The reactivity of natural organic matter to disinfection by-products formation and its relation to specific ultraviolet absorbance.

Five natural waters with a broad range of DOC concentrations were fractionated using various coal- and wood-based granular activated carbons (GAC) and alum coagulation. Adsorption and alum coagulation fractionated NOM solutions by preferentially removing components having high specific ultraviolet absorbance (SUVA). UV absorbing fractions of NOM were found to be the major contributors to DBP formation. SUVA appears to be an accurate predictor of reactivity with chlorine in terms of DBP yield; however, it was also found that low-SUVA components of NOM have higher bromine incorporation. SUVA has promise as a parameter for on-line monitoring and control of DBP formation in practical applications; however, the effects of bromide concentration may also need to be considered. Understanding how reactivity is correlated to SUVA may allow utilities to optimize the degree of treatment required to comply with DBP regulations. The reactive components that require removal, and the degree of treatment necessary to accomplish this removal, may be directly obtained from the relationship between SUVA removal and the degree of treatment (e.g., alum dose).

Firearm-related injuries and deaths among children and adolescents in Cape Town--1992-1996.

OBJECTIVE: To determine the epidemiological profile of firearm-related injuries among children and adolescents in Cape Town during recent years in order to further understand the epidemic of firearm violence as a public health problem in South Africa. DESIGN: A retrospective study was conducted of hospital, medico-legal laboratory (mortuary) and police data. SETTING: Metropolitan Cape Town, 1 January 1992-31 December 1996. STUDY POPULATION: All children and adolescents (under 19 years of age) with firearm injuries living in the Cape Town metropole during the study period. RESULTS: During the study period at least 1,736 children and adolescents were victims of firearm-related incidents; of these, 322 died (19%). The incidence of firearm injuries among this group almost tripled from 20.2/100,000 in 1992 to 58.1/100,000 in 1996. The firearm mortality rate also almost tripled during the period under review from 3.8/100,000 in 1992 to 10.3/100,000 in 1996. Approximately 60% of victims were coloured males, with 86% between 13 and 18 years of age. Twenty-one per cent of all victims aged over 12 years who died were intoxicated. Other characteristics of the victims and the circumstances surrounding the incidents are presented. CONCLUSIONS: These findings demonstrate the escalating epidemic of firearm-related injuries and deaths among children and adolescents in Cape Town. In addition, the study indicates the need for an integrated injury and death reporting system. Further research is needed to understand firearm-related injuries among children and adolescents in South Africa, and to develop policies and programmes for prevention that are effective in this setting.