MEASUREMENT OF VOLATILE ORGANIC-COMPOUNDS AT UK NATIONAL MONITORING PLAN STATIONS

The concentrations and distribution of 13 volatile organic compounds w ere determined in water samples collected from estuaries and offshore sites around the UK, using a purge and cryotrapping system coupled to GC/MS. The highest concentrations of volatiles obtained were from the Tees, Tyne, Wear, Humber, and Mersey estuaries, but very few compounds were found at detectable concentrations at the offshore sites. Chloro form and 1,1,1-trichloroethane were commonly detected (at concentratio ns up to 11 500 and 600 ng l-1 respectively), and a variety of other c hlorinated and brominated compounds (1,2-dichloroethane, carbon tetrac hloride, trichloroethylene, tetrachloroethylene, bromodichloromethane, dibromochloromethane and bromoform) were also detected at some sites. Benzene, toluene, xylene and ethylbenzene were rarely present at meas urable concentrations (> 10 ng l-1). A number of additional volatile o rganic compounds were tentatively identified in samples from the Tees estuary. Since the highest concentrations of volatile compounds occurr ed at sites close to known industrial sources it is concluded that the targeted volatile organic compounds originated mainly from anthropoge nic input into the estuaries.