Submitted to: Journal Of Water Air And Soil Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/2009
Publication Date: 6/14/2010
Citation: Sigua, G.C., Palhares, J., Kich, J., Mulinari, M., Mattei, R., Klein, J., Muller, S. 2010. Microbiology quality assessment of watershed associated with animal-based agriculture in Santa Catarina, Brazil. Journal of Water Air and Soil Pollution. 210:307-316. Interpretive Summary: The current high demand for quality protein and fiber production because of increasing world population has resulted in an intensification of agricultural production systems. As animal-based agriculture has evolved to larger production in limited watershed spaces, the problems associated with manure handling, storage and disposal have grown significantly. Results of our monitoring clearly reinforce the understanding that animal-based agriculture if not properly managed may result to significant health risks because of elevated concentrations of bacterial indicators at catchment areas associated with various livestock’s activities. Results indicated that stream water became contaminated with fecal coliforms, Escherichia coli and Salmonella from the main agricultural land-use inputs of livestock grazing and organic waste application. Much of the detected bacterial indicators were more closely associated with specific agricultural and animal-based management practices as shown by the results observed from catchment area associated with land use with no animal activities. Land use with animals had the lowest concentrations of fecal coliforms and Escherichia coli along with the lowest counts of Salmonella when compared with other catchment areas associated with animal and crop production. Our results suggest that spatial pattern of bacterial water quality is evident, which can be linked to the different land-uses and associated practices (present or absent of animal activities). Therefore, varying responses associated with the different land-uses would be critical in identifying the importance of different sources of bacteria in the catchment area and the mechanisms transferring them. The overall impact of animal-based agriculture on microbiological water quality demonstrated by the results of this study may be considered potential threat to the health of downstream recreational users and proportion of the local population of human and animals that rely on same water supplies. More focused investigation therefore, is clearly needed to build on our understanding of the dynamics of bacterial indicators particularly in terms of the different catchment sources and transfer mechanisms in the watershed.
Technical Abstract: Environmental problems many times could evolve when manure-containing pathogens is distributed into an open environment with no effort made to reduce the content of pathogens or limit their movement in the environment. Wind, surface flow and subsurface flow can all carry enough pathogens to receiving waters to exceed water quality standards. This study was conducted to assess the microbiological quality of water associated with animal-based agriculture in sub-basin of Pinhal River located in the rural area of Concordia, Santa Catarina, Brazil. Eight sampling points representing different land-uses (LU1 - dairy cattle; LU2 - without animals; LU3 - dairy + pigs + poultry + crops; LU4 – pigs + poultry + crops; LU5 – dairy + pigs + poultry + crops + human; and LU6 – dairy + pigs + crops) along the Pinhal River sub-basin (north to south) were sampled bi-weekly from August 2006 to December 2008. Concentrations of fecal coliforms and Escherichia coli varied significantly (p=0.05) with land-use (LU), but there was no interaction effect of LU, season and time. Water samples from the catchment area of LU1 had the highest concentration of fecal coliforms (4479 ± 597 CFU ml-1) when compared with other catchment areas. Catchment area associated with LU2 (no animal) had the lowest concentrations of fecal coliforms (39.2 ± 5.2 CFU ml-1). With the exception of LU2 (control site), all the maximum concentrations of Escherichia coli exceeded the single maximum allowable concentration for Escherichia coli (100 CFU ml-1). The next two highest maximum concentrations of Escherichia coli were measured from sampling points associated with LU4 (pigs + poultry + crops) and LU6 (pigs + dairy + crops). The lowest maximum concentration of Escherichia coli was measured from catchment area without animal activities (LU2). Moreover, when LU1 was compared with other catchment areas (LU3, 50%; LU4, 67%; LU5, 58% and LU6, 44%), it had the lowest counts (39%) of Salmonella sp.