16 research outputs found
Precocious Natural Mummification in a Temperate Climate (Western Cape, South Africa)
The general process and pattern of decomposition is well-documented and understood. However, specific environmental conditions may alter this pattern and prematurely terminate the decay process. An example of this is natural mummification – a preservative process characterized by desiccation, brittleness and shrinkage of the skin and body tissues. It is important to understand how, when, and where such variations may occur, and for this reason environmentally-specific studies of decay are required. The aim of the present study was the establish baseline data on soft-tissue decomposition in two terrestrial habitats in the Western Cape. A total of 16 pig carcasses serving as analogues for humans were deployed in these habitats during two successive winters and summers between 2014 and 2016. The rate and pattern of decomposition were assessed via measurement of weight loss over time and scoring the decomposition process using Megyesi et al. (2005) Total Body Score system and study-specific criteria for mummification. Carcasses typically followed the expected pattern of decay with a few exceptions, most notably instances of rapid natural mummification. Natural mummification, as defined by Megyesi et al. (2005), was observed to occur as early as 17 days postmortem, with five carcasses mummifying in less than one month. The timing of natural mummification varies widely, from a few days to several years, averaging around three months in temperate regions. Natural mummification occurring in less than one month is termed precocious mummification and is rarely observed in temperate regions. With only three reports globally, this study’s findings are globally significant, highlighting the importance of regionally-specific decomposition studies. Two local forensic cases wherein precocious mummification has been observed are also presented and, considered together with the study’s results, a possible mechanism driving this process is proposed
Natural archives of long-range transported contamination at the remote lake Letšeng-la Letsie, Maloti Mountains, Lesotho
Naturally accumulating archives, such as lake sediments and wetland peats, in remote areas may be used to identify the scale and rates of atmospherically deposited pollutant inputs to natural ecosystems. Co-located lake sediment and wetland cores were collected from Letšeng-la Letsie, a remote lake in the Maloti Mountains of southern Lesotho. The cores were radiometrically dated and analysed for a suite of contaminants including trace metals and metalloids (Hg, Pb, Cu, Ni, Zn, As), fly-ash particles, stable nitrogen isotopes, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants such as polychlorinated biphenyls (PCBs), polybrominated flame retardants (PBDEs) and hexachlorobenzene (HCB). While most trace metals showed no recent enrichment, mercury, fly-ash particles, high molecular weight PAHs and total PCBs showed low but increasing levels of contamination since c.1970, likely the result of long-range transport from coal combustion and other industrial sources in the Highveld region of South Africa. However, back-trajectory analysis revealed that atmospheric transport from this region to southern Lesotho is infrequent and the scale of contamination is low. To our knowledge, these data represent the first palaeolimnological records and the first trace contaminant data for Lesotho, and one of the first multi-pollutant historical records for southern Africa. They therefore provide a baseline for future regional assessments in the context of continued coal combustion in South Africa through to the mid-21st century
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Weather and Climate Numerical Models Development Programme in South Africa
In this document we propose that institutions embarking on model development activities work together and support each other, as well as new entrants to accelerate model development activities in the country and increase the critical mass with an advanced understanding of models faster. The ultimate purpose of this initiative is that South Africa becomes an independent user of models, and develops one or more home-grown models that can be used for operational and research purposes. Each participating institution can make contributions on any model of interest, and these contributions can include work with consortia on international models. The development of a critical mass of researchers that can develop models will require investment in human resource capital development. This programme will enhance collaboration between organisations with modelling capabilities towards jointly informing policy developments and implementation of frameworks in the country. Close collaboration between the South African Weather Service (SAWS) which is a mandated meteorological service organisation, and other research organisations will ensure that all modelling research taking place nationally, that can improve weather and climate early warning systems, is incorporated into the SAWS operations, for the benefit of the society and public in general. Moreover, the Council for Scientific and Industrial Research (CSIR) Earth System Model development programme and related generation of climate change projections for Africa will be furthered by this enhanced collaboration