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The ecological risk assessment (ERA) process of the US EPA was summarised and evaluated for South African conditions. The objective was to facilitate a common understanding, on-going debate and increasing application of ERA in South Africa. Many of the individual steps in the process have been interpreted and/or reworded to improve communication of the concepts. Although the basic principles were retained, a few changes were suggested. The changes relate specifically to agreeing on management objectives, the development and evaluation of hypotheses, and the collection, collation and evaluation of information. The derived process has been documented as Guidelines for ERA in South Africa.

The effect of ultrasound on human leucocytes was examined using the BUDR-Giemsa procedure. Cells were cultured in Minimum Essential Medium (Eagle) with Spinner Salts for 72 hr after irradiation. Sister chromatid exchange (SCE) rate was evaluated in cells irradiated in G 0 . No effect on SCE could be demonstrated at any of the ultrasound intensities used (15.3–36 W/cm 2 ).