Effects of sewage sludge on the growth of coffea arabica seedlings and cell cycle of Allium cepa

Resumo

Sewage sludge can contain toxic compounds and pathogens therefore it agronomic use must occur in a safer way to the population and environment. The objective of this study was to investigate the effects of substrates containing different proportions of sanitized sewage sludge in the growth of Coffea Arabica seedlings and to verify the cytogenotoxic potential of these substrates using the analysis of Allium cepa cell cycle. The substrate with the lowest proportion of sewage sludge (15%) was the one that obtained the greatest growth performance and did not present cytogenotoxic activity. Substrates with the highest concentrations of sanitized sewage sludge (30, 45 e 60%) were toxics. For coffee seedlings, all the growth variables decreased and the significant induction of aberrant meristematic cells in A. cepa was observed. However, the sewage toxicity was not related to the presence of metals, whose levels were within the maximum limits allowed by the Brazilian legislation, indicating that these biological tests are essential for the determination of the quality of sewages before their agricultural use.