Distribution and persistence of the anthelmintic drug albendazole in yellowtail aquaculture

Beko disease, caused by Microsporidium seriolae infection, is a serious disease affecting yellowtail aquaculture. The administration of albendazole (ABZ), a benzimidazole anthelmintic drug, via fish feed is effective in preventing beko disease and is widely used in yellowtail aquaculture. However, the environmental impact of ABZ use in aquaculture has not been investigated. Therefore, we monitored ABZ and its active metabolites in water, sediment, and marine organisms collected from yellowtail aquaculture sites where ABZ was used. Additionally, we developed a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS)-based analytical method for the detection of ABZ and its metabolites, incorporating membrane filtration for clean-up. While ABZ and its metabolites were undetectable in water even during administration, ABZ was detected in sediment, at a maximum concentration of 200 ng/g. ABZ levels initially fluctuated and then declined below detectable levels within five months of administration, suggesting that ABZ does not persist in sediment. ABZ residues were also found in marine organisms collected at the aquaculture site, with the highest concentration of 6 ng/g detected in Ulva spp. from the seabed. However, these levels were much lower than the maximum residue limits set by the Japanese government. In marine organisms, detection levels using the membrane filtration method were consistent with those obtained using a conventional method. Although ABZ residues were present in sediment and in marine organisms after administration to cultured yellowtail, chronic accumulation at aquaculture sites appears unlikely. Given the known environmental risks of ABZ, continuous monitoring is essential to assess its long-term impact on marine ecosystems. • ABZ and its metabolites were detected in the aquaculture environment. • Some ABZ residues were found, but no evidence of chronic accumulation was observed. • A QuEChERS-based method with membrane filtration was developed for detection.