Js Harington

South African asbestos: Production, exports, and destinations, 1959–1993

Production and export figures of South African asbestos were analyzed over 1959-1993. They show stable sales of chrysotile. Those of crocidolite and amosite reached their peaks in the mid-1970s, after which trade fell drastically, crocidolite to 5% of its earlier peak and amosite to nil. Factors responsible for these virtual collapses were health issues, stricter legislation in First World countries, and litigation. In 1992, 21 countries continued to import crocidolite, although in reduced quantities. In the early 1960s, Europe and North America were the major recipients of South African asbestos. By 1989-91, these regions were surpassed by the Far East, which took over 90% of chrysotile and 70% of amosite. For crocidolite at that time, the Middle East took nearly 40%, Europe 28%, and Africa 21%. This implies that the newly importing countries can confidently expect an increase in asbestos-related disease and death well into the twenty-first century, even if the trade ceased now.

Changes in the geographical and temporal patterns of cancer incidence among black gold miners working in South Africa, 1964–1996

We describe here the results of the final 8 years of geographical and temporal data of a 33-year study of the cancer experience of 12.8 million man-years of black miners working on the gold fields of South Africa over the period 1964–96. These workers were recruited from 15 territories, the major areas during the most recent period being Lesotho (26.8%), Transkei (21.5%) and Mozambique (15%). The earliest analyses, 1964–71 and 1972–79, showed hepatocellular and oesophageal cancers to be the most frequent cancers. The final analysis, for 1989–96, however, shows marked temporal changes in the relative position of four cancers or grouped malignancies: respiratory cancer up by 236%, hepatocellular carcinoma down to 32%, oesophageal holding steady, and lymphatic system cancers up by 420%, almost certainly because of association with HIV/AIDS infection. Significant geographical variations occurring between the home areas of the miners are important, as mining operations have little to do with the cancers that develop. The causes are essentially socio-environmental rather than occupational, and this means that the rates of the major cancers in the miners are surrogate measures of the same cancers in the home areas.

Mseleni joint disease: A potential model of epigenetic chondrodysplasia

OBJECTIVE In this paper past research on the natural history of Mseleni joint disease, a crippling endemic osteoarthritis, its socio-economic impacts, the demographics, diet, geology and the genetic background of affected people are reviewed. In addition, some new research ideas are suggested to continue the search for etiological avenues for this disease such as stable isotope analysis and epigenetic mechanisms. RESULTS Mseleni joint disease is a chondrodysplasia first described in 1970. It is geographically confined to a remote area in the Maputaland region in northern Kwazulu Natal, South Africa. This disease affects most joints but primarily those of the hip; it is a progressive condition beginning with pain and stiffness until the patients ability to walk becomes compromised. Mseleni joint disease is characterized by two distinct abnormalities, protrusio acetabuli that mainly affects females and increases in frequency with age, and hip dysplasia that is more frequent with age. Much research has been conducted on the people with the disease and their surrounding environment. CONCLUSION Despite intensive investigations into the etiology of Mseleni joint disease, it remains unknown. As a result the examination of epigenetic mechanisms and stable isotope analysis of teeth are suggested as a means of providing information on the etiology of the disease. These methods can also be applied to other chondroplasias of unknown etiology.

South Africa's export trade in asbestos: Demise of an industry

BACKGROUND South Africas export of each of its three types of asbestos, crocidolite, amosite, and chrysotile, and the total amounts to 84 countries in metric tonnes is examined over a 24-year period, 1980-2003. METHODS For convenience, the countries are divided into nine world regional groups, Europe, Eastern Europe, North America with the Caribbean, South America, Africa, Middle East, Far East, South Asia, and Oceania. RESULTS The three greatest importing countries of total asbestos in metric tonnes were all in the Far East region, ranging from Japan, South Korea to Thailand, and followed by USA and Italy. All exports to all countries diminished steadily as the South African trade came virtually to an end by 2003, due to ever increasing international pressure. CONCLUSION The export trade has changed significantly since 1960 from being dominantly to European countries to being directed in recent years to the Far East, with serious implications for asbestos-related ill-health in those countries.

A review of DNA analyses of archaeological and ancient tissues

Recently, there has been an increase in genetic research involving the extraction and analysis of DNA to obtain information on human and other animal remains. This paper reviews selected aspects of research on ancient and archaeological tissues to address anthropological problems. Factors influencing successful and authentic DNA extraction and amplification, such as molecular preservation, degradation and contamination, are considered. Good molecular preservation and minimising DNA contamination are essential to obtain authentic DNA results. Genetic analyses on skeletal material is still at an early stage in South Africa, but would be of great value to the countrys rich historical, archaeological and palaeoanthropological assemblages.