A previous regional soil and stream sediment sampling program (cf. RB 2000/00002) has delineated areas of heavy metal contamination in the Dawesley-Bremer Catchment. Heavy metal contamination was found to occur sporadically along both Dawesley Creek and the Bremer River, but occurs consistently along Mount Barker Creek, from its junction with Dawesley Creek down to the Bremer River. After consultation and review of results with CSIRO Land and Water Div., an infill soil, stream sediment and water sampling program (the subject of this report) was designed to provide much better definition of heavy metal contamination along the Mount Barker Creek, and to follow up elevated soil Cd values in the Langhorne Creek area. Vegetation sampling was also conducted along the Dawesley Creek at all soil sample sites that had previously recorded Cd values which are elevated above acceptable levels (ANZECC'92). Soil and stream sediment sampling along the Mount Barker Creek revealed heavy metal concentrations above acceptable ANZECC'92 levels. The heavy metal contamination is generally restricted to the top 20 cm of the soil profile, but in the Mount Barker Creek channel itself contamination continues to the maximum depth of sampling (i.e. to 1 m). These results indicate that precipitation of heavy metals from Dawesley Creek water is taking place due to the stream pH conditions changing between Dawesley Creek and Mount Barker Creek. The precipitated heavy metals are deposited in streambed sediments and point bar deposits. Reworking of these deposits during floods results in sporadic deposition of heavy metals further downstream. Stream water sampling along the Dawesley and Mount Barker creeks revealed elevated concentrations of heavy metals in solution, with only Cd exceeding stock water guidelines (ANZECC'92). Cd and other metals are precipitated from solution when the waters of Dawesley Creek intermix with those of Mount Barker Creek, due to changing pH conditions. Dawesley Creek water has a low pH (ie. it is acidic), whereas Mount Barker Creek water has a high pH (ie. it is alkaline). Dissolved heavy metals in the Dawesley Creek water are considered to be due to Acid Mine Drainage (AMD) from the Brukunga Mine, with some contribution coming also from the Aclare Mine. Vegetation samples were collected from upstream of the Brukunga Mine to determine background levels of heavy metals in a variety of plants, and additional samples were taken from plants growing on the Brukunga tailings dam. Analysis results revealed various heavy metals occurring in these plants, with Cd, Zn, Cu, Fe and Ni recording the highest concentrations. Translocation of heavy metals into the vegetation is not consistent between plant families and between sites, indicating that there is complex bioavailability behaviour of the heavy metal contaminants. The regional program that identified elevated Cd in soil samples at Langhorne Creek was followed up by more detailed sampling of soils and vegetation. Soil metal values were found to be below detection or at background levels, except for some sites in close proximity to the Bremer River. Zn was found to be elevated at or above the ANZECC'92 investigation level (i.e. 200 ppm) at these sites, and is restricted to the top 20 cm of the soil profile. Concentrations of Cd in the soil were slightly elevated, but not above ANZECC'92 guideline values. All grapevines, vegetation and pastures sampled along Langhorne Creek returned Cd values below detection. One potato sample (B108) recorded 2 ppm Cd, but the cultivation of such vegetables is no longer practised at this location. A preliminary stream sediment sampling investigation of the drainage around the Kanmantoo Mine site showed no evidence of any heavy metal contamination associated with mine runoff. Based on the results of these surveys the following recommendations are proposed: · Fencing along Mount Barker Creek from its junction with Dawesley Creek down to the Bremer River. · Liming along Mount Barker Creek from its junction with Dawesley Creek down to the Bremer River. · Vegetation sampling along Mount Barker Creek from its junction with Dawesley Creek down to the Bremer River. · Further investigations of vegetation growing immediately downstream from the Brukunga Mine, and along Mount Barker Creek between its junctions with Dawesley Creek and the Bremer River, to better define heavy metal contamination in plant species. · Mine site remediation of Aclare Mine to prevent it contributing to heavy metal contamination of Dawesley Creek.