{'wetlands': [0, 0, 0, 3], 'ecosystem': [10, 0, 0, 4], 'sediments': [0, 0, 0, 4], 'nutrient recovery': [0, 0, 0, 1], 'rivers': [3, 2, 8, 8], 'plants': [11, 0, 4, 4], 'siltiation': [0, 0, 0, 1], 'absorption': [0, 0, 0, 2], 'heavy metals': [1, 0, 0, 0]}