Influence of sewage inputs and fish farm effluents on dissolved nitrogen species in a chalk river

• Published in: Water, air & soil pollution: Focus Vol. 4; no. 6; pp. 117 - 125
• Main Authors: Homewood, J M, Purdie, DA, Shaw, P J
• Format: Journal Article
• Language: English
• Published: 01.01.2005
• Subjects: Freshwater; British Isles, England, Hampshire; British Isles, England, Hampshire, Test R
• ISSN: 1567-7230; 1573-2940
• DOI: 10.1007/s11267-005-3021-0

Nitrate, ammonium and dissolved organic nitrogen (DON) concentrations were measured in the lower reaches of the River Test in Hampshire to assess the impact of two effluent point sources. An 18-month survey from July 2001 to December 2002 was carried out at locations above and below fish farm inputs and a sewage effluent outfall. The concentration of nitrate exceeded 400 kM at the four sites on all sample dates. A consistent increase in ammonium concentration was measured downstream of the fish farm, but not the sewage effluent input. DON samples collected downstream of the fish farm did not show a consistent increase in concentration, compared with the upstream sampling location, whereas the sewage effluent input at Romsey was a point source of DON to the River Test with a mean increase of 15 kM. Nitrate was the major component of dissolved nitrogen in this aquifer-fed chalk-bed river system, with up to 10% being DON and ammonium comprising <1%.