Acid sulphate soil disturbance and metals in groundwater: implications for human exposure through home grown produce.

A significant emerging environmental problem is the disturbance and oxidation of soils with high levels of iron sulphide minerals resulting in acidification and causing the mobilization of metals into groundwater. This process is occurring in many parts of the world. In Western Australia, impacted groundwater is extracted by residents for domestic use. We sought to establish domestic use patterns of bore water and the concentration of metals. Sixty-seven domestic bore water samples clearly indicated oxidation of sulphidic materials with heavy metal concentrations ranging for aluminium (<DL-37.0 mg/L), arsenic (<DL-6.6 mg/L), iron (<DL-1200 mg/L), cadmium (<DL-0.021 mg/L), lead (<DL-0.040 mg/L), selenium (<DL-0.006 mg/L). A high proportion of residents used bore water on home grown produce. The study suggests that there is potential for human exposure to heavy metals via the consumption of home grown produce. This warrants further investigation in light of increasing acid sulphate soil disturbance in many locations.