PAS 61:2006

Summary PAS 61 describes a method for the determination of time-weighted average concentrations of priority pollutants in surface water by passive sampling, followed by analysis. It has been sponsored by the University of Portsmouth, UK and developed through the British Standards Institution (BSI) as a Work Package of an EU sponsored research project, to support the E U Water Framework Directive (2000/60/EC). Pollutant levels in surface water have traditionally been monitored by spot sampling (also known as bottle or grab sampling). Such sampling gives a snapshot of pollutant levels at a particular time. But pollutant levels in surface water have a tendency to fluctuate and so it is desirable to monitor pollutant levels over time. Passive sampling involves the deployment of a calibrated device that uses a diffusion gradient to collect pollutants over a period of days to weeks, followed by extraction and analysis of the pollutants in a laboratory. This provides a measure of time-weighted average concentrations of pollutants to which the sampling device was exposed. Passive sampling devices used in surface water typically consist of a receiving phase (typically a solvent or sorbent) that acts as a sink for compounds of interest, which may be held behind or surrounded by a membrane through which the target substances can permeate. In its simplest form a passive sampling device is comprised solely of a membrane, or fibre, or bulk sorbent which acts as a receiving phase. Priority pollutants have been defined by the EU and are listed in Council Decision 2455/2001/EC. Contents Foreword Introduction 1 Scope 2 Normative references 3 Terms and definitions 4 Principle 5 Handling sampling devices