Toxicological effects of disinfections using sodium hypochlorite on aquatic organisms and its contribution to AOX formation in hospital wastewater

• Published in: Environment international Vol. 30; no. 7; pp. 891 - 900
• Main Authors: Emmanuel, Evens, Keck, Gérard, Blanchard, Jean-Marie, Vermande, Paul, Perrodin, Yves
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01-09-2004; Elsevier
• Subjects: Animal, plant and microbial ecology; Animals; AOX; Applied ecology; Applied sciences; Biodiversity and Ecology; Biological and medical sciences; Biological Assay; Daphnia; Daphnia - drug effects; Daphnia magna; Disinfectants - chemistry; Disinfectants - toxicity; Dose-Response Relationship, Drug; Earth sciences; Earth, ocean, space; Ecotoxicology, biological effects of pollution; Engineering and environment geology. Geothermics; Enterobacteriaceae; Environmental Sciences; Exact sciences and technology; France; Fresh water environment; Fundamental and applied biological sciences. Psychology; Hospital effluents; Hospitals, Urban; Hydrocarbons, Halogenated - chemistry; Hydrocarbons, Halogenated - toxicity; Linear Models; Luminescent Measurements; Medical Waste Disposal - methods; Other wastewaters; Pollution; Pollution, environment geology; Sodium hypochlorite; Sodium Hypochlorite - chemistry; Sodium Hypochlorite - toxicity; Toxicity; Toxicity Tests, Acute; Vibrio - drug effects; Vibrio fischeri; Waste Disposal, Fluid - methods; Wastewaters; Water treatment and pollution; Rhône Alpes; Rhône; France; Europe; France, Southeast; Sodium hypochlorite; Daphnia; Hospital effluents; AOX; Toxicity; Chlorination; Microbiology; Cladocera; Pollutant formation; Liquid waste; Crustacea; Sodium Hypochlorites; Aquatic environment; Vibrio fischeri; Infectious risk; Pathogenic; Bacteria; Pretreatment; Waste water discharge; Branchiopoda; Biological contamination; Organic compounds; Hospital waste; Ecotoxicology; Reaction product; Disinfection; Secondary pollutant; Arthropoda; Environment impact; Vibrionaceae; Physicochemical purification; Water pollution; Invertebrata; Waste water purification; Daphnia magna
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/j.envint.2004.02.004

Sodium hypochlorite (NaOCl) is often used for disinfecting hospital wastewater in order to prevent the spread of pathogenic microorganisms, causal agents of nosocomial infectious diseases. Chlorine disinfectants in wastewater react with organic matters, giving rise to organic chlorine compounds such as AOX (halogenated organic compounds adsorbable on activated carbon), which are toxic for aquatic organisms and are persistent environmental contaminants. The aim of this study was to evaluate the toxicity on aquatic organisms of hospital wastewater from services using NaOCl in pre-chlorination. Wastewater samples from the infectious and tropical diseases department of a hospital of a large city in southeast of France were collected. Three samples per day were collected in the connecting well department at 9 a.m., 1 p.m. and 5 p.m. during 8 days from 13 March to 22 March 2001, and a mixture was made at 6 p.m. with the three samples in order to obtain a representative sample for the day. The toxicity test comprised the 24-h EC
50 on
Daphnia magna and a bioluminescence assay using
Vibrio fischeri photobacteria. Fecal coliforms and physicochemical analyses such as total organic carbon (TOC), chloride, AOX, total suspended solids (TSS) and chemical oxygen demand (COD) were carried out. Wastewater samples highlighted considerable acute toxicity on
D. magna and
V. fischeri photobacteria. However, low most probable numbers (MPN), ranging from <3 to 2400 for 100 ml, were detected for fecal coliforms. Statistical analysis, with a confidence interval of 95%, gave a strong linear regression assessed with
r=0.98 between AOX concentrations and EC
50 (TU) on daphnia. The identification of an ideal concentration of NaOCl in disinfecting hospital wastewater, i.e. its non-observed effect concentration (NOEC) on algae and
D. magna, seems to be a research issue that could facilitate the control of AOX toxicity effects on aquatic organisms. Therefore, it would be necessary to monitor the biocide properties of NaOCl on fecal coliforms at various doses and its toxicity effects on aquatic organisms.