Sachet water quality and Vendors’ practices in Damongo, northern Ghana during the emergence of SARS-CoV-2 using multivariate statistics, water quality and pollution indices, and panel assessment

The emergence of the SARS-CoV-2 has affected several production services including the water production and delivery processes. This study considered sachet water quality during the advent of the SARS-CoV-2 pandemic using multivariate statistics and Water Quality Index, Water Pollution Index and, hygienic and sanitation practices of sixty-two (62) sachet water vendors using a panel assessment approach. The findings showed that vendors did not adhere to proper hygienic practices as ninety-four (94%) of them did not have health clearance, ninety (90%) did not frequently wash their receptacles for selling daily, and most of them stored and sold in unhygienic environments. Majority of the producers violated Food and Drugs Authority Regulations. The Empirical Orthogonal Function analysis showed that total iron, Total Heterotrophic Bacteria, Salmonella, Cl⁻, E. coli, and fecal and total coliforms were the controlling elements in the water. All the brands were below threshold limits based on the physical water assessment. However, enteric bacteria were observed in all the brands. Water Quality and Water Pollution Indices (WQI and WPI) described all the sachet water brands (vendors and production sites) as excellent for drinking. The WQI computations for samples from the production and vending sites respectively ranged from 0.12 to 0.36 and 0.27–0.42 whereas WPI presented 0.22–0.31 and 0.23–0.32. Comparatively, samples from vendors had elevated elemental concentrations and loads. This suggests that besides sachet water contamination during production and transportation, vendors significantly impacted the quality of sachet water. Sensitization on proper hygienic practices for sachet water production and vending and routine assessment of the quality of sachet water produced or sold is recommended.

Polyethylene Nanocomposites for the Next Generation of Ultralow-Transmission-Loss HVDC Cables: Insulation Containing Moisture-Resistant MgO Nanoparticles

The use of MgO nanoparticles in polyethylene for cable insulation has attracted considerable interest, although in humid media the surface regions of the nanoparticles undergo a conversion to a hydroxide phase. A facile method to obtain MgO nanoparticles with a large surface area and remarkable inertness to humidity is presented. The method involves (a) low temperature (400 °C) thermal decomposition of Mg(OH)2, (b) a silicone oxide coating to conceal the nanoparticles and prevent interparticle sintering upon exposure to high temperatures, and (c) heat treatment at 1000 °C. The formation of the hydroxide phase on these silicone oxide-coated MgO nanoparticles after extended exposure to humid air was assessed by thermogravimetry, infrared spectroscopy, and X-ray diffraction. The nanoparticles showed essentially no sign of any hydroxide phase compared to particles prepared by the conventional single-step thermal decomposition of Mg(OH)2. The moisture-resistant MgO nanoparticles showed improved dispersion and interfacial adhesion in the LDPE matrix with smaller nanosized particle clusters compared with conventionally prepared MgO. The addition of 1 wt % moisture-resistant MgO nanoparticles was sufficient to decrease the conductivity of polyethylene 30 times. The reduction in conductivity is discussed in terms of defect concentration on the surface of the moisture-resistant MgO nanoparticles at the polymer/nanoparticle interface.

Hydrogen in rocks: an energy source for deep microbial communities

To survive in deep subsurface environments, lithotrophic microbial communities require a sustainable energy source such as hydrogen. Though H2 can be produced when water reacts with fresh mineral surfaces and oxidizes ferrous iron, this reaction is unreliable since it depends upon the exposure of fresh rock surfaces via the episodic opening of cracks and fissures. A more reliable and potentially more voluminous H2 source exists in nominally anhydrous minerals of igneous and metamorphic rocks. Our experimental results indicate that H2 molecules can be derived from small amounts of H2O dissolved in minerals in the form of hydroxyl, OH- or O3Si-OH, whenever such minerals crystallized in an H2O-laden environment. Two types of experiments were conducted. Single crystal fracture experiments indicated that hydroxyl pairs undergo an in situ redox conversion to H2 molecules plus peroxy links, O3Si/OO\SiO3. While the peroxy links become part of the mineral structure, the H2 molecules diffused out of the freshly fractured mineral surfaces. If such a mechanism occurred in natural settings, the entire rock column would become a volume source of H2. Crushing experiments to facilitate the outdiffusion of H2 were conducted with common crustal igneous rocks such as granite, andesite, and labradorite. At least 70 nmol of H2/g diffused out of coarsely crushed andesite, equivalent at standard pressure and temperature to 5,000 cm3 of H2/m3 of rock. In the water-saturated, biologically relevant upper portion of the rock column, the diffusion of H2 out of the minerals will be buffered by H2 saturation of the intergranular water film.