Indication of metal homeostasis disturbance in earthworm Eisenia fetida after exposure to semi-solid depot sludge.
Treated sewage sludge is commonly used in agriculture as fertilizer. It is, therefore, necessary to determine possible detrimental influences of sludge application on soil contamination and accumulation of contaminants in tissues of terrestrial animals, which in the long run could also have undesirable effects on humans. With that aim, the study was performed using earthworm Eisenia fetida as test organism and semi-solid depot sludge from a wastewater treatment plant as exposure media. The concentrations of 26 metals/metalloids were determined in depot sludge, and their bioaccumulation was estimated in whole tissue of E. fetida, and for the first time in the soluble tissue fraction, which represents metal fraction available for metabolic requirements and toxic effects. Obtained results have revealed acceptable levels of several elements (Cd, Cr, Cu, Ni, Pb, Zn) in depot sludge, when compared to currently valid regulations, and only moderate accumulation of some elements (e.g. As, Ba, Cd, Co, Fe, Tl, V, and Zn) in earthworms, as a consequence of exposure to depot sludge. However, a concentration increase after exposure to depot sludge was observed in E. fetida for several elements (Cd, Mo, and Zn), which were present in lower concentrations in the exposure mixtures than in soil. Contrary, a concentration decrease was observed for Cs, Mn, and Rb, although they were present in higher concentrations in depot sludge than in soil. It was an indication of disturbance in metal homeostasis in earthworms, possibly caused by exposure to complex mixture of contaminants present in depot sludge. The cumulative effect of exposure to a number of various contaminants (inorganic, organic, microbiological and pharmaceutical), even if each of them was not present in very high concentrations, could have caused distress in earthworms exposed to depot sludge.
Ruđer Bošković Institute, Division of Materials Chemistry, Laboratory for Ichtyopathology - Biological Materials, Zagreb, Croatia.
Sanja
S
Babić
Ruđer Bošković Institute, Division for Marine and Environmental Research, Laboratory for Biological Effects of Metals, Zagreb, Croatia. Electronic address: zdragun@irb.hr.
Zrinka
Z
Dragun
Ruđer Bošković Institute, Division of Materials Chemistry, Laboratory for Ichtyopathology - Biological Materials, Zagreb, Croatia.
Roberta
R
Sauerborn Klobučar
Ruđer Bošković Institute, Division for Marine and Environmental Research, Laboratory for Biological Effects of Metals, Zagreb, Croatia.
Dušica
D
Ivanković
Ruđer Bošković Institute, Division for Marine and Environmental Research, Laboratory for Inorganic Environmental Geochemistry, Zagreb, Croatia.
Niko
N
Bačić
Ruđer Bošković Institute, Division for Marine and Environmental Research, Laboratory for Inorganic Environmental Geochemistry, Zagreb, Croatia.
Željka
Ž
Fiket
Ruđer Bošković Institute, Division of Materials Chemistry, Laboratory for Ichtyopathology - Biological Materials, Zagreb, Croatia.
Josip
J
Barišić
Ruđer Bošković Institute, Division for Marine and Environmental Research, Laboratory for Biological Effects of Metals, Zagreb, Croatia.
Nesrete
N
Krasnići
Ruđer Bošković Institute, Division of Materials Chemistry, Laboratory for Ichtyopathology - Biological Materials, Zagreb, Croatia.
Ivančica
I
Strunjak-Perović
Ruđer Bošković Institute, Division of Materials Chemistry, Laboratory for Ichtyopathology - Biological Materials, Zagreb, Croatia.
Natalija
N
Topić Popović
Ruđer Bošković Institute, Division of Materials Chemistry, Laboratory for Ichtyopathology - Biological Materials, Zagreb, Croatia.
Rozelindra
R
Čož-Rakovac
D000383:Agriculture / Q000379:methods; D000818:Animals; D004784:Environmental Monitoring; D005308:Fertilizers; D006706:Homeostasis; D008670:Metals / Q000378:metabolism*; D009835:Oligochaeta / Q000378:metabolism*; D012722:Sewage; D012989:Soil Pollutants / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods
D005308:Fertilizers; D008670:Metals; D012722:Sewage; D012989:Soil Pollutants
Earthworms; Metal bioaccumulation; Metals in soluble tissue fraction; Semi-solid depot sludge; Soil metal contamination