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Using trace elements in particulate matter to determine the geographic sources of pesticides in air at an alpine ecosystem in New Zealand
Abstract   Peer reviewed

Using trace elements in particulate matter to determine the geographic sources of pesticides in air at an alpine ecosystem in New Zealand

K Levin, K Hageman, Samuel K Marx, B S Kamber and P Dillingham
31st Society of Environmental Toxicology and Chemistry North America Annual Meeting: Abstract Book, p.176
Society of Environmental Toxicology and Chemistry (SETAC) North America Annual Meeting: Bridging Science with Communities, 31st (Portland, United States, 07-Nov-2010–11-Nov-2010)
2010
url
http://portland.setac.org/View
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Abstract

Physical Geography and Environmental Geoscience pesticide alpine
Semi-volatile organic contaminants (SOCs) are known to undergo atmospheric transport via a series of volatilisation-transport-condensation steps and therefore have been detected in remote ecosystems far from where they have been used. In previous studies, local wind direction observations and/or air-mass back-trajectory modelling have been used to gain information about the geographic sources of SOCs in remote ecosystems. However, these approaches are limited. The local wind direction is highly variable, especially in mountainous and complex terrain, and does not adequately describe long-range sources, while air-mass back-trajectory modelling uses spatially and temporally discrete (gridded) weather observations to model continuous weather events. Therefore, more robust methods for measuring the contributions of different regional and longrange sources to the contaminant burden in cold remote ecosystems are needed. The aim of our study was to investigate a new geographic source apportionment method for SOCs that uses trace element profiles in atmospheric particulate matter (PM) to determine SOC origin. Daily samples of PM and SOCs were simultaneously collected using two high-volume air samplers from 16 January to 16 February 2009 at Temple Basin, a remote alpine ecosystem in New Zealand's Southern Alps. For each sample day, the source of PM was determined using a binary mixing model of the trace element profiles of potential Australian and New Zealand PM source regions. This allowed us to calculate a percent Australian PM (%AustralianDust) for each day. Correlation analysis was conducted between %AustralianDust and the measured pesticide concentrations in air. Air concentrations of Endosulfan I, which is banned in New Zealand, were positively correlated (p <0.05) with %AustralianDust, indicating that it is undergoing transport from Australia to New Zealand. In contrast, the concentrations of chlorpyrifos, which is used in both Australia and New Zealand, were not correlated with %AustralianDust but were well-correlated (p <0.05) with the percent of time that local winds came from a southerly direction. This result indicates that chlorpyrifos concentrations in air at Temple Basin are largely influenced by regional transport from the agriculturally-rich Canterbury Plains of New Zealand.

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