As engineered nanoparticles (NPs) are increasingly used, their entry into the environment has become an important topic for water sustainability. Recent investigations point to the critical role of ...natural organic matter (NOM) in altering the persistence of NPs by complexing with their surfaces. The NP-NOM complex, in turn, is the new entity that may potentially influence subsequent fate of NPs. To understand the relative impact of humic (HA) and fulvic fraction of NOM on the stability and mobility of silver nanoparticles (AgNPs), a combination of dynamic light scattering and quartz crystal microgravimetry with dissipation monitoring was used. In the absence of unbound NOM, (1) surface modification on either AgNP or silica substrate by different NOM fractions could lead to substantial changes in the extent and kinetics of AgNP aggregation and deposition, and (2) HA has a greater capability to enhance the transport of AgNPs by reducing their aggregation and deposition. With unbound NOM, HA seems to compete more successfully for binding sites on the substrate under electrostatically favorable conditions and formed a steric layer to prevent subsequent deposition of AgNPs. These findings highlighted the importance of NOM fraction in the overall environmental partitioning of AgNPs.
Lifetime contaminant and hormonal profiles have been reconstructed for an individual male blue whale (Balaenoptera musculus , Linnaeus 1758) using the earplug as a natural aging matrix that is also ...capable of archiving and preserving lipophilic compounds. These unprecedented lifetime profiles (i.e., birth to death) were reconstructed with a 6-mo resolution for a wide range of analytes including cortisol (stress hormone), testosterone (developmental hormone), organic contaminants (e.g., pesticides and flame retardants), and mercury. Cortisol lifetime profiles revealed a doubling of cortisol levels over baseline. Testosterone profiles suggest this male blue whale reached sexual maturity at approximately 10 y of age, which corresponds well with and improves on previous estimates. Early periods of the reconstructed contaminant profiles for pesticides (such as dichlorodiphenyltrichloroethanes and chlordanes), polychlorinated biphenyls, and polybrominated diphenyl ethers demonstrate significant maternal transfer occurred at 0–12 mo. The total lifetime organic contaminant burden measured between the earplug (sum of contaminants in laminae layers) and blubber samples from the same organism were similar. Total mercury profiles revealed reduced maternal transfer and two distinct pulse events compared with organic contaminants. The use of a whale earplug to reconstruct lifetime chemical profiles will allow for a more comprehensive examination of stress, development, and contaminant exposure, as well as improve the assessment of contaminant use/emission, environmental noise, ship traffic, and climate change on these important marine sentinels.
Pharmaceuticals and personal care products are being increasingly reported in a variety of biological matrices, including fish tissue; however, screening studies have presently not encompassed broad ...geographical areas. A national pilot study was initiated in the United States to assess the accumulation of pharmaceuticals and personal care products in fish sampled from five effluent-dominated rivers that receive direct discharge from wastewater treatment facilities in Chicago, Illinois; Dallas, Texas; Orlando, Florida; Phoenix, Arizona; and West Chester, Pennsylvania, USA. Fish were also collected from the Gila River, New Mexico, USA, as a reference condition expected to be minimally impacted by anthropogenic influence. High performance liquid chromatography-tandem mass spectrometry analysis of pharmaceuticals revealed the presence of norfluoxetine, sertraline, diphenhydramine, diltiazem, and carbamazepine at nanogram-per-gram concentrations in fillet composites from effluent-dominated sampling locations; the additional presence of fluoxetine and gemfibrozil was confirmed in liver tissue. Sertraline was detected at concentrations as high as 19 and 545 ng/g in fillet and liver tissue, respectively. Gas chromatography-tandem mass spectrometry analysis of personal care products in fillet composites revealed the presence of galaxolide and tonalide at maximum concentrations of 2,100 and 290 ng/g, respectively, and trace levels of triclosan. In general, more pharmaceuticals were detected at higher concentrations and with greater frequency in liver than in fillet tissues. Higher lipid content in liver tissue could not account for this discrepancy as no significant positive correlations were found between accumulated pharmaceutical concentrations and lipid content for either tissue type from any sampling site. In contrast, accumulation of the personal care products galaxolide and tonalide was significantly related to lipid content. Results suggest that the detection of pharmaceuticals and personal care products was dependent on the degree of wastewater treatment employed.
One of the most important challenges researchers and managers confront in conservation ecology is predicting a population's response to sub-lethal stressors. Such predictions have been particularly ...elusive when assessing responses of large marine mammals to past anthropogenic pressures. Recently developed techniques involving baleen whale earplugs combine age estimates with cortisol measurements to assess spatial and temporal stress/stressor relationships. Here we show a relationship between baseline-corrected cortisol levels and corresponding whaling counts of fin, humpback, and blue whales in the Northern Hemisphere spanning the 20th century. We also model the impact of alternative demographic and environmental factors and determine that increased anomalies of sea surface temperature over a 46-year mean (1970-2016) were positively associated with cortisol levels. While industrial whaling can deplete populations by direct harvest, our data underscore a widespread stress response in baleen whales that is peripheral to whaling activities or associated with other anthropogenic change.
German Environment Specimen Bank (GESB) fish tissue samples, collected from 14 different GESB locations, were analyzed for 15 pharmaceuticals, 2 pharmaceutical metabolites, and 12 personal care ...products. Only 2 pharmaceuticals, diphenhydramine and desmethylsertraline, were measured above MDL. Diphenhydramine (0.04–0.07 ng g–1 ww) and desmethylsertraline (1.65–3.28 ng g–1 ww) were measured at 4 and 2 locations, respectively. The maximum concentrations of galaxolide (HHCB) (447 ng g–1 ww) and tonalide (AHTN) (15 ng g–1 ww) were measured at the Rehlingen sampling site in the Saar River. A significant decrease in HHCB and AHTN fish tissue concentrations was observed from 1995 to 2008 at select GESB sampling sites (r 2 = 0.69–0.89 for galaxolide and 0.89–0.97 for tonalide with p < 0.003). Galaxolide and tonalide fish tissue concentrations in Germany were ∼19× and ∼28× lower, respectively, as compared to fish tissue concentrations measured in a United States nationwide PPCP study conducted in 2006. Proximity of the sampling locations to the upstream wastewater treatment plant discharging point and mean annual flow at the sampling location were found to significantly predict galaxolide and tonalide fish tissue concentrations (HHCB: r 2 = 0.79, p = 0.021 and AHTN: r 2 = 0.81, p = 0.037) in Germany.
Parabens are common antimicrobial agents found in thousands of pharmaceuticals and personal care products. Parabens are introduced into aquatic ecosystems from wastewater treatment plant effluents ...and have been detected in surface waters in the low microgram per liter range. Although these compounds display low toxicity in mammals, paraben toxicity to aquatic organisms has not been investigated. Standardized acute and subchronic endpoints in larval fish (Pimephales promelas) and cladoceran (Daphnia magna) models were examined for seven different parabens (methyl-, ethyl-, isopropyl-, propyl-, isobutyl-, butyl-, benzylparaben), which encompassed a range of log P values. Paraben 48 h median lethal concentration values (LC50) ranged from 4.0 to 24.6 mg/L in D. magna and 3.3 to > 160.0 mg/L in fathead minnow. Growth and reproduction in D. magna had lowest-observed-effect concentrations (LOECs) ranging from 0.12 to 9.0 mg/L and 1.5 to 6.0 mg/L, respectively. Fathead minnow growth was adversely affected at levels ranging from 1.0 to 25.0 mg/L. Aquatic toxicity of the parabens was inversely related to lipophilicity, suggesting that responses using standardized endpoints resulted from narcosis. Utilizing toxicity benchmark concentrations (e.g., LC50s, LOECs) for each compound, chemical toxicity distributions, a probabilistic hazard assessment technique, were developed to assess the probabilities of detecting parabens that elicit a response at or below a given concentration. For the responses assessed in the present study, the 5th centile values (the concentration at which 5% of parabens elicit a response) ranged from 15 microliter to 2.43 mg/L, with D. magna growth eliciting the lowest 5th centile value and acute D. magna mortality eliciting the highest. The distributions demonstrated that at environmentally relevant concentrations in developed countries there is limited acute or subchronic aquatic hazard of parabens to the organisms and responses examined.
The population of Texas has increased rapidly in the past decade. The San Antonio Field Study (SAFS) was designed to investigate ozone (O3) production and precursors in this rapidly changing, ...sprawling metropolitan area. There are still many questions regarding the sources and chemistry of volatile organic compounds (VOCs) in urban areas like San Antonio which are affected by a complex mixture of industry, traffic, biogenic sources and transported pollutants. The goal of the SAFS campaign in May 2017 was to measure inorganic trace gases, VOCs, methane (CH4), and ethane (C2H6). The SAFS field design included two sites to better assess air quality across the metro area: an urban site (Traveler's World; TW) and a downwind/suburban site (University of Texas at San Antonio; UTSA). The results indicated that acetone (2.52 ± 1.17 and 2.39 ± 1.27 ppbv), acetaldehyde (1.45 ± 1.02 and 0.93 ± 0.45 ppbv) and isoprene (0.64 ± 0.49 and 1.21 ± 0.85 ppbv; TW and UTSA, respectively) were the VOCs with the highest concentrations. Additionally, positive matrix factorization showed three dominant factors of VOC emissions: biogenic, aged urban mixed source, and acetone. Methyl vinyl ketone and methacrolein (MVK + MACR) exhibited contributions from both secondary photooxidation of isoprene and direct emissions from traffic. The C2H6:CH4 demonstrated potential influence of oil and gas activities in San Antonio. Moreover, the high O3 days during the campaign were in the NOx-limited O3 formation regime and were preceded by evening peaks in select VOCs, NOx and CO. Overall, quantification of the concentration and trends of VOCs and trace gases in a major city in Texas offers vital information for general air quality management and supports strategies for reducing O3 pollution. The SAFS campaign VOC results will also add to the growing body of literature on urban sources and concentrations of VOCs in major urban areas.
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•PMF revealed three VOC factors for San Antonio: biogenic, aged urban mixed source and acetone.•High concentrations of acetone and acetaldehyde at both sites indicate high contribution of regional, oxidized VOCs.•Methane to ethane ratios reveal periods of oil and natural gas influence on San Antonio.•High O3 episode occurs from the combination of northern continental airmass, high actinic flux and high nighttime O3 precursors (VOCs and NOx) on the preceding day.
To investigate major sources and trends of particulate pollution in Houston, total suspended particulate (TSP) and fine particulate matter (PM2.5) samples were collected and analyzed. ...Characterization of organic (OC) and elemental (EC) carbon combined with realtime black carbon (BC) concentration provided insight into the temporal trends of PM2.5 and coarse PM (subtraction of PM2.5 from TSP) during the Deriving Information on Surface Conditions from Column and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) Campaign in Houston in 2013. Ambient OC, EC, and BC concentrations were highest in the morning, likely due to motor vehicle exhaust emissions associated with the morning rush hour. The morning periods also had the lowest OC to EC ratios, indicative of primary combustion sources. Houston also had significant coarse EC at the downtown site, with an average (±standard deviation) PM2.5 to TSP ratio of 0.52 ± 0.18 and an average coarse EC concentration of 0.44 ± 0.24 µg·C·m−3. The coarse EC concentrations were likely associated with less efficient industrial combustion processes from industry near downtown Houston. During the last week (20–28 September, 2013), increases in OC and EC concentrations were predominantly in the fine fraction. Both PM2.5 and TSP samples from the last week were further analyzed using radiocarbon analysis. Houston’s carbonaceous aerosol was determined to be largely from contemporary sources for both size fractions; however, PM2.5 had less impact from fossil sources. There was an increasing trend in fossil carbon during a period with the highest carbonaceous aerosol concentrations (September 24 night and 25 day) that was observed in both the PM2.5 and TSP. Overall, this study provided insight into the sources and trends of both fine and coarse PM in a large urban U.S. city impacted by a combination of urban, industrial, and biogenic emissions sources.
Two screening methods have been developed for simultaneous determination of ten extensively used personal care products (PCPs) and two alkylphenol surfactants in fish. The methods consisted of ...extraction, clean-up, derivatization and analysis by gas chromatography–mass spectrometry with selected ion monitoring (GC–SIM–MS) or gas chromatography–tandem mass spectrometry (GC–MS/MS) techniques. Among solvents tested to assess recovery of target compounds from 1-g tissue homogenates, acetone was selected as optimal for extracting compounds with dissimilar physicochemical properties from fish tissue. Initial experiments confirmed that GC–SIM–MS could be applied for analysis of lean fillet tissue (<1% lipid) without gel-permeation chromatography (GPC), and this approach was applied to assess the presence of target analytes in fish fillets collected from a regional effluent-dominated stream in Texas, USA. Benzophenone, galaxolide, tonalide, and triclosan were detected in 11 of 11 environmental samples at concentrations ranging from; 37 to 90, 234 to 970, 26 to 97, and 17 to 31
ng/g, respectively. However, performance of this analytical approach declined appreciably with increasing lipid content of analyzed tissues. Successful analysis of samples with increased lipid content was enabled by adding GPC to the sample preparation protocol and monitoring analytes with tandem mass spectrometry. Both analytical approaches were validated using fortified fillet tissue collected from locations expected to be minimally impacted by anthropogenic influences. Average analyte recoveries ranged from 87% to 114% with RSDs <11% and from 54% to 107% with RSDs <20% for fish tissue containing <1% and 4.9% lipid, respectively. Statistically derived method detection limits (MDLs) for GC–SIM–MS and GC–MS/MS methodologies ranged from 2.4 to 16
ng/g, and 5.1 to 397
ng/g, respectively.
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