The evolution of the physical-chemical quality state of the Danube Delta aquatic ecosystem in the period May-October 2005/2006

The objective of this paper is to provide useful data concerning the quality of the Danube Delta aquatic ecosystem (surface water and sediment). Samples were collected from May to October in two consecutive years (2005 and 2006) from two different locations situated on Sfantul Gheorghe (Saint George) branch (Murighiol and Uzlina). A particular observation is that a high concentration of polyaromatic hydrocarbons (PAHs) was recorded in the sediments collected from Murighiol confirming the pollution of the environment from that area. The comparative analysis of the quality characteristics of the Danube Delta aquatic ecosystem in 2005 and 2006 (by physico-chemical determinations) emphasized a dynamic character of water quality that can lead to unfavorable stages and, thus, to worse life conditions for aquatic organisms.