Mitigating biofouling in cooling water system: Actibromide ^® to combat <i>Perna viridis</i> infestation and environmental impact

Efficacy of Actibromide^® (formulation of bromide with sodium hypochlorite) as a supplementary biocide for process seawater heat exchangers was evaluated on <i>Perna viridis</i> at Madras Atomic Power Station. Continuous chlorination (0.2 mg/L) required prolonged exposure for 100% mortality. Actibromide^® at 0.2, 0.5 and 1.0 mg/L achieved complete mussel mortality within 12, 7 and 4 days, respectively. Reactive oxygen species generation increased antioxidant enzyme activity like superoxide dismutase, catalase which was found to be higher in the digestive gland. Inhibition of cellular functions was evident in haemolymph, inducing DNA damage (34%) and acetylcholinesterase inhibition (80-91%). The study clearly demonstrated that Actibromide^® penetrates at the cellular level, causing severe damage to the gills and digestive glands, reducing feed consumption and inducing both neurotoxic and genotoxic effects resulting in mortality. Supplemental targeted dosing at 0.2 mg/L seems to be a promising strategy for effective green mussel control in cooling water systems.