Natural waters, classification river

Considering evidence from both field and mesocosm studies, it may be concluded that certain groups of aquatic macroinvertebrates are sensitive to pyrethroids and that there can be changes, in the short term, at the population level and above with exposure to environmentally realistic concentrations of them. It should be possible to pick up effects of this kind in natural waters using ecological profiling, for example, the River Invertebrate Prediction and Classification System (RIVPACS). There is... 

There are different classifications of natural waters. Depending on the salt content waters are divided into fresh water (salt content <0.5 g/dm - rivers and lakes), brackish water (<10 g/dm - estuarine), and salt water (about 35 g/dm - sea water, although some closed seas like the Baltic and the Black Sea have lower salt content). Depending on their origin, waters may de classified as river and lake, precipitation (snow and rain), sea water, waste water and underground water. 

The formation receiving water from a certain river basin is called a water recipient. It is formed either in a natural way or artificially by man s interference. The water in the recipient may be either moving or stagnant (motionless). Considering this classification the following waters exist ... 

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