Heavy metal uptake by some vegetables grown on sewage sludge-treated soils
| dc.contributor.author | Msongaleli, barnabas | |
| dc.date.accessioned | 2026-05-26T15:55:33Z | |
| dc.date.available | 2026-05-26T15:55:33Z | |
| dc.date.issued | 2003 | |
| dc.description | Dissertation | |
| dc.description.abstract | A glasshouse pot experiment was conducted to determine the uptake of heavy metals by Chinese cabbage (Brassica chniensis), lettuce (Lactuca sativa L.) and cowpea {Vigiza unguiculatd) from sewage sludge-treated soils. A sandy loam (pH 6.9) and a loamy sand (pH 7.1) were amended with sewage sludge at rates of 0, 10, 20 and 30 ton/ha (oven-dry weight basis). Total and extractable heavy metals in soils and sludge, plant materials, vegetable heavy metals concentrations and uptake, were determined. Results on characterization of the soils and the sludge indicated that the soils contained small amounts of heavy metals, thus having a low potential for causing pollution and the sludge had elevated levels of heavy metals. Amendment with sewage sludge significantly (P=0.05) increased the yields of all vegetables. ry.y • 1 ; —F Chinese cabbage dry matter yields ranged from 3.34 to 15.89 and 9.83 to 17.09 g/plant for Msimbazi and Mjimpya soils, respectively. For lettuce they ranged from 3.43 to 14.29 and 6.69 to 13.63 g/plant for Msimbazi and Mjimpya soils, respectively, while for cowpea they ranged from 5.89 to 15.74 and 13.77 to 19.94 g/plant for Msimbazi and Mjimpya soils, respectively. The highest yields were observed with applications of sewage sludge at 30 ton/ha. The analysis of the edible parts of vegetables for heavy metals revealed higher uptake of Cd, Cu and Zn by all vegetable species with increased rates of sewage sludge application. The uptake of Pb and Cr by the vegetables was low and not consistent with the rates of sewage sludge application. There were, significant differences between the uptake of heavy metals by the different vegetable species. DTPA-extractable Cu and Zn concentrations in post-harvest soil increased significantly with sewage sludge application rate. However, the increase of DTPA-extractable Pb and Cd was not consistent with the rates of application of sewage sludge. Chromium was not detected in the post harvest soil. Vegetables grown in amended soils showed higher N and P concentrations than control plants. The results indicate that there should be close monitoring over the use of the sludge for edible crop production. | |
| dc.description.sponsorship | Norwegian Agency for Development Co operation (NORAD) | |
| dc.identifier.uri | https://www.suaire.sua.ac.tz/handle/20.500.14820/7609 | |
| dc.language.iso | en | |
| dc.publisher | Sokoine University of Agriculture | |
| dc.subject | Heavy metal | |
| dc.subject | vegetables grown | |
| dc.subject | reated soils | |
| dc.subject | contol plant | |
| dc.title | Heavy metal uptake by some vegetables grown on sewage sludge-treated soils | |
| dc.type | Thesis |