Pd-Specific Analytical Traceability and Reproducibility Dataset

The package includes the 52 individual analytical records derived from paired physical subsamples of 26 independent green-space topsoil composites, the 26 final site-level response classifications, seven full-procedure blanks (AB1–AB7), ¹⁰⁶Pd calibration and low-end performance data, the study-specific operational response threshold and operational LLOQ, three technical reruns (records 3759, 3760 and 3764), the complete n = 83 ¹¹⁵In internal-standard stability sequence, Pd-targeted method documentation, source data and reproducible scripts for Figures 1–3, vector PDF and 600 dpi PNG figure files, and README documentation.</p><p dir="ltr">Following procedural-background correction, all 52 instrumentally corrected m/z 106 responses exceeded the study-specific operational response threshold, and both physical subsamples from all 26 independent composites were concordantly classified as ABOVE PROCEDURAL BACKGROUND / BELOW LLOQ.

No observation reached the operational LLOQ of 1.570 µg L⁻¹ on the analysed-solution scale. Numerical sub-LLOQ responses are therefore provided solely for analytical traceability, reproducibility and auditing and should not be interpreted as validated environmental Pd concentrations.</p>