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Friday 18 September 2009 at 10.30 am,
B2 Conference Room, Ground Floor, CSIRO
The bioavailability, accumulation and toxicity of Cu and Zn from antifouling paint particles to the benthic bivalve Tellina deltoidalis in marine sediments
Ms Anne Cremazy, University of Bordeaux
Abstract
The marine benthic bivalve Tellina deltoidalis was exposed for 30 days to three types of sediments amended with two concentrations of copper-based antifouling paint particles. The three sediment types had varying particle sizes ranges (10%, 30% and 60% <180 µm) and were spiked with dried paint to achieve concentrations of 200 and 1000 mg Cu/kg. Zinc was also present at concentrations of 64 and 320 mg/kg, respectively. The accumulation of Cu and Zn by T. deltoidalis, and effects to growth and survival measured as effect endpoints at the termination of the test. Labile metals exposure in porewater was monitored for 24 h every 15 days with DGT (diffuse gradient in thin film) probes. As sediment particle size is directly related to sediment binding sites, this parameter was studied to investigate how it affects the amount of bioavailable metal in the sediment.
Labile Cu and Zn species leached from the paint to the porewater were found as the most bioavailable species to T. deltoidalis. Labile Zn species concentrations were greater than Cu. However, Cu accumulated to a greater extent by T. deltoidalis than Zn. It indicated that the major metal uptake resulted from particle ingestion, as Cu is the main paint biocide and its concentration in paint is superior to Zn. Metal accumulation increased as the percentage of fine particles decreased. 100% mortality was observed in 1000 µg/g Cu-spiked sediments and in the largest grain size sediment. Effects to growth were not significant except from the finest grain size sediment.
The antifouling paint particles were an important source of Cu, and to a lesser extent Zn, to T. deltoidalis. This source is amplified with larger grain size sediment as there are less binding sites for bioavailable metals.
Thursday 30 July 2009 at 3 pm,
B21 Conference Room, Ground Floor, ANSTO*
Germs and Geology: Emerging Issues in Waterborne Pathogen Research
By Professor Larry McKay, University of Tennessee, Knoxville
Abstract
Professor Larry McKay will address how recent hydrological research and development of new analytical methods in molecular microbiology can combine to change how we detect, monitor and predict the exposure of human populations to waterborne pathogens. Much of our understanding of waterborne pathogen occurrence and transport is based on conceptual models and investigative methods that have changed little in the past 30-50 years. Traditional paradigms for waterborne pathogens can be described with terms as simple as coliforms=pathogen-risk, surface-water=bad, groundwater=good, karst=bad, sand=good, true-groundwater=good, and groundwater-under-the-direct-influence-(GWUDI)-of-surface-water=bad. Recent investigations at UT and many other institutions challenge the existing paradigms. For example, a study of community water supply wells in karst aquifers in east Tennessee indicated that enteric viruses are common and can occur even in wells that don’t exhibit other indicators of fecal contamination. Other studies at UT show that very rapid transport of bacteria and viruses can occur in fractured clay-rich sediments and in partially-saturated soils, both of which are settings where slow transport of pathogens is usually expected. There is a great need for additional field-based studies of pathogen occurrence and transport, as well as better collaboration between hydrologists, microbiologists and the public health community. Development of faster or easier to use microbial assays, as well as better sample collection and concentration methods, are providing hydrological researchers with improved tools to help carry out this research. Chief amongst these tools is the development of molecular assays, such as qPCR, which detect pathogens or other fecal microorganisms based on their DNA or RNA signature. Investigators at UT have developed a series of qPCR assays for Bacteroides (a major constituent of feces), which can be used to rapidly and inexpensively determine both the fecal concentration in a water sample and the likely source (human, cattle, horse, etc.). These assays have been used to delineate contaminant sources in watershed studies and have the potential for use in field experiments, allowing bacteria from different fecal sources to be traced throughout a flow system.
Wednesday 29 July 2009 at 10 am
B21 Conference Room, Ground Floor, ANSTO*
Early Agriculture and human activity in the Yangtze River delta, China
By Pia Atahan
Abstract
The Yangtze delta is renowned for its long history of rice cultivation and high density of pre-historic sites. The rich archaeological record provides an ideal backdrop to the study of long term human-environment interaction and impacts of developing rice agriculture on environments in the area. This seminar will review the main findings from three sites on the delta plain, using pollen, charcoal and biomarker analyses, and placed them within the context of the region’s developing agricultural society.
*All external visitors to ANSTO seminars are required to RSVP to Ms Jodi Colbran, Email: jha@ansto.gov.au
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