AUSTRALASIAN JOURNAL OF ECOTOXICOLOGY
A journal of the Australasian Society for Ecotoxicology
 


Volume 11 Number 2 - May 2005

57-58. BAYESIAN APPROACHES CAN HELP MAKE BETTER SENSE OF ECOTOXICOLOGICAL INFORMATION IN RISK ASSESSMENTS.
Carmel A Pollino and Barry T Hart.
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59-71. TOXICITY STUDIES OF LANDFILL LEACHATES USING JAPANESE MEDAKA (ORYZIAS LATIPES).
Shosaku Kashiwada, Kae Osaki, Akio Yasuhara and Yoshiro Ono.
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Abstract: We used Japanese medaka (Oryzias latipes) to study the toxicities of leachates from waste disposal landfill sites in terms of their LC50s, induction of vitellogenin (Vtg), and induction of CYP1A as measured by ethoxyresorufin-O-deethylase (EROD) activity. Raw leachates exhibited highly lethal toxicity to medaka, but this toxicity was reduced in leachates subjected to water treatment. EROD activity and Vtg induction were observed in response to exposure to either raw or treated leachate. Water treatment was not effective in reducing Vtg or EROD induction. Fine filtration of raw or treated leachates through a 0.45-μm membrane effectively removed Vtg-inducing chemicals, which we considered were adsorbed onto suspended substances in the leachates. Leachates were mixtures of uncountable and unknown chemicals, and the exposure effects varied with exposure time and leachate source. We analysed 165 chemical properties, to which we applied multiple regression analysis (MRA) in a search for correlations with each biomarker (LC50, Vtg, or EROD). MRA was not useful for defining the effects of individual chemicals on biomarkers. There is a risk of leachates from landfill sites contaminating the aquatic environments into which they are discharged with endocrine disruptors and EROD-inducing chemicals. Key words: medaka; leachate; vitellogenin; EROD; lethal toxicity.

73-83. THE EFFECTS OF CADMIUM ON POPULATION, GROWTH AND CADMIUM ACCUMULATION OF PROISOTOMA MINUTA IN SOME AUSTRALIAN SOILS.
Ayulungit Intan Nursita, Balwant Singh and Edith Lees.
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Abstract: Laboratory studies were conducted to evaluate the sensitivity of Proisotoma minuta toward cadmium using four Australian soils. Mortality of Collembola was determined weekly throughout the experimental period and at the end of the experiments the numbers of juveniles and adults (dead and alive) were counted. Cadmium accumulation in body tissues was determined by atomic absorption spectroscopy of acid digests of the Collembola. There was increased mortality and reduced reproduction with increasing Cd levels after seven weeks for all soils. Mortality was greater and production of juveniles much less in soils without added yeast. Tissue Cd concentrations increased with increasing Cd levels in all soils. At some lower Cd levels the concentration of tissue Cd was greater in soils with no yeast supplied. This may have resulted from increased exposure to Cd through greater scavenging activity and consumption of contaminated soil. Mortality was greatest and no reproduction observed at the highest Cd level in Box Hill soil with or without added yeast. The combination of low pH, iron content and organic matter of Box Hill soil may be responsible for the lower reproduction and higher mortality in this soil at high Cd concentrations. In experiment with yeast supplied, insignificant differences in EC50 values for reproduction, population and growth of P. minuta between soils may due to small differences in their soil properties. Key words: Proisotoma minuta; Collembola; cadmium; accumulation.

85-92. IDENTIFYING SUITABLE INVERTEBRATE SPECIES FROM A UNIQUE HABITAT FOR ECOTOXICOLOGICAL TESTING.
R Hughes, A J Reichelt-Brushett and L J Newman.
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Abstract: In this study a variety of Australian rocky shore species were used to identify a suitable species for future ecotoxicological testing. Static-renewal experiments were conducted to determine the sensitivity of several rocky shore species exposed to a range of copper concentrations for 96 hours. The copper 96-h LC50 values for the flatworm, Phrikoceros baibaiye, ranged from 14 to 17 μg/L. The larvae of this flatworm showed phototactic responses, which may be suitable for sub lethal studies in the future. The shrimp, Alope orientalis, also had low 96-h LC50 values for copper from 54 to 128 μg/L. The sea anemone, Actinia sp., was relatively tolerant to copper with LC50 values ranging from 182 to 347 μg/L. Austrocochlea constricta was unsuitable for toxicity tests as it moved out of the water in the test containers for long periods of time. No one species meets all the criteria of an ideal test species, however, further work is warranted on three of the species. Key words: Copper; marine; invertebrates; rocky shore.

93-99. TOXICITY OF ACID WATER FROM MT MORGAN MINE SITE, CENTRAL QUEENSLAND, TO THE FRESHWATER SHRIMP CARADINA INDISTINCTA.
Heather F Chapman and Stuart L Simpson.
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Abstract: A combination of toxicity testing using the freshwater shrimp Caradina indistincta and modelling of metal speciation has been used to assess water quality requirements for mine pit water releases from the Mt Morgan gold and copper mine site in Central Queensland to the Dee River. Analysis of the mine pit water indicated concentrations of some metals (730 mg/L Al, 35 mg/L Cu, 25 mg/L Zn) were several orders of magnitude above the Australian water quality guideline trigger values. Dilution of the mine pit water (pH 2.9) with Fletchers Creek (pH 8.3) water (a tributary of the Dee River) resulted in neutralisation to pH 5.3 and pH 6.4 at 1.5% and 0.8% dilutions, respectively, and precipitate formation. At a dilution of 0.8% mine water, dissolved concentrations of Al, Cu and Zn were calculated to be approximately 300, 2.5 and 5 times the guideline trigger values, respectively. The acute toxicity of the diluted pit water to C. indistincta (96-h exposures) was observed to be very pH dependent and was least toxic at pH 6 and most toxic at pH 5. No toxicity was observed at dilutions of 0.8% mine water at pH 6 or 7. For waters of pH 4, 5, 6 and 7, LC50 values of 1.8, 5.7, 20.5 and 12.9% pit water were determined, respectively. Calculated metals concentrations indicated that dissolved aluminium would contribute most to the observed toxicity. Speciation modelling calculations indicated that the lowest concentrations of bioavailable aluminium would occur at pH 6, consistent with waters of this pH being least toxic. The study indicated that neutralisation of pit waters to pH 6 prior for discharge would minimise toxicity to C. indistincta. Further testing using species such as algae, water fleas and fish is suggested to better assess the impact of the metal-rich waters on metal-sensitive biota. Key words: Caradina sp.; toxicity; acid mine water; Queensland.

101-110. ARSENIC TOLERANCE, ACCUMULATION AND ELEMENTAL DISTRIBUTION IN TWELVE FERNS: A SCREENING STUDY.
Weeraphan Sridokchan, Scott Markich and Pornsawan Visoottiviseth.
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Abstract: Twelve species of ferns were screened for their ability to tolerate and hyperaccumulate arsenic (As). Ferns were exposed to 50 or 100 mg As L-1 for 7 and 14 days using hydroponic (soil free) experiments. The fronds and roots were analysed for As, selected macronutrients (K, Ca, Mg, P and S) and micronutrients (Al, Fe, Cu and Zn). Five fern species (Asplenium aethiopicum, Asplenium australasicum, Asplenium bulbiferum, Doodia heterophylla and Microlepia strigosa) were found to be sensitive to As. However, only A. australasicum and A. bulbiferum could hyperaccumulate arsenic up to 1240 and 2630 μg As g-1 dry weight (dw), respectively, in their fronds after 7 days at 100 mg As L-1. This is the first known report of ferns that are sensitive to As, yet are As hyperaccumulators. All As tolerant ferns (Adiantum capillus-veneris, Pteris cretica var. albolineata, Pteris cretica var. wimsetti and Pteris umbrosa) were from the Pteridaceae family. P. cretica and P. umbrosa accumulated the majority of As in their fronds (up to 3090 μg As g-1 dw) compared to the roots (up to 760 μg As g-1 dw). In contrast, A. capillus-veneris accumulated the majority of As in the roots (1190 μg As g-1 dw) compared to the fronds (370 μg As g-1 dw). The root uptake of K, P and S was significantly (P ≤ 0.05) reduced when ferns were exposed to As, but the translocation factor, or the movement of nutrients from the roots to the fronds, increased in most ferns to maintain nutrient requirements and ion balance. P. cretica and P. umbrosa may be useful for phytoremediating As contaminated sites because of their ability to hyperaccumulate and tolerate high As levels. Key words: Pteridaceae; fern; arsenic; hyperaccumulator; tolerance.

 

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