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The National Poison Data System (NPDS) comprises self-reported information from people who call US poison center hotlines. NPDS data have proven to be important in identifying emerging public health threats. We used NPDS to examine records of people who had self-reported exposure to harmful algal blooms (HABs). Participating poison centers then contacted people who had called their centers from May through October 2019 about their HAB exposure to ask about exposure route, symptoms, health care follow-up, and awareness of possible risks of exposure. Of 55 callers who agreed to participate, 47 (85%) reported exposure to HABs while swimming or bathing in HAB-contaminated water. Nine callers reported health symptoms from being near waters contaminated with HABs, suggesting potential exposure via aerosolized toxins. Symptoms varied by the reported routes of exposure; the most commonly reported symptoms were gastrointestinal and respiratory. More public and health care provider education and outreach are needed to improve the understanding of HAB-related risks, to address ways to prevent HAB-related illnesses, and to describe appropriate support when exposures occur.

This report summarizes trends in outbreaks associated with untreated recreational water exposure from 2000–2014; this includes infections with pathogens of concern for transplant recipients, such as norovirus, Shigella, and Cryptosporidium.

In the United States, the proportion of foodborne illness outbreaks associated with consumption of contaminated domestic and imported fresh fruits and vegetables (produce) has increased over the past several decades. To address this public health concern, the goal of this work was to identify and quantify factors associated with microbial contamination of produce in preand postharvest phases of the farm-to-fork continuum. From 2000 to 2003, we collected 923 samples of 14 types of produce (grown in the southern United States or in the northern border states of Mexico) from 15 farms and eight packing sheds located in the southern United States. To assess microbial quality, samples were enumerated for Escherichia coli, total aerobic bacteria, total coliforms, and total Enterococcus. Most produce types had significantly higher microbial concentrations when sampled at the packing shed than when sampled at the farm. In addition, we observed seasonal differences in the microbial concentrations on samples grown in the United States, with higher mean indicator concentrations detected in the fall (September, October, and November). We developed a predictive, multivariate logistic regression model to identify and quantify factors that were associated with detectable concentrations of E. colicontamination on produce. These factors included produce type (specifically, cabbage or cantaloupe), season of collection (harvested in the fall), and packing step (bin, box, conveyor belt, or turntable). These results can be used to identify specific mechanisms of produce contamination and propose interventions that may decrease the likelihood of produce-associated illness.

Objective. Ciguatera fish poisoning is a potentially life-threatening disease caused by eating coral reef fish contaminated with ciguatoxins and is the most common marine poisoning. However, existing surveillance systems capture few cases. To improve regional ciguatera surveillance in South Florida, this study compared ciguatera illnesses in the Florida Poison Information Center–Miami (FPICM) call database to ciguatera cases in the Florida Department of Health (FDOH) disease surveillance systems.Methods. Univariate and multivariate logistic regression were used to identify predictors of when FPICM reported ciguatera illnesses to FDOH and whether FDOH confirmed reported ciguatera cases.Results. FPICM staff preferentially reported ciguatera illnesses that were of shorter duration (adjusted odds ratio [AOR]=0.84 per additional illness day; 95% confidence interval [CI] 0.74, 0.97); outbreak-associated (AOR=7.0; 95% CI 2.5, 19.5); and clinically more severe (AOR=21.6; 95% CI 2.3, 198.5). Among ciguatera illnesses reported to FDOH, outbreak-associated illnesses were more likely than single, sporadic illnesses to become confirmed surveillance cases (crude OR=11.1; 95% CI 2.0, 62.5).Conclusions. The over-representation of outbreak-associated ciguatera cases underestimates the true contribution of sporadic illnesses to ciguatera disease burden. This bias should be considered when evaluating surveillance systems that include both outbreak-associated and sporadic illness reports.

Amendments to the Safe Drinking Water Act in 1996 directed the US Environmental Protection Agency (USEPA) and the Centers for Disease Control and Prevention to jointly conduct research to explore adverse health effects from exposure to sulfate in drinking water. The studies described here were undertaken to provide USEPA with information about these health effects, especially as they affect sensitive subpopulations such as infants and travelers. A planned study of infants had to be abandoned when the authors were unable to identify enough exposed individuals. Some information was gleaned from a questionnaire that included questions about using tap water to mix infant formula. An experimental trial with adult volunteers did not uncover a significant dose‐response association between acute exposure to sodium sulfate and reports of diarrhea. An expert workshop convened to review these findings and the existing sulfate literature concluded there was insufficient scientific evidence on which to base a regulation creating a maximum contaminant level for sulfate in drinking water. On the basis of this work, the literature, and the recommendation of the expert workshop, USEPA will decide whether and at what level to regulate sulfate in drinking water.

Exposure to drinking water disinfection by-products (DBPs), such as trihalomethanes (THMs), has been associated with bladder and colorectal cancer in humans. Exposure to DBPs has typically been determined by examining historical water treatment records and reconstructing study participants' water consumption histories. However, other exposure routes, such as dermal absorption and inhalation, may be important components of an individual's total exposure to drinking water DBPs. In this study, we examined individuals' exposure to THMs through drinking, showering, or bathing in tap water. Thirty-one adult volunteers showered with tap water for 10 min (n=11), bathed for 10 min in a bathtub filled with tap water (n=10), or drank 1 l of tap water during a 10-min time period (n=10). Participants provided three 10 ml blood samples: one sample immediately before the exposure; one sample 10 min after the exposure ended; and one sample 30 min (for shower and tub exposure) or 1 h (for ingestion) after the exposure ended. A sample of the water (from the tap, from the bath, or from the shower) was collected for each participant. We analyzed water samples and whole blood for THMs (bromoform, bromodichloromethane, dibromochloromethane, and chloroform) using a purge-and-trap/gas chromatography/mass spectrometry method with detection limits in the parts-per-quadrillion range. The highest levels of THMs were found in the blood samples from people who took 10-min showers, whereas the lowest levels were found in the blood samples from people who drank 1 l of water in 10 min. The results from this study indicate that household activities such as bathing and showering are important routes for human exposure to THMs.Journal of Exposure Analysis and Environmental Epidemiology (2000) 10, 321–326. 10.1038/sj.jea.7500098

The objective of this study was to examine age-specific population-based values for serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels in women in the U.S. population.

Synaptonemal complex aberrations can provide a sensitive measure of chemical-specific alterations to meiotic chromosomes. Mitomycin C, cyclophosphamide, amsacrine, ellipticine, colchicine, vinblastine sulfate, and cis platin exposures in mice have been shown to cause various patterns of synaptonemal complex structural damage and synaptic irregularity. These effects are suggestive of abnormal homologue pairinglsynapsis/recombination effects which, theoretically, could be implicated in mechanisms leading to aneuploidy and other potentially heritable chromosomal disorders.

Arsenic from geologic sources is widespread in groundwater within the United States (U.S.). In several areas, groundwater arsenic concentrations exceed the U.S. Environmental Protection Agency maximum contaminant level of 10 μg per liter (μg/L). However, this standard applies only to public-supply drinking water and not to private-supply, which is not federally regulated and is rarely monitored. As a result, arsenic exposure from private wells is a potentially substantial, but largely hidden, public health concern. Machine learning models using boosted regression trees (BRT) and random forest classification (RFC) techniques were developed to estimate probabilities and concentration ranges of arsenic in private wells throughout the conterminous U.S. Three BRT models were fit separately to estimate the probability of private well arsenic concentrations exceeding 1, 5, or 10 μg/L whereas the RFC model estimates the most probable category (≤5, >5 to ≤10, or >10 μg/L). Overall, the models perform best at identifying areas with low concentrations of arsenic in private wells. The BRT 10 μg/L model estimates for testing data have an overall accuracy of 91.2%, sensitivity of 33.9%, and specificity of 98.2%. Influential variables identified across all models included average annual precipitation and soil geochemistry. Models were developed in collaboration with public health experts to support U.S.-based studies focused on health effects from arsenic exposure.