Environmetrical treatment of water quality survey data from Yantra river, Bulgaria

The environmetrical analysis carried out has indicated that the short-term water quality survey may give a very important information on the latent fa ctors influencing the water quality of Yantra river basin. The principal co mponents analysis carried out reveals that at least four principal componen ts are necessary for multivariate statistical modeling of the water quality - combination of natural and anthropogenic influences ("mixed" factor) ref lecting parameters such as water hardness, marine influence, organic pollut ion; typical anthropogenic influences ("anthropogenic" factor) explaining t he metal contamination of the river water; everyday wastes, usually N-conta ining pollutants such as nitrates, nitrites or ammonia, form the "N-contain ing wastes" factor and a "temperature" factor formed by typical physical pa rameters such as water and air temperature. The formation of these special features of the river waters from Yantra bas in is also confirmed by the results of cluster analysis (variable clusterin g) where the content of the significant clusters of the variables is the sa me as the content of the principal components modeling over 75% of the tota l variance of the system. Additionally, the cluster analysis of the objects has proved that the water quality during both sampling traverses is very s table and reproducible. Few exceptions are observed due to momentary local pollution in an industrial area along the river stream. Comparison with sta ndard requirements for water quality has indicated that the Yantra river wa ters are of high quality and could be used after minor pretreatment as pota ble water sources. The environmetrical approaches applied reveal a specific information concer ning the river water quality. In this way the ecological problem treated ha s not a local importance but suggests a strategy for estimation of similar ecosystems in global sense.