Assessment of water and sediment characteristics of the Northern Danube Delta Lakes - Matita, Babina and Merhei, Romania

At the end of its course of 2857 km running to the Black Sea, the Danube River - the
longest river in the European Union shapes a river delta, an exclusive area consisting
of a complexity of water and land, numerous lakes, ponds, marshes and unique
waterways. The Danube Delta, considered the Europe's largest wetlands, is included
in Unesco's World Heritage list, due to its outstanding importance conferred by the
many natural habitats with their specific characteristics and bio diversities, preserved
in a near pristine state. Even though considerable conservation efforts have been made
lately, the Danube Delta is still subject to threats due to both natural and anthropogenic
stressors that may alter its ecosystems. This study aims to investigate the water and
bed-sediment general characteristics of some lakes from the Matița - Merhei
Depression located in the fluvial delta plain, to assess the current quality status of
water and sediments. A significant number of water and sediment samples were
collected from each lake in October 2016, for determination of water physicalchemical parameters, lithological components and some heavy metals - analysed in
random bed-sediment samples. The investigation results show that the water
environment-related indicators fluctuated in terms of sampling sites and generally
agreed with the Romanian environmental quality criteria. Average lithological
composition of the bed-sediments indicates an autochthonous source for the recent
accumulation of sediments. Overall, the technophyllic heavy metal concentrations of
the bed-sediments were below the limits of the quality criteria. The exceptions were
represented by local values, incidentally exceeding the recommended limit.