Improving the Quantification of Cyanotoxins Using a Mass Balance-Based Effective Concentration-Equivalent Concentration Approach.

Two commonly used methods for cyanotoxin analysis are enzyme-linked immunosorbent assay (ELISA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Each method has its advantages and disadvantages, and discrepancies are commonly observed between the two methods due to various factors including the ELISA antibody cross-reacting to different cyanotoxin congeners. However, reliable cyanotoxin monitoring methods and accurate interpretation of results are needed for water utilities to guide recreational water planning and drinking water treatment operations.

Distributions of waterborne pathogens in raw wastewater based on a 14-month, multi-site monitoring campaign.

The California State Water Resources Control Board is the first regulatory body in the United States to develop statewide regulations for direct potable reuse (DPR). To support this effort, a pathogen monitoring campaign was undertaken to develop and implement an optimized standard operating protocol to better characterize the concentration of human pathogens in raw wastewater. Methods to detect relevant viral and protozoan pathogens in raw wastewater were optimized and implemented during a 14-month monitoring campaign.

Reproducibility and sensitivity of 36 methods to quantify the SARS-CoV-2 genetic signal in raw wastewater: findings from an interlaboratory methods evaluation in the U.S.

In response to COVID-19, the international water community rapidly developed methods to quantify the SARS-CoV-2 genetic signal in untreated wastewater. Wastewater surveillance using such methods has the potential to complement clinical testing in assessing community health. This interlaboratory assessment evaluated the reproducibility and sensitivity of 36 standard operating procedures (SOPs), divided into eight method groups based on sample concentration approach and whether solids were removed.

Changes in Escherichia coli to Cryptosporidium ratios for various fecal pollution sources and drinking water intakes.

Assessing the presence of human pathogenic Cryptosporidium oocysts in surface water remains a significant water treatment and public health challenge. Most drinking water suppliers rely on fecal indicators, such as the well-established Escherichia coli (E. coli), to avoid costly Cryptosporidium assays.

Total and infectious Cryptosporidium oocyst and total Giardia cyst concentrations from distinct agricultural and urban contamination sources in Eastern Canada.

Cryptosporidium and Giardia (oo)cyst concentrations are frequently used for assessing drinking water safety. The widely used USEPA Method 1623 provides total counts of (oo)cysts, but may not be accurate for human health risk characterization, since it does not provide infectivity information. The total counts and infectious fraction of Cryptosporidium oocysts and the total counts of Giardia cysts were assessed in major fecal pollution sources.

Pressure monitoring and characterization of external sources of contamination at the site of the payment drinking water epidemiological studies.

The 1990s epidemiological studies by Payment and colleagues suggested that an increase in gastrointestinal illnesses observed in the population consuming tap water from a system meeting all water quality regulations might be associated with distribution system deficiencies. In the current study, the vulnerability of this distribution system to microbial intrusion was assessed by characterizing potential sources of contamination near pipelines and monitoring the frequency and magnitude of negative pressures. Bacterial indicators of fecal contamination were recovered more frequently in the water from flooded air-valve vaults than in the soil or water from pipe trenches.

Improved risk analysis by dual direct detection of total and infectious Cryptosporidium oocysts on cell culture in combination with immunofluorescence assay.

The inactivation of Cryptosporidium oocysts is a main driver in the selection of water treatment disinfection strategies, and microbial risk analysis provides a sound basis for optimizing water treatment processes. U.S.

Evaluation of swine-specific PCR assays used for fecal source tracking and analysis of molecular diversity of swine-specific "bacteroidales" populations.

In this study, we evaluated the specificity, distribution, and sensitivity of Prevotella strain-based (PF163 and PigBac1) and methanogen-based (P23-2) PCR assays proposed to detect swine fecal pollution in environmental waters. The assays were tested against 222 fecal DNA extracts derived from target and nontarget animal hosts and against 34 groundwater and 15 surface water samples from five different sites. We also investigated the phylogenetic diversity of 1,340 "Bacteroidales" 16S rRNA gene sequences derived from swine feces, swine waste lagoons, swine manure pits, and waters adjacent to swine operations.

Aged HCT-8 cell monolayers support Cryptosporidium parvum infection.

Cell culture assays in various formats have been used to study the infectivity of Cryptosporidium spp. as well as to determine the infectivity of naturally occurring oocysts in water. Currently, cell culture assays for infectious Cryptosporidium spp.

Genotype diversity of Escherichia coli isolates in natural waters determined by PFGE and ERIC-PCR.

Most library-dependent bacterial source tracking studies using Escherichia coli (E. coli) have focused on strain diversity of isolates obtained from known human and animal faecal sources for library development. In contrast, this study evaluated the genotype variation of E.

Investigation of potential zooanthroponotic transmission of cryptosporidiosis and giardiasis through agricultural use of reclaimed wastewater.

A field study in the Juarez Valley of Mexico was performed to investigate the potential transmission of Cryptosporidium and Giardia to sheep livestock grazing on forage irrigated with reclaimed wastewater, and the potential for disease transmission back to humans. United States Environmental Protection Agency Method 1623 immunofluorescent assay (IFA) revealed high levels of pathogens in reclaimed wastewater, with 183 to >7000 Giardia cysts and 9 - 762 Cryptosporidium oocysts detected per litre. Infectious Cryptosporidium were detected in the reclaimed wastewater using the cell culture focus detection method (FDM).

Quantitative-PCR assessment of Cryptosporidium parvum cell culture infection.

A quantitative TaqMan PCR method was developed for assessing the Cryptosporidium parvum infection of in vitro cultivated human ileocecal adenocarcinoma (HCT-8) cell cultures. This method, termed cell culture quantitative sequence detection (CC-QSD), has numerous applications, several of which are presented. CC-QSD was used to investigate parasite infection in cell culture over time, the effects of oocyst treatment on infectivity and infectivity assessment of different C.

Comparison of method 1623 and cell culture-PCR for detection of Cryptosporidium spp. in source waters.

Analysis of Cryptosporidium occurrence in six watersheds by method 1623 and the integrated cell culture-PCR (CC-PCR) technique provided an opportunity to evaluate these two methods. The average recovery efficiencies were 58.5% for the CC-PCR technique and 72% for method 1623, but the values were not significantly different (P = 0.