Coastal Aquaculture and Mariculture (2+1)

Unit 4 - Water and soil quality management

4.1.2.g. Hydrogen sulphide

• Hydrogen sulphide is generated by certain heterotrophic bacteria under anaerobic conditions.
• The distribution of hydrogen sulphide and other sulfur species is regulated by water pH.
• The un-ionized form accounts for about 99% of the total sulfide. As the value of pH rises, the percent of hydrogen sulfide decreases.
• Un-ionized hydrogen sulfide is toxic to fish and invertebrates at low concentrations. Therefore, detectable concentrations should be considered as hazardous.