ISSN:
1365-2494
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
In the short term, surface-applied, digested, liquid sewage sludge may remain on grass leaf surfaces, leading to enhanced direct intake of potentially toxic elements by stock. The purpose of this field experiment was to investigate metal adhesion to herbage from liquid sewage sludge applications. Liquid digested sludge was applied at 0, 55 or 110 m3 ha−1 to an Agrostis capillaris and Holcus lanatus sward that had been cut to either 4 cm (short) or 13 cm (long). The application rate of metals was relatively low. One day after application (day 1), 8–13% of the sludge solids applied had adhered to the short grass treatment, accounting for 35–62% of the dry-matter (DM) yield. On the long grass, 20–42% of the sludge dry solids adhered, accounting for 46–47% of the herbage DM yield. The content of all heavy metals in and on the grass herbage (Cu, Fe, Ni, Pb, Zn, Cr, Cd) was significantly increased (P 〈 0·05) at day 1. Cu concentrations in and on the grass decreased to 25 mg kg−1 after 16–29 d, Fe took 33–45 d to decline to 1000 mg kg−1 whereas Pb took 12–18 d to decline to 30 mg kg−1. It took 36 d for Cd, 43 d for Fe, Cu and Ni, and 57 d for Zn and Pb to be not significantly (P 〈 0·05) different from the control. Grass growth was the most significant factor(P 〈 0·05 for all treatments and metals) influencing the decline in grass metal concentration, explaining 65–96% of the variation. The cutting treatment, sludge application rate and metal species also significantly affected the extent and rate of reduction in metal contamination over time.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1365-2494.1997.00056.x
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