No abstract

The water quality assessment of Arges River and its tributary Dambovita River is presented in this paper as second part of an extended study on the evaluation of some freshwater resources quality located in Bucharest and surrounding areas [1]. This case study was carried out mainly for the water in the confluence area of Arges and Dambovita rivers, where a water and sediment sampling campaign was organized in June 2018. 21 quality parameters were determined for water samples and for the sediment samples the heavy metals content was evaluated. The results of the water samples analysis allowed the framing in quality classes, and for sediment samples the values obtained were compared with the chemical quality standards for sediments, according to the current national regulations. Following the assessment, it was established that the freshwaters in both Arge� River and Dambovita River, downstream the confluence with the Dambovita River are loaded with different pollutants, such as organic substances and nutrients leading to a lower water quality classification.

Taking into consideration that fish are valuable bioindicators for assessing pollution with potentially toxic elements (PTEs) such as heavy metals from aquatic environments, this study aimed to assess bioaccumulation factors in relation to water (BAF) and sediment (BASF) for the following potential toxic elements: Cd, Pb, Hg, Cu, Cr, Ni and Zn from 6 different fish species (Alburnus alburnus, Carassius gibelio, Scardinius erythrophthalmus, Ameiurus nebulosus, Perca fluviatilis, Lepomis gibbosus). Fish species have been captured from the waters of the Arges River (Hotarele village area) and the Colentina River (particularly from Mogosoaia, Herastrau and Panteliom lakes), from crowded areas located in the southern part of Romania. The results of the analysis indicated BAF values > 1 for the most fish species captured from the Colentina River. BASF values > 1 were obtained for BASFPb (Carassius gibelio - Arges River), BASFNi (Scardinius erythrophthalmus - Herastaru L. and Perca fluviatillis - Pantelimon L.), BASFCr (Perca fluviatillis - Pantelimon L.) and BASFZn (Alburnus alburnus and Scardinius erythrophthalmus - Mogosoaia L. and Carassius gibelio - Pantelimon L.). The obtained results can be used to describe the transfer of these elements from water and sediments to the fish tissue.

The quality of the aquatic environment was strongly influenced by the development of urbanization, industrialization and population growth, and therefore water pollution, mainly due to the presence of heavy metal, becoming a widespread concern. The objective of this work was to evaluate the possibility to remove heavy metals Cd, Zn, Cr and Ni from wastewater using two aquatic plants, water hyacinth (Eichornia crassipes) and water lettuce (Pistia stratiottes). These plants possess excellent abilities to metabolize and bioaccumulate heavy metals from various polluted aquatic environments. For a period of 30 days, the content of heavy metals from wastewater and aquatic plants samples was monitored weakly and the efficacy of these plants to remove heavy metals was quantified. Heavy metals were determined by atomic absorption spectrophotometry with graphite furnace (GFAAS). The obtained results have shown the efficacy of Eichornia crassipes and Pistia stratiottes to remove metals from the studied wastewater. The bioaccumulation rate of heavy metals in plants was effective until day 24 of the period of 30 days of the experiment, as the plants become inefficient beyond this period. The uptake of heavy metals in the studied aquatic plants depends on the concentration of each heavy metal present in the used wastewater and the exposure time.

The purpose of this study is to evaluate the water quality in the lakes along Colentina River according to Romanian regulations referring to the norms on surface water quality classification, MO 161/2006. To achieve this goal, two sampling sections (entry and exit points) for each lake have been established, and the following indicators have been determined: pH, water temperature, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, nitrites, nitrates and ammonium nitrogen, total nitrogen, orthophosphates, total phosphorus, electrical conductivity, filterable residue, chlorides, sulphates, calcium, magnesium and sodium. Following this study, the variation of the concentrations of determined indicators in the two sampling sections for each lake has been assessed, as well as the classification into quality classes according to the before mentioned order.