Yellowfin tuna Thunnus albacores, loaded to truck for transportation. Palabuhanratu, West Java.
Don't worry—the good news is that you can still eat tuna. Just make your ahi-tuna meal that less frequent (it's already a high mercury fish so you shouldn't be eating that much anyway). There have been a few studies done over the years connecting post-industrial mercury levels in the ocean with our food source's levels of mercury. A new study, re-analyzing previous papers on the subject,
was just released:
Evidence in support of this hypothesis has been hard to find, however, and some studies have suggested that analyses of fish show no change in mercury concentration. By compiling and re-analyzing published reports on yellowfin tuna (Thunnus albacares) caught near Hawaii (USA) over the past half century, the authors found that the concentration of mercury in these fish currently is increasing at a rate of at least 3.8% per year. This rate of increase is consistent with a model of anthropogenic forcing on the mercury cycle in the North Pacific Ocean and suggests that fish mercury concentrations are keeping pace with current loading increases to the ocean. Future increases in mercury in yellowfin tuna and other fishes can be avoided by reductions in atmospheric mercury emissions from point sources.
None of this is surprising. The research supports other work in the field. However, the analysis of earlier studies includes a strong takedown
of a previous paper:
[Which] suggested that mercury levels were not rising, but this re-analysis shows that paper didn’t account for the declining size of fish being caught, due to overfishing, says Krabbenhoft, who wasn’t involved in either study. [...]
A series of rules known as the Mercury and Air Toxics Standards that are meant to reduce mercury pollution from coal plants and other sources will go into effect in the United States this spring, Krabbenhoft says.
Unfortunately, or maybe just
predictably, energy industry groups have challenged the
Mercury and Air Toxic Standards on the grounds of its legality and the
Supreme Court recently agreed to hear the case.
The industry groups say the Environmental Protection Agency is overstepping its authority under the Clean Air Act by issuing the series of regulations. Republicans have attacked the rules as a “war on coal” and an example of what they say is the executive branch’s overreach.
The basic question in the new case is whether and when the E.P.A. must take regulation costs into account. The agency’s interpretation is that the Clean Air Act, which requires regulations to be “appropriate and necessary,” does not demand that costs be taken into consideration early in the regulatory process.
Sigh.