Determination of anatoxin-a stability under certain abiotic factors

• We re-examined ANTX-a stability under conditions including pH, temperature, light and UV-B irradiation.
• Irradiation at high fluence had a weak effect on ANTX-a stability regardless of the pH.
• High temperature or high UV-B irradiation, ANTX-a underwent faster degradation in neutral or alkaline conditions.
• Hydro-ANTX-a and hemiacetyl-ANTX-a were detected amongst the products of degradation.

Research into the effects of physicochemical factors on the stability of anatoxin-a (ANTX-a) has been limited. In the present results the impact of such factors as temperature, high intensity of light, pH and UV irradiation on the stability of ANTX-a were examined. Irradiation at high fluence for 5 h had a weak effect on stability of ANTX-a regardless of the pH. The result was similar after red irradiation of an aqueous mixture of ANTX-a and the cyanobacterial photosynthetic pigment phycocyanin C. Under high temperature or high UV-B irradiation, ANTX-a underwent faster degradation (maximum 84% after 1 h) in neutral or alkaline conditions. Hydro-ANTX-a and hemiacetyl-ANTX-a were detected amongst the products of this reaction. The results show a significant effect of physical factors on the stability of ANTX-a molecule. Some physical factors occurring in natural conditions can contribute to the accumulation of toxins in environment, whereas the others can be useful to reduce the concentration or total elimination of ANTX-a from raw water in water treatment technology processes.