Plant-availability of metals in biosolids-treated soils may be mathematically described by Mt = C x 1 - e- (k x t)] where Mt (mg kg-1) is the cumulative metal removal from the biosolids-treated soils by growing and harvesting plants for t years, C is the total phytoavailable metal pool of the soil (mg kg-1) at t = 0, and k is the metal absorption rate coefficient (yr-1). The total available metal pool, C, is defined as metals extractable by organic acids in the rhizosphere of growing plants and k is related to the kinetics of metal release by organic acids. Half-life of the available metals...