Thus, emission reductions outside NA are likely very important for reducing fish Hg burdens and human exposure for freshwater fish consumers in this region.
The two freshwater fish consumers had hair δHg values of 1.46 and 1.77‰, which are approximately 2‰ higher than those measured in Florida largemouth bass.
The associations were particularly obvious in freshwater fish consumers, probably reflecting that fish is a source of both MeHg and selenium.
Hair from the two freshwater fish consumers measured here showed low ΔHg values (0.49 and 0.81‰) that were similar to those measured in fish from some low-clarity shallow freshwater lakes in Florida.
We did not include shellfish or freshwater fish consumers in this analysis because we do not have sufficient data on Hg isotopes in these organisms to parameterize the model.
Emissions controls in NA can substantially reduce exposure of freshwater fish consumers in areas dominated by NA deposition (e.g., U.S. Northeast), especially those who harvest fish from rapidly responding lakes dominated by direct atmospheric deposition to the water surface and with low ratios of watershed to water surface area (Knightes et al. 2009).
After the release of a new government study that documents the prevalence of mercury in freshwater fish, American consumers are aware that all fish are not equal, or at least not equally good to consume.The new study was conducted by the US Geological Survey (USGS), a scientific agency run by the government.
Some studies suggest that thermoelectric generation is also a major consumer of freshwater resources; however, U.S.-based estimates indicate that consumption for thermoelectric generation was ∼3% of total freshwater consumption in the U.S.
It found that the United States, which has only 5 percent of the world's population, is the third-largest consumer of freshwater, after the vastly more populated China and India.
It is to be noted that the agriculture sector is the largest consumer of freshwater, in which the share of the livestock farms is significant (Al-Zahrani and Baig 2011; Al-Shayaa et al. 2012; Mekonnen and Hoekstra 2012).
