Application of capillary electrophoresis combined with a modified BCR sequential extraction for estimating of distribution of selected trace metals in PM2.5 fractions of urban airborne particulate matter

The capillary electrophoresis (CE) method combined with a sequential extraction was applied to determine the distribution of Fe, Zn, Cu, Mn and Cd in urban ambient air PM2.5 samples. PM2.5 was collected on Teflon filters with dichotomous sampler, and the modified extraction procedure following the BCR leaching procedure was used to chemically fractionate metals into "easily exchangeable" with water, "acid extractable" with 0.11 mol/l acetic acid, "reducible" with 0.1 mol/l hydroxylamine hydrochloride acidified to pH 2.0 with nitric acid, and "oxidisable" with oxidation by 8.8 mol/l hydrogen peroxide (H2O2) followed by extraction with 1.0 mol/l ammonium acetate. Based on the obtained results it was concluded that the application of the studied methodology provides chemical fractionation data that reflect the general sources and potential health hazards of the studied metals.     

Solubilization of manganese and trace metals in soils affected by acid mine runoff

Manganese solubility has become a primary concern in the soils and water supplies in the Alamosa River basin, Colorado due to both crop toxicity problems and concentrations that exceed water quality standards. Some of the land in this region has received inputs of acid and trace metals as a result of irrigation with water affected by acid mine drainage and naturally occurring acid mineral seeps. The release of Mn, Zn, Ni, and Cu following saturation with water was studied in four soils from the Alamosa River basin. Redox potentials decreased to values adequate for dissolution of Mn oxides within 24 h following saturation. Soluble Mn concentrations were increased to levels exceeding water quality standards within 84 h. Soluble concentrations of Zn and Ni correlated positively with Mn following reduction for all four soils studied. The correlation between Cu and Mn was significant for only one of the soils studied. The soluble concentrations of Zn and Ni were greater than predicted based on the content of each of these metals in the Mn oxide fraction only. Increases in total electrolyte concentration during reduction indicate that this may be the result of displacement of exchangeable metals by Mn following reductive dissolution of Mn oxides.     

Trace elements and organochlorines in surf scoters from San Francisco Bay, 1985

Surf scoters (Melanitta perspicillata) were collected from 6 locations in San Francisco Bay during January and March 1985. Overall, mean concentrations of cadmium and zinc were higher in livers of scoters from the southern region of the Bay, whereas mean iron and lead were higher in those from the northern Bay region. Mean concentrations of arsenic, copper, lead, zinc, aluminum (January only) and iron (January) also differed among individual locations. Mean concentrations of copper and zinc increased, arsenic decreased, and cadmium remained the same between January and March. Selenium and mercury concentrations in scoter livers were not significantly correlated (P>0.05), but cadmium concentrations in livers and kidneys were positively correlated (P<0.0001), and body weight was negatively related to mercury concentration in the liver (P<0.05). Body weight differed among locations but not between January and March. Body weight was correlated with lipid content (P<0.0001). DDE and PCBs were each detected in 34 of 36 scoter carcasses. DDE increased significantly between January and March at Richmond Harbor, but BCBs did not differ between January and March at the 3 locations that could be tested.     

THE DETERMINATION OF PRIMARY PRODUCTION IN A STREAM USING AN EXACT SOLUTION TO THE OXYGEN BALANCE EQUATION1

ABSTRACT. A promising technique for recognition of early stages of cultural eutrophication relies on determining production and respiration in streams. The most successful and most widely used method of estimating production of a segment of a stream is the upstream-downstream, diurnal curve method introduced by Odum [1956]. This technique is equivalent to obtaining an approximate solution to the oxygen balance equation. We report here an exact solution of the balance equation as a method for calculating primary production. Data presented by Owens [1966] are analyzed; effects of depth and oxygen saturation are studied. A major advantage of the method described here is that continuous temporal variation of net production may be rigorously handled. The method is shown to be well suited to our ultimate goal of studying energy budgets of streams, and thereby the eutrophication process.     

Use of Hygiene Protocols to Control the Spread of Viruses in a Hotel

The goals of this study were to observe the spread of viruses in a hotel setting and to assess the effectiveness of a hygiene intervention in reducing their spread. Selected fomites in one hotel room were inoculated with bacteriophage ?x-174, and fomites in a conference center within the same hotel were inoculated using bacteriophage MS2. Cleaning of the contaminated room resulted in the spread of viruses to other rooms by the housekeeping staff. Furthermore, viruses were transferred by hotel guests to the conference center and a communal kitchen area. Additionally, conference attendees transferred viruses from the conference center to their hotel rooms and a communal kitchen area. This study demonstrated how viruses can be spread throughout a hotel setting by both housekeepers and guests. A hygiene intervention, which included providing hand hygiene products and facial tissues to the guests and disinfecting solutions with disposable wipes to the housekeeping staff, was successful in reducing the spread of viruses between the hotel guest rooms and conference center. The hygiene intervention resulted in significantly reduced transfer of the ?x-174 between the contaminated hotel room and other hotel rooms, communal areas, and the conference center (p = 0.02).     

Wild meat trade over the last 45 years in the Peruvian Amazon

The trade in wild meat is an important economic component of rural people's livelihoods, but it has been perceived to be among the main causes of the decline of wildlife species. Recently, the COVID-19 pandemic has brought to light an additional concern of wildlife markets as a major human-health challenge. We analyzed data from the largest longitudinal monitoring (1973–2018) of the most important urban wild-meat markets in Iquitos, Peru, to examine the trends in and impacts of these markets on people's livelihoods. Over the last 45 years, wild meat sales increased at a rate of 6.4 t/year (SD 2.17), paralleling urban population growth. Wild meat sales were highest in 2018 (442 t), contributing US$2.6 million (0.76%) to the regional gross domestic product. Five species of ungulates and rodents accounted for 88.5% of the amount of biomass traded. Vulnerable and Endangered species represented 7.0% and 0.4% of individuals sold, respectively. Despite growth in sales, the contribution of wild meat to overall urban diet was constant: 1–2%/year of total meat consumed. This result was due to greater availability and higher consumption of cheaper meats (e.g., in 2018, poultry was 45.8% cheaper and was the most consumed meat) coupled with the lack of economic incentives to harvest wild meat species in rural areas. Most wild meat was sold salted or smoked, reducing the likelihood of foodborne diseases. Community-based wildlife management plans and the continued trade bans on primates and threatened taxa may avoid biodiversity loss. Considering the recent COVID-19 pandemic, future management plans should include potential viral hosts and regulation and enforcement of hygiene practices in wild-meat markets.     

The effect of alkaline pretreatment on the anaerobic digestion of fruit and vegetable wastes from a central food distribution market

Journal of Material Cycles and Waste Management - Anaerobic digestion of the organic fraction of municipal solid wastes is a well-established process for biogas production and various forms of...     

Chronic exposure to lead acetate promotes changes in the alveolar bone of rats: microstructural and physical–chemical characterization

Environmental Science and Pollution Research - There are a few data relating to the effects of lead (Pb) exposure on the alveolar bone, which has very distinct morphophysiological characteristics...