Metals in the waters and sediments of Port Curtis, Queensland

[摘要] Executive SummaryFollowing recent concerns about the impacts of dredging in Gladstone Harbour, Gladstone Ports Corporation (GPC) requested assistance from CSIRO to accurately determine the concentrations of metals in the waters and sediments of Port Curtis.The CSIRO group at Lucas Heights, Sydney has extensive experience in low level metals analysis and the assessment of contaminant impacts on aquatic systems. The CSIRO laboratory is fully equipped with state-of-the-art instrumentation and has a dedicated trace metals clean laboratory which is National Association of Testing Authorities, Australia (NATA) accredited. Its range of sensitive analytical techniques allows the accurate determination of dissolved metal concentrations in marine waters at sub-μg/L concentrations. There are few laboratories in Australia that possess this capability. The group has worked in Port Curtis previously as part of the Cooperative Research Centre (CRC) for Coastal Zone, Estuary and Waterway Management and has produced a number of peer reviewed publications which detail metal contaminant concentrations in Port Curtis (Jones et al., 2005, Angel et al., 2010).This report describes a study of water and sediment quality within Port Curtis. The study was funded by GPC but conducted independently by CSIRO.Water and sediment samples were collected over the period 6-8 December 2011 at 21 sites across the Port Curtis region. The study design was based on a sampling campaign conducted by CSIRO in 2003 and 2004 (Angel et al. 2010). Sampling and analysis was conducted using internationally-accepted protocols and state-of-the art QA/QC procedures including the use of Certified Reference Materials. A detailed interpretation of the data was provided including comparison to existing trace metals data for Port Curtis and other coastal locations impacted by anthropogenic activities. The data from the current study were also compared to water and sediment quality guidelines for marine waters (ANZECC/ARMCANZ 2000) that currently apply in Australia. The findings of the study were as follows:1. The concentrations of dissolved metals were below the available ANZECC/ARMCANZ marine water quality guideline trigger values (95% protection, high or moderate reliability) that apply in Australia at all 21 sites sampled. 2. Dissolved aluminium concentrations were above the ANZECC/ARMCANZ (2000) environmental concern level (ECL) of 0.5 µg/L at the majority of sites sampled. It should be noted that there is no reliable guideline value for Al in marine waters in Australia and the ECL value is a highly conservative value based on very limited toxicity data. There are no water quality guidelines that apply for aluminium in marine waters in Europe or North America.From the current data set, it was not possible to attribute a specific source of the dissolved aluminium.3. Dissolved copper and nickel concentrations were noticeably higher in December 2011 compared to concentrations measured in the CSIRO surveys in 2003 and 2004, indicating increased inputs of these metals from various sources. Dissolved copper concentrations are of concern as they are approaching the ANZECC/ARMCANZ guideline value of 1.3 µg/L in some parts of Port Curtis.4. Apart from arsenic, the concentrations of particulate metals in benthic sediments were below the ANZECC/ARMCANZ sediment quality guideline values.Particulate arsenic concentrations exceeded the ANZECC/ARMCANZ ISQG-low trigger value in two samples from the Narrows and one site off Quoin Island. Previous studies indicate that the source of this arsenic is natural (geological formation in the area) and is not associated with anthropogenic inputs.5. Metal concentrations in suspended sediments were not elevated and were comparable to the concentrations of metals in the 63 µm (fine) fraction of benthic sediments. This is consistent with the resuspension of fine sediments into the water column.6. The study did not detect any ‘h

[发布日期] 2012-04-23 [发布机构] CSIRO

[学科分类] 地球科学(综合)