ABSTRACT: The Environmental Protection Agency (EPA) has an inventory of more than 38,000 uncontrolled waste sites, of which 1,400 are listed on EPA's National Priorities List as posing the greatest threat to public health and the environment. These polluted sites - heavy metal- and organic residue-contaminated waste storage or treatment plants and mining and weapons manufacture facilities - will have to be cleaned up. The traditional approach in soil remediation is to remove the topsoil and bury it somewhere else...at a cost of about $1 million per acre! One potentially cost-effective alternative to traditional methods being explored is phytoremediation - the use of native plant species or genetically engineered plants to remediate (remove or neutralize) toxic organic and inorganic wastes (xenobiotics) in soils. Plants selected or engineered for resistance to and uptake of the xenobiotic are grown in contaminated soils, allowed to extract, accumulate and/or metabolize the xenobiotic and then harvested when soil levels of the xenobiotic have been decreased sufficiently. For non-reclaimable xenobiotics or xenobiotics of little or no commercial value, the plant harvest is decreased in volume and weight by thermal, microbial, physical or chemical means, so diminishing handling, processing and subsequent landfill costs. For valuable xenobiotics, such as heavy metals, the plant harvest is smelted. However, if phytoremediation is to work the xenobiotic must be rapidly metabolized to an innocuous derivative or somehow insulated from the plant's metabolic machinery. Crucial, therefore, for the phytoremediation of many substances is the presence of a large intracellular compartment, the central vacuole, in most plant cells. Bounded by a selectivity filter (the vacuolar membrane), the plant vacuole often represents 40-70%, sometimes as much as 99%, of total intracellular volume. This talk will focus on recent advances in our understanding of the molecular identity of the machinery - transporters and metal-binding polymers - that enable plants to deploy their vacuoles as intracellular landfills for the sequestration of organic and inorganic xenobiotics without themselves succumbing to the toxic action of these agents.