Leachable

Leachable is an adjective describing a substance or material that can be dissolved and transported out of a solid into a liquid under certain conditions. The degree of leachability depends on chemical properties, the nature of the solvent, temperature, contact time, and the physical characteristics of the material. The liquid that results from leaching is called leachate.

In soil and environmental science, leachability refers to how water can mobilize nutrients, salts, pesticides, metals, or organic contaminants from soils, wastes, or geological materials. Leachate can affect groundwater quality and surface waters, making leachability a key factor in risk assessments and waste management. Leaching tests, such as percolation tests or standardized procedures, are used to estimate potential leaching under simulated environmental conditions.

In pharmaceuticals and packaging, leachables are chemical species that migrate from packaging, closures, or manufacturing surfaces into a drug product. These substances can originate from polymers, adhesives, coatings, or residual processing additives. Regulatory guidance calls for identifying, characterizing, and controlling leachables to ensure product safety, including risk assessment and appropriate testing throughout the product lifecycle.

In mining and metallurgy, leaching describes processes that dissolve valuable metals from ore into a solvent, enabling extraction and recovery. Common approaches include heap or tank leaching using acids or cyanide solutions, with leachability dependent on ore chemistry, particle size, and process conditions.

Measurement and regulation often rely on standardized leaching tests, such as the Toxicity Characteristic Leaching Procedure (TCLP) or the Synthetic Precipitation Leaching Procedure (SPLP), to classify wastes or assess environmental and product safety implications.