(137)Cs baseline levels in the Mediterranean and Black Sea: a cross-basin survey of the CIESM Mediterranean Mussel Watch programme

The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify (137)Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured (137)Cs levels were found to be very low (usually < 1 Bq kg(-1) wet wt) (137)Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.     

Evolution of groundwater quality in intensive agricultural zone: case of Chtouka-Massa Aquifer,Morocco

The Chtouka-Massa area in Southern Morocco has shown an increase in water scarcity during the last decades, caused mainly by withdrawal of water resources aggravated by agricultural intensification and climate change impacts. To better understand the changes of groundwater quality, a sampling campaign was conducted in many wells during March 2015 and compared to historical chemical data from the hydraulic basin agency, as well as previous studies performed at Ibn Zohr University. All data were used to assess the spatial-temporal evolution of nitrate and salinity relevant to the recent sampling. This paper describes the current state of groundwater quality in the Chtouka-Massa zone with an overview of different sources of water mineralization and the nitrate evolution in an agricultural area. Our results indicate a general increase in mineralization from the north to the south, and from the east to the west. The plain, dominated by farms, shows a relatively high conductivity (up to 2000 μS/cm), while in both costal area and Anti-Atlas Mountain the water salinity shows a gradient increase from the north to the south. However, the highest electrical conductivity is observed along the Massa River. The water type is bicarbonate, chloride, and sodium for farm samples, while from the other parts, it is mostly dominated by chloride and sodium. The spatial-temporal analysis of nitrates generally shows an increasing trend. However, the levels remain overall lower than the limit. The temporal evolution of control points set by the hydraulic agency shows a decreasing trend decline that can be explained by the improvement of agriculture practices, including the conversion towards drip irrigation mode. Different chemical tracers highlighted some processes involving the changes of mineralization of groundwater (e.g., irrigation water return, marine intrusion, and water/rock interaction). The results will be used to improve water management in this area showing water quality degradation.     

Cs baseline levels in the Mediterranean and Black Sea: A cross-basin survey of the CIESM Mediterranean Mussel Watch programme

The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify ¹³⁷Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured ¹³⁷Cs levels were found to be very low (usually <1 Bq kg⁻¹ wet wt) ¹³⁷Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.