title: Perchlorate uptake in spinach as related to perchlorate, nitrate, and chloride concentrations in irrigation water.
abstract: Several studies have reported on the detection of perchlorate (ClO(4)(-)) in edible leafy vegetables irrigated with Colorado River water. However, there is no information on spinach as related to ClO(4)(-) in irrigation water nor on the effect of other anions on ClO(4)(-) uptake. A greenhouse ClO(4)(-) uptake experiment using spinach was conducted to investigate the impact of presence of chloride (Cl(-)) and nitrate (NO(3)(-)) on ClO(4)(-) uptake under controlled conditions. We examined three concentrations of ClO(4)(-), 40, 220, and 400 nmol(c)/L (nanomoles of charge per liter of solution), three concentrations of Cl(-), 2.5, 13.75, and 25 mmol(c)/L, and NO(3)(-) at 2, 11, and 20 mmol(c)/L. The results revealed that ClO(4)(-) was taken up the most when NO(3)(-) and Cl(-) were lowest in concentration in irrigation water. More ClO(4)(-) was detected in spinach leaves than that in the root tissue. Relative to lettuces, spinach accumulated more ClO(4)(-) in the plant tissue. Perchlorate was accumulated in spinach leaves more than reported for outer leaves of lettuce at 40 nmol(c)/L of ClO(4)(-) in irrigation water. The results also provided evidence that spinach selectively took up ClO(4)(-) relative to Cl(-). We developed a predictive model to describe the ClO(4)(-) concentration in spinach as related to the Cl(-), NO(3)(-), and ClO(4)(-) concentration in irrigation water.
authors.affiliation: U.S. Salinity Laboratory, USDA-ARS, 450 W. Big Springs Rd., Riverside, California 92507, United States. Wonsook.Ha@gmail.com
authors.forename: Wonsook
authors.initials: W
authors.lastname: Ha
authors.forename: Donald L
authors.initials: DL
authors.lastname: Suarez
authors.forename: Scott M
authors.initials: SM
authors.lastname: Lesch
mesh_terms: D057914:Agricultural Irrigation; D002712:Chlorides / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D010472:Perchlorates / Q000378:metabolism*; D018724:Spinacia oleracea / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D002712:Chlorides; D009566:Nitrates; D010472:Perchlorates; D014874:Water Pollutants, Chemical; C494474:perchlorate