Trace Elements in Fish Tissue With Commercial Value of the Danube Delta Biosphere Reserve

Abstract

Researches and analysis of heavy metals concentrations in the fish species exploited as a food source are of great interest due to long term toxic effects on human health even at very low concentrations. Therefore, we have conducted this study in an area of great interest in terms of aquatic biodiversity, but also of tourism and trade. Depending on the degree of toxicity in delta aquatic ichtyofauna, five heavy metals (Cr, Cu, Hg, Ni, Pb) and a metalloid (As) concentrations were measured in the muscle tissue of fifteen commercial value fish species in order to assess their impact on human health. Samples were collected seasonally (twice a year) between 2013-2014 from Somova-Parches aquatic complex (situated near Tulcea -Romania industrial area in predeltaic area) and four representative aquatic complexes for Danube Delta, respectively Sontea-Fortuna, Matita-Merhei, Gorgova-Uzlina and Rosu-Puiu. The determination of elements from collected samples was done differently, mercury was analysed by cold vapor atomic absorption, while the other five elements (arsenic, chromium, copper, nickel and lead) were determined using mass spectrometry with inductively coupled plasma. The investigations of heavy metals revealed interspecific differences, important not only because of each specie particularities and food chain, but also for intraspecific variation caused by geographical location. The statistical analysis of the 4800 measurements in correlation with the analysis of the bioaccumulation factor (BCF) reflected the degree of contamination on the exploited Danube Delta Biosphere Reserve fish resources and also showed an irregular distribution of heavy metals and metalloids depending on anthropogenic pollutants.

The variations of physico-chemical parameters during summer in Lake Erenciuc from the Danube Delta (Romania)

“…There are detailed studies at a national level for the Danube Delta and the great wetlands: Balta Ialomitei and Balta Brailei along the lower course of the Danube river (Banaduc et al 2016;Burada et al 2014;Catianis et al 2014;Coops et al 2008;Navodaru et al 2001;Raischi et al 2016). The quality and productivity of the biota within meander lakes localized in deltaic systems within the temperate area constituted the main topic of the studies within which we explain the variation and interdependence between the water flows communicating seasonally between the lotic and the lentic systems.…”

Monitoring of soil moisture in Long-Term Ecological Research (LTER) sites of Romanian Carpathians

“…The p thresh-old level was considered at p = 0.05. The two approaches are frequently used (Timofti et al 2016), mainly because they are complementary; the first is used for data analysis, while the second is used for the analysis of the correlation coefficient matrix (Iticesu et al 2016, Burada et al 2017.…”

Assessment of Water Quality State Dynamics Using Adaptive Filtering Methods and Neural Networks Approaching. Case study - Danube River in Galati area

“…A classical tuning of the state magnitude vector, h[k] could be achieved by the familiar algorithm RLS [22][23][24]: (5) with the adapting improvement g[k] is computed as [22][23][24]: (6) where the autocorrelation matrix inverse, c xx -1 is updated iteratively: (7) For comparison, it was considered useful to build an approximation model using neural networks [3,4,11].…”

“…From this point of view, it has caused a severe degradation of water quality. In addition, as a direct consequence, there is a strong influence and a major restriction on the sustainable development of local economies [1,6,7].…”