Derived data and analysis code: within-study pH contrasts of acute aquatic toxicity from the ECOTOX Knowledgebase

Restricted-access deposit of the record-level derived data and the analysis code for a manuscript under review (a secondary analysis of within-study pH contrasts in the US EPA ECOTOX Knowledgebase). Contents: Data S1, duplicate reports removed; Data S2, ECOTOX reference list; Data S3, chemical classification and pKa with PubChem text; Data S4, observed versus predicted shift for each weak-acid contrast; Data S5, all within-study contrasts with fitted slopes and flags; Code S1, the analysis scripts (Python 3.13; R 4.3 with metafor and clubSandwich); README. Source data: ECOTOX Knowledgebase ASCII release of 15 September 2026 and PubChem, both accessed 24 October 2026. Summary results are published with the article. Access: the files are available from the corresponding author on reasonable request ([e-mail]). Funding: Umm Al-Qura University, Saudi Arabia, grant 26UQU4340520GSSR28.