Forms of Nutrients in Rivers Flowing into Lake Chaohu: A Comparison between Urban and Rural Rivers

Abstract

Nutrient inputs from rivers play an important role in lake eutrophication. To compare the forms characteristics of phosphorus (P) and nitrogen (N) in rivers flowing through rural and urban areas, water samples were collected seasonally from five urban rivers and six rural rivers flowing to Lake Chaohu, China. Higher total phosphorus (TP), particulate phosphorus (PP), soluble reactive phosphorus (SRP), and dissolved nonreactive phosphorus (DNP) concentrations and SRP/TP percentages were observed in urban rivers than in rural rivers, and PP/TP and DNP/TP ratios were lower in urban rivers than in rural rivers. The concentrations of total nitrogen (TN) and all N forms other than dissolved organic nitrogen (DON) were significantly higher in urban rivers than in rural rivers. NH4 + /TN levels were higher in urban rivers, whereas PN/TN and DON/TN ratios were significantly lower in urban rivers compared with rural rivers. NO3 − /TN and NO2 − /TN levels were similar between the two groups of rivers. TP, BD-P, and NaOH-P levels in urban river surface sediments were significantly higher than those in rural rivers. NaOH-P/TP ratios were significantly elevated in urban rivers, whereas HCl-P/TP and Res-P/TP ratios were significantly lower compared with rural rivers. Urban rivers have transferred large quantities of NH4 + and SRP into Lake Chaohu, resulting in higher TP and TN levels and and SRP into urban rivers is a high priority for mitigating eutrophication and algal blooms in Lake Chaohu.

The Functioning of a Water Body Within a Fluvio-Lacustrine System as an Effect of Excessive Nitrogen Loading—The Case of Lake Symsar and its Drainage Area (Northeastern Poland)

“…Although the lakes of the Babant River accumulate nitrogen, phosphorus is transported outside the system, which the authors explained by the internal enrichment of this component [29]. In catchments dominated by anthropogenic activity, nitrogen in the ammonium form dominates; its source is mainly wastewater [36]. In fluvio-lacustrine systems, it is very important to predict the system's response to increased nutrient loading [1].…”

Water quality and spatio‐temporal hot spots in an effluent‐dominated urban river

“…In many urban rivers, discharge from wastewater treatment plants and industrial processes create nutrient hot spots which significantly alter the overall water quality in these systems (Carey & Migliaccio, 2009; Luthy et al, 2015; McClain et al, 2003). Elevated concentrations of nitrogen, especially ammonia (NH 3 ), nitrate (NO 3 − ), and nitrite (NO 2 − ) (Groffman et al, 2004; Larned et al, 2016; Schoonover et al, 2005) and phosphorus, including total phosphorus (TP) and orthophosphate (PO 4 3− ) (Carpenter et al, 1998; Nagy et al, 2012; Zhang et al, 2015) have been observed in many urban rivers. In addition, elevated biochemical oxygen demand (BOD) and decreased dissolved oxygen (DO) are commonly associated with point source pollution in urban areas (Magdaleno et al, 2001; Olatunde et al, 2015; Rice & Bridgewater, 2012).…”

Heavy Metal Pollution, Fractionation, and Potential Ecological Risks in Sediments from Lake Chaohu (Eastern China) and the Surrounding Rivers

“…Of the three sites located in Chaohu, water content, LOI, TP, and TN were the lowest at MC, while higher values were detected at the WC and EC sites. This is because large amounts of pollutants from Hefei City and Feixi County have been discharged into WC through the NF, SW, TX, and PH rivers, resulting in serious eutrophication and harmful algae blooms in western Chaohu [ 35 , 37 ].…”