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Cadmium and Zinc Availability to Corn following Termination of Sewage Sludge Applications
Author(s) -
Bidwell A. M.,
Dowdy R. H.
Publication year - 1987
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1987.00472425001600040025x
Subject(s) - stover , cadmium , sewage sludge , corn stover , loam , zinc , zoology , chemistry , agronomy , environmental chemistry , sewage , soil water , environmental science , environmental engineering , field experiment , biology , food science , soil science , organic chemistry , fermentation
To assess the availability of sludge‐borne Cd and Zn over time, corn ( Zea mays L.) and soil (Typic Hapludoll silt loam) were sampled for 6 yr following termination of three annual applications of sewage sludge. Cumulative sludge applications totaled 0, 60, 120, and 180 Mg ha −1 . Sludge treatments consistently resulted in greater Cd and Zn accumulation in stover than did the control treatment for each of the 6 yr following the final sludge application. Cadmium and Zn concentration in stover increased linearly within treatment levels for all years. Concentrations of Cr, Cu, Ni, and Pb in stover and grain fluctuated annually, with no predictable effect of sludge rate. Of the metals measured in stover and grain, only stover Cd exceeded the suggested National Research Council tolerance level of 0.5 mg kg −1 in animal feed for all sludge treatments in all years. Cadmium uptake decreased over time at all sludge rates, and was inversely related ( P > 0.01) to time in years following terminal application. Zinc uptake declined slightly over time, although not to the same degree or with the same predictability as Cd uptake. Soil Cd and Zn extractable with DTPA and 1 M HNO 3 were highly correlated with plant metal uptake within years. However, metal uptake diminished with consecutive croppings for constant levels of extractable Cd and Zn. Hence, the reliability of either DTPA or 1 M HNO 3 in the prediction of Cd and Zn uptake in subsequent croppings is questionable.