Geochemical comparisons between estuaries with non‐industrialised and industrialised catchments: the Huon and Derwent River estuaries, Tasmania*

Abstract

The adjacent Huon and Derwent estuaries in Tasmania have similar climatic and physical characteristics, and provide a good comparison between relatively uncontaminated and industrially polluted estuaries, respectively. Representative samples were collected from both estuaries and analysed for grainsize and trace-element content (using X-ray fluorescence and neutron activation analyses). The Huon estuary drains a predominantly forested and agricultural catchment and contains low (baseline) concentrations of trace elements, including lead, zinc and copper. In contrast, the Derwent estuary has a geologically similar yet larger catchment and it passes through an industrialised area in the midestuarine reach. A zinc refinery has, in the past, been a major source of trace-element contamination. These contaminants are distributed downstream from the refinery by combined fluvial and tidal activity, while the latter also causes upstream movement of contaminants during non-flood periods. Significant upstream contamination is limited by fluvial bottom flows remobilising contaminated fine sediment during flood periods. Maximum contamination occurs in the region around the refinery with values in the surface sediments ranging from 40 to 565 times baseline levels and from 2 to 55 times the Australian Interim Sediment Quality Guidelines high-levels for aquatic sediments (maximum 22593 ppm Zn, 3866 ppm Pb and 1182 ppm Cu). In the lower Derwent estuary, contaminant distribution is inversely related to tidal-flow velocities and is most prominent in the lower energy muddy substrates. Trace-metal levels in the more recent surficial aquatic sediments are slightly lower than those recorded in a previous study from the area, possibly reflecting the stricter environmental controls now operating.

Geochemical Assessment of Trace Element Pollution in Surface Sediments from the Georges River, Southern Sydney, Australia

“…The mean values of trace element pollution for Cu, Zn and Pb in the surface sediments of the study areas generally had higher concentrations compared with the more pristine environments in both Burrill Lake and the Huon estuary (Killian, 1999;Jones et al, 2003b). The surface sediments in both the Huon estuary and Burrill Lake are dominated by clean sand fractions and low percentages of organic matter, and their catchment areas are non-industrialised and lightly developed (Killian, 1999;Jones et al, 2003a). The results for the current study are slightly higher than for a previous study in Botany Bay (Birch et al, 1996).…”

“…Surface sediments in Sydney Harbour (Irvine and Birch, 1998) and the Derwent River (Jones et al, 2003a) have been subject to large amounts of contamination from urban, industrial and commercial activities, such as a zinc refinery, stormwater runoff, mine discharges, vehicles exhausts, sewage effluent and watercraft, as well as leaching from reclamation areas.…”

Spatial and Temporal Distribution and Pollution Assessment of Trace Metals in Marine Sediments in Oyster Bay, NSW, Australia

“…Therefore, the red and green groups were considered to be moderately to highly polluted with samples located in the inner bay, while the blue group represents areas with low or no pollution and samples located at some of the edges of the bay. The trace metal concentrations that were measured in Oyster Bay were compared with the levels of trace metals determined in a range of studies (Table 3; Birch and Taylor 1999;Jones et al 2003). Huon estuary is essentially a nonindustrialised zone and consequently should contain a low level of potentially toxic trace metals Jones et al (2003).…”

Using stylet elemental signatures to determine the population structure of Octopus maorum

“…Although the natal origin of the EHB individuals is speculative, the elevated levels of Pb and As suggest that they hatched in coastal waters comparatively close to the industrialised Derwent estuary. Pollution has resulted in significantly elevated levels of Pb and As in the Derwent estuary, compared to surrounding waters (Jones et al 2003), making the southeast region comparatively heterogeneous in elemental distributions. If the aggregating animals are hatching within this region, it would explain the very broad range of As and Pb (and potentially Co and Mn) levels between the individuals from EHB.…”