Comment on Perchlorate Identification in FertilizersŽ and the Subsequent Addition Correction

°Correspondencekeep statistics on fertilizer application by N-P-K ratio,Comment on “Perchlorate Identification inbutthere is usually not a breakdown into individual com-Fertilizers” and the Subsequent Addition/ ponents. Therefore, even if some fertilizers contain perchlo-rate, it is difficult to correlate fertilizer consumption andCorrectionapplication with exposure risk. For example, the Office ofthe Indiana State Chemist (OISC) tracks of the- top 10 fertilizers semi-annually by N-P-K ratio per county.SIR: Perchlorate (ClO ) contamination has been reported4Some single component formulations are tracked, such asin several fertilizer materials (1, 2) and not just in mined82-0-0 (NH ) and 46-0-0 (urea). Multiple componentChile saltpeter, where it is a well-known natural impurity 3formulations are also tracked, but the compounds providing(3). To survey fertilizers for perchlorate, two analyticaleach nutrient are not tracked. The OISC reported that Indianatechniques have been applied to 45 products that spanfarmers applied 48 478 tons of urea and 193 347 tons ofagricultural, horticultural, and retail markets, includinganhydrous ammonia in 1998 (7), neither of which isseveral lots for some (see Supporting Information for details).contaminated with perchlorate. Fertilizer application toOn the basis of the results presented here, it appears thatfamily gardens and lawns is not monitored at all in Indiana,fertilizers are not significant contributors to ...