Methodological heterogeneity outweighs geography in shaping reported riverine microplastic concentrations: a global meta-analysis and implications for water-quality monitoring

Concentrations are harmonised to items m-3 for water and items kg-1 dry weight for sediment. Values that could not be converted to a particle concentration are retained in the workbook and flagged rather than deleted, so the exclusion decisions are auditable. Microplastics_Rivers_Meta_Analysis_CODE.zip contains the Python code that reproduces every statistic and figure in the associated article from this workbook alone: a shared module of loading, harmonisation and statistical helpers, eight numbered analysis scripts, a runner that executes them in order and then compares each recomputed value against the value printed in the manuscript, a README and a pinned requirements file.

There is no network access, no external data and no hidden state. Known gaps, stated plainly. Two groups of fields used in the published analysis are not columns of this workbook.

First, the standard deviation reported by original authors alongside their mean is absent, so the random-effects branch of the analysis (DerSimonian-Laird pooled estimates, Cochran Q, tau-squared, I-squared, prediction intervals and the 55-water / 44-sediment study counts) cannot be regenerated from this deposit; nine of the ninety-eight verified statistics are affected and are reported as "missing input" rather than silently omitted.

Second, catchment drainage area and river length were joined from an external gazetteer and are likewise not included. Everything else reproduces exactly.