In October, the New York Times sent a reporter to buy tuna sushi at some of Manhattan's finest restaurants and gourmet food shops. After an analysis at a toxicology lab, the small-scale tuna survey revealed that all of the tuna available for sale had mercury rates far above the recommended FDA amount for daily intake. In fact, there seemed to be a correlation between the quality of the fish and the amount of mercury contained. At the famed Blue Ribbon Sushi restaurant, their Bluefin sushi registered 1.4 parts per million of Methylmercury, which means that one could eat less than 3 pieces of the sushi before reaching the government recommended maximum for weekly mercury intake. Consider that many people have made sushi a regular staple of their diet as a healthy, protein and omega-rich meal and you can imagine the public health consequences of this. Other affected restaurants read like a list of the best places in town to eat raw fish: Nobu, Japonica, Bar Masa and Megu. Even Whole Foods did not emerge unscathed: only 5 pieces of tuna would achieve the weekly maximum intake.

The Food and Drug Administration and the Environmental Protection Agency regularly issue warnings to children and pregnant women about the dangers of overdoing it with canned tuna, but no advisory has been put in place for fresh tuna and there is no evaluation system in place for restaurants, either. An FDA spokesman confirmed that the agency does not conduct mercury testing of restaurant or ready-made grocery foods. He did say that the FDA is looking to revise its advisory in light of increasing mercury levels.

When told of the findings, the restaurant and grocery owners all said that they would investigate with their fish suppliers, but many had long suspected that the tuna had an increase in mercury. Eric Bromberg, the owner of Blue Ribbon Sushi said that he instructed his staff to warn parents about letting their children eat the tuna on the menu and had made a habit of discussing the mercury with regular customers who often ordered tuna.

The mercury analysis was conducted by Drs. Michael Gochfeld and Joanna Burger at the Environmental and Occupation Health Sciences Institute in New Jersey - a research institute that marries environmental and clinical medicine. Dr. Gochfeld has a specialt in mercury toxicity and regularly treats patients with mercury poisoning. The team conducted the analysis several times to ensure that their mercury readings were accurate.

Methymercury - the type of mercury compound found in fish that is dangerous to human health - is emitted as an industrial pollutant and enters the water supply through wastewater dumping. Every organism in the water - from plankton to sharks - ingests it and the amount is magnified up the food chain so that piscivorous fish, who eat contaminated prey fish, are the most toxic to humans. These fish include bluefin tuna, shark, swordfish and other fish at the top of the food chain. The mercury settles in the fatty tissue of the animal, so the highest grade fish cuts are the most toxic, as these are also the most fatty.

Mercury affects the central nervous system, endocrine system and kindeys, among other organs. The damage to the central nervous system is particularly damaging for fetuses and children, as it can lower their IQs, inhibit memory function, motor and language skills, and some say even contribute to the emergence of autism spectral disorders. Although the role of mercury in causing autism is highly controversial, a large number of autism advocates believe that the connection is real. In adults, mercury toxicity can cause neurological problems like periosthesis, anemia, cardiovascular problems, low sperm count in men, and - in extreme cases - regression of motor skills, reduced vision, autoimmune disorder and death.

The FDA and EPA should come out with additional warnings within the year, but until that time, we must count on restaurateurs to be upfront about the dangers of their sushi.