Toxic Effects of Dietary and Waterborne PCB-153 on Survival, Growth, Grazing, and Physiological Responses in Artemia salina Using an Intermittent Exposure Approach.

Polychlorinated biphenyls (PCBs), as ubiquitous persistent organic pollutants (POPs), pose substantial threats to the physiological and ecological homeostasis of aquatic organisms. To minimize cross-contamination and better simulate fluctuating pollutant exposure dynamics in natural aquatic ecosystems, an intermittent exposure regime was employed in this study. This study investigated the effects of PCB-153 (2,2',4,4',5,5'-hexachlorobiphenyl) on growth, ingestion, and the antioxidant-detoxification system in Artemia via dietary (4:20 stress:non-stress, 4 days) and waterborne (22:2 stress:non-stress, 6 days) pathways. Both exposure routes concentration-dependently suppressed Artemia growth and grazing rate, accompanied by impaired reactive oxygen species scavenging capacity and aggravated lipid peroxidation. The 96-h LC50 of PCB-153 was 45.71 μg/L. Notably, glutathione S-transferase (GST) activity showed the opposite trend: being enhanced under waterborne exposure but inhibited under dietary exposure. With respect to other antioxidant and detoxification pathways, dietary exposure resulted in a typical activation-then-inhibition pattern of the glutathione cycle. Under waterborne exposure, hydrogen peroxide scavenging was impaired, and the cytochrome P450 (CYP450) detoxification system exhibited a biphasic induction-inhibition response. Overall, PCB-153 exerted adverse effects on Artemia survival, ingestion, and antioxidant-detoxification homeostasis through both pathways. Under the experimental conditions of this study, Artemia exposed via the waterborne route tended to show more pronounced responses in survival, growth, and ingestion than those exposed via the dietary route, based on preliminary observations. Meanwhile, GST activity showed opposite patterns between the two exposure groups. These findings clarify the ecotoxicological effects and mechanisms of PCBs on Artemia, a keystone species in aquatic food webs, and highlight their ecological risks under realistic exposure scenarios.