An external monitoring plan (EMP) is being implemented in the region of Opo
rto, Portugal, to follow the potential effects of a future incinerator of m
unicipal solid waste. Polychlorinated dibenzo-p-dioxins and polychlorinated
dibenzofurans (PCDD/PCDF) were measured during 1998 and the first semester
of 1999, prior to the working up of the incineration unit. The baseline le
vels obtained through this intensive monitoring work are presented and disc
ussed in the present paper. (C) 2001 Elsevier Science Ltd. All rights reser
ved.