Carbohydrates in surface waters and its relation to the nutrients and organic matter content
T.A. Efremova
Section: Chemistry of natural environments and objects
The results of a long-term research of the content of carbohydrates in natural waters of Republic of Karelia (Russia) from 2011 to 2020 are summarized. In total, 34 water bodies (29 lakes and 5 rivers) were studied in different hydrological seasons. The presented sample of water bodies captures almost all types of surface waters in the humid zone in terms of trophicity and humus content. It was found that the carbohydrates concentration varies widely from 0.7 to 53.1 mg/L (average 3.3 mg/L) and its share of total organic matter averages 16%. It was revealed that the content and distribution of carbohydrates in surface waters depends both on natural (the level of trophicity and humus content in the reservoir) and anthropogenic factors (eutrophication, trout farms, industrial wastewater discharge, seepage waters of solid waste landfills, communal wastewater). In addition, all the studied water bodies were categorized into two groups according to the water pollution degree: contaminated and uncontaminated. It was revealed that the concentration of carbohydrates in contaminated water bodies of Karelia is on average 1.4 times higher than in uncontaminated ones. In addition, the content of carbohydrates increases together with such chemical parameters as 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD Cr), permanganate oxygen demand (COD Mn), chlorophyll a, mineral and total phosphorus (Pmin and Р total relatively) and ammonium (N-NH 4+). In particular, these relations are pronounced in contaminated water bodies, where the highest values of the correlation coefficient between the above parameters are noted. The content of carbohydrates in surface waters is a complex indicator of both organic and biogenic water pollution.