PHOTOS 5 GRAPHICS 3; Delaney Dubow helps her mother, Rhonda, pick out canned tuna in Bolingbrook. The federal government has failed to adequately inform consumers that canned tuna might be risky for children because of mercury contamination. Swordfish and halibut have been identified as high- mercury fish, but there is no federal testing to tell stores or shoppers how much mercury is in a particular piece of seafood. Author [Ayelet Waldman] says her daughter was diagnosed with mercury poisoning at age 5. One of the girl's favorite meals was deemed the culprit: tuna sandwiches made with canned albacore. [Sam Roe] Roe Michael Hawthorne How much can you safely eat? The Tribune bought fish at area stores and had it tested for mercury. Below are the amounts of various fish a 161-pound person* can eat per week before being exposed to potentially unsafe amounts of the toxic metal. SUGGESTED WEEKLY LIMITS A typical serving is 6 ounces. SWORDFISH 1.3 oz. About 1/4 serving ORANGE ROUGHY 3.2 oz. About 1/2 serving WALLEYE 3.5 oz. About 1/2 serving YELLOWFIN (Tuna steak) 5.2 oz. More than 3/4 ALBACORE (Canned tuna) 6.0 oz. 1 serving SALMON 60.1 oz. About 10 servings SKIPJACK (Canned light tuna) 16.4 oz. bout 2 3/4 servings GROUPER: 6.9 oz. About 1 serving *The average weight of women ages 18-45 is 161 pounds; women who are or may become pregnant are advised to avoid some types of fish because of mercury. Tribune illustrations by Rick Tuma GRAPHIC: TRIBUNE INVESTIGATION: THE MERCURY MENACE What the testing found The Tribune bought samples of eight kinds of fish commonly sold at Chicago-area stores and had a lab analyze them for mercury. Results showed some samples to be above the U.S. limit for what can be sold legally. The average for swordfish was well above the limit. FISH: 18 SAMPLES OF EACH HIGH Swordfish Orange roughy Walleye Tuna steak (yellowfin) Canned albacore tuna Grouper Canned light tuna (mostly skipjack) Salmon MERCURY THRESHOLDS Amount that prompted an FDA warning 0.35 Legal limit for fish sold in Canada 0.50 Legal limit for fish sold in the U.S. 1.0 In 2004, the FDA warned children and pregnant women to limit their consumption of canned albacore tuna because it has averaged 0.35 parts per million of mercury in FDA testing. Also, the U.S. and Canada have set legal limits on the amount of mercury allowed in fish sold in stores. How the tests were conducted - Eighteen samples each of eight kinds of fish were tested: tuna steak, swordfish, walleye, orange roughy, grouper, canned light tuna, canned albacore tuna and salmon, both wild and farm-raised. A total of 144 samples were tested. - The fish were bought from randomly selected fish markets and supermarket chain stores in the 312, 773, 847, 708, 630 and 224 area codes, an area encompassing Chicago and dozens of suburbs. - Two reporters bought samples between May 18 and Sept. 27. For fresh fish, the counter help selected the samples. For canned tuna, the reporters picked a variety of brands. - The samples were packed in ice and shipped overnight to the Environmental and Occupational Health Sciences Institute in New Jersey, which is jointly sponsored by Rutgers University and the University of Medicine & Dentistry of New Jersey. - The institute's laboratory determined the mercury content of each sample, testing 10 percent twice for quality control. The Tribune, which paid for the testing, used the raw data to analyze the findings. Source: Tribune research Chicago Tribune GRAPHIC: Mercury's effect on humans Mercury does not stay in the body forever. It takes about six months to a year to leave the bloodstream once exposure stops. Some researchers think mercury can permanently damage the nervous system in children. An organic form of the metallic element mercury, called methylmercury, is found in nearly all fish and can lead to health problems in humans at high concentrations. RELATED HEALTH PROBLEMS Exposure to mercury can damage the central nervous system (the brain and spinal cord) in fetuses and young children. Some scientists believe that increased exposure to mercury can raise the risk of heart attacks in men. SYMPTOMS OF MERCURY POISONING SMALL CHILDREN Subtle decreases in learning abilities Delays in walking and talking Decreases in attention or memory ADULTS Numbness in hands and feet Headaches Fatigue Loss of concentration, coordination or memory Blurred vision Hair loss Nausea Tremors PROGNOSIS Mercury does not stay in the body forever. It takes about six months to a year to leave the bloodstream once exposure stops. Some researchers think mercury can permanently damage the nervous system in children. An organic form of the metallic element mercury, called methylmercury, is found in nearly all fish and can lead to health problems in humans at high concentrations. Sources: U.S.