Naslov
The Effect of Ni2+, Co2+, Zn2+, Cd2+ and Hg2+ on the Growth Rate of Marine Diatom Phaeodactylum tricornutum Bohlin: Microplate Growth Inhibition Test

Autori
Horvatić, Janja ; Peršić, Vesna

Izvornik
Bulletin of Environmental Contamination and Toxicology (0007-4861) 79 (2007), 5; 494-498

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
heavy metals; toxicity; marine algae; Phaeodactylum tricornutum; microplate bioassay

Sažetak
The toxicity tests were carried out with the unicellular marine diatom Phaeodactylum tricornutum Bohlin 1897 strain CCAP 1052/1A in the f/2 medium at 20°C under continuous white light exposed to irradiance by PAR 120 μ mol m-2s-1 measured with flat sensor. The basic design of toxicity tests followed the International Standard ISO 10253 marine algal growth inhibition test (ISO 1995) and were modified according to Lukavský (1992) and Lukavský and Simmer (2001). To determine the toxicity of metals (Ni2+, Co2+, Zn2+, Cd2+ and Hg2+), on the growth rate of marine phytoplankton diatom P. tricornutum Bohlin, nickel sulphate (NiSO4 • 6H2O), cobalt chloride (CoCl2 • 6H2O), zinc sulphate (ZnSO4 • 7H2O), cadmium nitrate (Cd(NO3)2 • 4H2O), mercury chloride (HgCl2) and mercury sulfate (HgSO4) of analytical grade (99%, Kemika, Zagreb) and cobalt nitrate (Co(NO3)2 • 6H2O) of analytical grade (99%, Fluka) were used. By comparing these toxicity curves the differences in slopes could be observed. Zn, Cd, Co and Ni have a gradual “ slow” curve, while Hg has a “ sharp” one thus indicating high toxicity of Hg. The following order of toxicity was achieved: Hg>Cd>Ni>Co>Zn in the exponential phase of growth (72 h), and Hg>Ni>Co>Zn>Cd after 336 h of experiment duration (in the stationary phase of growth) with mercury as the most toxic metal. Although toxic, the effect of Hg could be attenuated under chronic conditions.P. tricornutum in the exponential phase of growth showed more tolerance to nickel than cadmium. In the stationary phase of growth a high tolerance to cadmium, zinc and cobalt was observed, while nickel showed an increase in toxicity. Besides providing screening toxicity profiles this method can be useful in determining the effects of pollutants on cell growth and viability of organisms. Also, establishing the maximum tolerance levels for organisms, this method could be used for evaluating the potential impact of pollution on aquatic system.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

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