HEAVY METAL POLLUTION STUDIES OF SUSPENDED SEDIMENTS IN WAIWHETU STREAM WATER BY PIXE

Abstract

PIXE measurements on filtered water samples were conducted to investigate the possibility of using nuclear based analytical techniques to measure elemental concentrations of heavy metals in suspended sediments in the Waiwhetu Stream (Lower Hutt, New Zealand). It was found that most of the elements detected have a concentration of around 100 ppm by weight with 10 percent variation. Heavy metals like Cu , Zn , Pb and Cd were also present at higher than normal concentrations in the stream. Previous studies of the sediments collected from the Waiwhetu stream had showed that high levels of heavy metals were present at locations close to industrial sites, Nowadays, industries are no longer permitted to dump their waste into the stream. However, high-levels of heavy metals were found to be still present in the water samples indicating that these elements are slowly washed out of the sediments into the surface waters. The present results of Waiwhetu stream water samples revealed that heavy metals are distributed throughout the stream indicating that industrial wastes from industry discharges still linger after 30-40 years.