URBAN GEOCHEMISTRY AND ASSOCIATED HEALTH HAZARDS IN THE SEDIMENTS OF VICTORIA, BRITISH COLUMBIA

Over the past decade there has been an increasing number of reported incidents involving trace elements (e.g. arsenic, lead, cadmium and mercury) and their adverse effects on human health. The impact of these and other geogenic contaminants on human health and the environment has been recorded around the world (e.g., India, China, U.S.A., and Bangladesh). This study involves an investigation of the relationship between geology, geochemistry and childrens health in the city of Victoria, Canada.

A total of 305 soil samples have been taken from 17 census tracts within the municipality of Victoria. At each site, samples were collected from the top 5 cm of soil, and at selected sites deeper, C-horizon samples (>50 cm), were collected. Local bedrock, till samples and the deep soil samples will be used to estimate the background concentrations of the elements. Additional surface samples were collected from playgrounds and school yards within the census tracts sampled.

All samples have been evaluated by ICP-MS for 35 trace elements at two size fractions: 80 microns and 2 millimeters. Loss on ignition analysis has been conducted the 2 mm fraction. The ICP-MS results indicate that a number of the samples are well above the Canadian Environmental Quality Guidelines for Soils for lead (25%), zinc (8%), copper (6%) and arsenic (4%). Detailed interpretation of the data awaits the completion of sample collection, health data compilation and further analysis. However, preliminary interpretation of the results indicates that dangerous levels of various trace elements occur in the urban environment and do pose a threat to the health of the general populace.