Carcinogenic formaldehyde in U.S. residential buildings: Mass inventories, human health impacts, and associated healthcare costs.

Formaldehyde, a human carcinogen, is formulated into building materials in the U.S. and worldwide. We used literature information and mass balances to obtain order-of-magnitude estimates of formaldehyde inventories in U.S. residential buildings as well as associated exposures, excess morbidity, and healthcare costs along with other economic ramifications. Use of formaldehyde in building materials dates to the 1940s and continues today unabated, despite its international classification in 2004 as a human carcinogen. Global production of formaldehyde was about 32 million metric tons (MMT) in 2006. In the U.S., 5.7 ± 0.05 to 7.4 ± 0.125 MMT of formaldehyde were produced annually from 2006 to 2022, with 65 ± 5 % of this mass (3.7 ± 0.03 to 4.8 ± 0.08 MMT) entering building materials. For a typical U.S. residential building constructed in 2022, we determined an average total mass of formaldehyde containing chemicals of 48.2 ± 10.1 kg, equivalent to 207 ± 40 g of neat formaldehyde per housing unit. When extrapolated to the entire U.S. housing stock, this equates to 29,800 ± 5760 metric tons of neat formaldehyde. If the health threshold in indoor air of 0.1 mg/m3 is never surpassed in a residential building, safe venting of embedded formaldehyde would take years. Using reported indoor air exceedances, up to 645 ± 33 excess cancer cases may occur U.S. nationwide annually generating up to US$65 M in cancer treatment costs alone, not counting ~16,000 ± 1000 disability adjusted life-years. Other documents showed health effects of formaldehyde exist, but could not be quantified reliably, including sick building syndrome outcomes such as headache, asthma, and various respiratory illnesses. Opportunities to improve indoor air exposure assessments are discussed with special emphasis on monitoring of building wastewater. Safer alternatives to formaldehyde in building products exist and are recommended for future use.

Seasonality of respiratory, enteric, and urinary viruses revealed by wastewater genomic surveillance.

Wastewater surveillance can reveal population-level infectious disease burden and emergent public health threats can be reliably assessed through wastewater surveillance. While molecular methods for wastewater monitoring of microorganisms have traditionally relied on PCR-based approaches, next-generation sequencing (NGS) can provide deeper insights via genomic analyses of multiple diverse pathogens. We conducted a year-long sequencing surveillance of 1,408 composite wastewater samples collected from 12 neighborhood-level access points in the greater Tempe area, Arizona, USA, and show that variation in wastewater viruses is driven by seasonal time and location. The temporal dynamics of viruses in wastewater were influenced cyclically, with the most dissimilarity between samples 23 weeks apart (i.e., winter vs summer, spring vs fall). We identified diverse urinary and enteric viruses including polyomaviruses, astroviruses, and noroviruses, and showed that their genotypes/subtypes shifted across seasons. We show that while wastewater data of certain respiratory viruses like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strongly correlate with clinical case rates, laboratory-reported case incidences were discordant with surges of high viral load in wastewater for other viruses like human coronavirus 229E. These results demonstrate the utility of wastewater sequencing for informing decision-making in public health.IMPORTANCEWastewater surveillance can provide insights into the spread of pathogens in communities. Advances in next-generation sequencing (NGS) methodologies allow for more precise detection of viruses in wastewater. Long-term wastewater surveillance of viruses is an important tool for public health preparedness. This system can act as a public health observatory that gives real-time early warning for infectious disease outbreaks and improved response times.

Human adenovirus outbreak at a university campus monitored by wastewater and clinical surveillance.

Areas of dense population congregation are prone to experience respiratory virus outbreaks. We monitored wastewater and clinic patients for the presence of respiratory viruses on a large, public university campus. Campus sewer systems were monitored in 16 locations for the presence of viruses using next generation sequencing over 22 weeks in 2023. During this period, we detected a surge in human adenovirus (HAdV) levels in wastewater. Hence, we initiated clinical surveillance at an on-campus clinic from patients presenting with acute respiratory infection. From whole genome sequencing of 123 throat and/or nasal swabs collected, we identified an outbreak of HAdV, specifically of HAdV-E4 and HAdV-B7 genotypes overlapping in time. The temporal dynamics and proportions of HAdV genotypes found in wastewater were corroborated in clinical infections. We tracked specific single nucleotide polymorphisms (SNPs) found in clinical virus sequences and showed that they arose in wastewater signals concordant with the time of clinical presentation, linking community transmission of HAdV to the outbreak. This study demonstrates how wastewater-based epidemiology can be integrated with surveillance at ambulatory healthcare settings to monitor areas prone to respiratory virus outbreaks and provide public health guidance.

Systematic scoping review evaluating the potential of wastewater-based epidemiology for monitoring cardiovascular disease and cancer.

Cardiovascular disease (CVD) and cancer are collectively responsible for tens of millions of global deaths each year. These rates are projected to intensify as the COVID-19 pandemic has caused delays in individualized diagnostics, or exacerbated prevalence due to Post Acute Coronavirus (COVID-19) Syndrome. Wastewater-based epidemiology (WBE) has successfully been employed as a useful tool for generating population-level health assessments, and was examined here in this systematic scoping literature review to (i) identify endogenous human biomarkers reported to indicate CVD or cancer in clinical practice, (ii) assess specificity to the indicated diseases, (iii) evaluate the utility for estimating population-level disease prevalence in community wastewater, and (iv) contextualize the obtained information for monitoring CVD and cancer presence via WBE. A total of 48 peer-reviewed papers were critically examined identifying five urinary protein biomarkers: cardiac troponin I (cTnI) (heart attack/heart failure), cystatin C (atherosclerosis), normetanephrine (tumor presence), α-fetoprotein (prostate and liver cancer), and microtubule assisted serine/threonine kinase 4 (MAST4) (breast cancer). Next, urinary excretion information was utilized to predict biomarker concentrations extant in community wastewater, resulting in average healthy concentrations ranging from 0.02 to 1159 ng/L, and disease-indicating thresholds from 0.16 to 3041 ng/L. Finally, estimating prevalence-adjusted wastewater measurements was explored in order to assess community-level CVD and cancer presence utilizing U.S. reported prevalence rates. Results obtained suggest that WBE can serve as a viable tool in support of current methods for CVD and cancer assessment to reduce morbidities and mortalities worldwide.

Impact of sample clarification by size exclusion on virus detection and diversity in wastewater-based epidemiology.

The use of wastewater-based epidemiology (WBE) for early detection of virus circulation and response during the SARS-CoV-2 pandemic increased interest in and use of virus concentration protocols that are quick, scalable, and efficient. One such protocol involves sample clarification by size fractionation using either low-speed centrifugation to produce a clarified supernatant or membrane filtration to produce an initial filtrate depleted of solids, eukaryotes and bacterial present in wastewater (WW), followed by concentration of virus particles by ultrafiltration of the above. While this approach has been successful in identifying viruses from WW, it assumes that majority of the viruses of interest should be present in the fraction obtained by ultrafiltration of the initial filtrate, with negligible loss of viral particles and viral diversity. We used WW samples collected in a population of ~700,000 in southwest USA between October 2019 and March 2021, targeting three non-enveloped viruses (enteroviruses [EV], canine picornaviruses [CanPV], and human adenovirus 41 [Ad41]), to evaluate whether size fractionation of WW prior to ultrafiltration leads to appreciable differences in the virus presence and diversity determined. We showed that virus presence or absence in WW samples in both portions (filter trapped solids [FTS] and filtrate) are not consistent with each other. We also found that in cases where virus was detected in both fractions, virus diversity (or types) captured either in FTS or filtrate were not consistent with each other. Hence, preferring one fraction of WW over the other can undermine the capacity of WBE to function as an early warning system and negatively impact the accurate representation of virus presence and diversity in a population.

Genome Sequences of Anelloviruses, Genomovirus, and Papillomavirus Isolated from Nasal Pharyngeal Swabs.

The genome sequences of three anelloviruses (genus Alphatorquevirus), a genomovirus (genus Gemykolovirus), and an unclassified papillomavirus were identified in four human nasopharyngeal swabs, and one was positive for influenza A and one for influenza B virus. The influenza B virus-positive sample had a coinfection with an anellovirus and a papillomavirus.

Application of wastewater-based epidemiology for estimating population-wide human exposure to phthalate esters, bisphenols, and terephthalic acid.

Phthalates, bisphenols (BPs), and terephthalic acid (TPA) are widely used plasticizers and monomers in plastic manufacturing. Most of them are known to have an adverse effect on the human body, functioning as endocrine disruptors and suspected carcinogens. Access to near real-time data on population exposure to plasticizers is essential for identifying vulnerable communities and better protecting and managing public health locally. The objective of the present study was to evaluate population-level exposure to phthalates, BPs, and TPA by measuring urinary metabolites in community wastewater. Composited community wastewater (24-h samples) from five sewer sub-catchments of a southwestern city within the United States were analyzed for urinary biomarkers of phthalates, BPs, and TPA using solid-phase extraction-liquid chromatography-tandem mass spectrometry in conjunction with the isotope dilution method for absolute quantification. Ten of 16 analytes were detected at least once in community wastewater above the method detection limit (MDL), with MDLs ranging from 37 to 203 ng/L. The population normalized mass load of TPA was the highest, followed by the human metabolite of di-(2-ethylhexyl) phthalate (DEHP). Bisphenol S and monoethyl phthalate were detected with the highest frequency. Study findings suggest that analyzing municipal wastewater for chemical indicators of human exposure to plastic constituents is feasible, practicable, and informative, as long as appropriate steps are taken to determine, quantify and account for background levels of plastic analytes in the laboratory environment.

Towards a novel application of wastewater-based epidemiology in population-wide assessment of exposure to volatile organic compounds.

In this study, we investigated the feasibility of detecting 35 urinary biomarkers of volatile organic compounds (VOCs) exposure in community wastewater. 24-h composited municipal wastewater samples were collected from two communities (n = 8) in the southeastern US. Using isotope-dilution liquid chromatography-tandem mass spectrometry, results showed 16 metabolites were detected in wastewater samples, including indicators of exposure to acrolein, acrylonitrile, 1,3-butadiene, crotonaldehyde, n,n-dimethylformamide (DMF), ethylbenzene, nicotine, propylene oxide, styrene, tetrachloroethylene, toluene, and xylene. Additional metabolites qualitatively identified exposure to acrylamide and trichloroethylene. Community 1 (closer proximity to manufacturing facilities) had a greater number of detects (n = 36) and higher VOC loadings, 22,000 mg day-1 per 1000 people, as compared to Community 2 (n = 28), 7100 mg day-1 per 1000 people. Normalizing to nicotine consumption biomarkers to account for differences in smoking behaviors, Community 1 continued to have higher levels of propylene oxide, crotonaldehyde, DMF, and acrylonitrile exposures, VOCs generally sourced from manufacturing activities and vehicle emissions. This is the first study to utilize wastewater to detect urinary biomarkers of VOCs exposure. These preliminary results suggest the WBE approach as a potentially powerful tool to assess community health exposures to indoor and outdoor air pollutants.

Decline and Pronounced Regional Disparities in Medical Cocaine Usage in the United States.

Background: Cocaine is a stimulant and Schedule II drug used as a local anesthetic and vasoconstrictor. Objective: This descriptive study characterized medical cocaine use in the United States. Methods: Retail drug distribution data from 2002 to 2017 were extracted for each state from the Drug Enforcement Administration, which reports on medical, research, and analytical chemistry use. The percentage of buyers (pharmacies, hospitals, and providers) was obtained. Use per state, corrected for population, was determined. Available cross-sectional data on cocaine use as reported by the Medicare and Medicaid programs for 2013-2017 and electronic medical records were examined. Results: Medical cocaine use decreased by -62.5% from 2002 to 2017. Hospitals accounted for 84.9% and practitioners for 9.9% of cocaine distribution in 2017. The number of pharmacies carrying cocaine dropped by -69.4%. The percentages of hospitals, practitioners, and pharmacies that carried cocaine in 2017 were 38.4%, 2.3%, and 0.3%, respectively. There was a 7-fold difference in 2002 (South Dakota, 76.1 mg/100 persons; Delaware, 10.1 mg/100 persons). Relative to the average state in 2017, those reporting the highest values (Montana, 20.1; North Dakota, 24.1 mg/100 persons) were significantly elevated. Cocaine use within the Medicare and Medicaid programs was negligible. Cocaine use within the Geisinger system was rare from 2002 to 2007 (<4 orders/100 000 patients per year) but increased to 48.7 in 2018. Conclusion and Relevance: If these pharmacoepidemiological patterns continue, licit cocaine may soon become a historical relic. The pharmacology and pharmacotherapeutics education of health care providers may need to be adjusted accordingly.

Alcohol, nicotine, and caffeine consumption on a public U.S. university campus determined by wastewater-based epidemiology.

Alcohol, nicotine, and caffeine use in at-risk populations is a public health concern that claims over 550,000 lives annually. Self-reported surveys from college students often reveal overconsumption of these substances. Unfortunately, the costs of these surveys are high, and consequently, the results from few studies are often extrapolated across the entire target population. Here we employed wastewater-based epidemiology (WBE) to directly measure the levels of these three psychotropic substances and their metabolites in sewage from a large public Southwestern U.S. university campus during the 2017-2018 academic year. Results showed per person alcohol consumption was 11.3 ± 7.5 g d-1 person-1 or 0.8 ± 0.5 drinks d-1 person-1, similar to averages of nationwide estimates from self-reporting of this subpopulation aged 18-25 years (10.1 ± 0.8 g d-1 person-1 or 0.7 ± 0.06 drinks d-1 person-1). Caffeine and nicotine consumption determined by WBE were significantly lower (p < 0.05) than nationwide estimates from self-reporting (caffeine: 114 ± 49 vs. 178 ± 19 mg d-1 person-1; nicotine: 627 ± 219 vs. 927 ± 243 µg d-1 person-1). Strong positive correlations were found for consumption of alcohol and nicotine (Spearman rs: 0.71; p < 0.01), and nicotine and caffeine (0.59, p < 0.01), but not alcohol and caffeine (0.17). Alcohol and nicotine consumption were significantly higher on weekends compared to weekdays (p < 0.01), while caffeine consumption was higher during the week (p < 0.05). This first U.S. WBE study on alcohol, nicotine, and caffeine use among U.S. college students demonstrated the feasibility and practicality of longitudinally tracking the behavior of an entire campus population of 60,000 students directly, repeatedly, and more inexpensively (US$0.58/person) compared to conventional questionnaires (US$127/person).

Chemical and physical changes of microplastics during sterilization by chlorination.

Wastewater treatment plants are known to release microplastics that have been detected in aquatic and terrestrial organisms constituting part of the human diet. Chlorination of wastewater-borne microplastics was hypothesized to induce chemical and physical changes detectable by Raman spectroscopy and differential scanning calorimetry (DSC). In the laboratory, virgin plastics (∼0.05 × 2 × 2 mm) were exposed to differing sterilization conditions representative of dosages used in the disinfection of drinking water, wastewater, and heavily contaminated surfaces. Polypropylene (PP) was most resistant to chlorination, followed by high density polyethylene (HDPE) and polystyrene (PS). Polystyrene showed degradation, indicated by changes in Raman peak widths, at concentration-time regimes (CT values) as low as 75 mg min/L, whereas HDPE and PP remained unaltered even at chlorine doses characteristic of wastewater disinfection (150 mg min/L). However, HDPE and PS were not completely resistant to oxidative attack by chlorination. Under extremely harsh conditions, shifts in Raman peaks and the formation of new bonds were observed. These results show that plastics commonly used in consumer products can be chemically altered, some even under conditions prevailing during wastewater treatment. Changes in polymer properties, observed for HDPE and PP under extreme exposure conditions only, are predicted to alter the risk microplastics pose to aquatic and terrestrial biota, since an increase in carbon-chlorine (C-Cl) bonds is known to increase toxicity, rendering the polymers more hydrophobic and thus more prone to adsorb, accumulate, and transport harmful persistent pollutants to biota in both aquatic and terrestrial environments.

Alcohol and nicotine consumption trends in three U.S. communities determined by wastewater-based epidemiology.

Wastewater-based epidemiology (WBE), an emerging tool for monitoring public health in near real-time, is used extensively in Europe but applications to U.S. populations are still scarce. In this longitudinal study, raw wastewater was collected monthly from three U.S. cities as 24-h weekday composites and analyzed for evidence of alcohol and tobacco consumption. Over the 11-month sampling period, biomarkers of stimulant use were detected in wastewater by isotope dilution liquid chromatography tandem mass spectrometry in units of µg/L (ethyl sulfate, 1.6-25.1; nicotine, 0.6-26.7; cotinine, 0.2-3.8; and 3­hydroxycotinine, 0.3-3.8). Average consumption rates in the three communities were calculated using detected biomarker levels in conjunction with wastewater flow rates, metabolic excretion factors, and population size data. Computed average per-capita consumption rates estimated for the sub-population aged 15 and above for alcohol (13.4 ±â€¯5.6 L/y/person) and daily consumption of nicotine by smokers (14.2 ±â€¯3.6 cigarettes/d/person) were in good agreement with U.S. survey data (9.0 L/y/person; 14.2 cigarettes/d/smoker). The WBE approach also captured impacts of temporal population influx on substance consumption patterns. This first U.S. WBE study to track recreational use of stimulants longitudinally and concurrently in multiple American cities highlights opportunities for collecting robust public health information from wastewater anonymously, economically and in near real-time.

Critical review of major sources of human exposure to N-nitrosamines.

More than 24 N-nitrosamine compounds contribute to the total N-nitrosamine (TNA) burden monitored routinely to assess human exposure to this important group of known and suspected human carcinogens. A literature review (n = 122) identified multiple sources of human exposure to TNAs, including waters (40 ±â€¯10.5 ng/L; average ± standard deviation), food and beverages (6.7 ±â€¯0.8 ng/g), tobacco (16,100 ±â€¯3650 ng/g) and personal care products (1500 ±â€¯750 ng/g). Due to source control interventions, levels of TNAs in beer have dropped by about 96% between 1980 and 1990, whereas N-nitrosamine levels in other known sources have shown little to no change. Maximum daily TNA exposure in the U.S. in units of ng/d is estimated at 25,000 ±â€¯4,950, driven by consumption of tobacco products (22,000 ±â€¯4350), food (1900 ±â€¯380), alcohol (1000 ±â€¯200), and drinking water (120 ±â€¯24). Behavioral choices of individuals in non-occupational settings were calculated to result in a spectrum of exposure values ranging from a lower bound of 1900 ±â€¯380 ng/d to a higher bound of 25,000 ±â€¯4950 ng/d, indicating opportunities for a possible 12-fold reduction in TNA exposure to 8% of the above maximum through deliberate choices in diet and lifestyle.

Activated carbon as a means of limiting bioaccumulation of organochlorine pesticides, triclosan, triclocarban, and fipronil from sediments rich in organic matter.

Addition of activated carbon to contaminated sediment is an established means of remediation but its applicability to sediments high in organic carbon is presently unknown. We evaluated the effects of adding either granular activated carbon (GAC) or pelletized fine-grained activated carbon (PfAC, containing ∼ 50% AC) to contaminated sediments from Lake Apopka featuring a very high total organic carbon content (∼39% w/w dry). Sediments showing background levels of legacy pesticides were spiked with a mixture of 5 chemicals (p,p'-DDE, dieldrin, triclosan, triclocarban, and fipronil) to a nominal concentration of 2 µg/g sediment for each chemical. Following incubation of spiked sediments with the addition of activated carbon for 30 days, we assessed the success on limiting bioaccumulation using Lumbriculus variegatus (blackworm). In contaminant-spiked sediments amended with PfAC, blackworm body burdens of triclosan, triclocarban, and fipronil decreased by >50% and those of p,p'-DDE and dieldrin decreased by <30%. GAC addition to spiked sediments was less impactful, and yielded notable benefits in worm body burden reduction only for fipronil (40%). Fipronil achieved high treatment efficiency within the 30 day amendment with both GAC and PfAC. This is the first study to examine AC treatment in artificially contaminated sediments intrinsically very rich in organic matter content. PfAC exhibited superior performance over GAC for mitigating the uptake of certain organochlorines by aquatic organisms. These results indicate that further studies focusing on additional types of sediments and a broader spectrum of hydrophobic pollutants are warranted.

Occurrence, temporal variation, and estrogenic burden of five parabens in sewage sludge collected across the United States.

Five parabens used as preservatives in pharmaceuticals and personal care products (PPCPs) were measured in sewage sludges collected at 14 U.S. wastewater treatment plants (WWTPs) located in nine states. Detected concentration ranges (ng/g, dry weight) and frequencies were as follows: methyl paraben (15.9 to 203.0; 100%), propyl paraben (0.5 to 7.7; 100%), ethyl paraben (<0.6 to 2.6; 63%), butyl paraben (<0.4 to 4.3; 42%) and benzyl paraben (<0.4 to 3.3; 26%). The estrogenicity inherent to the sum of parabens detected in sewage sludge (ranging from 10.1 to 500.1pg/kg 17ß-estradiol equivalents) was insignificant when compared to the 106-times higher value calculated for natural estrogens reported in the literature to occur in sewage sludge. Temporal monitoring at one WWTP provided insights into temporal and seasonal variations in paraben concentrations. This is the first report on the occurrence of five parabens in sewage sludges from across the U.S., and internationally, the first on temporal variations of paraben levels in sewage sludge. Study results will help to inform the risk assessment of sewage sludge destined for land application (biosolids).

Methyl mercury, but not inorganic mercury, associated with higher blood pressure during pregnancy.

Prior studies addressing associations between mercury and blood pressure have produced inconsistent findings; some of this may result from measuring total instead of speciated mercury. This cross-sectional study of 263 pregnant women assessed total mercury, speciated mercury, selenium, and n-3 polyunsaturated fatty acids in umbilical cord blood and blood pressure during labor and delivery. Models with a) total mercury or b) methyl and inorganic mercury were evaluated. Regression models adjusted for maternal age, race/ethnicity, prepregnancy body mass index, neighborhood income, parity, smoking, n-3 fatty acids and selenium. Geometric mean total, methyl, and inorganic mercury concentrations were 1.40µg/L (95% confidence interval: 1.29, 1.52); 0.95µg/L (0.84, 1.07); and 0.13µg/L (0.10, 0.17), respectively. Elevated systolic BP, diastolic BP, and pulse pressure were found, respectively, in 11.4%, 6.8%, and 19.8% of mothers. In adjusted multivariable models, a one-tertile increase of methyl mercury was associated with 2.83mmHg (0.17, 5.50) higher systolic blood pressure and 2.99mmHg (0.91, 5.08) higher pulse pressure. In the same models, an increase of one tertile of inorganic mercury was associated with -1.18mmHg (-3.72, 1.35) lower systolic blood pressure and -2.51mmHg (-4.49, -0.53) lower pulse pressure. No associations were observed with diastolic pressure. There was a non-significant trend of higher total mercury with higher systolic blood pressure. We observed a significant association of higher methyl mercury with higher systolic and pulse pressure, yet higher inorganic mercury was significantly associated with lower pulse pressure. These results should be confirmed with larger, longitudinal studies.

Prenatal exposure to tobacco smoke leads to increased mitochondrial DNA content in umbilical cord serum associated to reduced gestational age.

We investigated if prenatal exposures to tobacco smoke lead to changes in mitochondrial DNA content (mtDNA) in cord serum and adversely affect newborns' health. Umbilical cord serum cotinine levels were used to determine in utero exposure to smoking. Cord serum mtDNA was measured by quantitative polymerase chain reaction analysis of the genes coding for cytochrome c oxidase1 (MT-CO1) and cytochrome c oxidase2 (MT-CO2). Log transformed levels of mtDNA coding for MT-CO1 and MT-CO2 were significantly higher among infants of active smokers with higher serum level of cotinine (p < 0.05) and inversely associated with gestational age (p = 0.08; p = 0.02). Structural equation modeling results confirmed a positive association between cotinine and MT-CO1 and2 (p < 0.01) and inverse associations with gestational age (p = 0.02) and IGF-1 (p < 0.01). We identified a dose-dependent increase in the level of MT-CO1 and MT-CO2 associated to increased cord serum cotinine and decreased gestational age.

Occurrence of N-nitrosamines in U.S. freshwater sediments near wastewater treatment plants.

In the present study, 40 freshwater sediments collected near 14 wastewater treatment plants (WWTPs) across the United States were analyzed for eight N-nitrosamines by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Three N-nitrosamines were detected for the first time in freshwater sediments in units of ng/g dry weight at the specified detection frequency: N-nitrosodibutylamine (NDBA; 0.2-3.3; 58%), N-nitrosodiphenylamine (NDPhA; 0.2-4.7; 50%), and N-nitrosopyrrolidine (NPYR; 3.4-19.6; 18%). At least one N-nitrosamine was detected in 70% (28/40) of sediments analyzed. Non-detect values in units of ng/g dw were obtained for N-nitrosodimethylamine (NDMA; <10.2), N-nitrosomethylethylamine (NMEA; <1.7), N-nitrosodiethylamine (NDEA; <3.9), N-nitroso-di-n-propylamine (NDPA; <1.7), and N-nitrosopiperidine (NPIP; <3.6). Principal component analysis specifically points to two of multiple potential pathways explaining N-nitrosamine occurrences in sediment: NDBA and NDPhA were positively correlated with bulk water ammonia and pH levels, and NPYR with sediment content of organic carbon and iron. Interestingly, N-nitrosamine occurrences up- and downstream of WWTPs were statistically indistinguishable (p>0.05). This is the first report on the occurrence of the carcinogenic N-nitrosamines NDBA, NDPhA, and NPYR in U.S. freshwater sediments. Discovery of this phenomenon warrants further research on the compounds' origin, environmental persistence, aquatic toxicity, and risks posed.

Tissue distribution of organochlorine pesticides in largemouth bass (Micropterus salmoides) from laboratory exposure and a contaminated lake.

Tissue concentrations of persistent organochlorine pesticides in laboratory-exposed largemouth bass (Micropterus salmoides) and in bass collected from Lake Apopka, FL were determined by both total mass and lipid normalized mass to better understand the bioaccumulation pathways of contaminants. In the laboratory study, male bass were orally administered a single dose of a mixture of two pesticides (p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and dieldrin) and then fed uncontaminated food for 28 days. Gastrointestinal tract, liver, brain, gonad, kidney, spleen, and muscle were collected for chemical analysis. Different profiles were observed by total contaminant mass in tissues compared to lipid normalized mass. On a lipid normalized basis, p,p'-DDE was highest in the gastrointestinal tract followed by the liver, gonad, spleen, muscle, kidney and then brain. Dieldrin, on the other hand, was highest in the gastrointestinal tract and spleen and then followed by the gonad, muscle, liver, kidney, and brain. Distribution of the chemicals among the organs differed by their log KOW values and generally followed the blood flow path after the gastrointestinal tract. The low contaminant levels found in kidney and brain suggest insufficient time for equilibration into these tissues, especially into the brain where the blood-brain barrier may be slow to traverse. In Lake Apopka fish, dichlorodiphenyltrichloroethanes (DDXs, sum of p,p'-DDE, p,p'-DDD, and p,p'-DDT), Drins (sum of aldrin, dieldrin, and endrin), and hexachlorocyclohexanes (HCHs) were found. For DDXs, the lipid normalized concentrations in each tissue were about the same, as predicted from theory. For Drins and HCHs, the lipid normalized concentrations were similar for kidney, spleen, brain, gonad and muscle, but much lower in the gastrointestinal tract and liver, probably because of metabolism occurring in those tissues.

Cord Blood Methylmercury and Fetal Growth Outcomes in Baltimore Newborns: Potential Confounding and Effect Modification by Omega-3 Fatty Acids, Selenium, and Sex.

BACKGROUND: Methylmercury (MeHg) may affect fetal growth; however, prior research often lacked assessment of mercury speciation, confounders, and interactions. OBJECTIVE: Our objective was to assess the relationship between MeHg and fetal growth as well as the potential for confounding or interaction of this relationship from speciated mercury, fatty acids, selenium, and sex. METHODS: This cross-sectional study includes 271 singletons born in Baltimore, Maryland, 2004-2005. Umbilical cord blood was analyzed for speciated mercury, serum omega-3 highly unsaturated fatty acids (n-3 HUFAs), and selenium. Multivariable linear regression models controlled for gestational age, birth weight, maternal age, parity, prepregnancy body mass index, smoking, hypertension, diabetes, selenium, n-3 HUFAs, and inorganic mercury (IHg). RESULTS: Geometric mean cord blood MeHg was 0.94 µg/L (95% CI: 0.84, 1.07). In adjusted models for ponderal index, ßln(MeHg) = -0.045 (g/cm(3)) × 100 (95% CI: -0.084, -0.005). There was no evidence of a MeHg × sex interaction with ponderal index. Contrastingly, there was evidence of a MeHg × n-3 HUFAs interaction with birth length [among low n-3 HUFAs, ßln(MeHg) = 0.40 cm, 95% CI: -0.02, 0.81; among high n-3 HUFAs, ßln(MeHg) = -0.15, 95% CI: -0.54, 0.25; p-interaction = 0.048] and head circumference [among low n-3 HUFAs, ßln(MeHg) = 0.01 cm, 95% CI: -0.27, 0.29; among high n-3 HUFAs, ßln(MeHg) = -0.37, 95% CI: -0.63, -0.10; p-interaction = 0.042]. The association of MeHg with birth weight and ponderal index was affected by n-3 HUFAs, selenium, and IHg. For birth weight, ßln(MeHg) without these variables was -16.8 g (95% CI: -75.0, 41.3) versus -29.7 (95% CI: -93.9, 34.6) with all covariates. Corresponding values for ponderal index were -0.030 (g/cm(3)) × 100 (95% CI: -0.065, 0.005) and -0.045 (95% CI: -0.084, -0005). CONCLUSION: We observed an association of increased MeHg with decreased ponderal index. There is evidence for interaction between MeHg and n-3 HUFAs; infants with higher MeHg and n-3 HUFAs had lower birth length and head circumference. These results should be verified with additional studies.