Test­ing mer­cury in tuna un­der­lines sci­en­tists’ fight

The Washington Post Sunday - - POLITICS & THE NATION - BY DAR­RYL FEARS dar­ryl.fears@wash­post.com

Molly Lut­cav­age thought she had a deal. For more than a decade, she had col­lected hun­dreds of tis­sue sam­ples from bluefin tuna in the hope of set­tling a ques­tion that has long vexed preg­nant women and the par­ents of young chil­dren: Should they eat the big fish, a ben­e­fi­cial source of pro­tein and fatty acids? Or did mer­cury con­tam­i­na­tion make them too dan­ger­ous?

Lut­cav­age hoped to test the the­ory that se­le­nium, a key chem­i­cal found in tuna, prevents mer­cury from be­ing trans­ferred to the peo­ple who eat them and that, there­fore, the fish are safe to eat. So she gave her hard-won sam­ples to a col­league, Nick Fisher, to an­a­lyze in his lab.

But Fisher, it seems, didn’t have as much in­ter­est in Lut­cav­age’s se­le­nium the­ory. Two years later, he pro­duced a study fo­cused al­most ex­clu­sively on his own hy­poth­e­sis: that low­er­ing pol­lu­tion emis­sions from power plants re­duced the lev­els of mer­cury in bluefin tuna.

Lut­cav­age was fu­ri­ous, and the two sci­en­tists went to war.

“We kept fight­ing on this,” said Lut­cav­age, a re­searcher at the Univer­sity of Mas­sachusetts at Bos­ton. “I feel that the pa­per didn’t ad­vance the is­sue what­so­ever on this di­vide be­tween sci­en­tists over methylmer­cury. I can’t tell you how much [my col­leagues and I] ag­o­nized over tak­ing our names off the pa­per.”

The bat­tle, rag­ing for two years, sheds light on the un­set­tled is­sue of seafood safety, par­tic­u­larly for large, long-lived fish, such as tuna and sword­fish, that tend to ac­cu­mu­late mer­cury.

Fed­eral agen­cies such as the En­vi­ron­men­tal Pro­tec­tion Agency, the Food and Drug Ad­min­is­tra­tion and the Na­tional In­sti­tutes of Health urge cau­tion for some types of fish, es­pe­cially for preg­nant women and young chil­dren, be­cause high lev­els of mer­cury con­tam­i­na­tion can cause devel­op­men­tal dis­or­ders. But the agen­cies base their rec­om­men­da­tions on a body of re­search that of­ten comes to con­flict­ing con­clu­sions.

Tuna and seafood, in gen­eral, is de­li­cious and health­ful. Nutri­tion­ists em­pha­size that its nu­tri­ents are great for grow­ing brains. But mer­cury con­tam­i­na­tion could po­ten­tially out­weigh those ad­van­tages. So Lut­cav­age’s ques­tion about whether se­le­nium could bind to mer­cury and pro­tect peo­ple from its ef­fects is a po­ten­tially im­por­tant one.

But Fisher, a pro­fes­sor of marine science at Stony Brook Univer­sity on Long Is­land, ar­gues that it makes more sense to try to fig­ure out how to keep the mer­cury out of the fish in the first place by keep­ing it out of the en­vi­ron­ment.

“We specif­i­cally did not ad­dress the tox­i­col­ogy of mer­cury in tuna,” he said, “only what the con­cen­tra­tions in tuna are and how they change over time.” At the start of the re­search, he said his team could not iso­late enough se­le­nium from the sam­ples for a re­li­able test. But later, near the end, they did.

“When we gen­er­ated some good se­le­nium data, I said to Molly I would ship that data . . . and you can take the lead on pub­lish­ing this. She chose not to do any­thing to do with that,” Fisher said.

Both Lut­cav­age and Fisher re­called her ex­act words: “I don’t want any­thing fur­ther to do with this.”

Mer­cury is re­leased into the at­mos­phere from coal-burn­ing plant emis­sions and other pol­lu­tion sources around the world, and it set­tles on fresh and salt waters. Mi­crobes con­vert it into methylmer­cury, which col­lects in small or­gan­isms and fish. Big preda­tors, such as tuna, ac­cu­mu­late higher lev­els of methylmer­cury by gob­bling hun­dreds of smaller fish.

Pre­vi­ous stud­ies of how methylmer­cury af­fects peo­ple who con­sume large quan­ti­ties of seafood have had mixed re­sults. In Sey­chelles, off the East African coast, few harm­ful ef­fects were found in moth­ers or chil­dren. In Ja­pan, how­ever, devel­op­men­tal prob­lems were de­tected in chil­dren who ate a lot of fish. In a study from an is­land off the coast of Nor­way, re­sults were mixed.

Lut­cav­age’s tis­sue sam­ples came from 1,300 bluefin tuna col­lected over 14 years. Bluefin tuna isn’t canned or widely eaten by Amer­i­cans — it’s fa­vored for sushi and largely con­sumed in Ja­pan. But the mix of methylmer­cury and se­le­nium in their bod­ies could have shed light on what’s hap­pen­ing in other fish.

“The story of whether eat­ing tuna is harm­ful is all over the me­dia, but the science it­self is rarely cov­ered,” Lut­cav­age said. “The pa­per [from her col­lab­o­ra­tion with Fisher] does not dis­cuss the very deep di­vide among sci­en­tists on whether methylmer­cury is dan­ger­ous to hu­mans.”

Speak­ing for her other labs’ sci­en­tists, she said: “We’re very sad. We feel that the best pos­si­ble science wasn’t used here, and we lost a lot in terms of this re­search.”

Fisher was dumb­founded that his former col­league spoke so openly about their fight­ing, to the point of ef­fec­tively dis­avow­ing their pub­lished study. “I’m not look­ing to pick a fight with her.”

The study had a sin­gle pur­pose, ac­cord­ing to Fisher. “It sim­ply shows that by im­ple­ment­ing changes in mer­cury emis­sions, it could very rapidly re­sult in changes in mer­cury con­cen­tra­tions in large fish like tuna. It did that ef­fec­tively, show­ing that clos­ing down coal-fired plants that belch pol­lu­tion re­duces mer­cury in the en­vi­ron­ment and the ocean food chain.”

Con­ser­va­tion­ists, who are con­cerned about the en­vi­ron­men­tal im­pact of over­fish­ing, have taken up the is­sue of mer­cury con­tam­i­na­tion. They have squared off against the seafood in­dus­try for decades, with ac­tivists say­ing be­ware of eat­ing fish and the in­dus­try say­ing there’s no solid ev­i­dence of harm.

Oceana, a non­profit en­vi­ron­men­tal group, launched a cam­paign to per­suade gro­cery stores to place the FDA’s mer­cury warn­ing on cans of tuna. Jointly with the EPA, the FDA says preg­nant women should avoid such fish as or­ange roughy and big­eye tuna.

But the Na­tional Fish­eries In­sti­tute, which rep­re­sents the seafood in­dus­try, points out that the same agen­cies say eat­ing a va­ri­ety of crab, lob­ster, scal­lops, shrimp and fish, in­clud­ing canned skip­jack tuna, is a good choice, even for preg­nant women and chil­dren.

“The level of mer­cury in canned tuna re­mains . . . com­pletely safe,” said Lynsee Fowler, a spokes­woman for the in­sti­tute. Lev­els of mer­cury in seafood, she said, “are sim­ply not mak­ing con­sumers sick.”

Af­ter three years of re­search yielded no ev­i­dence to con­trib­ute to the de­bate, Lut­cav­age now won­ders why she both­ered to con­tact Fisher and why she re­lied on only a ver­bal agree­ment.

“I blame my­self,” she said. “Ev­ery­one has dif­fer­ent ideas of what a col­lab­o­ra­tion might be. It’s like a re­la­tion­ship. Get it in writ­ing, like a prenup,” she said.

Sci­en­tists who want to bet­ter un­der­stand the re­la­tion­ship be­tween se­le­nium and methylmer­cury will have to look else­where for an­swers.

“We fought as hard as we could for our points of view on the science,” Lut­cav­age said of her re­search team. “And we lost.”

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