Aquatic toxicity tests using spore germination and gametophyte growth of the green alga, Ulva pertusa Kjellman, were developed and evaluated by assessing the toxicity of different organic and inorganic chemicals and elutriates of sewage or waste sludge. The toxic ranking of three metals was: Cu (EC50 of 0.017mg l_1)>Zn (0.378 mgl_1)>Cd (0.789 mgl_1) for spore germination and Cu (0.023–0.027 mg l_1)>Cd (0.189–0.200 mg l_1)>Zn (0.307–0.317 mgl_1) for gametophyte growth. Spore germination (EC50 of 3.95mg l_1) was more sensitive to formalin than gametophyte growth (6.92–7.18 mg l_1).
The EC50 for tributyltin oxide differed between the endpoints, with values of 0.586mg l_1 for germination and 0.391– 0.396mg l_1 for growth responses. After exposure to three different sludge elutriates the greatest and least toxic effects were found for urban sewage (7.6–8.3%) and filtration bed (>61%), respectively. The bioassays are simple, inexpensive,eco-relevant and have a potential application worldwide.