Effects of sewage sludge application on unfertile tropical soils evaluated by multiple approaches: A field experiment in a commercial Eucalyptus plantation

• Published in: The Science of the total environment Vol. 655; pp. 1457 - 1467
• Main Authors: Abreu-Junior, Cassio Hamilton, de Lima Brossi, Maria Julia, Monteiro, Regina Teresa, Cardoso, Paulo Henrique Silveira, da Silva Mandu, Thays, Nogueira, Thiago Assis Rodrigues, Ganga, Antonio, Filzmoser, Peter, de Oliveira, Fernando Carvalho, Firme, Lucia Pittol, He, Zhenli, Capra, Gian Franco
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 10.03.2019
• Subjects: Bioassay; Ecotoxicological tests; Eucalyptus - drug effects; Eucalyptus - growth & development; Eucalyptus - physiology; Fertilizers - analysis; Forestry; Multivariate statistics; Potentially toxic elements; Sewage - adverse effects; Soil - chemistry; Soil Pollutants - toxicity; Bioassay; Multivariate statistics; Ecotoxicological tests; Potentially toxic elements
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.11.334

Sewage sludge (SS) reuse in forest plantation as soil fertilizer/amendment has tremendously increased in recent years. However, SS may have high concentrations of potentially toxic elements (PTE), representing a potential risk for soil and the whole ecosystem. This paper was aimed to assess the toxicity of PTE in unfertile tropical soils amended with SS in a commercial Eucalyptus plantation, with an integrated multiple approaches combining: i) the use of a battery of bioassays (Daphnia magna, Pseudokcrichirella subcapitata, Lactuca sativa, and Allium cepa); and ii) the evaluation of some PTE (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and their availability into the pedoenvironment. Differences in total and available PTE between SS doses and time of treatments were evaluated using ANOVA; correlations between PTE and bioassays by a sparse partial robust M-regression (SPRM), while multiple correlations among parameters were performed by principal factor analysis (PFA). Results show that PTE contents in soils tended to increase with SS application doses. However this cannot be assumed as a general rule since in all the investigated treatments the PTE concentrations were consistently below both soil natural background concentrations and quality reference values. Bioassays showed a generalized low eco- and genotoxicity of SS with an increase in toxicity at increasing SS doses but with a clear decreasing trend as time went by. A. cepa was the most sensitive bioassay followed by P. subcapitata > D. magna > L. sativa. Overall, the results indicate that in realistic open field conditions SS risk may be lower than expected due to dynamic decrease in PTE toxicity with time after application. This study has an important implication that open-field trials should be strongly encouraged for evaluating environmental risk of SS application in forestry. [Display omitted] •Sewage sludge (SS) application in forest soils increased considerably in last years.•Toxicity of SS in unfertile tropical soil under Eucalyptus plantation was evaluated.•A battery of bioassays and PTE availability were assessed by a multiple approach.•In realistic open field conditions SS risk may be lower than expected.•Open-field trials should be preferred for evaluating SS toxicity in forestry002E