Use of Rattus norvegicus as biomonitor of environmental contamination by lead pollution in the Matanza-Riachuelo river basin, Argentine.

TRIPODI, MARIEL; MUSCHETTO E.,; ALVEDRO, ALEJANDRA; SUAREZ O.V

CABA

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

SETAC

Abstract Title:Preliminary analysis of the lead-bioaccumulation in liver and kidney of Rattus norvegicus captured in the Matanza Riachuelo basin (Argentina).A bioindicator is an organism containing qualitative information about the quality of the environment. In the urbanized environments, Rattus norvegicus is considered for its ecological characteristics one of the most proper species to be used as a contamination monitor for being a commensal species that lives in narrow relation with the humans. The Matanza Riachuelo basin is considered one of the most contamined basins in the world, where environments with different land uses prevail. It is divided into three sub-basins, where the bottom one presents high contamination levels due to cloacal and industrial wastes, which are lower in the middle and top basins. This study´s objective was to analyze the use of Rattus norvegicus rats as bioindicators of the environmental contamination with lead using as our study-case the Matanza-Riachuelo basin.The study was realized with 76 rats captured in 8 spots located in the middle and lower basins. The samplings were realized for a year, during winter and summer. Both general and mixed linear models were used in order to model the lead concentration in liver and kidney, using as explanatory variables morphometrical characteristics of the individuals (weight, total length and gender) and sediment and water concentrations of lead obtained from ACUMAR. Besides, we also incorporated to the model the capture seasons, the sampling sites, and if the individuals belonged either to the lowest or the top basin. The selection criterion in the models was based on the lowest value of the AIC index.The lead concentration in water and sediments and the capture season were the only variables that had a significant effect on the kidney´s lead concentration, where these concentrations were higher when the concentrations were higher both in the water (Value: 194,81; Std error: 61.72; DF: 52; t-value: 3,17, p: 0.0026) as in the sediments (Value:0.03; Std error: 0.04; DF: 3; t-value: 0,82; p: 0,4730). Also, the individuals captured in summer presented lower lead concentrations than those captured in winter (Value:-5.65; Std error:1.32; DF: 52; t-value: -4.25, p-value: 0.0001). On the other hand, for the lead concentrations in liver, the only significant variable was the lead concentration in water (Value: 13,83; Std error:3.99; DF: 61; t-value: 3,47, p-value: 0.0010). With the data obtained, we can conclude that R. norvegicus is a very good potential bioindicator for lead-contamination in terrestrial urban environments.