During a few decades, many fresh and marine water areas have been seri
ously affected by eutrophication, due to increasing discharges of phos
phorus (P) and nitrogen (N) from modern society. The aim of this paper
is to discuss the policies that are used and have been suggested to r
educe eutrophication, and the factors counteracting these efforts. Pol
icy options to reduce the fluxes of nutrients from point and non-point
sources are summarized. A number of processes and mechanisms countera
ct the control measures taken so far, namely: the growing world popula
tion, the increasing urbanization, the intensive land independent anim
al production, the over-consumption of N and P, the emissions of N to
the atmosphere, and the losses of P from P-enriched sediments. It is c
oncluded that the driving force for eutrophication, the losses of nutr
ients from food production, organic waste, sewage, sludge and ashes ca
n be expected to increase during the coming decades, as the world popu
lation continues to grow. Strong policies are needed to promote birth
control, and to stop over-consumption of N (animal protein) and unnece
ssary intake of P (food additives). There is a number of barriers to o
vercome to reduce large-scale eutrophication, but also a lot of space
for new policies and innovations. (C) 1998 IAWQ. Published by Elsevier
Science Ltd.