ams ▁per ▁liter ▁near ▁the ▁source ▁and ▁the ▁mouth , ▁respectively . ▁ ▁The ▁concentration ▁of ▁mang an ese ▁in ▁Lim estone ▁Run ▁ranges ▁from ▁ 2 4 . 9 ▁to ▁ 7 1 . 2 ▁mill igr ams ▁per ▁liter ▁at ▁the ▁stream ' s ▁mouth ▁and ▁source , ▁respectively . ▁The ▁iron ▁concentration ▁ranges ▁from ▁ 1 0 3 ▁to ▁ 1 3 5 ▁mill igr ams ▁per ▁liter ▁in ▁the ▁central ▁reaches ▁of ▁the ▁stream ▁and ▁near ▁its ▁source , ▁respectively . ▁The ▁concentration ▁of ▁co pper ▁in ▁the ▁stream ▁ranges ▁from ▁ 0 . 4 ▁to ▁ 1 . 6 ▁mill igr ams ▁per ▁liter ▁above ▁Lewis burg ▁and ▁at ▁the ▁mouth , ▁respectively . ▁The ▁z inc ▁concentration ▁ranges ▁from ▁ 0 . 5 ▁mill igr ams ▁per ▁liter ▁in ▁the ▁middle ▁reaches ▁of ▁the ▁stream ▁to ▁ 5 . 6 ▁near ▁the ▁mouth . ▁The ▁concentration ▁of ▁cad m ium ▁in ▁Lim estone ▁Run ▁is ▁so ▁low ▁as ▁to ▁be ▁und et ect able ▁in ▁some ▁locations , ▁but ▁is ▁as ▁high ▁as ▁ 0 . 0 6 ▁mill igr ams ▁per ▁liter ▁in ▁Lewis burg . ▁The ▁lead ▁concentration ▁is ▁so ▁low ▁as ▁to ▁be ▁und et ect able ▁in ▁some ▁locations , ▁but ▁is ▁as ▁high ▁as ▁ 0 . 0 4 ▁mill igr ams ▁per ▁liter ▁near ▁the ▁source . ▁ ▁Part s ▁of ▁Lim estone ▁Run ▁are ▁considered ▁to ▁be ▁imp a ired ▁by ▁the ▁Pennsylvania ▁Department ▁of ▁Environment al ▁Prote ction .