Current permissible levels of heavy metal pollutants harm terrestrial
invertebrates
Abstract
The current decline of invertebrates worldwide is alarming. Several
potential causes have been proposed but heavy metals, while being a
widespread and major pollutants of air, soils and water, have so far
been largely overlooked. Here, we ran a meta-analysis of 527 datasets on
the effects of arsenic, cadmium, lead and mercury on terrestrial
invertebrates. These four well-studied metals, for which international
guidelines exist, significantly impact the physiology and behavior of
invertebrates, even at levels below those recommended as ‘safe’ for
humans. Our results call for a revision of the regulatory thresholds to
better protect terrestrial invertebrates, which appear to be more
sensitive to metal pollution than vertebrates. More fundamental research
is needed to improve international guidelines for metal pollutants, and
to develop conservation plans to mitigate invertebrate declines and
protect ecosystem services.