Sulfur is a non-metallic element vital to biogeochemical cycles and biosynthesis and is amply available in different forms, such as sulfate SO4 2-, which is prevalent in water . Sulfate levels in freshwater are generally around 20 mg/L , whilst the Secondary Maximum Contaminant Level (SMCL) for sulfate in drinking water is 250 mg/L . However, clear guideline values for sulfate in water have not been fully administered yet , see also .