Water quality assessment using physical-chemical parameters of the Danube River (deltaic area) including Razim and Golovita Lakes, Romania

The present study assessed the spatial water quality variation of physical and chemical variables. The water quality data were collected during May 2018 from several sampling stations distributed between Ceatal Izmail and Sf. Gheorghe branch and up to the Dunavat Canal, as well as Razim and Golovita lakes. The sampling stations were selected on the basis of their contamination susceptibility, i.e., the station located along the above-mentioned sector of the Danube River were tended to be more impaired by the human related activities. Instead, the stations downstream to the Danube River (the lower course – deltaic area), i.e., Razim and Golovita lakes were supposed to be less impaired by the urban and rural contamination. The investigated sites are of particular interest since they belong to the Danube Delta Biosphere Reserve (DDBR). The following water quality parameters were measured: depth (m), temperature (oC), pH (units), dissolved oxygen content (mg/l), electrical conductivity (µS/cm), total dissolved solids (mg/l), sulphates (mg/l), nitrite-nitrogen (mg/l), nitrate-nitrogen (mg/l), orthophosphates
(mg/l), chlorophyll ”a” (µg/l), turbidity (NTU), total suspended solids (mg/l), Secchi visibility (m), silica content (mg/l) etc. Overall, the results indicated that some variables presented comparable values that have not exceeded those limits recommended by the reference standard. Instead, the fall in the quality of water (any
abnormal values encountered in a few situations) may be related to a wide range of local natural environmental circumstances, as well as anthropic factors. The
outcomes obtained from the present study shall be useful in the future environmental assessment of the aquatic ecosystems in DDBR area.