Towards understanding microbial degradation of chloroquine in large saltwater systems

Jinglin Hu, Nancy Hellgeth, Chrissy Cabay, James Clark, Francis J. Oliaro, William Van Bonn, Erica M. Hartmann*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Circulating saltwater aquariums hosting marine animals contain a wide range of microorganisms, which have strong implications on promoting animal health. In this study, we investigated the degradation of chloroquine phosphate, an anti-parasitic bath pharmaceutical used in saltwater quarantine and exhibition systems, and attributed the reduction in drug concentration to microbial degradation of chloroquine associated with pipeline microbial communities. To advance our knowledge on chloroquine degradation in aquatic systems, we conducted microbial and chemical analyses on three tropical saltwater systems. Our findings show that aquarium microbiome composition is shaped by sampling location (i.e., tank water and pipeline; PERMANOVA R2 = 0.09992, p = 0.0134), chloroquine dosing (PERMANOVA R2 = 0.05700, p = 0.0030), and whether the aquarium is occupied by marine animals (PERMANOVA R2 = 0.07019, p = 0.0009). Several microbial taxa belonging to the phyla Actinobacteria, Bacteroidetes, Chloroflexi, and Proteobacteria, along with functional genes related to pathways such as phenylethylamine degradation and denitrification, appeared to have differential (relative) abundance between samples where chloroquine degradation was observed and those without degradation (Benjamini-Hochberg adjusted p-value <0.05). Together, these results provide practical mitigation options to prevent or delay the development of chloroquine-degrading microbial communities in saltwater aquariums. Our results further demonstrate the need to improve our understanding of the interactions between nitrogen availability and microbial activity in saltwater systems.

Original languageEnglish (US)
Article number150532
JournalScience of the Total Environment
StatePublished - Feb 10 2022


  • Animal health
  • Aquarium antiparasitic drugs
  • Aquarium microbiome
  • Chloroquine degradation
  • Management of circulating aquarium systems
  • Nitrogen cycling

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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