Acute Toxicity of the Preparation PAX-18 for Juvenile and Embryonic Stages of Zebrafish (Danio rerio)

Abstract

The preparation PAX-18 is a coagulation agent, which is used in water and wastewater treatment facilities and for the treatment of natural waters. The active compound is polyaluminium chloride (9% of Al). The application to the water environment could present a potential risk to different developmental stages of fish. The aim of this study was to assess and compare the toxicity of the preparation PAX-18 for embryonic and juvenile developmental stages of zebrafish (Danio rerio). The acute toxicity tests with juvenile fish aged 2-3 months were conducted according to the method OECD No. 203 in 5 series. For embryo toxicity test the method OECD No. 212 was used in 5 series. The semistatic methods were selected. The results of toxicity tests (the number of dead individuals at particular test concentrations) were subjected to probit analysis using the EKO-TOX 5.2 programme to determine LC50 values of PAX. The LC50 mean value of PAX for juvenile D. rerio was 749.7 ± 30.6 mg·l -1 (67.5 ± 2.8 mg·l -1 of Al) and 731.5 ± 94.1 mg·l -1 (65.8 ± 8.5 mg·l -1 of Al) for embryonic stages of D. rerio. The sensitivity of juvenile and embryonic stages to PAX were comparable (p > 0.01). The acute toxicity values of PAX-18 found in tests on D. rerio were 6-13 × higher than the concentration which is usually applied to waters (5-10 mg·l -1 of Al). Therefore, the acute toxicity effect on fish can be considered minimal. Polyaluminium chloride, zebrafish, danio, developmental stagesThe preparation PAX-18 is used as one of the possible methods in the restoration of eutrophic lakes. High loads of nutrients, mainly phosphorus, that enter surface waters, cause the eutrophication and intensive development of the phytoplankton with a negative effect on the water quality and species diversity (Holz and Hoagland 1999;Klouček and Vaverová 2005). The active compound of the preparation PAX-18 is polyaluminium chloride (9% of Al). Polyaluminium chloride is one of the most effective coagulant agents in water and wastewater treatment facilities and for the treatment of natural waters. It is used as an eliminator of colloids and suspended particles, organic matter, metal ions and phosphates (Pitter 2009; Zouboulis and Tzoupanos 2010).Aluminium treatment was found to be effective in lowering phosphorus concentration in water. Aluminium binds phosphorus and forms complexes that permanently attach this element to the bottom sediments. Furthermore, during the sedimentation of these complexes, floccules remove plankton from the water column and the water transparency improves (Holz and Hoagland 1999;Klouček and Vaverová 2005). Direct application of PAX-18 into the water (usually at doses of 5-10 mg of Al per one litre) or to the sediments (in tens of grams per 1 m 2 of surface of the bottom sediments) is possible (Pitter 2009). The application of PAX-18 to the natural waters could present a potential danger to fish and other water non target organisms due to the presence and accumulation of aluminium.Aluminium is a ubiquitous element in natural water...

Behavior of Aluminum Compounds in Soft-Water Lakes Subjected to Experimental Reclamation with Polyaluminum Chloride

“…Cooke et al (2005) and Wauer et al (2004) specified that a safe level should not exceed 0.05 mg Al/L in terms of the dissolved fraction. The experiments of Mácová et al (2010) indicated that the acute toxicity values of PAX-18 (common commercial PAC-type coagulant) found in tests of Danio rerio were 6-13 times higher than the concentration that is usually applied to waters (5-10 mg/ L of Al). Due to the potential long-term effect of coagulant flocs on the aqueous environment, 0.05 mg Al/L seems to be an appropriate reference level for the dissolved form of aluminum.…”

A Field Experiment on Restoration of a Hyper-Eutrophic Urban Shallow Pool Using Polyaluminium Chloride in Thailand

“…Therefore, it can be stated that PAC application at the level used had no or low toxicity effects on the freshwater fauna. Acute toxicity of PAC was studied with juvenile zebrafish (Danio rerio) at approximately 2-3 months of age; the results showed that the mean±standard deviation of the LC50 at 96 hours was 749.7±30.6 mg/l [23]. The actual content of PAC used in the current study was much lower than that of LC50.…”