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Per and polyfluoroalkylated substances (PFAS) are common additives in ski waxes for their water repellent characteristic. Abrasion of ski wax leaves PFAS on the snow surface, however, little is known about the distribution and concentration of PFAS in snow and soil due to skiing. In this study we analysed different ski waxes, snowmelts and soil from family skiing areas from Alpine locations using targeted high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) to understand more about PFAS distribution in the environment. In general, we found a very diverse PFAS pattern in the analysed media. PFAS level was higher in skiing areas compared to the non-skiing ones that were used as control. ∑target PFAS ranged between <1.7 ng L−1 and 143 ng L−1 in snowmelt, <0.62 ng g−1 and 5.35 ng g−1 in soil and <1.89 and 874 ± 240 ng g−1 in ski wax samples. Snowmelt was dominated by short-chained PFAS, while soil and wax contained both short and long-chained PFAS. Extractable organic fluorine (EOF) was several orders of magnitude higher for waxes (0.5–2 mg g−1) than for soils (up to 0.3 μg g−1), while total fluorine (TF) content of the waxes was even higher, up to 31 210 ± 420 μg g−1. We also showed that the ∑ target PFAS accounts for up to 1.5% in EOF content, showing that targeted LC-MS/MS gives a limited measure of the pollution originated from ski waxes and non-targeted analysis and EOF is necessary for a better overview on PFAS distribution. [ABSTRACT FROM AUTHOR]

A variety of sunscreen products have been developed to afford the consumer protection against some of the deleterious effects, for example erythema, caused by solar ultraviolet radiation. The requirement that suncare products offer broad-spectrum protection has resulted in the use of inorganic oxides, such as micronized titanium dioxide (TiO2), in their formulation. However, there are now concerns about the photocatalytic effects of the TiO2 in these products and its potential phototoxicity to the skin through the generation of reactive oxygen species such as hydroxyl and superoxide anion radicals. It is important, therefore, that the amounts of TiO2 in suncare products be closely monitored and maintained within stipulated ranges. A simple, fast and reliable analytical method for the determination of TiO2 in commercial sunscreen products by inductively coupled plasma--optical emission spectrometry (ICP-OES) was developed and validated. The limits of detection and quantitation were found to be 0.018 and 0.062 µg mL-1, respectively. The average percentage recovery of TiO2 was 102.32 ± 2.87 % with a RSD of 2.81 %. The method was applied to determine the concentration of TiO2 in 22 commercial suncare samples of which 14 contained TiO2. The amounts of TiO2 measured in these sunscreens ranged from 0.05 to 3.21 %. To our knowledge this is the first study that reports the amounts of TiO2 in sunscreen products available on the South African market. [ABSTRACT FROM AUTHOR]

Changes in supramolecular properties of cellulose I, namely its lateral fibril aggregate dimension (LFAD), in bleached hardwood acid bisulphite pulp during drying was studied using cross-polarization/magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C-NMR) in combination with spectral fitting. A significant change in aggregate dimensions was noticed when each of the pulp grades were oven dried. The effect of drying was further investigated with pulp samples subjected to different drying methods. A comparison of a harsh oven drying, mild and rapid air drying, and a very mild and slow condition drying showed that the LFAD of the material decreases in the following order: oven drying > air drying > condition drying. The correlation between the total extractable material S10 (%) and LFAD and also the LFAD increment (ΔLFAD in %) are presented and shown to be intimately related. This means that the method of drying influences the size of the fibril aggregate dimensions and depends on the presence of extractable material within the fibre cell wall. Reactivity studies were carried out based on the acetylation of cotton linters and commercial 96α pulp. Results indicate that the initial reaction rate is proportional to the specific surface area of the two cellulose pulp samples. Accordingly, the specific surface area is directly related to initial reactivity of the performed acetylation. We demonstrated that it is possible to control the LFAD and hence specific surface area in laboratory-produced pulps 91α, 92α, and 96α by the drying method. Thus controlling LFAD can probably be one viable route for controlling the initial reactivity of dissolving pulp towards acetylation. [ABSTRACT FROM AUTHOR]

Abstract: Wetlands are well known to act as sinks for sediment and chemicals in the landscape. Within the Mkuze River floodplain in northern KwaZulu-Natal, South Africa, deposition of clastic sediment occurs predominantly in close proximity to the river channel, resulting in the formation of levees. Over time, this leads to channel avulsion, a process that may be accelerated by the activities of hippopotami whose trails create hydraulically favourable pathways. Sedimentation rates, determined using the isotopes 210Pb and 137Cs, indicate that the Mkuze River floodplain is a relatively rapidly aggrading system that should experience frequent avulsion, with average short-term rates in the order of 0.25 to 0.50cm/y. Sediments on the floodplain are also an important sink for solutes, which concentrate in the groundwater and precipitate out because of evapotranspiration. Over long timescales, chemical sedimentation affects the landscape by influencing salinity, vegetation distribution, hydrological flows, and local topography. The Mkuze River floodplain is an actively evolving system, which continues to aggrade as a result of the combination of clastic and chemical sedimentation. In a region characterised by a strong annual water deficit, temporal patterns of clastic and chemical sedimentation are likely to exert influence on the long-term development of wetland systems elsewhere in southern Africa. This study, the first on sediment accretion rates using 210Pb and 137Cs dating for a southern African wetland, demonstrates that radioisotopic methods are an important tool that can be applied toward fully understanding wetland formation, evolution, and functioning in the region. [Copyright &y& Elsevier]

The elemental distribution in ginger rhizome and the impact of the soil quality on the elemental uptake by the rhizome were investigated. The focus of the study was on eight elements, i.e. Cu, Zn, Mn, Fe, Ni, Pb, Cr and Mg. Ginger and soil samples from four different farms of KwaZulu-Natal (South Africa) were collected and after microwave digestion, the elemental concentrations were estimated using ICP-OES. The method for the ginger analysis was validated by the analysis of a certified reference material (leaves of Poplar). The accumulation of the elements in the ginger rhizome was investigated as well as the metal-metal interactions that exist based on the total and the bioavailable concentrations of the elements were determined. It was found that the soil quality influences the elemental distribution within the ginger rhizome; however, the plant has the inherent ability to control the amount of each element entering the rhizome. The levels of Cd and As in the soil and ginger samples from all four sites were below the lower detection limits. The ginger 'flesh' tends to accumulate Mn and Mg. A synergistic relationship between Cr and Mn; and an antagonistic relationship between Fe and Cu; and Fe and Cr were noticed. The concentration of none of the elements exceeded the threshold upper intake levels, and thus does not pose toxicity issues. [ABSTRACT FROM AUTHOR]

The total concentrations of 7 selected metals, namely manganese, iron, zinc, titanium, boron, arsenic and mercury, were monitored for one annual cycle covering four seasons in the seaweed, Gelidium abbottiorum , at four sampling sites at Zinkwasi, Ballito, Treasure beach and Park Rynie along the South-East coastline of KwaZulu-Natal, South Africa to assess the current status of the marine environment. Inductively Coupled Plasma Optical Emission Spectrophotometry, Mercury Cold Vapour AAS, and Hydride Generation AAS were used for the determination of metal concentrations. Mn concentrations were particularly high in the G. abbottiorum species, followed by Fe, As and B concentrations which were in the 3–8 ppm range. Ti and Zn were in the 100–400 ppb range, while Hg was low and below 100 ppb. A typical sample of G. abbottiorum at Treasure beach, a site close to Durban metropolis in winter had Mn (8.6 ppm), Fe (4.6 ppm), As (5.6 ppm), B (3.0 ppm), Ti (420 ppb), Zn (167 ppb) and Hg (7.5 ppb). All metals recorded a decrease in concentrations from winter to spring with the exception of Hg. The Hg levels increased considerably from winter to spring. [ABSTRACT FROM AUTHOR]

The elemental uptake and the growth response of Spinacia oleracea (spinach) to the soil contaminated with the South African bituminous coal mine dump soil, viz. 0%, 5%, 15%, and 25% w/w, was investigated. The contaminated soils were analyzed for pH, cation exchange capacity (CEC), soil organic matter (SOM), and concentrations of selected heavy metals. The pH, SOM, and CEC decreased with an increase in contamination indicating the acidic nature of coal mine soil and the raise in the soil binding sites. The distribution of Fe, Mn, Ni, Cd, and Pb in the in roots and leaves of the plants was determined in two stages of plant growth. Spinach showed high accumulation of Fe and increased levels of Ni and Cd with an increase in contamination. No plant growth was recorded with 25% contamination. [ABSTRACT FROM AUTHOR]

The molecular geometry in the title compound, C19H21N, is as expected for a compound of this kind. The mol­ecules are interconnected to form layers by C—H⋯π interactions, some between edge-to-face mol­ecules in the manner characteristic of polycyclic hydro­carbon compounds and others involving H atoms of both methyl groups of the methyl­diethyl­amine substituent. [ABSTRACT FROM AUTHOR]

The traditional method of manually checking and grading student laboratory practical scripts has several disadvantages: manual checking is time consuming and therefore causes longer script turnaround times than necessary; it is labour-intensive, especially for non-uniform quantitative data; there is potential for inconsistency, and, for large student groups, a great deal of tedium for the checker. Automation of checking such scripts has the potential to alleviate these disadvantages. The School of Pure and Applied Chemistry, University of Natal, Durban, in cooperation with the School of Pharmacy and Biomolecular Sciences, University of Brighton, has adopted a procedure to automate the checking of practicals. This manuscript describes the method of checking one such practical; the Level Two practical entitled Determination of the Effectiveness of an Extraction. This is the first in a series of analytical practicals and is aimed at revising neutralisation titrations as well as introducing the concept of solvent extraction. The practical requires a number of calculations that are time consuming for the marker to check individually. The manuscript describes a web-based form into which students enter their results via the School Intranet. The students' results are downloaded by file transfer protocol (FTP) and imported into a Microsoft Excel Trademark spreadsheet. The spreadsheet then calculates the correct answer based upon the primary data used, compares them with the students', grades the students' scripts and is potentially able to add educators' comments for feedback to the student. [ABSTRACT FROM AUTHOR]