Current methods for the evaluation of chemical contamination risks from abandoned coal and lead-zinc mine lands: protocol for a systematic evidence map

Abandoned mine lands (AMLs) pose significant environmental risks by releasing contaminants that can adversely affect plants, animals, and human health, especially in highly contaminated areas. Guidance exists on conducting contaminated land risk assessments. Understanding and documenting changes in the methods used for AMLs risk assessments can help identify gaps and advances in practice, influencing future research, policy, and remediation efforts. The study aims to synthesise current methods for characterising the risks of chemical contamination associated with AMLs, with a focus on coal and lead-zinc mines due to their enduring toxic legacies. Searches will be conducted across six electronic databases, including Web of Science, Scopus, ScienceDirect, PubMed, Academic Search Complete, and Business Source Premier (via EbscoHost), as well as grey literature sources. Eligible studies must include primary research assessing chemical risks from abandoned coal and lead-zinc mines. They must have assessed or measured risks associated with chemicals on ecological or human receptors at the community, population, or individual level. Studies retrieved from literature searches will undergo title and abstract screening, followed by a full-text assessment for eligibility. Following pilot screening, a single reviewer will screen all articles independently, with a second reviewer verifying accuracy for 20% of the sources. Data on methods for exposure assessment, including exposure modelling where relevant, selected safety thresholds, risk characterisation will be extracted from all eligible studies. Accuracy of the extraction process will also be verified by a second reviewer for 20% of the eligible articles. Collated methods will be categorised to establish current practices and compared with existing guidance to assess alignment and deviations. Results will be summarised narratively and presented in interactive, publicly accessible visualisations.