Investigation of the Organic Pollution and Contaminants' Biological Destruction of the River Kamchiya

ABSTRACT

The subject of the present work is an investigation of the water quality of the river Kamchiya with regard to the organic pollution and contaminants' biodegradability. Nutrients content (ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate), Dissolved oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxigen Demand (COD) were analyzed in 10 monitoring stations downstream for three years period. The river was characterized with good oxygen status. The nitrates corresponded to the national water quality standards. Concentrations of ammonium nitrogen, nitrite nitrogen and phosphates over the threshold limits were determined in most of the monitoring stations. The average annual concentrations of nitrite pollution at the nearest to the river mouth monitoring stations Poda exceeded the threshold limits 4 times for 2006, 9 times for 2007 and 5 times for 2008 year. The highest concentration measured at this station during June 2007 year was 0, 91 mg/dm³ at 0,04 mg/dm³ threshold limit. The highest levels of ammonia and nitrites exhibited disturbance of the nitrification processes. The coefficient of conservatism of the organic pollutants was calculated by the correlation between BOD and COD values. In most of the cases the coefficient value was under 0,5 which determined the organic pollutants as highly conservative with regard to biological destruction.

Keywords:

• the river Kamchiya
• organic pollution
• biological destruction
• conservative pollutants
• threshold limits