The researchers used a sand culture method to find plants that can absorb high levels of uranium from contaminated soil. They tested 32 plant species from 5 different families and found that some plants, like those from the pea and acacia families, absorbed more uranium than others. They also discovered that adding citric acid increased uranium absorption in certain plant species. This study suggests that the sand culture method is effective for selecting plants for phytoremediation of uranium-contaminated soil.