This trend has meant that relatively pristine landscapes are at increasingly greater risk from offsite contamination from the billions of tonnes of mine waste produced (Mudd, 2013). Evaluating recent mining influences on previously non-mining impacted systems enables greater insight into the short-term effects from environmental contamination compared to networks subjected to long-term cumulative damage (Hildén and Rapport, 1993 and Arkoosh et al., 1998). Given that river systems are the primary conduit for metal transport in catchments, their adjoining

environments are ideal for assessing upstream mining impacts and risks associated with their use. Metal mining pollutants that become stored in alluvial RGFP966 mw sediments can produce long-term risks to the environment (Miller, 1997, Hudson-Edwards et al., 2001, Macklin et al., 2003 and von der Heyden and New, 2004). These pollutants also provide potential pathways for exposure via the food chain (Miller et al., 2004). Therefore, evaluating and quantifying risks associated with off site mine waste provides guidance to users of environments that are subject to contamination (e.g. graziers, fisherman, irrigators, potable water extractors, cf. Foulds et al., 2014). Analysis of impact can also assist with the implementation of tighter regulatory regimes where necessary. The increase in environmental Ceritinib regulations

governing contemporary mining operations (as opposed to historic mining) suggests that the release of mine-contaminants into relatively pristine areas will likely be associated with instantaneous accidental spills, particularly during times of flood. In fact, during the past 40 years, 75 major spills of mining contaminated materials have released contaminated waters and sediments to river systems, averaging nearly two per year, mafosfamide not including those in secluded regions (Miller and Orbock Miller, 2007). Few studies have documented the downstream extent to which the contaminants affect ecosystem health, the trends in contaminant distributions that result

from these spills (Miller and Orbock Miller, 2007), or the potential short-and long-term environmental impacts that result. Even fewer spills have been studied along rivers devoid of previous mining activity generating contrasting results. Graf (1990), for example, found that the downstream transport and deposition of contaminated sediment resulting from the 1979 Church Rock uranium tailings spill led to a non-systematic downstream trend in 230Th concentrations. Rather, concentrations varied as a function of stream power and the duration over which shear stress exceeded critical values along the channel. In contrast, the 1998 Aznalcóllar Mine spill in Spain generated a high sediment-laden flow that produced a semi-systematic downstream decrease in the thickness of the deposited, mine-contaminated sediment (Gallart et al., 1999).