▁rec ycle ▁the ▁numerous ▁ch lor in ated ▁organ ic ▁hydro car b ons ▁that ▁have ▁bio acc um ulated ▁in ▁animal ▁and ▁human ▁t issues ▁across ▁the ▁glo be , ▁the ▁co pper ▁dispers ed ▁in ▁fung ic ides , ▁the ▁lead ▁in ▁widely ▁applied ▁pain ts , ▁or ▁the ▁z inc ▁ox ides ▁present ▁in ▁the ▁fin ely ▁dispers ed ▁rub ber ▁pow der ▁that ▁is ▁ab rad ed ▁from ▁autom obile ▁t ires ?" ▁ ▁As ▁with ▁environmental ▁econom ics , ▁care ▁must ▁be ▁taken ▁to ▁ensure ▁a ▁complete ▁view ▁of ▁the ▁costs ▁and ▁benefits ▁involved . ▁For ▁example , ▁paper board ▁pack aging ▁for ▁food ▁products ▁is ▁more ▁easily ▁rec yc led ▁than ▁most ▁pl astic , ▁but ▁is ▁heav ier ▁to ▁ship ▁and ▁may ▁result ▁in ▁more ▁waste ▁from ▁spo il age . ▁ ▁Energy ▁and ▁material ▁flows ▁▁ ▁The ▁amount ▁of ▁energy ▁saved ▁through ▁rec y cling ▁depends ▁upon ▁the ▁material ▁being ▁rec yc led ▁and ▁the ▁type ▁of ▁energy ▁account ing ▁that ▁is ▁used . ▁Correct ▁account ing ▁for ▁this ▁saved ▁energy ▁can ▁be ▁accomplished ▁with ▁life - cycle ▁analysis ▁using ▁real ▁energy ▁values , ▁and ▁in ▁addition , ▁exer gy , ▁which ▁is ▁a ▁measure ▁of ▁how ▁much ▁useful ▁energy ▁can ▁be ▁used . ▁In ▁general , ▁it ▁takes ▁far ▁less ▁energy ▁to ▁produce ▁a ▁unit ▁mass ▁of ▁rec yc led ▁materials ▁than ▁it ▁does ▁to ▁make ▁the ▁same ▁mass ▁of ▁vir gin ▁materials . ▁ ▁Some ▁sch ol ars ▁use ▁emer gy ▁( sp