TOXIC EFFECTS OF SULFAMETHOXAZOLE (SMX) ON A TROPICAL FRESHWATER MICROALGA, CHLORELLA SP.
Thanh Luu PHAM1,*, Thi Hoang Yen TRAN2 & Thanh Thai TRAN2,3
1Faculty of Environment and Labour Safety, Ton Duc Thang University, 19 Nguyen Huu Tho street, Tan Phong ward, District 7, Ho Chi Minh City 700000, Vietnam
2Institute of Tropical Biology, Vietnam Academy of Science and Technology (VAST), 85 Tran Quoc Toan Street, District 3, Ho Chi Minh City 700000, Vietnam
3Graduate University of Science and Technology, Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Street, Cau Giay District, Hanoi 100000, Vietnam
*Corresponding author: phamthanhluu@tdtu.edu.vn
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Abstract
DOI: 10.26471/cjees/2025/020/322
This study investigates the acute and sub-chronic toxicity of the emerging antibiotic, sulfamethoxazole (SMX) on the tropical freshwater microalga Chlorella sp. under laboratory condition. An acute exposure for 96 h and a sub-chronic exposure for 10 days were conducted to explore the adverse effects, utilizing growth inhibition, pigment content, and cell diameter as endpoints. The calculated half maximal (50 %) effective concentration (EC50) values for SMX after 24 h and 96 h were estimated to be 0.56 mg/L and 0.41 mg/L, respectively. Sub-chronic exposure unveiled a pronounced inhibitory effect of SMX on algal growth, with significant and dose-dependent increases in growth inhibition observed. Across all treatments, exposure to SMX resulted in growth inhibition and a decline in chlorophyll-a (Chl-a) concentration in the test algae. Notably, at a concentration of 1 mg/L, SMX completely inhibited the growth of Chlorella sp. and reduced Chl-a content by up to 98 %. High concentrations of SMX (0.5 and 1.0 mg/L) led to a decrease in cell diameter in the tested algae. This study contributes valuable insights into the acute and sub-chronic toxic effects of environmentally relevant concentrations of antibiotics on tropical freshwater microalgae.
Keywords:
- antibiotics
- acute
- exposure
- sub-chronic
- toxicity
- growth
- inhibition
- cell
- diameter
How to cite
Thanh Luu PHAM, Thi Hoang Yen TRAN & Thanh Thai TRAN (2025). TOXIC EFFECTS OF SULFAMETHOXAZOLE (SMX) ON A TROPICAL FRESHWATER MICROALGA, CHLORELLA SP., Carpathian Journal of Earth and Environmental Sciences February 2025 Vol. 20, No. 1, p. 161 – 168; https://doi.org/10.26471/cjees/2025/020/322