The Free On-line Aquaculture Dictionary

Hydrogen Sulphide tables
Toxic form hydrogen sulphide with pH Toxicity to fish

Hydrogen sulphide toxicity with pH 

pH

% H2S

5.0

99

5.5

97

6.0

91.1

6.5

76.4

7.0

50.6

7.5

24.4

8.0

9.3

8.5

3.1

9.0

1.0

 

 

Most species are extremely sensitive to H2S gas, toxic levels are given below; 

Concentration

Effect

0.002 - 0.4mg/l

Sublethal effects, gill damage, depending on species*

0.01 - 5.3 mg/l

Lethal depending on species*

*Generally the lower the organic loading of the fishes natural habitat, the more sensitive it is e.g. salmonids are more sensitive than carps