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Transport of zinc, copper, and lead in a sewage sludge amended calcareous soil
Author(s) -
Yeganeh M.,
Afyuni M.,
Khoshgoftarmanesh A. H.,
Rezaeinejad Y.,
Schulin R.
Publication year - 2010
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/j.1475-2743.2010.00270.x
Subject(s) - sewage sludge , calcareous , organic matter , subsoil , environmental science , agronomy , soil structure , leaching (pedology) , soil organic matter , sewage , chemistry , environmental chemistry , soil water , environmental engineering , soil science , geology , organic chemistry , paleontology , biology
The application of sewage sludge on farmland is practised in many countries since sludge is rich in macro‐ and micro‐ nutrients. However, increasing use of sewage sludge on farmland has raised concerns about the potential transport of heavy metals into food chains and groundwater. This study determined for a calcareous soil the effects of sludge application on soil physical properties and transport of zinc (Zn), copper (Cu), and lead (Pb). Secondary anaerobic digested sewage sludge was applied at rates of 0, 25, 50, and 100 t/ha (on a dried weight basis) for four consecutive years and mixed in the top 20‐cm of soil. Corn ( Zea mays L.) was planted as a spring crop, followed by wheat ( Triticum aestivum ) as a winter crop. Sludge application increased the dissolved organic matter content and modified the soil structure, increased the soil infiltration rate, saturated hydraulic conductivity, and aggregate stability, and decreased the bulk density. Sludge application greatly increased DTPA (diethylenetriamine pentaacetic acid)‐extractable soil metal concentrations to 50 cm depth and significantly to 1 m. In the plots that received four application of 100 t/ha sewage sludge, the mean concentrations of Zn, Cu, and Pb in subsoil increased by 1600, 7, and 4.5 times, respectively, compared with the control. The results indicate that a combination of enhanced soil physical properties, heavy and inefficient irrigation and high organic matter content with heavy metals cause significant metal mobility. High sludge applications pose risks of groundwater and food chain contamination and rates are best restricted to those reflecting the nutrient demand of crops (20 t/ha every 4 to 5 yr or an average of 4 to 5 t/ha/yr).