Mamopeli Matooane

CSIR Research and Innovation Conference: 1st CSIR Biennial Conference, CSIR International Convention Centre Pretoria, 27-28 February 2006 South Africa hosts a number of different communities, both in terms of wealth and access to environmental and social services. Poor communities located in close proximity to industrial developments are of particular concern to the risk assessor as they are often exposed to elevated levels of air pollution arising from both the ambient and indoor environments. The risks of adverse health effects associated with air pollution are influenced by a number of environmental, social and economic factors which ultimately affect their level of vulnerability. This paper examines some of the vulnerability factors surrounding South African communities in relation to air pollution. A conceptual framework briefly outlining an innovative methodology to improve management of environmental risk is presented and challenges associated with this process are discussed

Concern about health risks from sulfur dioxide (SO2) pollution prompted a health risk assessment for residents of the heavily polluted industrial region of South Durban, South Africa. The U.S. Environmental Protection Agency health risk assessment model was used to evaluate health effects for individuals in 4 age groups on the basis of data for a 3-yr period, from 1997-1999. Under normal exposure conditions, the level of risk was low (Hazard Quotient < 1); only under the worst-case scenario (exposure 24 hr/day) was there a significant risk of developing health effects. Inasmuch as these results are contrary to the popularly held belief that residents have a high risk of developing SO2-related respiratory diseases under normal exposure conditions, future studies should more thoroughly investigate exposure patterns and verify the authors' assumption that indoor SO2 levels are zero.

ABSTRACT South Africa is characterised by a mix of air pollution problems associated with urban-industrial activities and the domestic use of biofuels, both of which have negative human health impacts. The recent promulgation of new air quality legislation with an emphasis on the control of air pollution for the protection of public health, increases the need for studies aimed at assessing human health effects. One such approach is the widely used United States Environmental Protection Agency Health Risk Assessment (HRA) framework. Based on empirical data collected for South African conditions, it is shown that it is of critical importance to have locally derived exposure values rather than default values. This can shift an outcome from one of no risk to one of severe health risk. It is concluded that the HRA framework provides a rapid and simple method for assessing health risk, provided cognisance is taken of certain local input parameters, in particular exposure values.

Despite the existence of numerous sources and continuing use, information regarding emissions and airborne concentrations of organochlorine pesticides in Africa is extremely limited. This paper presents results of a monitoring program conducted in Durban, South Africa that was designed to characterize levels, trends and possible sources of pesticides in both industrial and residential areas. Three monitoring sites were established, two in an industrialized area in the southern part of the city, and the third in a northern residential area. Particulate and vapor samples were sampled over the 2004-5 period and analyzed by GC/MS to estimate long-term levels of a wide range of pesticides. Based on a year of sampling, the sites had comparable levels of many pesticides with exceptions of alpha-chlordane and lindane. Levels of p,p'-DDT (42+/-27 pg m(-3)) and its derivatives were relatively high and showed an unusual mixture with high levels of p,p'-DDD (12+/-11 pg m(-3)). Other pesticides detected and quantified included aldrin, chlordanes, hexachlorobenzene and dieldrin. Potential source areas, identified using concentration patterns, local and regional gradients, compositional information and trajectory analyses, suggest that chlordane and lindane arise from both local sources as well as regional/global sources; DDT from regional sources elsewhere in South Africa, Africa and India; and most of the other long-lived pesticides detected, including gamma-nonachlor, hexachlorobenzene and toxaphene, from global sources. This monitoring results, which represent the most detailed study to date of pesticides in air in Africa, serve several purposes, including documenting the presence and use of long-banned pesticides like aldrin, aiding the understanding of the fate of persistent compounds, identifying pollutants that may contribute to health problems, and informing decision-making aimed at reducing exposures and risks.