Microbiological water quality assessment of sewage discharge through Barra da Tijuca (Rio de Janeiro, Brazil) submarine outfall.

Submarine outfalls have been employed to convey urban effluents to their fate in the open ocean due to their dilution capacity and organic matter decay. This work analysed Escherichia coli concentrations in the Barra da Tijuca (Rio de Janeiro, Brazil) submarine outfall plume, considering an hourly variable bacterial die-off due to environmental parameters associated with dynamic changes, vertical plume position, and thickness in response to hydrodynamic conditions. The adopted modelling procedure included coupling a near-field mixing zone model, NRFIELD, with the far-field Lagrangian transport and water quality model of the SisBaHiA® ( http://www.sisbahia.coppe.ufrj.br ). The coupling methodology simulated E. coli concentrations considering simultaneous variations in temperature, salinity, solar radiation, and hydrodynamic conditions. The results showed substantial variability in E. coli concentrations in the marine environment due to variable environmental conditions, regulating solar radiation levels over the submerged plume.

Environmental assessment of sewage contamination in the surroundings of a marine outfall combining human mastadenovirus and fecal indicator bacteria.

This study assessed the microbiological contamination of the marine area of a metropolitan region, where a marine outfall is used as a sanitary solution for domestic sewage. For human mastadenovirus (HAdV) quantification 134 water samples were concentrated by skimmed milk flocculation method and analyzed with qPCR and PMAxx-qPCR, being the latter to assess the capsid integrity viral. HAdV with intact capsids were detected in 10 % (16/102) of samples classified as suitable for bathing using at least one fecal bacterial indicator. Spatial analysis of the results showed that the drainage channels of the basin that flow into the sea are the main sources of microbiological contamination in the foreshore zone, where intact HAdV reached a concentration of up to 3 log genomic copies/L. HAdV serotypes A12, D, F40 and F41 were characterized. Our results suggest the use of intact HAdV as a complementary parameter to assess the quality of recreational waters.

Microbiological assessment of an urban lagoon system in the coastal zone of Rio de Janeiro, Brazil.

This study aims to assess microbiological contamination using a molecular tool for detection of multiple enteropathogens in a coastal ecosystem area in Rio de Janeiro, Brazil. Ten litres of superficial water samples were obtained during the spring ebb tide from sampling sites along the Jacarepaguá watershed. Samples were concentrated using skimmed milk flocculation method for TaqMan array card (TAC), designed to identify 35 enteric pathogens simultaneously, and single TaqMan qPCR analysis for detecting human adenovirus (HAdV) and JC human polyomavirus (JCPyV) as faecal indicator viruses (FIV). TAC results identified 17 enteric pathogens including 4/5 viral species investigated, 8/15 bacteria, 4/6 protozoa and 1/7 helminths. Escherichia coli concentration was also measured as faecal indicator bacteria (FIB) using Colilert Quanti-Tray System with positivity in all samples studied. HAdV and JCPyV qPCR were detected in 8 and 4 samples, respectively, with concentration ranging from 8 × 102 to 2 × 106 genome copies/L. Partial nucleotide sequencing demonstrated the occurrence of species HAdV A, C, D, and F, present in faeces of individuals with enteric and non-enteric infections, and JCPyV type 3 (Af2), prevalent in a high genetically mixed population like the Brazilian. The diversity of enteropathogens detected by TAC emphasizes the utility of this methodology for quick assessment of microbiological contamination of the aquatic ecosystems, speeding up mitigation actions where the risk of the exposed population is detected, as well as pointing out the infrastructure gaps in areas where accelerated urban growth is observed.