Browsing by Author "Hanklin, SI"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Using hydro-geochemistry and isotopes to trace groundwater flow from Little Forest Burial Ground and surrounding landfills
    (Australian Nuclear Science and Technology Organisation, 2012-10-16) Cendón, DI; Hughes, CE; Harrison, JJ; Hanklin, SI; Johansen, MP; Payne, TE; Wong, HKY; Rowling, B; Vine, M; Wilsher, KL; Guinea, A; Thiruvoth, S
    Multiple tracer-element and isotope approaches were used to study groundwater near a legacy low-level radioactive waste burial site surrounded by municipal and industrial waste sites. The interaction of rainfall, with its marine-derived major ion ratios, and waste from the sites is apparent, however, clay-rich soils and shale at the site tend to retain many contaminants via ion exchange and other processes. High permeability of the disposal trenches provides a pathway for groundwater recharge, with discontinuous perched groundwater lenses found in their vicinity. Within the trenches, the degradation of organic matter results in localised methanogenesis, as suggested by enriched δ2H and δ13CDIC in adjacent subsurface water. Movement of contaminants from the waste sites is indicated by Na+, Brˉ and Iˉ concentrations, variations in 87Sr/86Sr, enriched δ13CDIC and evolution of δ34S of dissolved sulfate in perched water bodies above the shale. There is clear evidence of a tritium plume from the LFBG trenches, although the adjacent landfills provide an additional tritium source. Waste burial records show that over 1000 kg of Be (mostly BeO) were disposed in the LFBG trenches. However, beryllium concentrations in groundwaters near the trenches are quite low, and appear more likely to be controlled by the host lithologies and the other sources of contamination in the vicinity, rather than by leaching of Be from the LFBG waste. Past removal of the shale layer in an adjacent site, Harrington’s Quarry, has led to the mixing of municipal waste leachates into the underlying groundwater system as suggested by high TDS, Cl−/Br− ratios, Be, and 3H found in deeper wells. The multiple tracer approach addresses the complexities of transport at the site and differentiates various municipal, industrial, and radioactive waste sources