Restoration challenges for urban rivers.

Urban sources account for significant quantities of important diffuse pollutants, and urban watercourses are typically badly polluted. As well as toxic metals, hydrocarbons including PAHs, and suspended matter, priority urban pollutants include faecal pathogens and nutrients. Can urban watercourses be restored by sufficient reductions in pollution loads? Case studies in the UK and Sweden provide insights and some grounds for optimism. A major trans-Atlantic review of the performance of best management practices (BMPs) is informing BMP planning. New approaches such as the maximisation of self-purification capacity in the receiving waters may also need to be developed, alongside BMPs at source. Other initiatives in Europe, USA and China, including collaborative projects, are trying to address the intractable issues such as persistent pollutants from transport and urban infrastructure. The challenge is daunting, but there are clear ways forward and future research needs are evident.

Cardiac arrest during anaesthesia in two horses.

Unexpected cardiac arrest occurred in two horses during routine surgical anaesthesia. Both were successfully resuscitated. The aetiology of these occurrences and their possible relationship to second degree heart block is discussed.

A portable oxygen generator.

The use of a portable generator which liberates oxygen from hydrogen peroxide solutions has been investigated in veterinary anaesthesia to assess its potential as an alternative to conventional oxygen supplies both in emergency situations and in the event of failure of cylinder systems. The reliability of the supply appears to be good and the operation of the generator simple, making it suitable for a number of potential uses. It should compare favourably with oxygen concentrator devices used for similar purposes.