als ▁into ▁nearby ▁ground ▁water ▁sources . ▁Some ▁older ▁fruit ▁orch ards ▁may ▁contain ▁high ▁levels ▁of ▁ar sen ic , ▁once ▁used ▁as ▁a ▁p estic ide . ▁At ▁high ▁levels , ▁these ▁met als ▁pose ▁a ▁health ▁risk . ▁ ▁F ert il izers ▁and ▁p estic ides : ▁Farm ers ▁use ▁fert il izers ▁and ▁p estic ides ▁to ▁promote ▁growth ▁and ▁reduce ▁insect ▁damage . ▁These ▁products ▁are ▁also ▁used ▁on ▁golf ▁courses ▁and ▁sub urban ▁la wn s ▁and ▁gard ens . ▁The ▁chemical s ▁in ▁these ▁products ▁may ▁end ▁up ▁in ▁ground ▁water . ▁The ▁extent ▁of ▁cont am ination ▁depends ▁on ▁the ▁types ▁and ▁amounts ▁of ▁chemical s ▁used ▁and ▁how ▁they ▁are ▁applied . ▁Local ▁environmental ▁conditions ▁( such ▁as ▁soil ▁types , ▁season al ▁snow , ▁and ▁ra inf all ) ▁also ▁impact ▁their ▁cont am ination ▁potential . ▁Gr ound water ▁will ▁normally ▁look ▁clear ▁and ▁clean ▁because ▁the ▁ground ▁naturally ▁filters ▁out ▁partic ulate ▁matter . ▁But , ▁natural ▁and ▁human - indu ced ▁chemical s ▁can ▁be ▁found ▁in ▁ground water . ▁As ▁ground water ▁flows ▁through ▁the ▁ground , ▁met als ▁such ▁as ▁iron ▁and ▁mang an ese ▁are ▁dissol ved ▁and ▁may ▁later ▁be ▁found ▁in ▁high ▁concentr ations ▁in ▁the ▁water . ▁Indust rial ▁dis charg es , ▁urban ▁activities , ▁agricult ure , ▁ground water ▁p ump age , ▁and ▁dispos al ▁of ▁waste ▁all ▁can ▁affect ▁ground water ▁quality . ▁Cont amin ants ▁can ▁be ▁human