Realistic environmental mixtures of hydrophobic compounds do not alter growth of a marine diatom

We determined whether a realistic mixture of hydrophobic chemicals affects the growth dynamics of a marine diatom and how this effect compares to the effect of temperature, light regime and nutrient conditions. Passive dosing was used to expose a marine diatom to a realistic mixture of hydrophobic compounds accumulated from Belgian coastal waters using passive samplers. Although ∑7PCBs exceeded the environmental quality standards (2 ng L− 1), we did not observe adverse ecotoxicological effects in a 72 h algal growth inhibition test with P. tricornutum. Natural drivers such as nutrients, temperature and light availability, explaining about 85% of the observed variability, are more important drivers of the growth of P. tricornutum than the mixture of organic pollutants present in Belgian coastal waters. The main conclusion of the present study is that the mixture of hydrophobic substances present in Belgian marine waters, and for which the passive samplers had affinity, did not affect the growth of P. tricornutum.
 

Scientific abstract

In this paper we determine whether a realistic mixture of hydrophobic chemicals affects the growth dynamics of a marine diatom and how this effect compares to the effect of temperature, light regime and nutrient conditions. To do so, we examine the specific growth rate of Phaeodactylum tricornutum in a 72 h algal growth inhibition test using a full factorial design with three nutrient regimes, two test temperatures, three light intensities and three chemical exposures. Passive samplers were used to achieve exposure to realistic mixtures of organic chemicals close to ambient concentrations. Nutrient regime, temperature and time interval (24, 48 and 72 h) explained 85% of the observed variability in the experimental data. The variability explained by chemical exposure was about 1%. Overall, ambient concentrations of hydrophobic compounds present in Belgian coastal waters, and for which the passive samplers have affinity, are too low to affect the intrinsic growth rate of P. tricornutum.


Full reference (link)

Everaert G, De Laender F, Claessens M, Baert J, Monteyne E, Roose P, Goethals PLM, Janssen CR. Realistic environmental mixtures of hydrophobic compounds do not alter growth of a marine diatom. Marine Pollution Bulletin (Accepted article)
 

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