Traffic and Climate Change Impacts on Water Quality: Measuring Build-Up and Wash-Off of Heavy Metals and Petroleum Hydrocarbons

Introduction

The volume and characteristics of Australian urban traffic are expected to undergo extensive changes due to the continuously increasing urbanisation of the continent’s major cities. Climate change is also expected to result in longer periods of dry weather with fewer, but more intense, storms (CSIRO 2003, 2007). The dynamic scenarios of changes to rainfall characteristics due to climate change and changes to the urban traffic due to increased urbanisation can readily affect pollutant build-up and wash-off into the local water bodies. This, in turn, can have significant impacts on urban water quality.

Suspended solid is the most important stormwater runoff pollutant and has additional significance because other pollutants, such as heavy metals and hydrocarbons, are primarily attached to them (Sartor et al., 1974; Harrison & Wilson 1985). The main anthropogenic activities that generate heavy metals and hydrocarbons are vehicular traffic, combustion of fossil fuels and lubricants, and industrial activities. Toxic pollutants such as Total Petroleum Hydrocarbons (TPH) and heavy metals are transported into water bodies by urban stormwater runoff (Hunter et al., 1979; Hoffman et al., 1982, 1984; Herngren, 2005). Brown et al. (1985) found that vehicular crankcase oil is the most significant anthropogenic source of TPH contamination in urban stormwater runoff.

This chapter describes the experimental methodology developed to measure selected heavy metals and TPH contaminants in pollutant build-up and wash-off samples from road surfaces. Firstly, a general discussion on the impacts of urban traffic and climate change on water quality is provided. Then the selected study sites and their selection criteria are presented, followed by a novel method that combines vacuuming and spraying to collect pollutant build-up samples and presentation of an approach to collect wash-off samples. This is then followed by a discussion on sample collection, preservation, extraction and testing techniques.