Polychlorinated biphenyls in mountain pine (Pinus uncinata) needles from Central Pyrenean high mountains (Catalonia, Spain)

The polychlorobiphenyl (PCB) composition of pine needles of Pinus uncinata from the Pyrenean high mountains has been investigated. Samples from four altitudes (1750, 1950, 2150, and 2250 m above sea level) were collected in March 2002 and June 2002 in a central area near Lake Redon. The observed concentrations were similar to those found in pine trees from rural areas in Europe. A correlation between log-transformed PCB concentrations and reciprocal of absolute average air temperature was observed for all congeners studied except No. 28, the most volatile congener studied. The highest concentrations were found at the lowest temperatures. Phase-change enthalpies calculated from the slopes of the concentration–temperature dependencies showed a good agreement with the enthalpies of vaporization. The pine needle–atmosphere partition coefficients of the studied PCB congeners increased with higher degrees of compound chlorination and with lower average air temperatures. They exhibit a good linear relationship with log(Koa) but the temperature dependence was stronger for log(Kpa) than log(Koa).