Extractable soil heavy metals following the cessation of biosolids application to agricultural soil
Changes in soil heavy metal extractability following the cessation of biosolids applications were studied in a long-term field experiment. Two anaerobically digested biosolids from wastewater treatment plants in Madrid (Sur and Viveros) were applied to cropland from 1983 to 1990. Soil samples were collected in the 1st, 5th and 9th year after the last biosolids application. Soil pH did not vary significantly after biosolids applications. Organic matter and total heavy metals (Zn, Pb, Cd, Ni, Cr and Cu) concentrations initially increased but then declined over time, mostly after the first 5 years following biosolids application. Metal extracted with DPTA increased in Sur treatments during the 1st year and diminished thereafter. However, in Viveros treatments, heavy metals extracted increased during the 1st year, declined in 1995, and showed a slight increase in 1999. These changes in heavy metal extractability were widely observed in the percentage of extractable metal recovery (EMR). The differences observed in the pattern of the two sources of biosolids applied could be due to the different rates of decomposition of their organic matter. © 2002 Elsevier Science Ltd. All rights reserved.
| Main Authors: | , , , , |
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| Format: | journal article biblioteca |
| Language: | English |
| Published: |
Elsevier
2002
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| Subjects: | Long-term experiment, Biosolids, Organic matter, Total heavy metals, Extractable heavy metals, |
| Online Access: | http://hdl.handle.net/20.500.12792/5558 http://hdl.handle.net/10261/295057 |
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