The mold begins in New York City on a map with very concentrated food sources in the cities but few nutrients in the countryside.

模具开始就在食物来源非常集中城市的，但农村一些营养素地图来自纽约市。

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There are unknowns in this too, such as the degree to which radioactivity will become concentrated in the food chain.

也还有一些未知影响在里面，像是放射物在食物链里的富集程度。

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The current global food system worked well in a world of cheap, stable energy prices which allowed food to be grown in concentrated locations and transported over huge distances to meet demands.

当能源价格低廉而稳定的时候，人们可以集中种植粮食，并将产品输送到遥远的需求市场。

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"It could be taken up by crustaceans like shrimp crabs, things like that which are the base of the food chain and that could be passed up to fish and then mammals and the toxins could be concentrated and that could be harmful to animals that feed on these smaller organisms."

VOA: standard.2010.05.09

Ms. BRYN AUSTIN (Harvard School of Public Health): What we found was that the fast-food restaurants were concentrated in areas within a very short walking distance from schools.

NPR: Kids Have Easy Access to Junk Food

Another characteristic, it added, was that mercury became more concentrated as it moved up the food chain, reaching its highest levels in predator fish that could be consumed by humans.

BBC: Nations agree on legally binding mercury rules

Another characteristic is that mercury becomes more concentrated as it moves up the food chain, reaching its highest levels in predator fish that may be consumed by humans, the report adds.

BBC: UN: Rising mercury emissions increase risk to humans