The mercury entering the aquatic food chain and the plastic which absorbs it are both examples of which Planetary Boundary?

Level of Chemical Pollution Boundary

Explanation:

The planetary boundaries represent sets of environmental parameters that are used to limit or caution the effect of humans activities on the environment. This is aimed towards protecting and preserving the environment for the future.

The planetary boundary was established in 2009 to curb the effects of the activities of humans in the environment. It represents the set of allowable limits to which the environment can take the effects of human actions on the environment. These planetary boundaries are group into nine parts according to the parameters they represent, namely, they are;

ocean acidification; depletion of the ozone layer; State of the nitrogen and phosphorus; global biogeochemical cycles; freshwater resources use; change in land use; the level of loss of biodiversity; level of particulate emission into the atmosphere and; the level of chemical pollution

The level of chemical pollution and toxic substance emission creates an indelible change in the planetary environment. Substances such as heavy metals pollutants, organic, and inorganic pollutants cause irreversible changes in the environment. Heavy metals such as mercury and lead entering water bodies pose an environmental threat to fishes likewise plastics.

These pollutants pose a chemical threat to the fishes and the level of chemical pollution planetary boundary.