Subchronic toxicity evaluation of a treated urban sewage sludge.
Disposal of tons of sludge produced daily by sewage treatment plants in large cities is a serious problem. Because recycling and application in agriculture have been proposed, the Brazilian National Environmental Council (CONAMA, 2006) issued a legal norm that regulates the use of the sewage sludge (SS) in crops. Due to the complex chemical nature of such products, characterization by analytical methods for health and environmental risk assessment has severe limitations. To overcome such limitations, it is necessary to (1) assess the toxicological potential of SS and (2) identify possible adverse effects in vivo in order to provide critical information for future environmental regulations. The present study was conducted to determine the potential toxicity of SS obtained from a representative urban treatment plant located in the Sao Paulo State, Brazil. Male and female Wistar rats were fed ad libitum a pelleted diet containing varying amounts of SS. No relevant clinical, hematological, urinary, or gross organ morphological alterations were observed in both genders of rats orally exposed to SS at up to 3.8 g/kg/d for 90 d. Sewage slude produced increased incidence of centrilobular hepatocyte hyperplasia at the high dose and significantly increased aspartate aminotransferease (AST) activities at all doses in both genders. Although the present data indicate some liver involvement, these alterations were considered adaptative and not toxicologically relevant, as the responses were relatively mild, not dose dependent, and no other parameters were markedly affected. The present results may contribute to the establishment of protocols for potential usage in SS agricultural soil application.
Francisco Lozano Luvizutto
João
J
Center for the Evaluation of the Environmental Impact of Human Health, Department of Pathology, Botucatu Medical School, UNESP-Sao Paulo State University, Sao Paulo, Brazil.
de Lourdes Marzo Solano
Marize
M
Passareli
Daniele
D
Adriene da Silva Franchi
Carla
C
de Aragão Umbuzeiro
Gisela
G
Lauro Viana de Camargo
João
J
D000818:Animals; D001938:Brazil; D056486:Chemical and Drug Induced Liver Injury / Q000209:etiology* / Q000473:pathology; D005260:Female; D022781:Hepatocytes / Q000187:drug effects*; D006965:Hyperplasia / Q000139:chemically induced*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012722:Sewage / Q000009:adverse effects*; D014505:Urban Population
D012722:Sewage