# 1,2,4-Trichlorobenzene (P) — EPA national recommended water quality criteria for human health: pollutant concentration thresholds For 1,2,4-Trichlorobenzene (P), cas registry number is 120821; water + organism criterion (µg/l) is 0.071; organism only criterion (µg/l) is 0.076, verified against its source on 2026-08-17. - **Pollutant name:** 1,2,4-Trichlorobenzene (P) _(verified: appears in the quote below)_ - **CAS Registry Number:** 120821 _(verified: appears in the quote below)_ - **Water + Organism criterion (µg/L):** 0.071 _(verified: appears in the quote below)_ - **Organism Only criterion (µg/L):** 0.076 _(verified: appears in the quote below)_ ## What the source says > 1,2,4-Trichlorobenzene (P) | 120821 | 0.071 | 0.076 | 2015 ## Source - https://www.epa.gov/wqc/national-recommended-water-quality-criteria-human-health-criteria-table Last verified: 2026-08-17. Review by: 2028-08-16. Part of [EPA national recommended water quality criteria for human health: pollutant concentration thresholds](https://referencesource.org/epa-water-quality-criteria-human-health/).