American Children Not Eating Enough Seafood

A report from AAP has revealed that children in the United States are eating less fish and shellfish than in previous years.
 reveal v)明らかにする
 eating less 食事の量を減らす
 Actually, I've just started eating less in order to lose weight. 
 previous adj)以前の、前の
 in previous years ここ数年間
 shellfish n)甲殻類（こうかくるい）、海老・蟹・貝
The decline, according to the report, started in 2007. The trend is in part due to parents having qualms about letting their children eat seafood. Their hesitation comes from concerns about mercury in seafood. Although all fish have mercury in differing levels, high amounts of the substance can be dangerous to children's nervous system.
 decline n)下り坂
 trend n)大勢、流行
 in part　一部分、ある程度
 due to　～のため、～の結果
 in part due to... 　一つには...が原因である
 qualm n)気のとがめ、懸念
 having qualms about (something) 
 let v)～させる
 hesitation n)ためらい、躊躇
 concern n)心配、関わり  
 mercury n)水銀
 although con）...だけれども
 differ v)異なる、違う
 substance n)材料（化学・物理的な物質）
 Uranium is one of radioactive substances. ウランは放射性物質の一つである。
 ※material n)材料（何かの材料となる素材）
 This is a house built of good materials, isn't it? これは良い材料で建てられた家ですね。
 This material is weak to heat. この物質は熱に弱いです。
 I bought material to make a dining tablecloth. 私は食卓のテーブルクロスを作るための生地を買いました。 
 ※stuff n)材料（いろいろな物を構成する要素:日常会話的でsubstanceやmaterialの代わりに使われる）
 Are you going to buy the stuff to make the birthday cake?
 I'm going shopping today. I have to get some stuff.
children's nervous system 脳に情報を送るシステム（nervous=神経）