Compound Specific Isotope Analysis (CSIA). USEPA Publ. 2008, 600/R-08/1 (December), 1–82.

The adverse effects of improper disposal of collected and treated wastewater have become inevitable. In order to achieve the desired environmental standards, in addition to the construction of a wastewater treatment plant, there is also a need to evaluate the continuous performance of treatment systems. In Iran, treated wastewater is mostly used in agriculture. Therefore, the use of wastewater with poor quality characteristics can endanger health. In this study, the efficiency of the neural network model in order to predict the performance of the Parkandabad waste water treatment plant in Mashhad, with a semi-mechanical treatment system, was investigated. The first step in predicting the performance of the treatment plant was identification of factors affecting the Total Biochemical Oxygen Demand (TBOD) parameter which is one of the quality indicators of the effluent. In the next step, the neural network model optimized with a genetic algorithm, and effective features as network inputs were used for the predictions of the performance of the treatment plant. Based on the results obtained from the model, the parameters that affect the prediction of TBOD concentration the most were singled out. They are flow rate, organic matter load, dissolved oxygen concentration, temperature, and some active aerators. Paper will consider replacing the semi-mechanical treatment system with the activated sludge process.

Climate change, along with the high water demand, has increased the groundwater withdrawal and is severely affecting the food-energy-water (FEW) nexus worldwide, especially in the arid and semi-arid regions. In developing countries, like India, lack of awareness and resources for adaptation of advanced technological applications for irrigation has led to inefficient agriculture practices and excessive groundwater withdrawal. In India, more than 89% of extracted groundwater used in the agriculture sector, and at the same time, only 5% of the net irrigated area is drip irrigated. In this study, we aimed to calculate the water use efficiency (WUE) of a flood irrigated orange orchard in central India. The global sensitivity of soil hydraulic parameters also assessed. Thermal Dissipation Probe (TDP-30) sap flow sensor together with HYDRUS 1D model, used to calculate the actual water demand for orange trees and leakage of water below the root zone. The model was satisfactorily able to reproduce the daily sap flow and root water uptake with a Nash–Sutcliffe efficiency (NSE) index of 0.68. The results show that the WUE of flood irrigation is only 25% and 75% of net irrigated water drained below the root zone. The results of global sensitivity analysis (GSA) for the soil hydraulic parameters suggest that the pore-size distribution index and saturated hydraulic conductivity has a significant influence on the leakage below the root zone. Whereas, the air-entry-pressure parameter and saturated hydraulic conductivity have a significant influence on transpiration rates. The study also shows the significance of initial soil moisture condition in optimizing the irrigation schedule. In conclusion, the comprehensive study suggests that flood irrigation is a gravely inefficient irrigation system for the irrigation of orchards, and a sensor-based approach may be more effective in deciding the irrigation patterns.

Hydropower-based electricity production provides approximately 33% of renewable energy in Greece - an activity, however, associated with adverse environmental effects on watercourses. Therefore, it should be considered as a key factor of water management programs ensuring safety and optimising environmental performance of hydropower facilities in accordance to Greece’s obligations towards European Union (EU) water policy. Water Framework Directive (WFD) was created by the EU in order to help member states to protect and improve the status of water bodies and was incorporated in Greek legislation by Law 3199/2003 . Within the scope of this study, we assessed both Hydroelectric power generation and Water Resources Management in Greece and we recorded the current status of the EU Water Framework Directive implementation in this field. Given that social-ecological systems emphasise the link between people and the ecosphere, we investigated possible conflicts that arise between hydropower-related renewable electricity production and water courses conservation, according to both national and EU legislation. We also studied the tools that WFD provides in order to solve potential problems, maintain economic viability and ensure good ecological status between hydropower utilisation and water protection in the face of increased demands to a more effective and sustainable management of environmental resources.

Due to increasing anthropogenic activities, trace elements remain a major concern for river water quality, particularly when waste effluents are not always constraint. The intensity of the contamination, the origin and the distribution of these elements were not frequently investigated, particularly in carbonated areas from the southern countries of limited water resources. In this context, the present study aimed at understanding the geochemistry of trace elements in bottom sediments from the Sebou basin, representing 1/3 of the surface water resources of Morocco. Four spatial sampling campaigns have been carried out in 2018 and 2019 during contrasted hydrological periods. Total and non-residual concentrations (EDTA extraction) of trace elements (As, Cd, Co, Cr, Cu, Ni, Pb, Zn) were measured in the fine fraction (< 63µm), as well as some physico-chemical parameters.

The order of abundance of the elements was as follows: Zn>Cr>Cu>Ni>Pb>Co>As>Cd. Several sediment indices of contamination and of toxicity risk were used to assess sediment quality. The results showed that 70% of the samples were naturally enriched in trace elements, specially As and Ni, as well as Cd and Pb, except in some stations. On the opposite, the most enriched elements were Cr, Zn and Cu. Chromium presented an enrichment higher than 5 and toxicity risks at some stations, such as downstream the Fez city known for its important tanneries activities. A multi-variate analysis of the datas evidenced the strong link between the identified natural elements (As, Co, Ni) with clays, Fe, Al oxides, whereas elements (Cd, Cu, Cr, Pb, Zn) mainly originating anthropogenic activities (industrial and domestic wastes, homemade, and agricultural practices), were linked to phosphorus, to a lesser extent to particulate organic carbon.