Stable isotopic composition of perchlorate and nitrate accumulated in plants: Hydroponic experiments and field data
[4];
[1];
- Texas Tech Univ., Lubbock, TX (United States). Dept. of Civil, Environmental, and Construction Engineering
- U.S. Geological Survey, Reston, VA (United States). National Research Program
- Univ. of Delaware, Newark, DE (United States). Dept. of Geological Sciences
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division
- U.S. Air Force, Wright-Patterson AFB, OH (United States)
- North Carolina State Univ., Raleigh, NC (United States). USDA Agricultural Research Service
- Univ. of California, Riverside, CA (United States). Kearney Agricultural Center, Dept. of Botany and Plant Sciences
- Cornell Univ., Riverhead, NY (United States). Long Island Horticultural Research and Extension Center, Plant Pathology & Plant-Microbe Biology Section
- The Inst. of Environmental and Human Health (TIEHH), Lubbock, TX (United States). Dept. of Environmental Toxicology
- CB&I Federal Services, Lawrenceville, NJ (United States)
Natural perchlorate (ClO4-) in soil and groundwater exhibits a wide range in stable isotopic compositions (δ37Cl, δ18O, and Δ17O), indicating that ClO4- may be formed through more than one pathway and/or undergoes post-depositional isotopic alteration. Plants are known to accumulate ClO4-, but little is known about their ability to alter its isotopic composition. We examined the potential for plants to alter the isotopic composition of ClO4- in hydroponic and field experiments conducted with snap beans (Phaseolus vulgaris L.). In hydroponic studies, anion ratios indicated that ClO4- was transported from solutions into plants similarly to NO3- but preferentially to Cl- (4-fold). The ClO4- isotopic compositions of initial ClO4- reagents, final growth solutions, and aqueous extracts from plant tissues were essentially indistinguishable, indicating no significant isotope effects during ClO4- uptake or accumulation. The ClO4- isotopic composition of field-grown snap beans was also consistent with that of ClO4- in varying proportions from irrigation water and precipitation. NO3- uptake had little or no effect on NO3- isotopic compositions in hydroponic solutions. However, a large fractionation effect with an apparent ε (15N/18O) ratio of 1.05 was observed between NO3- in hydroponic solutions and leaf extracts, consistent with partial NO3- reduction during assimilation within plant tissue. We also explored the feasibility of evaluating sources of ClO4- in commercial produce, as illustrated by spinach, for which the ClO4- isotopic composition was similar to that of indigenous natural ClO4-. Our results indicate that some types of plants can accumulate and (presumably) release ClO4- to soil and groundwater without altering its isotopic characteristics. Lastly, concentrations and isotopic compositions of ClO4-and NO3- in plants may be useful for determining sources of fertilizers and sources of ClO4- in their growth environments and consequently in food supplies.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1394544
- Journal Information:
- Science of the Total Environment, Vol. 595, Issue C; ISSN 0048-9697
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
Similar Records
Origin of the isotopic composition of natural perchlorate: Experimental results for the impact of reaction pathway and initial ClOx reactant
SEMIANNUAL PROGRESS REPORT FOR THE PERIOD ENDING JUNE 30, 1960