Utilizing Lead Isotope Tracing to Investigate Sustainable Agriculture Practice in the Burdekin Catchment, Australia
2022 年 13 巻 1 号 p. 111-117
詳細
2022 年 13 巻 1 号 p. 111-117
The Burdekin delta is the largest sugarcane producing region in Australia (85,000 ha) and a major coastal output to the Great Barrier Reef (GBR). Run-off from cultivation areas contain heavy metals from fertilizers, contributing to elevated Cd, Hg, and Pb in waterways. Validating the efficacy of sustainable agriculture practice is necessary to determine if current strategies protect ecosystems and uphold environmental standards. The objective of this study is to utilize Pb isotope tracing (207/206Pb and 208/206Pb) and elevated trace-elements (Cd, Hg, and Pb) as a monitoring tool, to detect residual heavy metals from fertilizers and alternative pollutant sources in the Burdekin catchment. Lead-isotope ratios from dry-season samples of embankment soils/sediment (n=15, 2016, 2019) and water (n=35, 2016-2020), reveals sources of natural forest soils, cane soils (fertilizer enriched), ambient dust, and historic coal fly-ash (Collinsville Power Station). Pb isotope compositions and low levels of heavy metals (soil/sediment: TCd 0.11 mg/kg, THg 0.03 mg/kg and TPb 11.02 mg/kg; estuary: THg 0.011 μg/L and TPb 4.99 μg/L) indicate that fertilizers applied to soils have minimal impact on Burdekin waterways during the dry-season, suggesting effective agricultural practice and sustainable irrigation control.
