Microbial indicators and molecular markers used to differentiate the source of faecal pollution in the Bogotá River (Colombia)

Traceability of gushing water in the MiddleRoute of the South-to-North Water Diversion (Beijing section) through the river area

To trace the origin of the gushing water in the riverine area of the Beijing section of The Middle Route of South-to-North Water Diversion Project, a dataset was established comprising water chemistry, three-dimensional fluorescence spectra, and stable isotopes for different water bodies. Results indicated significant differences in Electrical Conductivity (EC), Total Dissolved Solids (TDS), and Ca2+ concentration among the gushing water, river water, and the water from the Middle Route of South-to-North Water Diversion Project (MRSD). Analysis using parallel factor analysis (PARAFAC) and fluorescence index revealed that dissolved organic matter (DOM) in the MRSD mainly originated from endogenous sources, while the river water and gushing water showed influences from both endogenous and exogenous sources. Nitrate sources varied among the water bodies, with distinct contributions from domestic sewage and fertilizer sources. The evaporation lines of river water and gushing water exhibited similar intercepts and slopes, but their intercepts and slopes are much smaller than those of the MRSD, suggesting stronger kinetic evaporative fractionation. In conclusion, the gushing water in the riverine area of the MRSD was determined to originate from the river, providing a fast and efficient method for gushing water source identification.

Helicobacter pylori virulence genotypes in Bogotá River and wastewater treatment plants in Colombia

BACKGROUND

Helicobacter pylori is a bacterium that infects 70%-80% of the population in Colombia, causing chronic gastritis in all those infected and gastric cancer in 1%-2% of those infected. In Colombia, some studies have identified the presence of vacA and cagA genes in environmental samples such as treated, surface, and wastewater, but they have not been evaluated in the Bogotá River. For this, the aim of this study was to identify the virulence genotypes of H. pylori present in samples from the Bogotá River and domestic wastewater treatment plants (WWTPs).

MATERIALS AND METHODS

A total of 75 water samples (51 from the Bogotá River and 24 from wastewater treatment plants) were collected. The presence of H. pylori DNA and its virulence genotypes was determined by polymerase chain reaction (PCR).

RESULTS

The presence of H. pylori DNA was demonstrated in 44% (33/75) of the samples, obtaining 63.6% (21/33) from the Bogotá River and 36.4% (12/33) from the WWTPs. The most prevalent H. pylori genotype was cagA (-) and vacAm1/s1/i1 being the most virulent of the vacA gene.

CONCLUSIONS

This is the first study in Colombia that determines the cagA and vacA genotypes in surface water and WWTPs, indicating the circulation of virulent genotypes in the population. The presence of this pathogen in the waters can be represent a risk to the health of the surrounding population since these waters are reused by the communities for different purposes.

Coliphages as viral indicators in municipal wastewater: A comparison between the ISO and the USEPA methods based on a systematic literature review

The use of traditional faecal indicator bacteria as surrogate organisms for pathogenic viruses in domestic wastewater has been noted as a problematic as concentrations and removal rates of bacteria and viruses do not seem to correlate. In this sense, bacteriophages (phages) emerge as potential viral indicators, as they are commonly found in wastewater in high levels, and can be quantified using simple, fast, low-cost methods. Somatic and F-specific coliphages comprise groups of phages commonly used as indicators of water quality. There are two internationally recognised methods to detect and enumerate coliphages in water samples, the International Standardization Organization (ISO) and the US Environmental Protection Agency (USEPA) methods. Both methods are based on the lysis of specific bacterial host strains infected by phages. Within this context, this systematic literature review aimed at gathering concentrations in raw and treated domestic wastewater (secondary, biological treatment systems and post-treatment systems), and removal efficiencies of somatic and F-specific coliphages obtained by ISO and USEPA methods, and then compare both methods. A total of 33 research papers were considered in this study. Results showed that the ISO method is more commonly applied than the USEPA method. Some discrepancies in terms of concentrations and removal efficiencies were observed between both methods. Higher removal rates were observed for both somatic and F-specific coliphages in activated sludge systems when using the USEPA method compared to the ISO method; in other secondary (biological) treatment systems, this was observed only for F-specific coliphages. The use of different standardised methods available might lead to difficulties in obtaining and comparing phage data in different conditions and locations. Future research comparing both ISO and USEPA methods as well as viral and bacterial pathogens and indicators in WWTP is recommended.

Characterization of Slaughterhouse Wastewater and Development of Treatment Techniques: A Review

Commercialization in the meat-processing industry has emerged as one of the major agrobusiness challenges due to the large volume of wastewater produced during slaughtering and cleaning of slaughtering facilities. Slaughterhouse wastewater (SWW) contains proteins, fats, high organic contents, microbes, and other emerging pollutants (pharmaceutical and veterinary residues). It is important to first characterize the wastewater so that adequate treatment techniques can be employed so that discharge of this wastewater does not negatively impact the environment. Conventional characterization bulk parameters of slaughterhouse wastewater include pH, color, turbidity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), and coliform counts. Characterization studies conducted have revealed the effects of the pollutants on microbial activity of SWW through identification of toxicity of antibiotic-resistant strains of bacteria. Due to the high-strength characteristics and complex recalcitrant pollutants, treatment techniques through combined processes such as anaerobic digestion coupled with advanced oxidation process were found to be more effective than stand-alone methods. Hence, there is need to explore and evaluate innovative treatments and techniques to provide a comprehensive summary of processes that can reduce the toxicity of slaughterhouse wastewater to the environment. This work presents a review of recent studies on the characterization of SWW, innovative treatments and technologies, and critical assessment for future research.

Bacteriophages as Fecal Pollution Indicators

Bacteriophages are promising tools for the detection of fecal pollution in different environments, and particularly for viral pathogen risk assessment. Having similar morphological and biological characteristics, bacteriophages mimic the fate and transport of enteric viruses. Enteric bacteriophages, especially phages infecting Escherichia coli (coliphages), have been proposed as alternatives or complements to fecal indicator bacteria. Here, we provide a general overview of the potential use of enteric bacteriophages as fecal and viral indicators in different environments, as well as the available methods for their detection and enumeration, and the regulations for their application.

Evaluation of the Effect of Gold Mining on the Water Quality in Monterrey, Bolívar (Colombia)

Gold mining uses chemicals that are discharged into rivers without any control when there are no good mining practices, generating environmental and public health problems, especially for downstream inhabitants who use the water for consumption, as is the case in Monterrey township, where the Boque River water is consumed. In this study, we evaluate Boque River water quality analyzing some physicochemical parameters such as pH, heavy metals, Hg, and cyanide; bioassays (Lactuca sativa, Hydra attenuata, and Daphnia magna), mutagenicity (Ames test), and microbiological assays. The results show that some physicochemical parameters exceed permitted concentrations (Hg, Cd, and cyanide). D. magna showed sensitivity and L. sativa showed inhibition and excessive growth in the analyzed water. Mutagenic values were obtained for all of the sample stations. The presence of bacteria and somatic coliphages in the water show a health risk to inhabitants. In conclusion, the presence of Cd, Hg, and cyanide in the waters for domestic consumption was evidenced in concentrations that can affect the environment and the health of the Monterrey inhabitants. The mutagenic index indicates the possibility of mutations in the population that consumes this type of water. Bioassays stand out as an alert system when concentrations of chemical contaminants cannot be analytically detected.