| Abstract |
Regional council monitoring data for the period 1995-1999, and new data for dissolved and acid-soluble As concentrations and for As bound to suspended particulate matter (SPM), have been used to clarify some unresolved aspects of As behaviour in the Waikato River system. A higher load of (total recoverable) As was consistently carried in the summer months of each year between 1995 and 1999. Dissolved As accounted for 73 -100% of all As carried in the water column. The degree of As adsorption on SPM was unaffected by temperature but influenced by the biological component of the SPM, specifically the presence of certain diatom species. The degree of As adsorption on SPM did not change significantly in the estuary, with As behaving conservatively in this zone. |