Effectiveness of amendments on the spread and phytotoxicity of contaminants in metal-arsenic polluted soil.
A metal-arsenic polluted soil from sulphide-mine waste was treated, in all possible combinations, with two different amounts of marble sludge (98% CaCO3), compost (41% organic carbon), and Byferrox (70% Fe). Lixiviate and pore water from each treated and untreated soil were analysed, and lettuce-seed bioassays were performed. None of the treatments decreased the electrical conductivity of lixiviates or the concentrations of all pollutants found in both solutions. Marble sludge and compost increased the pH values and decreased the zinc, cadmium, copper, and lead concentrations in both solutions while increasing the arsenic concentrations in the lixiviates. Byferrox did not alter the physicochemical parameters or the concentrations of zinc, cadmium, copper, or lead in either solution but significantly decreased the arsenic concentrations in pore water. Compared with the Byferrox treatment, the mixture of marble sludge and Byferrox decreased redox potential values, increasing the arsenic concentrations in both solutions and the electrical conductivity of the pore water. All lixiviates were highly phytotoxic and seeds did not germinate. Pore-water phytotoxicity was related to electrical conductivity values and heavy-metal concentrations. The combination of marble sludge and compost was most effective at diminishing toxicity in lettuce. The soils treated with Byferrox, alone or mixed with marble sludge or compost, were the most phytotoxic.
Departamento de Edafología y Química Agrícola, ESI CITE IIB, Universidad de Almería, Carretera de Sacramento s/n, 04129 Almería, Spain. vga220@ual.es
V
V
González
I
I
García
F
F
Del Moral
M
M
Simón
D001151:Arsenic / Q000032:analysis / Q000633:toxicity*; D002119:Calcium Carbonate / Q000494:pharmacology*; D018525:Germination / Q000187:drug effects; D007220:Industrial Waste / Q000009:adverse effects / Q000032:analysis; D058085:Iron Compounds / Q000494:pharmacology*; D018545:Lactuca / Q000187:drug effects* / Q000254:growth & development; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity*; D008903:Minerals / Q000494:pharmacology*; D008906:Mining; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D013440:Sulfides
D007220:Industrial Waste; D058085:Iron Compounds; D019216:Metals, Heavy; D008903:Minerals; D012987:Soil; D012989:Soil Pollutants; D013440:Sulfides; C094886:goethite; D002119:Calcium Carbonate; D001151:Arsenic