Assessing the performance of Hormosira banksii (Turner) Desicaine germination and growth assay using four reference toxicants

This study evaluated the performance of a Hormosira banksii germination inhibition bioassay developed to assess the toxicity of single compounds and complex effluents in the Australasian region. The reproducibility of 48 and 72 h germination and growth toxicity tests was determined using four reference toxicants, namely, ammonia, copper, phenol and zinc. H. banksii spore germination and growth was significantly inhibited following exposure to each of the toxicants. H. banskii spores were most sensitive to ammonia and showed decreasing sensitivity to copper, zinc and phenol. The EC50 values ranged from 0.07 to 0.08 mg L−1 for ammonia, 0.09 to 0.22 mg L−1 for copper, 36 to 1068 mg L−1 for phenol and 19 to 23 mg L−1 for zinc. Variability of the test method ranged from 14% to 144% and was comparable to that observed for commonly employed bioassays against appropriate reference toxicants.