152 research outputs found
Aero-dispersed mutagenicity attributed to particulate and semi volatile phase in an urban environment
Detection of pathogenic Campylobacter, E. coli O157:H7 and Salmonella spp. in wastewater by PCR assay
Removal of micropollutants by fungal laccases in model solution and municipal wastewater: evaluation of estrogenic activity and ecotoxicity
Comparison of UV, Peracetic Acid and Sodium Hypochlorite Treatment in the Disinfection of Urban Wastewater
One source of water contamination is the release of wastewater that has not undergone
efficient treatment. The aim of this study was to evaluate the reduction obtained with sodium
hypochlorite (NaClO), UV and peracetic acid disinfection treatment of Salmonella spp., pathogenic
Campylobacter, STEC and bacterial indicators in three full-scale municipal wastewater plants. A
general reduction in Salmonella was observed after disinfection, but these bacteria were detected
in one UV-treated sample (culture method) and in 33%, 50% and 17% of samples collected after
NaClO, UV and PAA disinfection treatments, respectively (PCR method). A better reduction was
also observed under NaClO disinfection for the microbial indicators. Independent of the disinfection
treatment, E. coli O157:H7 was not detected in the disinfected samples, whereas some samples treated
with UV and PAA showed the presence of the stx1 gene. No reduction in the presence of stx2 genes
was verified for any of the disinfection treatments. Campylobacter was not detected in any of the
analysed samples. The overall results highlight a better reduction in microbiological parameters with
a NaClO disinfection treatment in a full-scale municipal wastewater plant compared with UV and
PAA. However, the results indicate that a complete and specific monitoring program is necessary to
prevent a possible risk to public health
Cryptosporidium Oocyst Contamination in Drinking Water: A Case Study in Italy
The aim of this study was to evaluate the occurrence of Cryptosporidium oocysts in a drinking water treatment plant (DWTP) located in a rural area of northern Italy. Influent and effluent samples were collected at the DWTP over three years (2013–2016). In parallel, tap water samples from a public drinking fountain were collected as well. All samples were analyzed for the presence of Cryptosporidium spp. oocysts by a common method based on an immunomagnetic separation (IMS)/immunofluorescence assay (IFA), complemented by 4,6-diamidino-2-phenylindole (DAPI) staining. A reverse transcriptase-PCR (RT-PCR) protocol was added to evaluate oocyst viability. The results highlighted a high variability of oocyst concentrations across all samples (mean 4.3 ± 5.8/100 L) and a high variability in the percentage of DAPI-positive specimens (mean 48.2% ± 40.3%). Conversely, RT-PCR did not reveal the presence of viable C. parvum and C. hominis oocysts. A nested PCR targeting Cryptosporidium 18S ribosomal DNA, carried out in two water samples, confirmed the presence of a Cryptosporidium genotype associated with wild animals in the river and in tap water. The results obtained underline the vulnerability of the investigated surface water to Cryptosporidium spp. contamination. Although the recovered Cryptosporidium genotype is not a human pathogen, its presence demonstrates the existence of a potential pathogen Cryptosporidium spp. contamination risk. Moreover, these results underline the importance of also considering unconventional (not bacterial) biological contaminations (protozoa) in water resources in rural areas, including those of developed countries
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