Sensitivity of freshwater and marine green algae to three compounds of emerging concern

• Published in: Journal of applied phycology Vol. 31; no. 1; pp. 399 - 408
• Main Authors: Machado, Manuela D., Soares, Eduardo V.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-02-2019; Springer Nature B.V
• Subjects: Algae; Algal growth; Antibiotics; Aquatic plants; Biomedical and Life Sciences; Dunaliella; Dunaliella tertiolecta; Ecology; Ecotoxicology; Erythromycin; Freshwater; Freshwater & Marine Ecology; Herbicides; Inland water environment; Life Sciences; Metolachlor; Plant Physiology; Plant Sciences; Pollutants; Sensitivity; Surface water; Toxicants; Toxicity; Triclosan; Metolachlor; Erythromycin; Triclosan; Chlorophyta; Toxicity
• ISSN: 0921-8971; 1573-5176
• DOI: 10.1007/s10811-018-1511-5

In this study, the toxicity of three compounds of emerging concern (CEC) belonging to different classes [metolachlor (herbicide), erythromycin (antibiotic) and triclosan (antiseptic)], were evaluated and compared using the freshwater alga
Pseudokirchneriella subcapitata
and the marine alga
Dunaliella tertiolecta
. Toxicity assays were performed by exposing algal cells, in exponential phase of growth, to the toxicants for 72 h (
P. subcapitata
) or 96 h (
D. tertiolecta
). The toxicant concentrations that induced an inhibition of 50% of algal growth (EC
50
) of
P. subcapitata
or
D. tertiolecta
were 118 and 11.3 × 10
3
 μg L
−1
for metolachlor (MTC), 38 and 5.75 × 10
3
 μg L
−1
for erythromycin (ERT) and 27.1 and 93 μg L
−1
for triclosan (TCS), respectively. Based on these EC
50
values, it was possible to hierarchize (decreasing order) the toxicity of the CEC studied: TCS > ERT > MTC. The EC
50
values achieved for
P. subcapitata
were between 3.4- and 151-fold lower than those observed with
D. tertiolecta
, which demonstrated the higher sensitivity of the freshwater alga comparatively to the marine alga. All 72 h-EC
10
or 72 h-EC
50
values determined in this study with
P. subcapitata
are within the concentration range of these pollutants described in the literature, in ground and surface waters, which underlines the significance of this alga in the ecotoxicity assessment of freshwaters.