Trans-Tasman tropospheric transport of acid rain

Abstract

Rainwater samples collected at Karamea on the west coast of the South Island were analysed for pH and ionic composition, An attempt has been made to correlate rainwater samples with air mass origin using air mass back trajectories, Unexpectedly high levels of fluoride (> 1 ppm) were observed in rainwater event samples associated with air mass trajectories from Australia. Mean values for the observed ions were K⁺ 0.44 ppm, Na⁺ 4.7 rpm, Ca²⁺ 2.9 ppm, Mg²⁺ 0.31 ppm, F^- 0.50 ppm, Cl^- 12.0 ppm, N0₃ ^- 8.2 ppm and SO₄ ^-2 10.1 ppm.