kg / day ▁in ▁m ice ▁and ▁a ▁lowest ▁observed ▁effect ▁level ▁( LO EL ) ▁of ▁ 1 0   m g / kg / day ▁in ▁r ats . ▁The ▁lowest ▁or al ▁do se ▁which ▁caused ▁cancer ▁( LO A EL ) ▁in ▁B 6 C 3 F 1 - m ice ▁was ▁ 7 0   m g / kg / day . ▁These ▁are ▁ 1 – 3 ▁orders ▁of ▁magnitude ▁higher ▁than ▁human ▁expos ure , ▁which ▁is ▁princip ally ▁der mal ▁rather ▁than ▁or al .< ref > Se ctions ▁ 4 . 1 . 1 . 5 ▁& ▁ 4 . 1 . 3 . 5 , ▁European ▁Union ▁R isk ▁Ass ess ment ▁Report , ▁pp .   5 7 ▁and ▁ 1 0 9 – 1 1 0 .</ ref > ▁▁ ▁Environment al ▁concerns ▁ ▁The ▁first ▁concerns ▁about ▁mus k ▁x yl ene ▁arose ▁in ▁the ▁early ▁ 1 9 8 0 s , ▁with ▁the ▁detection ▁of ▁mus k ▁x yl ene ▁resid ues ▁in ▁fish ▁from ▁the ▁T ama ▁River ▁near ▁Tokyo , ▁and ▁subsequently ▁in ▁the ▁river ▁water ▁itself , ▁especially ▁at ▁the ▁out lets ▁of ▁se w age ▁treatment ▁plants . ▁This ▁led ▁to ▁a ▁volunt ary ▁mor ator ium ▁on ▁the ▁use ▁of ▁mus k ▁x yl ene ▁in ▁Japan ▁from ▁ 1 9 8 2 . ▁Similar ▁resid ues ▁were ▁subsequently ▁found ▁in ▁European ▁waters ▁such ▁as ▁the ▁El be , ▁St ör ▁and ▁Ru