Yunus, Kamaruzzaman and M. Rahman, Mustafizur and Junaidan, Nur Najihah Farhana and Chuan, Ong Meng and Yona, Defri and Pradit, Siripon and Abdurahman, Siti Waznah and Masduki, Mohd Masrul and Sabuti, Asnor Azrin (2026) Establishing water quality thresholds for sodium hypochlorite: acute toxicity assessment in nile tilapia (oreochromis niloticus). Water Conservation and Management (WCM), 10 (3). pp. 655-659. ISSN 2523-5664 E-ISSN 2523-5672
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Abstract
Sodium hypochlorite (NaOCl) is widely applied as a disinfectant, yet its discharge into freshwater systems poses a growing water quality concern. This study assessed the acute toxicity of NaOCl to juvenile Nile tilapia Oreochromis niloticus to establish water quality thresholds for chlorine management in tropical freshwater aquatic environments. Fish were exposed to graded NaOCl concentrations (1.40–1.60 ppm) for 96 hours under controlled experimental conditions. Probit analysis resulted a steep concentration–response relationship, with a 96-hour LC₅₀ of 1.55 ppm (95% CI: 1.52–1.58 ppm), LC₁₀ of 1.42 ppm, and LC₉₀ of 1.62 ppm. The narrow margin between these thresholds suggests that small increases in chlorine concentration can rapidly increase ecological risk. These findings provide critical baseline data for establishing chlorine discharge limits and suggest the need for improved monitoring of chlorinated effluents to protect freshwater resources in tropical environments.
| Item Type: | Article (Journal) |
|---|---|
| Uncontrolled Keywords: | Acute Toxicity, Aquaculture, Aquatic Pollution, Chlorine Disinfectants, Median Lethal Concentration, Probit Analysis |
| Subjects: | Q Science > QD Chemistry |
| Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button): | Kulliyyah of Science Kulliyyah of Science > Department of Marine Science |
| Depositing User: | Professor Dr. Kamaruzzaman Yunus |
| Date Deposited: | 04 Nov 2026 12:31 |
| Last Update: | 04 Nov 2026 12:31 |
| Queue Number: | 2026-10-Q5996 |
| URI: | http://irep.iium.edu.my/id/eprint/132448 |
| Indexed In: | UNSPECIFIED |
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