. 1 8 ▁mill igr ams ▁per ▁liter ▁and ▁the ▁load ▁is ▁ ▁down stream ▁of ▁Me ek er ▁Run . ▁At ▁He ber ly ▁Run ' s ▁mouth , ▁the ▁concentration ▁is ▁ 0 . 1 5 ▁mill igr ams ▁per ▁liter ▁and ▁the ▁daily ▁load ▁is ▁. ▁ ▁The ▁acid ity ▁concentration ▁at ▁the ▁head w aters ▁of ▁He ber ly ▁Run ▁is ▁ 4 . 4 0 ▁mill igr ams ▁per ▁liter ▁and ▁the ▁al kal inity ▁concentration ▁is ▁ 5 . 8 4 ▁mill igr ams ▁per ▁liter . ▁The ▁daily ▁loads ▁of ▁these ▁subst ances ▁are ▁ ▁and ▁, ▁respectively . ▁Down stream ▁of ▁Me ek er ▁Run , ▁the ▁acid ity ▁concentration ▁is ▁ 2 . 8 7 ▁mill igr ams ▁per ▁liter ▁and ▁the ▁acid ity ▁load ▁is ▁ ▁per ▁day . ▁The ▁al kal inity ▁concentration ▁is ▁ 6 . 8 3 ▁mill igr ams ▁per ▁liter ▁and ▁the ▁daily ▁load ▁is ▁. ▁At ▁the ▁mouth ▁of ▁He ber ly ▁Run , ▁the ▁acid ity ▁concentration ▁is ▁ 2 . 8 0 ▁mill igr ams ▁per ▁liter ▁and ▁the ▁concentration ▁of ▁al kal inity ▁is ▁ 6 . 9 3 ▁mill igr ams ▁per ▁liter . ▁The ▁daily ▁loads ▁for ▁these ▁subst ances ▁are ▁ ▁and ▁. ▁ ▁The ▁p H ▁of ▁He ber ly ▁Run ▁at ▁its ▁mouth ▁ranges ▁from ▁ 4 . 1 5 ▁to ▁ 6 . 4 0 , ▁with ▁an ▁average ▁of ▁ 5 . 6 0 . ▁Down stream