Regarding land application of sewage sludge and the accumulation of dangerous levels of toxic metals in the soil: Many, perhaps hundreds, of hyperaccumulating plants have been identified. These take up large quantities of toxic metals from the medium in which they are grown. Perhaps large tracts of marginal farmland could be devoted to sludge recycling where certain hyeraccumulating plants could be grown as cover crops, harvested and themselves recycled to reclaim the heavy metals. Tracts farmed this way could be rotated allowing a certain percentage of the total acreage to lay fallow for periods of time. The plant residue allowed to remain after harvest would serve to raise levels of organic matter in the soil, thus increasing soil tilth and reducing the time required for soil preparation with farm equipment. During fallow times, acreage could be used to produce cash crops such as ornamental nursery stock (esp. plant material used for erosion control, bioremediation (air cleaning in urban areas), wind, sound, visual buffers and wildlife habitat). Tree farming for saw timber, fuel, wood pulp and chips, growing of biomass for synfuel and paper production could be done as well. Collection basins below slopes on this farmland could collect runoff to be processed in partitioned lagoons inside greenhouses where a variety of marine organisims and aquatic plants could detoxify the effluent. -------- Could anyone suggest any references about hyperaccumulating plants, marine and soil organisims that are able to thrive under polluted conditions and bioremediation technology? Lawrence london@sunsite.unc.edu