Yes, nickel is more of a concern, but manganese is still toxic. Comparing heavy metal toxicity to human lethal doses can be misleading, however.
Invertebrates are much more sensitive to heavy metals. Again toxic doses for many marine invertebrates are in the ppb-ppm range.
Copper for instance is commonly used as a treatment for marine parasites on fish. However the dosing needs to be done carefully, since a doses in the range of 5ppm can start to kill the fish themselves.
Invertebrates are much more sensitive to heavy metals. Again toxic doses for many marine invertebrates are in the ppb-ppm range.
Copper for instance is commonly used as a treatment for marine parasites on fish. However the dosing needs to be done carefully, since a doses in the range of 5ppm can start to kill the fish themselves.