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More than 250 million U.S. residents, and millions more throughout the world, drink water treated by chemical disinfectants. Although it is important to kill harmful pathogens in water, chemical disinfection results in the formation of disinfection by-products (DBPs). DBPs represent a continuous, ubiquitous exposure, with levels much higher than other emerging contaminants that currently capture the public's attention, such as pharmaceuticals and per- and polyfluorinated alkyl substances (PFAS). Of all the chemicals that people are exposed to through their drinking water, DBPs are one of only a handful with a convincing body of evidence for adverse human health risks. Bladder cancer is the health effect noted most consistently in epidemiologic studies of DBP exposure. In their groundbreaking paper, Weisman et al. conducted the largest risk assessment of DBPs in the United States to date, focusing on bladder cancer cases associated with chlorinated drinking water. The authors, most of them from the U.S. Environmental Protection Agency (EPA) Office of Water, obtained DBP data from public water systems serving 198 million people from 42 states.

Although drinking water chlorination has reduced the incidence of waterborne disease, the reactions of chlorine with organic matter can lead to the formation of >700 halogenated disinfection by-products (DBPs). Epidemiological studies have linked the consumption of chlorinated drinking water with bladder cancer. With studies indicating that the one- and two-carbon-atom DBPs of current interest account for only ~16% of disinfected water cytotoxicity, there is a need to identify toxicity drivers within the poorly characterized higher-molecular-weight (more than two carbon atoms) DBP fraction. In this Review, we outline the current knowledge regarding this fraction and discuss novel analytical approaches to characterizing the much wider variety of structures that it contains. We detail the products formed from the reactions of chlorine with different categories of precursor, including the characteristics of the elemental formulae of products identified by high-resolution mass spectrometry, the halogenated aromatic DBPs formed from precursors in pristine waters and the products derived from biopolymer-bound monomers in algal- or wastewater-impacted waters. Finally, we discuss the key challenges for research into this important, but until recently, mostly overlooked by-product fraction.Recent toxicological studies have indicated that the poorly characterized high-molecular-weight fraction of disinfection by-products may contribute more to toxicity than the carbon disinfection by-products of current research interest. This Review summarizes what is known about the high-molecular-weight fraction and suggests pathways for future research in this area.

The articles published in JACMP are clinically relevant and directly impact patient care. Hospital and clinical staff were sent home, conscripted, or laid off. The parallel opposed article regarding medical physicists working from home was a great help for members trying to balance work and personal needs during this challenging time.2 I also read with great interest the article regarding the in-person AAPM meeting being a superspreader event—an event that I attended but remained healthy through.3 [IMAGE OMITTED. Medical image analysis 2023 4753 Moving on from the pandemic, the next topic that seems huge for the JACMP is the publication of Medical Physics Practice Guidelines (MPPGs).

Analysis of the population genetic structure of microbial species is of fundamental importance to many scientific disciplines because it can identify cryptic species, reveal reproductive mode, and elucidate processes that contribute to pathogen evolution. Here, we examined the population genetic structure and geographic differentiation of the sexual, dimorphic fungus Blastomyces dermatitidis, the causative agent of blastomycosis. Criteria for Genealogical Concordance Phylogenetic Species Recognition (GCPSR) applied to seven nuclear loci (arf6, chs2, drk1, fads, pyrF, tub1, and its-2) from 78 clinical and environmental isolates identified two previously unrecognized phylogenetic species. Four of seven single gene phylogenies examined (chs2, drk1, pyrF, and its-2) supported the separation of Phylogenetic Species 1 (PS1) and Phylogenetic Species 2 (PS2) which were also well differentiated in the concatenated chs2-drk1-fads-pyrF-tub1-arf6-its2 genealogy with all isolates falling into one of two evolutionarily independent lineages. Phylogenetic species were genetically distinct with interspecific divergence 4-fold greater than intraspecific divergence and a high Fst value (0.772, P<0.001) indicative of restricted gene flow between PS1 and PS2. Whereas panmixia expected of a single freely recombining population was not observed, recombination was detected when PS1 and PS2 were assessed separately, suggesting reproductive isolation. Random mating among PS1 isolates, which were distributed across North America, was only detected after partitioning isolates into six geographic regions. The PS2 population, found predominantly in the hyper-endemic regions of northwestern Ontario, Wisconsin, and Minnesota, contained a substantial clonal component with random mating detected only among unique genotypes in the population. These analyses provide evidence for a genetically divergent clade within Blastomyces dermatitidis, which we use to describe a novel species, Blastomyces gilchristii sp. nov. In addition, we discuss the value of population genetic and phylogenetic analyses as a foundation for disease surveillance, understanding pathogen evolution, and discerning phenotypic differences between phylogenetic species.

Blastomyces dermatitidis and Blastomyces gilchristii are dimorphic fungal pathogens that cause serious pulmonary and systemic infections in humans. Although their natural habitat is in the environment, little is known about their specific ecologic niche(s). Here, we analyzed 25 microsatellite loci from 169 strains collected from various regions throughout their known endemic range in North America, representing the largest and most geographically diverse collection of isolates studied to date. Genetic analysis of multilocus microsatellite data divided the strains into four populations of B. dermatitidis and four populations of B. gilchristii. B. dermatitidis isolates were recovered from areas throughout North America, while the B. gilchristii strains were restricted to Canada and some northern US states. Furthermore, the populations of both species were associated with major freshwater drainage basins. The four B. dermatitidis populations were partitioned among (1) the Nelson River drainage basin, (2) the St. Lawrence River and northeast Atlantic Ocean Seaboard drainage basins, (3) the Mississippi River System drainage basin, and (4) the Gulf of Mexico Seaboard and southeast Atlantic Ocean Seaboard drainage basins. A similar partitioning of the B. gilchristii populations was observed among the more northerly drainage basins only. These associations suggest that the ecologic niche where the sexual reproduction, growth, and dispersal of B. dermatitidis and B. gilchristii occur is intimately linked to freshwater systems. For most populations, sexual reproduction was rare enough to produce significant linkage disequilibrium among loci but frequent enough that mating-type idiomorphic ratios were not skewed from 1:1. Furthermore, the evolutionary divergence of B. dermatitidis and B. gilchristii was estimated at 1.9 MYA during the Pleistocene epoch. We suggest that repeated glaciations during the Pleistocene period and resulting biotic refugia may have provided the impetus for speciation as theorized for other species associated with temperate freshwater systems.

The number of chemical compounds registered in the Chemical Abstracts Service (CAS®) registry in 2020 reached 160 million [1]. [...]numerous reactions in the environment result in formation of many novel compounds, which do not yet have assigned CAS numbers. [...]it becomes more and more challenging to conduct comprehensive screening for known and emerging environmental contaminants. Results of the chemical analysis, including the levels of the targeted compounds and sediment ecotoxicity, were used to assess environmental risk. Since for most sediments, toxic effects were not observed in the toxicity tests with Heterocyprisinconguens and Aliivibrioficsheri, the results of environmental risk assessment indicate that the target analytes did not generate high impact on the aquatic life so far. A group from Arkhangelsk University (Arkhangelsk, Russia) for several years has studied the fate of UDMH in the environment and identified numerous transformation products. Since the majority of these products are rather polar, classic liquid-liquid extraction followed by GC-MS often leads to rather poor results.

Recent developments in gas chromatography (GC)-mass spectrometry (MS) have opened up the possibility to use the high resolution-accurate mass (HRAM) Orbitrap mass analyzer to further characterize the volatile and semivolatile fractions of environmental samples. This work describes the utilization of GC Orbitrap MS technology to characterize iodine-containing disinfection by-products (iodo-DBPs) in chlorinated and chloraminated DBP mixture concentrates. These DBP mixtures were generated in lab-scale disinfection reactions using Llobregat river water and solutions containing Nordic Lake natural organic matter (NOM). The DBPs generated were concentrated using XAD resins, and extracts obtained were analyzed in full scan mode with the GC Orbitrap MS. Integration of high resolution accurate mass information and fragment rationalization allowed the characterization of up to 11 different iodo-DBPs in the water extracts analyzed, including one new iodo-DBP reported for the first time. Overall, formation of iodo-DBPs was enhanced during chloramination reactions. As expected, NOM characteristics and iodide and bromide content of the tested waters affected the amount and type of iodo-DBPs generated. Graphical Abstract Characterization of iodo-DBPs in DBP mixtures based on high resolution accurate mass data obtained by means of GC Orbitrap MS analysis

Uncertainty remains regarding the magnitude of effectiveness of influenza vaccines for preventing serious outcomes, especially among young children. We estimated vaccine effectiveness (VE) against laboratory-confirmed influenza hospitalizations among children aged 6-59 months. We used the test-negative design in hospitalized children in Ontario, Canada during the 2010-11 to 2013-14 influenza seasons. We used logistic regression models adjusted for age, season, and time within season to calculate VE estimates by vaccination status (full vs. partial), age group, and influenza season. We also assessed VE incorporating prior history of influenza vaccination. We included specimens from 9,982 patient hospitalization episodes over four seasons, with 12.8% testing positive for influenza. We observed variation in VE by vaccination status, age group, and influenza season. For the four seasons combined, VE was 60% (95%CI, 44%-72%) for full vaccination and 39% (95%CI, 17%-56%) for partial vaccination. VE for full vaccination was 67% (95%CI, 48%-79%) for children aged 24-59 months, 48% (95%CI, 12%-69%) for children aged 6-23 months, 77% (95%CI, 47%-90%) for 2010-11, 59% (95%CI, 13%-81%) for 2011-12, 33% (95%CI, -18% to 62%) for 2012-13, and 72% (95%CI, 42%-86%) for 2013-14. VE in children aged 24-59 months appeared similar between those vaccinated in both the current and previous seasons and those vaccinated in the current season only, with the exception of 2012-13, when VE was lower for those vaccinated in the current season only. Influenza vaccination is effective in preventing pediatric laboratory-confirmed influenza hospitalizations during most seasons.

Disinfected water is the major source of haloacetic acids (HAAs) in humans, but their inter- and intra-individual variability for exposure and risk assessment applications is under-researched. Thus, we measured HAAs in cross-sectional and longitudinal urine and water specimens from 17 individuals. Five regulated HAAs—mono-, di-, and trichloroacetic acid (MCAA, DCAA, and TCAA) and mono- and dibromoacetic acid (MBAA and DBAA)—and one unregulated HAA—bromochloroacetic acid (BCAA)—were measured. Urinary DCAA, MBAA, DBAA, and BCAA levels were always below the limits of detection (LOD). Measured levels and interindividual variability of urinary MCAA were higher than urinary TCAA. Longitudinal urinary specimens showed MCAA levels peaked in after-shower specimens, while TCAA levels remain unchanged. Correlation between urinary MCAA and TCAA was moderate but statistically significant. The prevalence of MCAA and TCAA in urine suggest they can be considered as biomarkers of HAA. Peak urinary MCAA in post-shower specimens suggest MCAA captures short-term exposure via dermal and/or inhalation, while urinary TCAA captures long-term exposure via ingestion. However, further research is warranted in a large pool of participants to test the reliability of MCAA as exposure biomarker.