Perchlorate is Not a Common Contaminant of Fertilizers

Perchlorate consumption can cause mental retardation and tumour formation in humans. Recent suggestions that perchlorate may be present as a contaminant in fertilizers and fertilizer components have caused concern in the fertilizer industry. The present study developed methods for improving the HPLC analysis of perchlorate and used these methods to survey 15 US fertilizers for perchlorate. Extraction with 50 m M NaOH rather than water was found to improve extraction efficiency from 84 to 98%. The incorporation of Ca(HO)₂ into the extraction medium to yield 1 : 0.5 or 1 : 1, SO₄^– : Ca⁺² molar ratios reduced the analytical interference caused by SO₄^–2 by reducing the slope of the SO₄^–2 peak tail by ∼75%. The study found no perchlorate in any of the fertilizers investigated.