Investigation of metal accumulation and pathogenic bacterial loud in Nile tilapia farmed in treated water

Farming fish using treated wastewater is one of the most effective fish production methods. The following study goals to represent the influence of the quality of treated wastewater by sand filter system on heavy metals accumulation and some pathogenic bacteria loud on Nile tilapia fish. Nile tilapia fish were farmed in experimental basins aquaria in three different types of water [Bahr Elbakr drain as drainage water (DW), treated water (TWW), and River Nile at El-Kanater El-Khyria (RNW) as control]. Physicochemical parameters in water samples, heavy metals accumulation in fish liver and muscle, and some microbiological were analyzed. The obtained data showed poor water quality in DW compared with TWW and RNW. The accumulation of heavy metals was higher (p ≤ 0.05) in fish tissue collected from DW, while it was within the permissible safety levels for human consumption in TWW and RNW. In drainage water (DW), the diversity of pathogenic bacteria, such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Salmonella sp. Proteus vulgaris, and Bacillus sp., have exceeded the recommended permissible limit. Staphylococcus aureus was predominantly found in fish gills, followed by Bacillus in fish skin from DW. In contrast, treated water has significantly reduced pathogenic bacterial diversity. It could be concluded that the treatment of drainage water using a sand filter is efficient in producing high water quality for fish farming.