? Seawater moving inland below ground surface, displacing fresh water. ? Salt water encroachment occurs when groundwater resources in coastal areas are overused ? The salt water intrusion is not easy to reverse Saltwater Encroachment ? Infiltration of pollutants into groundwater ? Types of groundwater pollution include ? Septic tank drainage; mine drainage ? Agricultural chemicals--fertilizers, pesticides ? Industrial chemicals ? Petroleum products ? Landfills Groundwater Pollution Norman Landfill 331 330 329 ? Natural Arsenic compounds are toxic ? pigmentation changes, keratoses, cancer ? Death if exposure is long or concentration is sufficient. Arsenic and Old Rocks Arsenic in our drinking water? Lots of recent (2005) news about new standard maximum allowable levels of arsenic in drinking water ... Elevated arsenic in almost half wells used by Norman Longer flowpath allows groundwater to dissolve more arsenic from rock. ? Tri-State Mining District ? Oklahoma, Missouri, Kansas ? Lead-Zinc Mining district from the early 20th Century ? Sulfide minerals--metals bound with sulfur ? Mined through WWII ? Last mines closed in 1970?s Case Study: Picher, OK ? Primarily underground mining ? Over 300 mi of tunnels ? Some collapse occurring ? Continuous pumping during mining to keep water levels below mine tunnels ? Rain and groundwater filled mines after abandonment Case Study: Picher, OK ? 165 million tons of ?chat? ? Used in road construction and landfill ? School playgrounds ? Parks ? Residential yards ? Contain elevated levels of lead, and other metals ? Dust from workings of ?chat? piles enter houses Case Study: Picher, OK ? 1993 study: 34% of Native American children from area exhibited elevated lead blood levels ? More recent study suggests percentage has dropped, mostly through education of lead dangers as well as chat removal. ? Tar Creek listed as #1 Superfund site in U.S. by EPA ? Over $150 million spent to date on remediation efforts. ? Study by Oklahoma commission suggests it may require $10 BILLION to completely remediate site michael soreghan groundwater
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