Occurrence of micropollutants in the Yesilirmak River Basin, Turkey.

The European Water Framework Directive (WFD) (2000/60/EC) is the most visionary piece of European environmental legislation that aims to achieve good water status of both surface water and groundwater bodies. The Directive provides a fundamental basis for surface water monitoring activities in the European Member States. The objective of this study is to investigate the occurrence of micropollutants in the Yesilirmak River and to develop a cost-effective monitoring strategy based on spatiotemporal data. A 2-year seasonal monitoring program was conducted between 2016 and 2018, and the water samples were analyzed for 45 priority substances as defined by the WFD and 250 national river basin-specific pollutants. In the basin, 166 pollutants were quantified in at least one of the samples with individual concentrations ranging from 6 × 10-6µg/L to 100 mg/L. Fifty-four pollutants with a frequency of occurrence greater than 5% were selected for further evaluation. Based on statistical evaluation of the data, 20 pollutants were identified as the pollutants of primary concern. These 20 pollutants were grouped under three categories (metals, biocides, and industrial organic compounds) and their spatiotemporal distributions in the basin were assessed to establish a monitoring strategy specific to each pollutant category. The results of the study revealed that the common season for the monitoring of all pollutant categories was the spring. This study provides a generic methodology for the development of a cost-effective water quality monitoring strategy, which can be applicable for use in different basins and pollutant datasets.

Evaluation of the efficiency of chlorpyrifos-ethyl remediation by Methylobacterium radiotolerans and Microbacterium arthrosphaerae using response of some biochemical biomarkers.

This study reveals out detoxifying and antioxidant enzyme response of Gammarus pulex exposed/polluted to chlorpyrifos-ethyl insecticide before and after biodegradation/bioremediation by Methylobacterium radiotolerans and Microbacterium arthrosphaerae. Cytochrome P450 1A1, glutathione S-transferase, catalase, and superoxide dismutase activities in G. pulex exposed to chlorpyrifos-ethyl before and after bioremediation/biodegradation by these two bacteria during 24 and 96 h tested by using commercial ELISA kits. The activity of catalase enzyme was decreased depending on chlorpyrifos-ethyl before and after bioremediation/biodegradation the enzyme activity was increased repeatedly. Superoxide dismutase activity level increased after chlorpyrifos-ethyl exposure in 96 h (p > 0.05). Following bioremediation, superoxide dismutase enzyme activity decreased again during 24 h (p > 0.05) and increased during 96 h (p < 0.05). Statistical differences were not found in cytochrome P450 1A1 enzyme activity before and after the process (p > 0.05). No significant differences were determined during the activity of glutathione S-transferase in 24 h (p > 0.05). The activities of glutathione S-transferase were increased after exposure of chlorpyrifos-ethyl during 96 h. After bioremediation; the activity of glutathione S-transferase increased even more (p < 0.05). The results determined that activities of G. pulex at superoxide dismutase, catalase, and glutathione S-transferase are common biomarkers for revealing out the efficiency of bioremediation of chlorpyrifos-ethyl with these two types of soil bacteria. Graphical abstract.

Statistical evaluation of the bioremediation performance of Ochrobactrum thiophenivorans and Sphingomonas melonis bacteria on Imidacloprid insecticide in artificial agricultural field.

BACKGROUND: Pesticides are applied directly on the soil or on the vegetation, and thus, they can reach the receiving environment easily. In this way, environmental damage that stems from pesticides also affects public health and the natural habitat. Pesticides are one of the most harmful pollutant groups in terms of human health, fauna and the environment. They penetrate the application field and the applicator right after the application and start to show adverse effects. METHODS: The bioremediation of the Imidacloprid (C9H10ClN5O2) insecticide, which is used commonly in Mediterranean climate, was compared with some soil bacteria in artificially prepared fields. For this purpose, firstly, it was determined whether the soil samples taken from a field where cotton was cultivated in Adana in Turkey was suitable for bioremediation. Then, the bacteria were isolated from these soils with the 16sRNA method. The enhanced microbial consortia of these isolated bacteria were inoculated to the artificial fields, meanwhile, the recommended concentrations of Imidacloprid were added to these agricultural fields. Imidacloprid, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5) and Total Organic Carbon (TOC) measurements were performed every day for two weeks on the filtrate samples taken from the artificial fields. RESULTS: As a result of the monitoring, it was determined that Ochrobactrum thiophenivorans (Ot) and Sphingomonas melonis (Sm) species and their mixtures could eliminate the Imidacloprid pesticide within two weeks' time. The removal efficiencies were 100% for active ingredient for each bacterium and their mixtures while COD were 97% and 96% for Ot. and Sm., respectively. TOC and BOD5 removal rates were 97% for both types and their mixtures in one or two-week period. Mixture of Ot and Sm shows 98.5% for COD, BOD5 parameters and 97.5% for TOC parameter. CONCLUSIONS: The results that will be obtained will help in the rehabilitation of the receiving environments that are exposed to pesticides in our country and take precautions to avoid the accumulation of pesticides in the body of the humans who are at the top of the food chain.