The paper describe the sonochemical degradation of organochlorine compounds (Trichloroethylene, Tetrachloroethene and 1, 1, 2-Trichloroethane) from aqueous solutions. The experiments was realized with two types of equipment: ultrasound bath UCD-150 and sonotrode UP 200 Ht. The experimental results showed high efficient removal for all three compounds: Tetrachloroethene 93.8%, 1, 1, 2-Trichloroethane 92.9% and Trichloroethylene 86.6% in bath ultrasound treatment after 50 min. The ultrasound efficiency treatment depend by the sonotronde diameter. The degradation of Trichlorethylene and 1, 1, 2 -Trichloroethane is much better for sonotrode with 14 mm diameter (92.1% respectively 92.7%) than for sonotrode with 40 mm diameter (71.9% and 61.6%), while for Tetrachloroethene values were very close, 88.7% respectively 89.4% for the same above mentioned diameters.
The Danube nutrient loads are affected by human impacts mainly from agriculture and wastewater discharges. Knowledge about the Danube nutrient loads and the changes of these loads over time is essential for understanding the changes within the ecosystem of the Black Sea, induced by these loads. The paper shows the long term changes of the nutrient load along the Danube estimated by measurements from different countries and institutions. The results show large differences between Dissolved Inorganic Nitrogen (DIN) and Total Phosphorus (TP). For TP, the Danube River loads show a strong decrease since 1988–1992, especially in the Middle and Lower basin. This change is probably partly connected to the dramatic economic changes in the Middle and Eastern European countries following the collapse of the communist system. The DIN load does not show a decreasing trend in the last decade. The data indicate that there may be a decreasing trend in the anthropogenic emissions, but that such a trend is counteracted by a significantly increasing trend of the Danube discharge in the last decade. The accuracy of the available data is analysed in the paper as well.
The purpose of this paper is to assess the degree of pollution with volatile organic compounds (VOCs) and volatile aromatic hydrocarbons (BTEX) in water, sediment, biota in lessening the environmental risk. The mathematical model MacKay was performed for volatile organic compounds (dichloromethane, trichlorethylene, and perchlorethylene) and volatile aromatic hydrocarbons (benzene, toluene, ethylbenzene) and as a study areas were chosen sections Cremenari, Babeni-Marcea, Zavideni, Dragasani and Strejesti on the Olt River. The modeling revealed the tendency of transfer to section "air" a dichloromethane, trichloroethylene, benzene, toluene and ethylbenzene, are known that are volatile. However, based on modeling is observed a significant transfer of pollutant perchlorethylene in section "biota" in amounts that can generate medium to long term by taking over risks to human health in the food chain. The modeling has achieved its purpose, providing rapid and with a number of primary values low "fingerprint of pollution" in the accumulation lakes Babeni-Marcea, Zavideni, Dragasani and Strejesti, that indices conclusive risk assessment of rapid which underpin the conclusions on actions / preventive actions for future study area.
A new azulene (L 2352) synthesized in the laboratory was used for the design of a new stochastic sensor. L 2352 was physically immobilized in graphite paste. Four metallic cations: Cu(II), Pb(II), Hg(II) and Cd(II) served as model analytes. The new sensor was reliable used to prove the stochastic behavior of the proposed microsensors. The metal cations were determined directly from nine waste water.
Abstract. The aim of this paper is to assess the heavy metal pollution and potential ecological risk in surface sediments from accumulation lakes on the sector inferior of the Olt River: Govora, Babeni-Marcea, Zavideni, Dragasani and Strejesti. Heavy metals are among the most persistent of pollutants in the ecosystem such as water, sediments and biota because of their resistance to decomposition in natural condition. Accumulation of heavy metals in the environment results primarily from human activity. In addition, an important role in the "enrichment" heavy metal reservoirs they have natural processes, such as the disintegration of rocks and volcanic activities. Sediment is the ultimate destination for heavy metals discharged into the environment. The main aspects of the present work are to: determine to content and spatial distribution of heavy metals (Cd, Cu, Ni, Zn, Pb, Cr, Hg) in surface sediments from accumulation lakes on the sector inferior of the Olt River; calculating the pollution load index (PLI), the Nemerow pollution index (PI) and potential ecological risk (RI) in order to evaluate the potential ecological risk.Keywords: heavy metals, surface sediment, accumulation lakes, potential ecological risk
AIMS AND BACKGROUNDHeavy metals are among the most persistent of pollutants in the ecosystem such as water, sediments and biota because of their resistance to decomposition in natural condition. Metal have low solubility in water, get adsorbed and accumulated on bottom sediments 1 . The increase the heavy metal content in the reservoirs is shown notably by increasing their concentration in bottom sediments. Accumulation of heavy metals in the environment results primarily from human activity. In addition, an
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