Effects of Sewage Sludge on Di‐(2‐Ethylhexyl) Phthalate Uptake by Plants

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Abstract
Di‐(2‐ethylhexyl) phthalate (DEHP) is a priority organic pollutant frequently found in municipal sludges. A greenhouse study was conducted to determine the effects of sludge on plant uptake of 14C‐DEHP (carbonyl labeled). Plants grown included three food chain crops, lettuce (Lactuca sativa L.), carrot (Daucus carota L.), and chile pepper (Capsicum annuum L.) and tall fescue (Festuca arundinacea Schreb.) Net 14C concentration in plants grown in soil amended with 14C‐DEHP‐contaminated sludge was independent of sludge rate (at the same DEHP loading) for lettuce, chile fruit, and carrot roots. Net 14C concentration, however, was inversely related to sludge rate in carrot tops, fescue, and chile plants. Intact DEHP was not detected in plants by gas chromatography/mass spectrometry analysis. Calculated plant DEHP concentrations (based on measured net 14C concentrations and DEHP specific activities) were generally correlated better with DEHP soil solution concentrations than with total DEHP soil concentrations. Net 14C‐DEHP bioconcentration factors were calculated from initial soil DEHP concentration and plant fresh weights. Bioconcentration factors ranged from 0.01 to 0.03 for fescue, lettuce, carrots, and chile, suggesting little DEHP uptake. Additionally, because intact DEHP was not detected in any plants, DEHP uptake by plants was of minor importance and would not limit sludge additions to soils used to grow these crops.
Funding Information
  • Cooperative Agreement (CR-812687-02)