- Zinc DTPA, or zinc diethylenetriaminepentaacetate, is a chelated form of zinc in which a zinc ion (Zn²⁺) is tightly bound to DTPA (diethylenetriaminepentaacetic acid)—a powerful polyaminocarboxylic acid chelating agent. It is typically encountered as a white or off-white crystalline powder or granular solid that is highly soluble in water. The DTPA molecule coordinates the zinc ion through multiple nitrogen and oxygen donor atoms, forming a highly stable hexa- or heptadentate complex. This configuration ensures strong metal-ligand binding and high chemical stability, especially under a wide range of pH conditions.
- Zinc DTPA is widely used in agriculture, particularly as a micronutrient fertilizer in soils with high pH or high calcium content, where free zinc ions tend to become insoluble and unavailable to plants. The DTPA chelation protects the zinc ion from precipitation and fixation, maintaining it in a plant-absorbable form. Compared to other chelates like EDTA or EDDHA, DTPA offers superior performance in moderately alkaline soils, typically up to pH 7.5–8.0, making it suitable for hydroponic systems, foliar feeding, and fertigation practices.
- In medicine and radiopharmaceuticals, DTPA-based chelating agents, including zinc DTPA, have been used in chelation therapy, especially for the removal of radioactive isotopes and heavy metals such as plutonium, americium, or lead from the human body. While the calcium or sodium salts of DTPA are more commonly employed for this purpose, zinc DTPA may be used when it is necessary to avoid depleting essential metal ions like zinc during treatment. In this context, zinc DTPA acts as a detoxifying agent that binds toxic metal ions while sparing endogenous zinc levels, thereby minimizing metabolic disruptions.
- Zinc DTPA also finds application in industrial and analytical chemistry as a metal ion stabilizer and buffering agent. In water treatment, it is used to control metal ion concentrations in cooling systems, preventing scaling and corrosion. In cosmetics and personal care products, it may serve as a metal scavenger, improving product stability by neutralizing trace metal contaminants that could otherwise degrade active ingredients.
- While zinc DTPA is generally considered non-toxic and environmentally stable when used appropriately, its high stability and persistence in aquatic environments raise ecotoxicological concerns. If released into water systems, it can increase the mobility of heavy metals by forming soluble complexes, which may lead to unintentional environmental contamination. As such, its industrial and agricultural use is regulated in many regions to minimize ecological risk.
