The purpose of the investigation was to compare the morphology of fibroblasts cultured from healthy oral mucosa and mucosa of patients with oral submucous fibrosis (OSF) and to collate the occurrence of cell types of similar morphology. Cells cultured from biopsy specimens from the buccal mucosa of six subjects who did not chew the areca nut and six patients with OSF who chewed areca nut were grown according to standard techniques. Ninety cells per cell line were recorded daily for 8 days, classified into types F1, F2 and F3 according to their morphology, and the results statistically analyzed. We found that there was a relative increase of F3 cells in relation to F1 cells in OSF, resulting in the ratio of F3 to F1 cells being significantly larger in OSF than the ratio in the controls. As it has been reported that F3 cells in rat connective tissues produce significantly more collagen types I and III than F1 cells, we concluded that a change of fibroblast population has occurred in OSF and that this relative increase of F3 cells in humans, which could be committed to the production of large quantities of collagen, can be an explanation for the excessive collagen formation in OSF.

No abstract

In South Africa, fertiliser and herbicide pollutants resulting from agricultural practices indirectly lead to the degradation of surface freshwater and groundwater quality. Nitrogen and phosphorus, and glyphosate, derived from agricultural fertiliser and herbicide applications, respectively, contribute to watercourse toxicity. Adjacent to many of the surface freshwater systems are some of South Africa’s most productive agricultural lands, where natural ecosystems are converted to croplands, resulting in the degradation of natural vegetation and deterioration of freshwater quality. The critically endangered status of some Renosterveld vegetation types is the product of agricultural expansion, nutrient loading through fertilisation and the spraying of herbicides. A buffer of Renosterveld vegetation along river corridors may contribute to the remediation of agricultural pollutants prior to entering watercourses. The utilisation of wetland plants occurring within Renosterveld for agricultural pollutant extraction can increase river corridor biodiversity, creating indigenous refuges and facilitating habitat connectivity. A laboratory phytoremediation system was designed and constructed to investigate the pollutant-removal potential of indigenous species occurring in Renosterveld vegetation (amongst other areas), compared with commonly used invasive alien plants (IAP) in floating wetland designs. Five pollutant parameters – ammonia, nitrate, orthophosphate and two glyphosate concentrations – reflect environmental stresses on 14 wetland species naturally occurring within Renosterveld vegetation. Effluent analyses indicated significant removal efficiencies for the indigenous vegetation across both fertiliser and herbicide pollutants, with the two most effective species identified as Phragmites australis and Cyperus textilis, with 95.87% and 96.42% removal, respectively. All wetland species displayed greater pollutant removal than the unvegetated soil control and when compared to an IAP and palmiet assemblage, indicated similar pollutant-removal efficiencies, justifying their use as an acceptable alternative.

No abstract

This article demonstrates how household solid waste (HSW) generation patterns differ in neighbourhoods of the same town by determining the composition of the residual portion of the HSW stream in 2017 in Stellenbosch. HSW was collected from 10 pre-identified suburbs out of a total of 48. These chosen suburbs and their 17 830 households were representative of all the HSW from all households in the catchment area of the Devon Valley Landfill Site. A separation at source programme was in place in nine of the suburbs.The confidence level and level of precision were set at 95% and ±8%, respectively. A total of 1543 bags of HSW were collected with a total mass of 5748.01 kg and an uncompacted volume of 84.87 m3. The samples were sorted into 7 main and 18 final fractions. The main contributor to the total waste stream was organic waste by weight (35%) and plastic wrap and packaging by uncompacted volume (32%). The average HSW generation was 0.68 kg/capita/day. Households with access to a separation at source programme tended to have lower levels of highly recyclable materials in their samples. Roll-out of a separation programme is recommended for all 48 suburbs in the study area to save landfill airspace. Correlation analysis showed that household size influenced three of the seven main waste fractions, and household income five of the seven. No statistically significant results were obtained relating to household density and waste generation. Statistically significant results were obtained through an analysis of variance for all waste fractions, excluding organics, when considering household income, indicating that both household size and income could be explanatory socio-economic factors for variations seen. Other variables, such as human behaviour, could potentially also contribute to the differences and should be further explored.