Evaluating rainwater contamination and sources in southeast Australia using factor analysis

Factor analysis is used to evaluate inorganic ion relationships to provide a qualitative determination of continental sources of rainwater contamination in the Hunter Region, New South Wales, Australia. The rain water was collected between October 1984 and March 1986 at 32 sites and forms the database for the Hunter Region Acid Rain Project. The results show that soil and animal/fertilizer sources determine rainwater quality over most of the Hunter Region, and dominate as the major sources when the entire data set is analysed as a whole. When individual sites are analysed, the industrial emissions factor is important at six adjacent locations in the Middle Hunter, suggesting some transport of sulphate and nitrate from industrial sources 50 to 80 km to the east and southeast may be occurring. Factor analysis by rainfall event provides similar results to site analysis, with only 4 events out of 34 dominated by the industrial emissions factor. The results indicate that rainwater quality is influenced by local and regional sources, and not by long-range transport from Sydney, 175 km to the south. Comparison of the Hunter Region ion relationships to those from a more heavily acidic area, the northeast U.S.A. (MAP3S/RAINE Network), demonstrate some similarities in associations but the correlations associated with the hydrogen ion are better defined in the U.S. data set.