Measurement of pollution history.
D002140:California; D002244:Carbon / Q000032:analysis; D004787:Environmental Pollution / Q000032:analysis*; D005390:Fires; D006207:Half-Life; D007854:Lead / Q000032:analysis; D011868:Radioisotopes; D012989:Soil Pollutants / Q000032:analysis; D013997:Time Factors; D014877:Water Pollution, Chemical / Q000032:analysis
D011868:Radioisotopes; D012989:Soil Pollutants; D007854:Lead; D002244:Carbon