Tuna remains the largest source of mercury consumption by Americans, despite warnings from public health officials to limit tuna intake.

New research, however, suggests tuna aren't as carrying as much of the toxin as they used. According to a study published this week in the journal Environmental Science & Technology, Atlantic bluefin tuna host less mercury every year.

Scientists suggest efforts to reduce mercury emissions have paid off. The drop in mercury concentrations measured in adult bluefin mirrors the reduction of mercury measured exiting factory smokestacks, as well as in the atmosphere and the Atlantic Ocean.

Data collected during several previous studies suggest, between 1990 and 2007, mercury emissions shrank 2.8 percent annually. During that time, mercury concentrations in the ocean diminished 4.3 percent per year. Similar reductions were measured in atmospheric samples.

The same promising pattern revealed itself in the latest study.

Between 2004 and 2012, a team of scientists from Stony Brook University, the University of Massachusetts and Harvard University analyzed tissues samples from 1,300 Atlantic bluefin tuna. During that eight-year period, the concentration of mercury measured in tuna flesh went down 19 percent.

For now, recommendations from health officials remain the same; adults eat no more than six ounces of tuna per week.