Characterization of fine primary biogenic organic aerosol in an urban area in the northeastern United States

Scanning electron microscopy coupled to energy-dispersive x-ray spectroscopy (SEM/EDX) was used to quantify individual bioparticles in PM_2.5 samples collected during the Pittsburgh Air Quality Study. Microscopy-based estimates of primary biogenic organic aerosol (PBOA) mass were compared to carbohydrate mass associated with PM_2.5. Carbohydrates show substantial seasonal variations, with higher concentrations in the spring and the fall. During the summer, carbohydrates were about 30% of the estimated PBOA concentrations, but in the winter carbohydrate concentrations often greatly exceeded the PBOA mass estimate. Spores and insect detritus were the most abundant PBOA types in the summer samples, while winter samples were comprised predominantly of a mixture of microorganisms, insect and vegetative detritus. During the summer PBOA contributed on average 6.9 ± 5.4% by mass of the PM_2.5 versus 3.3 ± 1.4% of the PM_2.5 mass during the winter.     

The solitary median maxillary central incisor (SMMCI) syndrome: Associations,prenatal diagnosis,and outcomes

Solitary median maxillary central incisor (SMMCI) syndrome is a complex disorder consisting of multiple, developmental defects involving midline structures of the head, which includes the cranial bones, the maxilla, and its container dentition (specifically the central incisor tooth germ), together with other midline structures of the body. SMMCI may appear as an isolated trait or in association with other midline developmental anomalies. We describe the case of a patient with SMMCI. He presented with a solitary median maxillary incisor, short stature, corpus callosum anomalies and a microform of holoprosencephaly (HPE), diabetes insipidus, and neurodevelopmental delay. The diagnosis was performed postnatally based on clinical features, radiological imaging, and a comprehensive genetic study. SMMCI can be diagnosed during the prenatal or neonatal periods or during infancy. Evaluation of the superior maxillary bone is important for prenatal diagnosis. Direct evaluation through bidimensional ultrasound or the use of multiplanar ultrasound or tridimensional reconstruction should be performed in cases of brain or face malformations. Early diagnosis can contribute to improved prenatal assessment and postnatal management.     

A pilot study of pesticides and PCBs in the breast milk of women residing in urban and agricultural communities of California

Currently, there is no nationally representative human milk biomonitoring program in the United States (U.S.) and no studies have reported non-persistent pesticides in the milk of U.S. women. In this pilot study we developed a multiresidue laboratory method to measure non-persistent and persistent pesticides and polychlorinated biphenyl (PCB) congeners in human milk samples from women residing in the agricultural region of Salinas, CA (n = 13) and the urban San Francisco Bay Area, CA (n = 21). Samples were collected from 2002-2007. Median concentrations in pg g(-1) milk among urban and agricultural women, respectively were reported for: chlorpyrifos (24.5 and 28.0), cis-permethrin (81.9 and 103), trans-permethrin (93.1 and 176), hexachlorobenzene (191 and 223), β-hexachlorocyclohexane (220 and 443), o,p'-DDT (36.6 and 62.4), p,p'-DDT,(107 and 102), o,p'-DDE (5.65 and 5.17), p,p'-DDE (3170 and 3490), dacthal (2.79 and 3.43), PCB 118 (92.8 and 17.0), PCB 138 (183 and 38.2), PCB 153 (242 and 43.6) and PCB 180 (239 and 683). Among urban women, median concentrations were 4.02 and 4.32 pg g(-1) milk for chlorpyrifos-methyl and propoxur, respectively. These results suggest that neonates and young children may be exposed to persistent and non-persistent pesticides and PCBs via breast milk.     

Organic matter characteristics and nutrient content in eroded soils

Twenty-one severely eroded soils of SE Spain (Torriorthent xeric soils) were studied. These soils form a fragile system characterized by soils with a low density of plant cover (<5%), are loamy and occur in a semiarid climate. The soils formerly were used for agricultural purposes but were abandoned at least 15 years ago. These eroded soils had a low total organic carbon content, and their humic substances, humic acid carbon, and carbohydrates were lower compared with soils that had never been cultivated (natural soils). The variables in which the effects of erosion were particularly noted were those related with the active organic matter (respiration and water-soluble organic matter). Those eroded soils with higher salt content showed lower organic matter and carbohydrate contents. Only total nitrogen was correlated with the carbon fractions in the eroded soils.     

Changes in carbon fractions during composting and maturation of organic wastes

Seven mixtures from four organic residues—an aerobic sewage sludge, a city refuse, a peat residue, and a grape debris—were composted, and the changes undergone by their different carbon fractions during their composting and maturation were studied. In most cases a decrease in carbon fractions during the composting and maturation processes was observed. The extractable carbon, however, increased during maturation. Organic matter mineralization was greater in the composts with city refuse than in those with sewage sludge. The samples with peat residue showed the lowest decreases in carbon fractions. During maturation, an increase of humiclike fraction was observed, which was reflected by a decrease in the soluble carbon-precipitated carbon ratio at pH 2. Water-soluble carbon was the carbon fraction most easily degradable by microorganisms, and its amount correlated significantly with composting time in all the samples.     

Green synthesis silver nanoparticles Bougainvillea glabra Choisy/LED light with high catalytic activity in the removal of methylene blue aqueous solution

In this study, we evaluated, in a pioneering way, the influence of wavelengths from the decomposition of white light on the production and physicochemical properties of silver nanoparticles (AgNPs). Bearing in mind a process of green synthesis, an extract of the bracts of Bougainvillea glabra Choisy (BgC) was used, a species native to tropical and subtropical regions and frequently used in ornamentation, possessing in its photochemical composition, biomolecules capable of acting as reducing agents for convert Ag⁺ to Ag⁰. We used light-emitting diodes (LED) to obtain the desired wavelengths (violet, blue, green, yellow, orange, and red) in the test called rainbow, and we evaluated the obtaining of AgNPs compared to white LED light, nature, and absence of light. In the rainbow assay, we obtained a gradual increase in the intensity of the plasmonic band resonance from the red wavelength (0.124 ± 0.067 a.u.) to violet (0.680 ± 0.199 a.u.), indicating a higher reaction yield in obtaining AgNPs. Smaller hydrodynamic sizes (approximately 150 nm) at more energetic wavelengths (violet, blue, and green) about less energetic wavelengths (yellow, orange, and red) (approximately 400 nm) were obtained. Analysis by SEM microscopy, FTIR spectroscopy, and X-ray diffraction indicates the presence of silver nanoparticles in all LED colors used together with white LED light and Laboratory light (natural light). Due to the high environmental demand to remove pollutants from water sources, including textile dyes, we applied AgNPs/BgC to remove methylene blue (MB) dye from an aqueous solution. A minimum removal percentage greater than 65%, with emphasis on formulations synthesized by the colors of violet LED (84.27 ± 2.65%) and orange LED (85.91 ± 1.95%), was obtained.

     

Is Standardized Precipitation Index (SPI) a Useful Indicator to Forecast Groundwater Droughts? — Insights from a Karst Aquifer

The study sought to understand the relationships between meteorological and groundwater droughts on water levels and spring discharges in Edwards Aquifer, Texas. Standardized Precipitation Index (SPI)‐styled Standardized Groundwater Index (SGI) was used to quantify groundwater droughts. SGI time series signal was delayed and damped, while SPI was volatile. SGI values correlated well with SPI values that were observed five to eight months ago. Dynamic regression models with lagged SPI terms and autoregressive integrated moving average errors indicated a statistically significant yet weak relationship between Lag‐1 SPI and SGI. The utility of SPI for groundwater drought forecasting was minimal in this aquifer. Nonseasonal and seasonal autoregressive terms played an important role in forecasting SGI and highlighted the need for long‐term, high‐resolution monitoring to properly characterize groundwater droughts. Spring flows exhibited stronger and quicker responses to meteorological droughts than changes in storage. In aquifers with spring discharges, groundwater monitoring programs must make efforts to inventory and monitor them. Groundwater drought contingency measures can be initiated using SPI but this indicator is perhaps inappropriate to remove groundwater drought restrictions.     

Trace element concentration and speciation in selected urban soils in New York City

A long history of urbanization and industrialization has affected trace elements in New York City (NYC) soils. Selected NYC pedons were analyzed by aqua regia microwave digestion and sequential chemical extraction as follows: water soluble (WS); exchangeable (EX); specifically sorbed/carbonate bound (SS/CAR); oxide-bound (OX); organic/sulfide bound (OM/S). Soils showed a range in properties (e.g., pH 3.9 to 7.4). Sum of total extractable (SUM_TE) trace elements was higher in NYC parks compared to Bronx River watershed sites. NYC surface horizons showed higher total extractable (TE) levels compared to US non-anthropogenic soils. TE levels increased over 10 year in some of the relatively undisturbed and mostly wooded park sites. Surface horizons of park sites with long-term anthropogenic inputs showed elevated TE levels vs. subsurface horizons. Conversely, some Bronx River watershed soils showed increased concentrations with depth, reflective of their formation in a thick mantle of construction debris increasing with depth and intermingled with anthrotransported soil materials. Short-range variability was evident in primary pedons and satellite samples (e.g., Pb 253?±?143 mg/kg). Long-range variability was indicated by Pb_TE (348 versus 156 mg/kg) and Hg_TE (1 versus 0.3 mg/kg) concentrations varying several-fold in the same soil but in different geographic locations. Relative predominance of fractions: RES (37 %)?>?SS/CAR (22 %)?>?OX (20 %)?>?OM/S (10 %)?>?EX (7 %)?>?WS (4 %). WS and EX fractions were greatest for Hg (7 %) and Cd (14 %), respectively. RES was predominant fraction for Co, Cr, Ni, and Zn (41 to 51 %); SS/CAR for Cd and Pb (40 and 63 %); OM/S for Cu and Hg (36 and 37 %); and OX for As (59 %).     

Geochemical evidence for the origin of vanadium in an urban environment

The city of Salamanca in central Mexico is surrounded by heavy industry, i.e., a refinery, a thermoelectric plant and chemical industries. Variable concentrations of vanadium (V) have been reported in the groundwater, and their presence has been related to particulates so this hypothesis was tested by sampling soil in the urban area and the surrounding uncontaminated country site. The 0-10-cm soil layer in the industrial and rural area was analyzed for V and other metal trace elements found in hydrocarbons, i.e., chromium (Cr), lead (Pb), zinc (Zn), and nickel (Ni). The concentrations of V were higher in the urban rather than in the rural soil, reaching values of >600 mg kg(-1) in the urban soils. In the rural area, V in the soil was related to regional geology, i.e., volcanic rocks such as basalts and rhyolites but not in the urban area where it was related to particulate distribution mostly emitted from the industries burning fuel oil number 6.