Phytoremediation,why it is opposed by public?

As is known to all, Phytoremediation is a green way to remove environmental pollutants. Not only that,it also is low cost and low  harmf to our environment,it makes re-use of valuable metals be possible.How ever,I read a paper,which says that phytoremediation is opposed by public:

Land, surface waters, and ground water worldwide, are increasingly affected by contaminations from industrial, research experiments, military, and agricultural activities either due to ignorance, lack of vision, carelessness, or high cost of waste disposal and treatment. The rapid build-up of toxic pollutants (metals, radionuclide, and organic contaminants in soil, surface water, and ground water) not only affects natural resources, but also causes major strains on ecosystems. Interest in phytoremediation as a method to solve environmental contamination has been growing rapidly in recent years. This green technology that involved “tolerant plants” has been utilized to clean up soil and ground water from heavy metals and other toxic organic compounds. Phytoremediation involves growing plants in a contaminated matrix to remove environmental contaminants by facilitating sequestration and/or degradation (detoxification) of the pollutants. Plants are unique organisms equipped with remarkable metabolic and absorption capabilities, as well as transport systems that can take up nutrients or contaminants selectively from the growth matrix, soil or water. As extensive as these benefits are, the costs of using plants along with other concerns like climatic restrictions that may limit growing of plants and slow speed in comparison with conventional methods (i.e., physical and chemical treatment) for bioremediation must be considered carefully. While the benefits of using phytoremediation to restore balance to a stressed environment seem to far outweigh the cost, the largest barrier to the advancement of phytoremediation could be the public opposition. The long-term implication of green plant technology in removing or sequestering environmental contaminations must be addressed thoroughly. As with all new technology, it is important to proceed with caution.

I don’t understand the reason very well.Is there anyone can help?