{"query":{"parameter":"silver","place":"US-CO","medium":null,"statistic":null,"kind":null},"searched":{"places":["US-CO","US"],"parameter_keys":["cas:7440-22-4","cas:93-72-1","cas:506-61-6","cas:506-64-9","name:silver - total","name:silver, total","name:silver, total recoverable","name:total silver"],"names_matched":[["silver","cas:7440-22-4"],["2 4 5 tp silver","cas:93-72-1"],["potassium silver cyanide","cas:506-61-6"],["silver cyanide","cas:506-64-9"],["silver cyanide ag cn","cas:506-64-9"],["silver total","name:silver - total"],["silver total","name:silver, total"],["silver total recoverable","name:silver, total recoverable"],["total silver","name:total silver"],["total silver freshwater","name:total silver"],["total silver marine","name:total silver"]],"match":"exact+contains","order":"The place's own instruments first, then each place above it, each in its register's order; rows for a marine receiving water after the rest, as none of the place's own rows names a marine, salt, estuarine, coastal or ocean water","not_sent":{"rows":9,"names":["Trichlorophenoxypropionic acid, -2,4,5","Chlorophenoxy Herbicide (2,4,5-TP) [Silvex]","Trichlorophenoxypropionic acid (2,4,5-tp) (Silvex)"],"says":"9 rows share a parameter key with a longer name holding \"silver\" but are printed under names without these words (that key is wider than the name): not sent. Ask for one by its name or CAS number."}},"total":476,"offset":0,"returned":50,"next_offset":50,"rows":[{"id":"2e9d7024a236b6be","parameter":"Silver","value":"0.5*e(1.72*ln(hardness)-6.52)","unit":"µg/L","direction":"max","kind":"guideline","medium":"surface_water","level":"regional","parameter_key":"cas:7440-22-4","place":["US-CO"],"conditions":["receiving_water is freshwater","a segment whose standards adopt the table value standards (TVS) of Table III (segment tables in Regulations 32 to 38)","segments classified for aquatic life","hardness-dependent: the cell's equation of the hardness (mg/L CaCO3, at most 400; Table III footnote 3); Table IV works it at set hardness"],"cite":{"instrument":"us_co_wqs","title":"Colorado Regulation No. 31 (5 CCR 1002-31) Basic Standards and Methodologies for Surface Water: Table B organic chemicals, Table III metals, Table IV metals at selected hardness","issuer":"State of Colorado, Water Quality Control Commission (Department of Public Health and 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values of the Table III equations, footnote 1)"],"cite":{"instrument":"us_co_wqs","title":"Colorado Regulation No. 31 (5 CCR 1002-31) Basic Standards and Methodologies for Surface Water: Table B organic chemicals, Table III metals, Table IV metals at selected hardness","issuer":"State of Colorado, Water Quality Control Commission (Department of Public Health and Environment)","edition":"5 CCR 1002-31 effective December 31, 2024 (adopted August 21, 2024), the Secretary of State's official PDF; US EPA posts the same compilation in effect for CWA purposes (cover January 28, 2025: no action on the phased TN/TP provisions only)","source_url":"https://www.coloradosos.gov/CCR/GenerateRulePdf.do?ruleVersionId=11749&fileName=5%20CCR%201002-31","source_sha256":"af2f5ee73f74fa7f1cb168059b88977c13a07369665f6dc9b96633ff189855f9","fetched_at":"2026-10-14","source_status":{"checked":"2026-10-15","status":"unchanged"},"section":"5 CCR 1002-31 31.16 Table 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0.164 0.068"}},{"id":"01807f84ca347258","parameter":"Silver","value":"0.068","value_num":0.068,"unit":"mg/troy ounce of silver reduced in solution","statistic":"monthly_avg","direction":"max","kind":"limit","medium":"water_discharge","level":"national","route":"direct","parameter_key":"cas:7440-22-4","place":["US"],"conditions":["route is direct","cites is 40 CFR 421","the discharge is of the Subpart W—Primary Precious Metals and Mercury Subcategory","existing sources (BPT)","(b) Silver chloride reduction spent solution.","table: BPT Limitations for the Primary Precious Metals and Mercury Subcategory"],"cite":{"instrument":"us_40cfr421","title":"40 CFR Part 421 — PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY","issuer":"U.S. Environmental Protection Agency","edition":"eCFR as of 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air pollution control.","table: BPT Limitations for the Primary Precious Metals and Mercury Subcategory"],"cite":{"instrument":"us_40cfr421","title":"40 CFR Part 421 — PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY","issuer":"U.S. Environmental Protection Agency","edition":"eCFR as of 2026-10-05","source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-10-05/title-40.xml?part=421","source_sha256":"d7cfd73b5bcf0e961e02ec53264492b2371277280003192841b7166b2a5012cf","fetched_at":"2026-10-09","source_status":{"checked":"2026-10-15","status":"unchanged"},"section":"40 CFR 421.252 (BPT)","page":null,"quote":"Silver 81.180 33.660"}},{"id":"f218ef047d36e3f5","parameter":"Silver","value":"0.021","value_num":0.021,"unit":"mg/troy ounce of silver in electrolyte produced","statistic":"daily_max","direction":"max","kind":"limit","medium":"water_discharge","level":"national","route":"direct","parameter_key":"cas:7440-22-4","place":["US"],"conditions":["route is direct","cites is 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