Cyanotoxins and their environmental health risk in marine and freshwaters of Saudi Arabia

Occurrence of toxic cyanobacteria and cyanotoxins in drinking, recreational, and irrigation waters represents a health hazard to wildlife and humans. This review describes the most common cyanotoxins and their producing taxa and the potential environmental health risks in marine and freshwaters of Saudi Arabia. The most common genera of toxigenic cyanobacteria detected in Saudi waters included Anabaena/Dolichospermum, Anabaenopsis, Cylindrospermopsis, Lyngbya, Microcystis, and Oscillatoria. The cyanotoxins produced by these taxa and have been detected in Saudi Arabia are microcystins (MCYSTs), cylindrospermopsin (CYN), saxitoxins, and lyngbyatoxin-like toxins. Anatoxin has not been investigated in Saudi Arabia, and extensive research is running for this toxin. Studies have detected microcystins in treated drinking waters, groundwater wells, and hot springs and their accumulation in vegetables and fish. Toxin amounts in these commodities often exceeded the WHO guidance values for safe exposure. This indicates that a human health risk could be occurring upon exposure to such potent toxins. Beyond a comprehensive analysis of cyanotoxins in marine and freshwater environments, this paper also identifies and prioritizes research gaps and suggests future research on cyanotoxins in Saudi Arabia.