Nitrogen Fertilization Effects on Stream Water Cadmium Concentration

• Published in: Journal of environmental quality 2001-01, Vol.30 (1), p.189-193
• Main Authors: Högbom, Lars, Nohrstedt, Hans‐Örjan, Nordlund, Sten
• Format: Article
• Language: English
• Subjects: Acidity; Agronomy. Soil science and plant productions; Ammonium; Ammonium nitrate; Applied sciences; Biological and medical sciences; Cadmium; Cadmium - analysis; Cadmium - chemistry; Continental surface waters; Drinking water; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring; Exact sciences and technology; Fertilizers; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Lysimeters; Metal concentrations; Moisture content; Natural water pollution; Nitrogen - chemistry; Pollution; Pollution, environment geology; Rainwaters, run off water and others; Soil and water pollution; Soil pH; Soil Pollutants; Soil profiles; Soil science; Soil water; Solubility; Surface water; Sweden; Water Pollutants, Chemical - analysis; Water Supply; Water treatment and pollution
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2001.301189x

High transition metal concentrations were previously unexpectedly observed in soil water extracted by suction lysimeters following forest N fertilization. This observation called for additional measurements to investigate if the finding is a general phenomenon and, if so, whether stream water concentrations of transition metals could increase as a result of N fertilization. The measured levels of Cd in the preliminary findings were well above health limits for drinking water. Hence, the problem could be of major concern. Here we report on soil water and stream water concentrations at two partly fertilized watersheds. All sites were situated in the central part of Sweden. The N application (150 kg N ha−1 in the form of calcium ammonium nitrate) resulted in increased concentrations of nitrate, and a pulse of acidity through the soil profile, which increased the solubility of transition metals (mainly Cd and Zn) and Al. Stream water concentrations of transition metals, on the other hand, were not affected during the studied period by the increased solubility of transition metals in the soil. The data imply that the solubilized transition metals probably insolubilize further down the soil profile, and that there is no risk from forest N fertilization (at normal soil pH levels) of transition metal levels increasing in nearby surface waters. To our knowledge, this is the first time this side effect of N fertilization has been considered.