Document Type
Article
Publication Date
12-2026
Journal / Book Title
Journal of Trace Elements and Minerals
Abstract
Background: Heavy metal pollution in sediments poses persistent ecological risks due to metal toxicity, bioaccumulation, and potential for remobilization. Legacy indices have been widely used for decades but suffer from fundamental flaws, including arbitrary background dependence, lack of grain-size normalization, and poor ecological relevance.
Objective: This review critically evaluates three emerging sediment pollution indices, the Modified Nemerow, Mean Enrichment Quotient (MEQ), and Aggregated Multivariate Environmental Risk (AMER) index, to assess their methodological advances and potential to replace legacy approaches.
Methods: A structured literature search was conducted in Web of Science, Scopus, and Google Scholar (2010–2026). Using an adapted Birch framework, each index was evaluated across six criteria: background independence, grain-size normalization, classification thresholds, multi-metal integration, ecological relevance, and statistical robustness.
Results: The Modified Nemerow Pollution Index is a first-generation correction to the original Nemerow framework that eliminates double-counting artifacts, although it still relies on background values and lacks grain-size normalization. The Mean Enrichment Quotient (MEQ) is a second-generation normalization approach that overcomes major limitations of Igeo and EF by using grain-size normalization and improved enrichment assessment when reliable background and reference-element data are available. The Aggregated Multivariate Environmental Risk (AMER) index is a third-generation predictive framework that integrates Principal Component Analysis (PCA)-derived weighting with time-series forecasting to support dynamic environmental risk assessment. Current evidence supports MEQ as the preferred methodological evolution for enrichment assessment under appropriate data conditions, whereas AMER extends assessment toward predictive monitoring rather than serving as a direct replacement for existing indices.
Conclusions: No single index is universally optimal. A tiered decision framework is proposed: Modified Nemerow for rapid screening, MEQ for standard enrichment assessment, and AMER for predictive monitoring when time-series data are available. Future priorities include inter-index validation, AMER threshold development, bioavailability integration, and harmonized background databases.
DOI
10.1016/j.jtemin.2026.100335
MSU Digital Commons Citation
Islam, Md Shahnul and Ara, Anjuman, "Beyond legacy indices: A critical review of the modified Nemerow, mean enrichment quotient, and aggregated multivariate environmental risk (AMER) indices for heavy metal pollution in sediments" (2026). Department of Earth and Environmental Studies Faculty Scholarship and Creative Works. 838.
https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/838
Rights
This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Published Citation
Islam, Md Shahnul, and Anjuman Ara. “Beyond Legacy Indices: A Critical Review of the Modified Nemerow, Mean Enrichment Quotient, and Aggregated Multivariate Environmental Risk (AMER) Indices for Heavy Metal Pollution in Sediments.” Journal of Trace Elements and Minerals, vol. 18, Dec. 2026, p. 100335. https://doi.org/10.1016/j.jtemin.2026.100335.