Sewage sludge toxicity in edaphic organism: Analysis of midgut responses in the diplopodRhinocricus padbergi

Abstract

Diplopods are agile saprophagous invertebrates with the ability to colonize several soil layers. They feed on waste and decaying organic matter, making the soil in which they are present better aerated and mineral-enriched. Because of their habits, diplopods have been suggested to be used in studies to analyze possible toxic effects of impacted soils in edafic fauna. In that respect, this study aimed at checking the feasibility of using morphological analysis from millipede's midgut as a biomarker for soils exposed to sewage sludge from sewage treatment plants. Histological and histochemical techniques, applied to the species Rhinocricus padbergi's midgut, were used. Two sewage sludge samples were used; they were collected in two small towns in the countryside of São Paulo State. Both cities are part of the Piracicaba-Capivari-Jundiaí basin (PCJ-1 and PCJ-3). For 7 and 15-day periods, the animals were exposed to 10% concentrations and crude sludge for the PCJ-1sample and to 1, 10, and 50% concentrations and sludge for the PCJ-3 sample. The material exposed to the PCJ-1 sample showed an increase in the presence of cytoplasmic granules in both concentrations in all periods and a slight increase in the rate of epithelial renewal. The material of PCJ-3 sample presented the same alterations observed in PCJ-1 sample in higher frequence and over that high quantity of neutral polysaccharides in the hepatic cells layer. We can conclude that with the increase of sewage sludge concentrations tested, there is an increase in morphophysiologicals alterations frequencies found in the diplopods' midgut.

Structure of the midgut epithelium in four diplopod species: histology, histochemistry and ultrastructure

“…It is worth mentioning that the material synthesized in the cytoplasm of digestive cells is transferred to the hepatic cells which surround the midgut epithelium (Hubert 1988;Godoy and Fontanetti 2010;Nogarol and Fontanetti 2011;Nardi et al 2016;Rost-Roszkowska et al 2018b). Monosaccharides and polysaccharides are transported to the hepatic cells, where they are accumulated as glycogen granules, which explains the fact that glycogen has not been detected in the cytoplasm of digestive cells (Hubert 1978;Bozzatto and Fontanetti 2012;Rost-Roszkowska et al 2018b). The reserve material, mainly lipids and glycolipids, accumulated in the cytoplasm of the digestive cells or even in hepatic cells, could be utilized due to autophagy, the pathway of lipid metabolism through the lysosomal degradative pathway of autophagy (Liu and Czaja 2013).…”

“…As has been described in arthropods, the regenerative cells will take over specific functions to regenerate/self-repair epithelium damaged by any type of cell death (autophagy, apoptosis and/ or necrosis) (Bonelli et al 2019;Franzetti et al 2016;Bruno et al 2019;Caccia et al 2019;Tettamanti et al 2019). In the millipede, the regenerative cells have also been described as cells that could replace damaged parts in the midgut epithelium (Godoy and Fontanetti 2010;Souza and Fontanetti 2011;Bozzatto and Fontanetti 2012;Christofoletti et al 2012;Fontanetti et al 2015;Rost-Roszkowska et al 2018a. Because of the fact that midgut regenerative cells of arthropods, e.g.…”

Toxicity evaluation of vinasse and biosolid samples in diplopod midgut: heat shock protein in situ localization

“…The success of the Brazilian millipede species R. padbergi in the evaluation of toxicity of complex substances was attested by several studies using different concentrations of vinasse (Christofoletti et al 2016), sewage sludge (Nogarol and Fontanetti 2010;Godoy and Fontanetti 2010;Perez and Fontanetti 2011;Bozzatto and Fontanetti 2012), landfarming soil originated from oil refinery (Souza and Fontanetti 2011), and the herbicide trifluralin (Merlini et al 2012). Thus, this organism proved to be an excellent bioindicator to evaluate soil quality (Souza and Fontanetti 2011;Souza et al 2014).…”

Diplopods as Soil Bioindicators of Toxicity After Application of Residues From Sewage Treatment Plants and Ethanol Industry

“…Diplopods are important cosmopolitan soil macroinvertebrates capable of colonizing different soil layers, and act as decomposers (Petersen & Luxton, 1982). Because of these traits and the responsiveness of their tissues as biomarkers (Fontanetti et al, 2011), diplopods have been successfully used as bioindicators of soil quality (Godoy & Fontanetti, 2010; Nogarol & Fontanetti, 2010, 2011; Perez & Fontanetti, 2011 a ; Souza & Fontanetti, 2011; Bozzatto & Fontanetti, 2012; Christofoletti et al, 2012; Souza et al, 2014).…”