Acid leached analyses of stormdrain and harbor sediments, New Zealand

Sediments from stormdrain catchments in Wellington city and sediment traps from Wellington Harbor were sampled for trace metal content. Samples were a nalyzed for acid leached metal content by extraction with 0.11 mol acetic a cid l(-1) and using ICP-MS. Cu and Zn levels in harbor sediment traps incre ased towards the periphery of the harbor, while Pb levels adjacent to a roa d almost doubled. In general, areas of light industry in the Inner City sto rmdrain catchments exhibited higher acid leached metal concentrations. Howe ver, large-scale renovation work probably contributed to point sources of h igh metal levels. The proximity of stormdrain outlets to recreational activ ities, such as wharf fishing and shellfish gathering, should be of prime co ncern to local authorities. Some positive correlations are found between acid leached and total metal l evels. These may prove useful for assessing the biological impact of signif icant increases in total metal concentrations in the vicinity of Wellington Harbor. Significant savings in the time and costs of analyses may be achie ved.