Showing papers in "Environmental Science & Technology in 2003"
TL;DR: Aromatic carbon and the presence of specific aromatic compounds resulted in EEMs that aided in differentiating wastewater effluent DOM from drinking water DOM, and the highest cumulative EEM volume was observed for hydrophobic neutral DOM fractions.
Abstract: Excitation−emission matrix (EEM) fluorescence spectroscopy has been widely used to characterize dissolved organic matter (DOM) in water and soil. However, interpreting the >10,000 wavelength-dependent fluorescence intensity data points represented in EEMs has posed a significant challenge. Fluorescence regional integration, a quantitative technique that integrates the volume beneath an EEM, was developed to analyze EEMs. EEMs were delineated into five excitation−emission regions based on fluorescence of model compounds, DOM fractions, and marine waters or freshwaters. Volumetric integration under the EEM within each region, normalized to the projected excitation−emission area within that region and dissolved organic carbon concentration, resulted in a normalized region-specific EEM volume (Φi,n). Solid-state carbon nuclear magnetic resonance (13C NMR), Fourier transform infrared (FTIR) analysis, ultraviolet−visible absorption spectra, and EEMs were obtained for standard Suwannee River fulvic acid and 15 h...
4,407 citations
TL;DR: Data indicate that SUVA, determined at 254 nm, is strongly correlated with percent aromaticity as determined by 13C NMR for 13 organic matter isolates obtained from a variety of aquatic environments and is shown to be a useful parameter for estimating the dissolved aromatic carbon content in aquatic systems.
Abstract: Specific UV absorbance (SUVA) is defined as the UV absorbance of a water sample at a given wavelength normalized for dissolved organic carbon (DOC) concentration. Our data indicate that SUVA, determined at 254 nm, is strongly correlated with percent aromaticity as determined by 13C NMR for 13 organic matter isolates obtained from a variety of aquatic environments. SUVA, therefore, is shown to be a useful parameter for estimating the dissolved aromatic carbon content in aquatic systems. Experiments involving the reactivity of DOC with chlorine and tetra- methylammonium hydroxide (TMAH), however, show a wide range of reactivity for samples with similar SUVA values. These results indicate that, while SUVA measurements are good predictors of general chemical characteristics of DOC, they do not provide information about reactivity of DOC derived from different types of source materials. Sample pH, nitrate, and iron were found to influence SUVA measurements.
3,618 citations
TL;DR: The sorption data indicate that, under most of the chemical conditions investigated in this study, reduction of As(V) in the presence of HFO or goethite would have only minor effects on or even decrease its mobility in the environment at near-neutral pH conditions.
Abstract: Arsenic derived from natural sources occurs in groundwater in many countries, affecting the health of millions of people. The combined effects of As(V) reduction and diagenesis of iron oxide minerals on arsenic mobility are investigated in this study by comparing As(V) and As(III) sorption onto amorphous iron oxide (HFO), goethite, and magnetite at varying solution compositions. Experimental data are modeled with a diffuse double layer surface complexation model, and the extracted model parameters are used to examine the consistency of our results with those previously reported. Sorption of As(V) onto HFO and goethite is more favorable than that of As(III) below pH 5−6, whereas, above pH 7−8, As(III) has a higher affinity for the solids. The pH at which As(V) and As(III) are equally sorbed depends on the solid-to-solution ratio and type and specific surface area of the minerals and is shifted to lower pH values in the presence of phosphate, which competes for sorption sites. The sorption data indicate tha...
2,115 citations
TL;DR: It could be shown that the second-order rate constants determined in pure aqueous solution could be applied to predict the behavior of pharmaceuticals dissolved in natural waters.
Abstract: This study investigates the oxidation of pharmaceuticals during conventional ozonation and advanced oxidation processes (AOPs) applied in drinking water treatment. In a first step, second-order rate constants for the reactions of selected pharmaceuticals with ozone (k(O3)) and OH radicals (k(OH)) were determined in bench-scale experiments (in brackets apparent k(O3) at pH 7 and T = 20 degrees C): bezafibrate (590 +/- 50 M(-1) s(-1)), carbamazepine (approximately 3 x 10(5) M(-1) s(-1)), diazepam (0.75 +/- 0.15 M(-1) s(-1)), diclofenac (approximately 1 x 10(6) M(-1) s(-1)), 17alpha-ethinylestradiol (approximately 3 x 10(6) M(-1) s(-1)), ibuprofen (9.6 +/- 1.0 M(-1) s(-1)), iopromide ( 5 x 10(4) M(-1) s(-1), indicating that these compounds are completely transformed during ozonation processes. Values for k(OH) ranged from 3.3 to 9.8 x 10(9) M(-1) s(-1). Compared to other important micropollutants such as MTBE and atrazine, the selected pharmaceuticals reacted about two to three times faster with OH radicals. In the second part of the study, oxidation kinetics of the selected pharmaceuticals were investigated in ozonation experiments performed in different natural waters. It could be shown that the second-order rate constants determined in pure aqueous solution could be applied to predict the behavior of pharmaceuticals dissolved in natural waters. Overall it can be concluded that ozonation and AOPs are promising processes for an efficient removal of pharmaceuticals in drinking waters.
1,483 citations
TL;DR: The advantage of Co/PMS compared to the traditional Fenton Reagent is attributed primarily to the oxidizing strength of the radicals formed, since sulfate radicals are stronger oxidants than hydroxyl and the thermodynamics of the transition-metal-oxidant coupling.
Abstract: A highly efficient advanced oxidation process for the destruction of organic contaminants in water is reported. The technology is based on the cobalt-mediated decomposition of peroxymonosulfate that leads to the formation of very strong oxidizing species (sulfate radicals) in the aqueous phase. The system is a modification of the Fenton Reagent, since an oxidant is coupled with a transition metal in a similar manner. Sulfate radicals were identified with quenching studies using specific alcohols. The study was primarily focused on comparing the cobalt/peroxymonosulfate (Co/PMS) reagent with the traditional Fenton Reagent [Fe(II)/H2O2] in the dark, at the pH range 2.0-9.0 with and without the presence of buffers such as phosphate and carbonate. Three model contaminants that show diversity in structure were tested: 2,4-dichlorophenol, atrazine, and naphthalene. Cobalt/peroxymonosulfate was consistently proven to be more efficient than the Fenton Reagent for the degradation of 2,4-dichlorophenol and atrazine, at all the conditions tested. At high pH values, where the efficiency of the Fenton Reagent was diminished, the reactivity of the Co/PMS system was sustained at high values. When naphthalene was treated with the two oxidizing systems in comparison, the Fenton Reagent demonstrated higher degradation efficiencies than cobalt/peroxymonosulfate at acidic pH, but, at higher pH (neutral), the latter was proven much more effective. The extent of mineralization, as total organic carbon removed,was also monitored, and again the Co/PMS reagent demonstrated higher efficiencies than the Fenton Reagent. Cobalt showed true catalytic activity in the overall process, since extremely low concentrations (in the range of microg/L) were sufficient for the decomposition of the oxidant and thus the radical generation. The advantage of Co/PMS compared to the traditional Fenton Reagent is attributed primarily to the oxidizing strength of the radicals formed, since sulfate radicals are stronger oxidants than hydroxyl and the thermodynamics of the transition-metal-oxidant coupling.
1,390 citations
TL;DR: The sources of PAHs to ambient air in Baltimore, MD, were determined by using three source apportionment methods, principal component analysis with multiple linear regression, UNMIX, and positive matrix factorization.
Abstract: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in urban atmospheres. Several PAHs are known carcinogens or are the precursors to carcinogenic daughter compounds. Understanding the contributions of the various emission sources is critical to appropriately managing PAH levels in the environment. The sources of PAHs to ambient air in Baltimore, MD, were determined by using three source apportionment methods, principal component analysis with multiple linear regression, UNMIX, and positive matrix factorization. Determining the source apportionment through multiple techniques mitigates weaknesses in individual methods and strengthens the overlapping conclusions. Overall source contributions compare well among methods. Vehicles, both diesel and gasoline, contribute on average 16−26%, coal 28−36%, oil 15−23%, and wood/other having the greatest disparity of 23−35% of the total (gas- plus particle-phase) PAHs. Seasonal trends were found for both coal and oil. Coal was the dominate PAH source dur...
1,110 citations
1,017 citations
TL;DR: This study provides a basis for prioritizing toxicology and exposure research for individual EDCs and mixtures and provides new tools for exposure assessment in health studies.
Abstract: Chemicals identified as endocrine-disrupting compounds (EDCs) have widespread consumer uses, yet little is known about indoor exposure. We sampled indoor air and dust in 120 homes, analyzing for 89 organic chemicals identified as EDCs. Fifty-two compounds were detected in air and 66 were detected in dust. These are the first reported measures in residential environments for over 30 of the compounds, including several detected at the highest concentrations. The number of compounds detected per home ranged from 13 to 28 in air and from 6 to 42 in dust. The most abundant compounds in air included phthalates (plasticizers, emulsifiers), o-phenylphenol (disinfectant), 4-nonylphenol (detergent metabolite), and 4-tert-butylphenol (adhesive) with typical concentrations in the range of 50−1500 ng/m3. The penta- and tetrabrominated diphenyl ethers (flame retardants) were frequently detected in dust, and 2,3-dibromo-1-propanol, the carcinogenic intermediate of a flame retardant banned in 1977, was detected in air an...
966 citations
TL;DR: This publication contains reprint articles for which IEEE does not hold copyright and which are likely to be copyrighted.
Abstract: This publication contains reprint articles for which IEEE does not hold copyright. Full text is not available on IEEE Xplore for these articles.
939 citations
TL;DR: Assessment of arsenic levels in paddy soils throughout Bangladesh showed that arsenic levels were elevated in zones where arsenic in groundwater used for irrigation was high, and where these tube-wells have been in operation for the longest period of time.
Abstract: Arsenic contaminated groundwater is used extensively in Bangladesh to irrigate the staple food of the region, paddy rice (Oryza sativa L.). To determine if this irrigation has led to a buildup of arsenic levels in paddy fields, and the consequences for arsenic exposure through rice ingestion, a survey of arsenic levels in paddy soils and rice grain was undertaken. Survey of paddy soils throughout Bangladesh showed that arsenic levels were elevated in zones where arsenic in groundwater used for irrigation was high, and where these tube-wells have been in operation for the longest period of time. Regression of soil arsenic levels with tube-well age was significant. Arsenic levels reached 46 μg g-1 dry weight in the most affected zone, compared to levels below 10 μg g-1 in areas with low levels of arsenic in the groundwater. Arsenic levels in rice grain from an area of Bangladesh with low levels of arsenic in groundwaters and in paddy soils showed that levels were typical of other regions of the world. Model...
938 citations
TL;DR: The relative importance in terms of loads was carbamazepine, followed by diclofenac, naproxen, ibuprofen, clofibric acid, and ketoprofen; an overall removal rate was estimated in surface waters, under real-world conditions (in a lake), using field measurements and modeling.
Abstract: Although various single-concentration measurements of pharmaceuticals are available in the literature, detailed information on the variation over time of the concentration and the load in wastewater effluents and rivers and on the fate of these compounds in the aquatic environment are lacking. We measured the concentrations of six pharmaceuticals, carbamazepine, clofibric acid, diclofenac, ibuprofen, ketoprofen, and naproxen, in the effluents of three wastewater treatment plants (WWTPs), in two rivers and in the water column of Lake Greifensee (Switzerland) over a time period of three months. In WWTP effluents, the concentrations reached 0.95 μg/L for carbamazepine, 0.06 μg/L for clofibric acid, 0.99 μg/L for diclofenac, 1.3 μg/L for ibuprofen, 0.18 μg/L for ketoprofen, and 2.6 μg/L for naproxen. The relative importance in terms of loads was carbamazepine, followed by diclofenac, naproxen, ibuprofen, clofibric acid, and ketoprofen. An overall removal rate of all these pharmaceuticals was estimated in surf...
TL;DR: Too little is known about the effects of these compounds, their metabolites, and degradation products on human health and the environment.
Abstract: Too little is known about the effects of these compounds, their metabolites, and degradation products.
TL;DR: The observation that As( III) is oxidized in parallel to the oxidation of Fe(II) by O2 and by H2O2 and that the As(III) oxidation is not inhibited by *OH-radical scavengers at neutral pH is significant for the understanding of arsenic redox reactions in the environment and in arsenic removal processes as well as for theUnderstanding of Fenton reactions in general.
Abstract: The oxidation kinetics of As(III) with natural and technical oxidants is still not well understood, despite its importance in understanding the behavior of arsenic in the environment and in arsenic removal procedures. We have studied the oxidation of 6.6 μM As(III) by dissolved oxygen and hydrogen peroxide in the presence of Fe(II,III) at pH 3.5−7.5, on a time scale of hours. As(III) was not measurably oxidized by O2, 20−100 μM H2O2, dissolved Fe(III), or iron(III) (hydr)oxides as single oxidants, respectively. In contrast, As(III) was partially or completely oxidized in parallel to the oxidation of 20−90 μM Fe(II) by oxygen and by 20 μM H2O2 in aerated solutions. Addition of 2-propanol as an •OH-radical scavenger quenched the As(III) oxidation at low pH but had little effect at neutral pH. High bicarbonate concentrations (100 mM) lead to increased oxidation of As(III). On the basis of these results, a reaction scheme is proposed in which H2O2 and Fe(II) form •OH radicals at low pH but a different oxidant...
TL;DR: Caffeine concentrations in lakes correlated with the anthropogenic burden by domestic wastewaters, demonstrating the suitability of caffeine as a marker.
Abstract: The suitability of caffeine as a chemical marker for surface water pollution by domestic wastewaters was assessed in this study. Caffeine concentrations in influents and effluents of Swiss wastewater treatment plants (WWTPs, 7−73 and 0.03−9.5 μg/L, respectively) indicated an efficient elimination of 81−99.9%. Corresponding loads in untreated wastewater showed small variations when normalized for the population discharging to the WWTPs (15.8 ± 3.8 mg person-1 d-1), reflecting a rather constant consumption. WWTP effluent loads were considerably lower (0.06 ± 0.03 mg person-1 d-1), apart from installations with low sludge age (≤5 d, loads up to 4.4 mg person-1 d-1). Despite the efficient removal in most WWTPs, caffeine was ubiquitously found in Swiss lakes and rivers (6−250 ng/L), except for remote mountain lakes (<2 ng/L; analytical procedure for wastewater and natural waters: SPE, GC−MS−SIM or GC−MS−MS−MRM, internal standard 13C3-labeled caffeine). Caffeine concentrations in lakes correlated with the anth...
TL;DR: Sewage sludge is suggested as the main reservoir of FQ residues and the importance of sludge management strategies to determine whether most of the human-excreted FQs enter the environment is outlined.
Abstract: The behavior of fluoroquinolone antibacterial agents (FQs) during mechanical−biological wastewater treatment was studied by mass flow analysis. In addition, the fate of FQs in agricultural soils after sludge application was investigated. Concentrations of FQs in filtered wastewater (raw sewage, primary, secondary, and tertiary effluents) were determined using solid-phase extraction with mixed phase cation exchange disk cartridges and reversed-phase liquid chromatography with fluorescence detection. FQs in suspended solids, sewage sludge (raw, excess, and anaerobically digested sludge), and sludge-treated soils were determined as described for the aqueous samples but preceded by accelerated solvent extraction. Wastewater treatment resulted in a reduction of the FQ mass flow of 88−92%, mainly due to sorption on sewage sludge. A sludge-wastewater partition coefficient (log Kd ∼ 4) was calculated in the activated sludge reactors with a hydraulic residence time of about 8 h. No significant removal of FQs occur...
TL;DR: Numerical experiments indicated that increasing the colloid excluded volume of the pore space resulted in earlier breakthrough and higher peak effluent concentrations as a result of higher pore water velocities and lower residence times, respectively.
Abstract: A conceptual model for colloid transport is developed that accounts for colloid attachment, straining, and exclusion. Colloid attachment and detachment is modeled using first-order rate expressions, whereas straining is described using an irreversible first-order straining term that is depth dependent. Exclusion is modeled by adjusting transport parameters for colloid-accessible pore space. Fitting attachment and detachment model parameters to colloid transport data provided a reasonable description of effluent concentration curves, but the spatial distribution of retained colloids at the column inlet was severely underestimated for systems that exhibited significant colloid mass removal. A more physically realistic description of the colloid transport data was obtained by simulating both colloid attachment and straining. Fitted straining coefficients were found to systematically increase with increasing colloid size and decreasing median grain size. A correlation was developed to predict the straining co...
TL;DR: The patterns of contamination showed differences among sub-basins which correlated with the presence of large human settlements and/or animal farms, and the ratio of measured to predicted concentrations (MEC/...
Abstract: A survey was done in the river Po (Italy) to check for therapeutic drugs in the environment. A number of pharmaceuticals were selected for analysis on the basis of high consumption and excretion as parent compound in humans. Eight sampling stations along the rivers Po and Lambro made it possible to plot the patterns of contamination in a highly populated region with a large number of animal farms. Atenolol, lincomycin, erythromycin, clarithromycin, bezafibrate, and furosemide were present at all the sampling sites, and other drugs were found only in some. Concentrations ranged from 0.1 to 250 ng/L, and several drugs exceeded the trigger value (10 ng/L) suggested by recent documents from the European Agency for the Evaluation of Medicinal Products (EMEA), assessing environmental risks for these chemicals. The patterns of contamination showed differences among sub-basins which correlated with the presence of large human settlements and/or animal farms. The ratio of measured to predicted concentrations (MEC/...
TL;DR: Experimental evidence suggests that haloacetic acid precursors have a higher aromatic content than trihalomethane precursor, and Waters with higher specific ultraviolet absorbance values were more amenable to removal of organic material by coagulation than waters with low specific ultraviolet absorbsance values.
Abstract: Various water quality and treatment characteristics were evaluated under controlled chlorination conditions to determine their influences on the formation and distribution of nine haloacetic acids and four trihalomethanes in drinking water Raw waters were sampled from five water utilities and were coagulated with alum and fractionated with XAD-8 resin The resulting four fractionsraw and coagulated water and the hydrophobic and hydrophilic extractswere then chlorinated at pH 6 and 8 and held at 20 °C for various contact times The results show that increasing pH from 6 to 8 increased trihalomethane formation but decreased trihaloacetic acid formation, with little effect on dihaloacetic acid formation More trihalomethanes were formed than haloacetic acids at pH 8, while the reverse was true at pH 6 Hydrophobic fractions always gave higher haloacetic acid and trihalomethane formation potentials than their corresponding hydrophilic fractions, but hydrophilic carbon also played an important role in disinfe
TL;DR: A design protocol is presented that involves the following steps: identifying system function and boundaries, establishing requirements, selecting appropriate technologies, developing a system design, evaluating anticipated performance, and devising a practical means for system deployment.
Abstract: Pursuit of sustainable development requires a systems approach to the design of industrial product and service systems. Although many business enterprises have adopted sustainability goals, the actual development of sustainable systems remains challenging because of the broad range of economic, environmental and social factors that need to be considered across the system life cycle. Traditional systems engineering practices try to anticipate and resist disruptions but may be vulnerable to unforeseen factors. An alternative is to design systems with inherent "resilience" bytaking advantage of fundamental properties such as diversity, efficiency, adaptability, and cohesion. Previous work on sustainable design has focused largely upon ecological efficiency improvements. For example, companies have found that reducing material and energy intensity and converting wastes into valuable secondary products creates value for shareholders as well as for society at large. To encourage broader systems thinking, a design protocol is presented that involves the following steps: identifying system function and boundaries, establishing requirements, selecting appropriate technologies, developing a system design, evaluating anticipated performance, and devising a practical means for system deployment. The approach encourages explicit consideration of resilience in both engineered systems and the larger systems in which they are embedded.
TL;DR: It is shown that if VOH and the rate constants of the reactions of *OH with the system's constituents are known, the oxidation rate of a dissolved organic compound can be predicted and that unknown reactants are either interfering with *OH production or consuming *OH in these systems.
Abstract: The iron oxide-catalyzed production of hydroxyl radical (•OH) from hydrogen peroxide (H2O2) has been used to oxidize organic contaminants in soils and groundwater. The goals of this study are to de...
TL;DR: A model that accounts for both hindered diffusion of salt ions and altered hydrodynamics within colloidal deposit layers is presented and successfully links permeate flux and salt rejection to cake-enhanced concentration polarization and provides new insight into the mechanisms through which salt-rejecting membranes foul.
Abstract: Results from well-controlled colloidal fouling experiments with reverse osmosis (RO) and nanofiltration (NF) membranes suggest the existence of a new source of flux decline for salt-rejecting membr...
TL;DR: Nanotechnology could substantially enhance environmental quality and sustainability through pollution prevention, treatment, and remediation.
Abstract: Nanotechnology could substantially enhance environmental quality and sustainability through pollution prevention, treatment, and remediation.
TL;DR: This paper presents data from a survey of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) concentrations in 191 global background surface soils, with OM-rich soils in the NH consistently contained the highest burdens; such soils are a key global compartment for these compounds.
Abstract: This paper presents data from a survey of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) concentrations in 191 global background surface (0−5 cm) soils. Differences of up to 4 orders of magnitude were found between sites for PCBs. The lowest and highest PCB concentrations (26 and 97 000 pg/g dw) were found in samples from Greenland and mainland Europe (France, Germany, Poland), respectively. Background soil PCB concentrations were strongly influenced by proximity to source region and soil organic matter (SOM) content. Most (>80%) of the estimated soil PCB burden remains in the “global source region” of the Northern Hemisphere (NH) temperate latitudes (30−60° N) or in the OM-rich soils just north of that. %SOM correlated with PCB and HCB in the global data set, with the correlation coefficients being greater for HCB and the lighter PCBs than for heavier homologues. OM-rich soils in the NH consistently contained the highest burdens; such soils are a key global compartment for these compounds. ...
TL;DR: The main outcome of the study was that a common municipal STP with an activated sludge system for nitrification and denitrification including sludge recirculation can appreciably eliminate natural and synthetic estrogens.
Abstract: The fate of the highly potent endocrine disrupters estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) was investigated in mechanical and biological sewage treatment as well as in sewage-sludge treatment at a municipal German sewage treatment plant (STP). The main outcome of the study was that a common municipal STP with an activated sludge system for nitrification and denitrification including sludge recirculation can appreciably eliminate natural and synthetic estrogens. As a consequence, the endocrine effects of biota in the receiving waters should be significantly reduced. All estrogen concentrations decreased gradually along the treatment train. In the STP effluent, the steroid estrogen concentrations were always below the quantification limit of 1 ng/L. The elimination efficiency of the natural estrogens (E1 and E2) exceeded 98%, and EE2 was reduced by more than 90%. The natural estrogens were largely degraded biologically in the denitrifying and aerated nitrifying tanks of the activate...
TL;DR: The ability of each individual steroid to contribute to the overall effect of a mixture, even at individual no-effect concentrations, combined with the high estrogenic potency of the steroids, particularly the synthetic steroid EE2, emphasizes the need to consider the total estrogenic load of these chemicals in the authors' waterways.
Abstract: The natural steroids estradiol-17beta (E2) and estrone (E1) and the synthetic steroid ethynylestradiol-17alpha (EE2) have frequently been measured in waters receiving domestic effluents. All of these steroids bind to the estrogen receptor(s) and have been shown to elicit a range of estrogenic responses in fish at environmentally relevant concentrations. At present, however, no relative potency estimates have been derived for either the individual steroidal estrogens or their mixtures in vivo. In this study the estrogenic activity of E2, E1, and EE2, and the combination effects of a mixture of E2 and EE2 (equi-potent fixed-ratio mixture), were assessed using vitellogenin induction in a 14-day in vivo juvenile rainbow trout screening assay. Median effective concentrations, relative to E2, for induction of vitellogenin were determined from the concentration-response curves and the relative estrogenic potencies of each of the test chemicals calculated. Median effective concentrations were between 19 and 26 ng L(-1) for E2, 60 ng L(-1) for E1, and between 0.95 and 1.8 ng L(-1) for EE2, implying that EE2 was approximately 11 to 27 times more potent than E2, while E2 was 2.3 to 3.2 times more potent than E1. The median effective concentration, relative to E2, for the binary mixture of E2 and EE2 was 15 ng L(-1) (comprising 14.4 ng L(-1) E2 and 0.6 ng L(-1) EE2). Using the model of concentration addition it was shown that this activity of the binary mixture could be predicted from the activity of the individual chemicals. The ability of each individual steroid to contribute to the overall effect of a mixture, even at individual no-effect concentrations, combined with the high estrogenic potency of the steroids, particularly the synthetic steroid EE2, emphasizes the need to consider the total estrogenic load of these chemicals in our waterways.
TL;DR: Real-time PCR assays using TaqMan or Molecular Beacon probes were developed and optimized for the quantification of total bacteria, the nitrite-oxidizing bacteria Nitrospira, and Nitrosomonas oligotropha-like ammonia oxidizing bacteria (AOB) in mixed liquor suspended solids from a municipal wastewater treatment plant (WWTP) using a single-sludge nitrification process.
Abstract: Real-time PCR assays using TaqMan or Molecular Beacon probes were developed and optimized for the quantification of total bacteria, the nitrite-oxidizing bacteria Nitrospira, and Nitrosomonas oligotropha-like ammonia oxidizing bacteria (AOB) in mixed liquor suspended solids (MLSS) from a municipal wastewater treatment plant (WWTP) using a single-sludge nitrification process. The targets for the real-time PCR assays were the 16S rRNA genes (16S rDNA) for bacteria and Nitrospira spp. and the amoA gene for N. oligotropha. A previously reported assay for AOB 16S rDNA was also tested for its application to activated sludge. The Nitrospira 16S rDNA, AOB 16S rDNA, and N. oligotropha-like amoA assays were log-linear over 6 orders of magnitude and the bacterial 16S rDNA real-time PCR assay was log-linear over 4 orders of magnitude with DNA standards. When these real-time PCR assays were applied to DNA extracted from MLSS, dilution of the DNA extracts was necessary to prevent PCR inhibition. The optimal DNA dilution range was broad for the bacterial 16S rDNA (1000-fold) and Nitrospira 16S rDNA assays (2500-fold) but narrow for the AOB 16S rDNA assay (10-fold) and N. oligotropha-like amoA real-time PCR assay (5-fold). In twelve MLSS samples collected over one year, mean cell per L values were 4.3 +/- 2.0 x 10(11) for bacteria, 3.7 +/- 3.2 x 10(10) for Nitrospira, 1.2 +/- 0.9 x 10(10) for all AOB, and 7.5 +/- 6.0 x 10(9) for N. oligotropha-like AOB. The percent of the nitrifying population was 1.7% N. oligotropha-like AOB based on the N. oligotropha amoA assay, 2.9% total AOB based on the AOB 16S rDNA assay, and 8.6% nitrite-oxidizing bacteria based on the Nitrospira 16S rDNA assay. Ammonia-oxidizing bacteria in the wastewater treatment plant were estimated to oxidize 7.7 +/- 6.8 fmol/hr/cell based on the AOB 16S rDNA assay and 12.4 +/- 7.3 fmol/hr/cell based on the N. oligotropha amoA assay.
TL;DR: A literature review to assess the current state of science regarding estrogen physicochemical properties, livestock excretion, and the fate of manure-borne estrogens in the environment found that estrogens are sufficiently mobile and persistent to impact surface and groundwater quality.
Abstract: Livestock wastes are potential sources of endocrine disrupting compounds to the environment. Steroidal estrogen hormones such as estradiol, estrone, and estriol are a particular concern because there is evidence that low nanogram per liter concentrations of estrogens in water can adversely affect the reproductive biology of fish and other aquatic vertebrate species. We performed a literature review to assess the current state of science regarding estrogen physicochemical properties, livestock excretion, and the fate of manure-borne estrogens in the environment. Unconjugated steroidal estrogens have low solubility in water (0.8-13.3 mg L(-1)) and are moderately hydrophobic (log Kow 2.6-4.0). Cattle excrete mostly 17alpha-estradiol, 17beta-estradiol, estrone, and respective sulfated and glucuronidated counterparts, whereas swine and poultry excrete mostly 17beta-estradiol, estrone, estriol, and respective sulfated and glucuronidated counterparts. The environmental fate of estrogens is not clearly known. Laboratory-based studies have found that the biological activity of these compounds is greatly reduced or eliminated within several hours to days due to degradation and sorption. On the other hand, field studies have demonstrated that estrogens are sufficiently mobile and persistent to impact surface and groundwater quality. Future research should use standardized methods for the analysis of manure, soil, and water. More information is needed about the types and amounts of estrogens that exist in livestock wastes and the fate of manure-borne estrogens applied to agricultural lands. Field and laboratory studies should work toward revealing the mechanisms of estrogen degradation, sorption, and transport so that the risk of estrogen contamination of waterways can be minimized.
TL;DR: The effective density provides the relationship between mobility and aerodynamic equivalent diameters and shows that mass distributions of diesel particles measured with the SMPS-APM are in good agreement with distributions measured with a MOUDI and a nano-MOUDI for particles larger than approximately 60 nm.
Abstract: We used the aerosol particle mass analyzer (APM) to measure the mass of mobility-classified diesel exhaust particles. This information enabled us to determine the effective density and fractal dimension of diesel particles as a function of engine load. We found that the effective density decreases as particle size increases. TEM images showed that this occurs because particles become more highly agglomerated as size increases. Effective density and fractal dimension increased somewhat as engine load decreased. TEM images suggest that this occurs because these particles contain more condensed fuel and/or lubricating oil. Also, we observed higher effective densities when high-sulfur EPA fuel (∼360 ppm S) was used than for Fischer−Tropsch fuel (∼0 ppm S). In addition, the effective density provides the relationship between mobility and aerodynamic equivalent diameters. The relationship between these diameters enables us to intercompare, in terms of a common measure of size, mass distributions measured with t...
TL;DR: Results show that low pH was, without heat treatment, sufficient to control hydrogen losses to methanogens in mixed batch cultures and suggest that methods will need to be found to limit acetogenesis in order to increase hydrogen gas yields by batch cultures.
Abstract: Hydrogen gas can be recovered from the microbial fermentation of organic substrates at high concentrations when interspecies hydrogen transfer to methanogens is prevented. Two techniques that have been used to limit methanogenesis in mixed cultures are heat treatment, to remove nonsporeforming methanogens from an inoculum, and low pH during culture growth. We found that high hydrogen gas concentrations (57-72%) were produced in all tests and that heat treatment (HT) of the inoculum (pH 6.2 or 7.5) produced greater hydrogen yields than low pH (6.2) conditions with a nonheat-treated inoculum (NHT). Conversion efficiencies of glucose to hydrogen (based on a theoretical yield of 4 mol-H2/mol-glucose) were as follows: 24.2% (HT, pH = 6.2), 18.5% (HT, pH = 7.5), 14.9% (NHT, pH = 6.2), and 12.1% (NHT, pH = 7.5). The main products of glucose (3 g-COD/L) utilization (> or = 99%) in batch tests were acetate (3.4-24.1%), butyrate (6.4-29.4%), propionate (0.3-12.8%), ethanol (15.4-28.8%), and hydrogen (4.0-8.1%), with lesser amounts of acetone, propanol, and butanol (COD basis). Hydrogen gas phase concentrations in all batch cultures reached a maximum of 57-72% after 30 h but thereafter rapidly declined to nondetectable levels within 80 h. Separate experiments showed substantial hydrogen losses could occur via acetogenesis and that heat treatment did not prevent acetogenesis. Heat treatment consistently eliminated the production of measurable concentrations of methane. The disappearance of ethanol produced during hydrogen production was likely due to acetic acid production as thermodynamic calculations show that this reaction is spontaneous once hydrogen is depleted. Overall, these results show that low pH was, without heat treatment, sufficient to control hydrogen losses to methanogens in mixed batch cultures and suggest that methods will need to be found to limit acetogenesis in order to increase hydrogen gas yields by batch cultures.
TL;DR: In this study, concentrations and distribution of PFOS, perfluorohexane sulfonate (PFHS), and perfluorobutane sulf onates (PFBS) were determined in samples of surface water, fish and bird blood and livers, and human blood collected in Japan.
Abstract: Occurrence of perfluorooctane sulfonate (PFOS) in the tissues of humans and wildlife is well documented. In this study, concentrations and distribution of PFOS, perfluorohexane sulfonate (PFHS), and perfluorobutane sulfonate (PFBS) were determined in samples of surface water, fish and bird blood and livers, and human blood collected in Japan. Notable concentrations of PFOS were found in surface water and fish from Tokyo Bay. PFOS was found in all of the 78 samples of fish blood and liver analyzed. Based on the concentrations of PFOS in water and in fish livers, bioconcentration factors were calculated to range from 274 to 41 600. Concentrations of PFOS in the blood of Japanese human volunteers ranged from 2.4 to 14 ng/mL. PFHS was detected in 33% of the fishes analyzed, at concentrations severalfold less than those of PFOS.