TITLE:
A Study of the Yesilirmak River Catchment in Northern Turkey: Spatial Patterns and Temporal Trends in Water Quality
AUTHORS:
Li Jin, Paul Whitehead, Michalis Hadjikakou
KEYWORDS:
Nutrients; Nitrate; Orthophosphate; Agriculture; Wastewater; Waste Water Treatment Plants
JOURNAL NAME:
Journal of Environmental Protection,
Vol.4 No.7A,
July
17,
2013
ABSTRACT: This
paper presents a comprehensive study of spatial and temporal patterns of water
chemistry (1995-2008) in the Yesilirmak River catchment in Northern Turkey.
Biological oxygen demand (BOD), dissolved oxygen (DO) and nutrient concentrations
(nitrogen and phosphorus) are variable across the catchment because the upland
areas are relatively undisturbed, and the lower catchment is dominated by
urban, industrial and agricultural inputs. Seasonally, high nutrient
concentrations occur in winter possibly due to flushing from the soil zone. Low
summer flow and reduced dilution lead to high orthophosphate concentrations.
However, denitrification seems to be more significant than dilution processes
and this generates low nitrate concentrations in summer. Nutrient levels since
1995 do not show a significant upward trend. The current water quality status
indicates that the river system is in poor condition. The majority of sites
fall in the Turkish water classification class II-III and more than half fail
the EU standards because of high nutrient concentrations. In order to improve
the status of water quality to achieve good chemical and ecological status,
there is clearly a need to improve pollution control within the river system by
installing waste water treatment plants, while keeping the agricultural
pollution to a minimum in the system.