Outdoor & Yard / Compounds / Copper sulfate pentahydrate

Copper sulfate pentahydrate in the yard and garden

Elevated risk for your yard

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Copper sulfate pentahydrate is the most common commercial hydrated form of copper(II) sulfate (distinct from the anhydrous form catalogued as hq-c-ino-000073). Used as an aquarium ich (Ichthyophthirius multifiliis) and external parasite treatment at carefully metered doses (typically 0.15-0.20 mg/L free Cu²⁺), as an algicide in ponds and reservoirs (legal, regulated), as a fungicide in vineyards (Bordeaux mixture, with hydrated lime), and as a feed micronutrient. Acutely toxic to invertebrate aquatic life — kills snails, shrimp, and most freshwater invertebrates at therapeutic fish doses. Chronically toxic to scaleless fish (catfish, loaches, tetras with thin scales) at standard doses; species-specific dose adjustment required. Wilson's disease patients are extremely vulnerable — hepatic copper accumulation. Acute oral ingestion: vomiting (cuproprotectant emetic effect), gastritis, hemolytic anemia, hepatotoxicity at large doses; fatal at ~10-20 g for adults. Aqueous solutions are corrosive to copper-incompatible metals (galvanized iron, aluminum). Bordeaux-mixture vineyard residues are an established environmental contamination concern in wine-growing regions; soil copper accumulation persists for decades.

What is copper sulfate pentahydrate?

The IUPAC name is copper(2+) sulfate pentahydrate.

Also known as: Cupric sulfate pentahydrate, Blue vitriol, Bluestone, Roman vitriol.

IUPAC name
copper(2+) sulfate pentahydrate
CAS number
7758-99-8
Molecular formula
CuO9S.5H2O
Molecular weight
249.69 g/mol
SMILES
[Cu+2].[O-]S(=O)(=O)[O-].O.O.O.O.O
PubChem CID
24463

Risk for people, pets,

Elevated risk

Copper sulfate pentahydrate is the most common commercial hydrated form of copper(II) sulfate (distinct from the anhydrous form catalogued as hq-c-ino-000073). Used as an aquarium ich (Ichthyophthirius multifiliis) and external parasite treatment at carefully metered doses (typically 0.15-0.20 mg/L free Cu²⁺), as an algicide in ponds and reservoirs (legal, regulated), as a fungicide in vineyards (Bordeaux mixture, with hydrated lime), and as a feed micronutrient. Acutely toxic to invertebrate aquatic life — kills snails, shrimp, and most freshwater invertebrates at therapeutic fish doses. Chronically toxic to scaleless fish (catfish, loaches, tetras with thin scales) at standard doses; species-specific dose adjustment required. Wilson's disease patients are extremely vulnerable — hepatic copper accumulation. Acute oral ingestion: vomiting (cuproprotectant emetic effect), gastritis, hemolytic anemia, hepatotoxicity at large doses; fatal at ~10-20 g for adults. Aqueous solutions are corrosive to copper-incompatible metals (galvanized iron, aluminum). Bordeaux-mixture vineyard residues are an established environmental contamination concern in wine-growing regions; soil copper accumulation persists for decades.

Regulatory consensus

1 regulatory bodyhas classified Copper sulfate pentahydrate.

AgencyYearClassificationNotes
Unknown

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where your yard encounter copper sulfate pentahydrate

  • Aquarium Water Treatment
  • Agricultural Fungicide
  • Algicide
  • Animal Feed

Frequently asked questions

Is copper sulfate pentahydrate safe for your yard?

Copper sulfate pentahydrate is the most common commercial hydrated form of copper(II) sulfate (distinct from the anhydrous form catalogued as hq-c-ino-000073). Used as an aquarium ich (Ichthyophthirius multifiliis) and external parasite treatment at carefully metered doses (typically 0.15-0.20 mg/L free Cu²⁺), as an algicide in ponds and reservoirs (legal, regulated), as a fungicide in vineyards (Bordeaux mixture, with hydrated lime), and as a feed micronutrient. Acutely toxic to invertebrate aquatic life — kills snails, shrimp, and most freshwater invertebrates at therapeutic fish doses. Chronically toxic to scaleless fish (catfish, loaches, tetras with thin scales) at standard doses; species-specific dose adjustment required. Wilson's disease patients are extremely vulnerable — hepatic copper accumulation. Acute oral ingestion: vomiting (cuproprotectant emetic effect), gastritis, hemolytic anemia, hepatotoxicity at large doses; fatal at ~10-20 g for adults. Aqueous solutions are corrosive to copper-incompatible metals (galvanized iron, aluminum). Bordeaux-mixture vineyard residues are an established environmental contamination concern in wine-growing regions; soil copper accumulation persists for decades.

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Sources (2)

  1. PubChem (2026) — database
  2. ALETHEIA Phase 62 compound mini-batch — Phase 54/55 product prerequisites (continuation of Phase 59) (2026) — batch_creation

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →