Piazza V.,CNR Institute of Neuroscience |
Ferioli A.,ARPA Emilia Romagna |
Giacco E.,University of Genoa |
Melchiorre N.,ARPA Liguria |
And 6 more authors.
Ecotoxicology and Environmental Safety | Year: 2012
A series of 10 intra-laboratory bioassays and an inter-laboratory assay involving nine laboratories, were performed to validate the use of Amphibalanus amphitrite larvae as test organisms for ecotoxicological studies. The standardization protocol utilized Cadmium Nitrate as a reference toxicant and larval immobilization (after 24 and 48h) as the end-point. The statistical data analysis showed high homogeneity in intra-laboratory EC 50 values among bioassay repetitions (coefficient of variation (CV)=15.8% after 24h and 16.9% after 48h); also CV values obtained in inter laboratory comparison exercise were not higher than the 50%, variation coefficient mentioned in the ISO standards for the precision of inter-laboratory assays. The results demonstrated that the protocol implemented for the balanus larval bioassay comply with the international standards both for intra- and inter-laboratory precision. © 2012 Elsevier Inc.
Manganelli M.,DIPIA Inc |
Scardala S.,Primary Prevention Instituto Superiore Of Sanita |
Stefanelli M.,Primary Prevention Instituto Superiore Of Sanita |
Vichi S.,Primary Prevention Instituto Superiore Of Sanita |
And 8 more authors.
Water Research | Year: 2010
Increasing concern for human health related to cyanotoxin exposure imposes the identification of pattern and level of exposure; however, current monitoring programs, based on cyanobacteria cell counts, could be inadequate. An integrated approach has been applied to a small lake in Italy, affected by Planktothrix rubescens blooms, to provide a scientific basis for appropriate monitoring program design. The cyanobacterium dynamic, the lake physicochemical and trophic status, expressed as nutrients concentration and recycling rates due to bacterial activity, the identification/quantification of toxic genotype and cyanotoxin concentration have been studied. Our results indicate that low levels of nutrients are not a marker for low risk of P. rubescens proliferation and confirm that cyanobacterial density solely is not a reliable parameter to assess human exposure. The ratio between toxic/non-toxic cells, and toxin concentrations, which can be better explained by toxic population dynamic, are much more diagnostic, although varying with time and environmental conditions. The toxic fraction within P. rubescens population is generally high (30-100%) and increases with water depth. The ratio toxic/non-toxic cells is lowest during the bloom, suggesting a competitive advantage for non-toxic cells. Therefore, when P. rubescens is the dominant species, it is important to analyze samples below the thermocline, and quantitatively estimate toxic genotype abundance. In addition, the identification of cyanotoxin content and congeners profile, with different toxic potential, are crucial for risk assessment. © 2009 Elsevier Ltd. All rights reserved.