trace amounts

Reader's Digest 3月号の記事 '50 Health Facts Your Doctor Wants You to Know' から引用します。
Vaccines can cause autism.
Myth! Some people have raised concerns that substance used in trace amounts in certain vaccines--including formaldehyde, aluminum salts, and thimerosal, a mercury-based preservative--could cause autism. But none of these substances has been shown to cause harm in the small doses used in vaccines.
"trace amounts" が分からないので辞書を引きます。
・Oxford English Dictionary: A very small quantity, especially one too small to be accurately measured.: his body contained traces of amphetamines
・Collins Dictionary: A trace of something is a very small amount of it.: Wash them in cold water to remove all traces of sand.
・Cambridge English Dictionary: a very slight amount: Traces of drugs were found in his blood
思い出しました。4年前（4/6/2015）に "trace mineral" で取り上げた "trace" と同じですね。

adulterate

Reader's Digest 3月号の記事 'I am the Food on Your Plate' から引用します。

Given that trend, it's not surprising that I also am perhaps your supermarket's most frequently adulterated food, laced with cheap sugar syrup or corn syrup to stretch the supply. In 2010, the largest food fraud in American history was busted when authorities discovered $80 millon in smuggled, tainted Chinese honey. That is among the reasons I hope you buy beekeepers.

"adulterated" で昔聖書を読んで覚えた単語 "adultery" を連想しましたが、食べ物なので可笑しい。辞書を見ます。

・Oxford English Dictionary: Render (something) poorer in quality by adding another substance, typically an inferior one.: the meat was ground fine and adulterated with potato flour

・Collins Dictionary: If something such as food or drink is adulterated, someone has made its quality worse by adding water or cheaper products to it.: There is a regulation against adulterated cosmetics.

・Cambridge English Dictionary: to make food or drink weaker or to lower its quality, by adding something else: There were complaints that the beer had been adulterated with water.

十年前に（4/23/2009）取り上げた "laced with" と似ていますね。