, ▁phot ol ysis ▁was ▁not ▁considered ▁to ▁be ▁relevant ▁in ▁the ▁pers istence ▁of ▁mus k ▁x yl ene ▁in ▁the ▁environment , ▁and ▁was ▁not ▁taken ▁into ▁account ▁in ▁class ifying ▁it ▁as ▁a ▁" very ▁persistent " ▁subst ance . ▁ ▁Several ▁different ▁primary ▁bio acc um ulation ▁studies ▁were ▁review ed ▁in ▁the ▁European ▁Union ▁R isk ▁Ass ess ment ▁Report , ▁with ▁bio acc um ulation ▁factors ▁varying ▁between ▁ 6 4 0   l / kg ▁and ▁ 6 7 4 0   l / kg . ▁Given ▁that ▁mus k ▁x yl ene ▁has ▁a ▁very ▁high ▁oct an ol – water ▁partition ▁coefficient ▁( log   K ow   = ▁ 4 . 9 ), ▁the ▁higher ▁bio acc um ulation ▁factors ▁were ▁considered ▁to ▁be ▁the ▁more ▁significant . ▁The ▁ 2 0 0 8 ▁add endum ▁considered ▁a ▁further ▁labor atory ▁study ▁from ▁the ▁Japanese ▁Ministry ▁of ▁International ▁Trade ▁and ▁Indust ry ▁which ▁was ▁not ▁available ▁to ▁the ▁authors ▁of ▁the ▁original ▁R isk ▁Ass ess ment ▁Report ▁and ▁which ▁also ▁showed ▁bio acc um ulation ▁factors ▁in ▁fish ▁( Cy pr inus ▁car pio ) ▁that ▁were ▁higher ▁than ▁the ▁RE AC H ▁threshold ▁of ▁ 5 0 0 0   l / kg ▁for ▁" very ▁bio acc um ulative " ▁subst ances . ▁Bio acc um ulation ▁factors ▁of ▁more ▁than ▁ 5 0 0 0   l / kg ▁( w et ▁weight ▁basis ) ▁have ▁also ▁been ▁found