Abstract: Ammonium ions (NH ), exist in the ecosystem by direct atmospheric deposition, mineralization of 4
+
organic matters from soil and fertilizer input in the form of NH and urea hydrolysis. Mineralization is the 4
+
process that breaks down organic nitrogen (N) compounds in the soil to release NH , Nitrification is the 4
+
process that converts NH into NO . NH is also easily converted into NH at high pH. NH is an intermediate 4 3 4 3 4
+ - + +
product that in favorable condition, converts into a stable product that causes major water pollution of water
bodies. Eight out of fifteen automatic water quality stations were chosen to represent NH influx in the 4
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Malaysian rivers for discussion in this paper. The paper synthesized published data from the Environmental
Quality Report of DOE for the year 2003-2006. The data analysis shows some rivers or Sungai (Sg.) such as Sg.
Batang Benar, Sg. Skudai, Sg. Langat and Sg. Labu were continuously experiencing NH influx in 2003-2006, 4
+
whereas Sg. Melaka, Sg. Keratong and Sg. Linggi the occurrence were recent. As for Sg. Putat no detection of
influx in the recent years. Thus Sg. Batang Benar, Sg. Skudai Sg. Langat and Sg. Labu, Sg. Melaka, Sg. Keratong
and Sg. Linggi require immediate action to control and reduce the influx. Early detection of NH is crucial to 4
+
determine the pollution caused by the presence of NH because in circumstances where NH would be 4 4
+ +
converted to nitrate, cause significant algal bloom to the water body and the impact is detrimental on aquatic
and water resources.