Risk screening assessment for ranking historic coastal landfills by pollution risk

Abstract

Globally there are significant numbers of historic landfills, and in England alone there are over 1200 in low-lying coastal areas. Approximately one-third of these historic coastal landfills are near designated ecological sites, and without intervention, 10% are expected to start eroding within 40 years. Indeed, some sites are already eroding and releasing waste, and erosion is likely to become more common with the anticipated effects of climate change. Mitigating the pollution risk from all historic coastal landfills under threat of erosion would be prohibitively expensive; consequently, it is necessary to understand which sites pose the greatest pollution risk to prioritise management resources. This paper proposes a new risk screening assessment that can support coastal managers in identifying which historic coastal landfills pose the greatest pollution risk at a national scale for minimal cost using existing datasets. The proposed method determines an overall risk index for each site by considering the risk of pollution from eroding historic coastal landfills in two stages: the first stage assesses the risk of waste being released (waste release index), and the second assesses the risk to various receptors (pollution index). The highest risk sites can then be prioritised for further investigation or remediation.

Potential pollution risks of historic landfills in England: Further analysis of climate change impacts

“…A comparison of inorganic contaminant concentrations in waste materials extracted from two historic landfills in England to Canadian freshwater sediment quality guidelines (adapted from Brand, 2017, p. 181; and Brand & Spencer, 2019, p. 288).…”

“…While there have been some national scale assessments of potential contaminant emissions resulting from historic landfills flooding or eroding (e.g. Laner et al, 2009; Neuhold, 2013) such assessments rarely consider the likely receptors, yet this is essential to regional and national planning and adaptation to climate change (Arrighi et al, 2018; Brand et al, 2018; Brand & Spencer, 2018). Determining the scale of the potential risk of historic landfills to controlled waters and other sensitive ecological sites requires an understanding of the likelihood of hydrological connectivity between historic landfills and water bodies, the probability of erosion, the magnitude of the chemical hazard, and vulnerability of receptors.…”

“…In the original article, we proposed that the large numbers of historic coastal landfills that pose a pollution risk, the limited resources available to investigate them, and the prohibitively high costs of investigation and mitigation, means there is a requirement for a method to prioritize expenditure based on which historic coastal landfills present the greatest risk (Alaska Department of Environmental Conservation, 2008; Brand et al, 2018; Weber et al, 2011). The “Risk screening assessment for ranking historic coastal landfills by pollution risk” proposed by Brand and Spencer (2018) meets this need. However, data presented here suggests there is also a requirement for a method to prioritize expenditure based on which historic landfills pose the greatest pollution risk in freshwater environments.…”

“…However, data presented here suggests there is also a requirement for a method to prioritize expenditure based on which historic landfills pose the greatest pollution risk in freshwater environments. Brand and Spencer (2018) found existing methods for prioritizing landfill sites by risk in freshwater environments typically concentrate on the risk from leachates or gasses under routine operating conditions, i.e. the landfills are not inundated or eroding.…”

“…Where flooding is considered as a pathway, often the sensitivity of receptors is not considered, and none of the methods identified consider the risk from solid waste materials eroding in freshwater environments. Some methods designed for prioritization of coastal landfills consider flooding, erosion of solid waste, and receptors, but use some parameters that are not applicable to noncoastal sites (e.g., Alaska Department of Environmental Conservation, 2015; Brand & Spencer, 2018). None of these methods intrinsically consider how the risk may change under different climate change scenarios, although some parameters could be varied to test these without needing to change the underlying methodology, for example, including additional landfills in the assessment by increasing the flood extents.…”