title: Acute phytotoxicity of seven metals alone and in mixture: Are Italian soil threshold concentrations suitable for plant protection?
abstract: Metals can pollute soils in both urban and rural areas with severe impacts on the health of humans, plants and animals living there. Information on metal toxicity is therefore important for ecotoxicology. This study investigated the phytotoxicity of different metals frequently found as pollutants in soils: arsenic, cadmium, chromium, lead, mercury, nickel and zinc. Cucumber (Cucumis sativus), sorghum (Sorghum saccharatum) and cress (Lepidium sativum) seeds were used as models for other plants used in human nutrition such as cereals, rice, fruits and vegetables. The 72-h germination rate and root elongations were selected as short-term ecotoxicological endpoints in seeds exposed to single metals and mixtures. Metals were spiked onto OECD standard soils in concentrations comparable to current Italian contamination threshold concentrations for residential and commercial soils. Arsenic, chromium, mercury and nickel were the most toxic metals in our experimental conditions, particularly to cress seeds (5.172, 152 and 255.4 mg/kg as 72 h IC50 for arsenic, mercury and nickel respectively). Italian limits were acceptable for plant protection only for exposure to each metal alone but not for the mixtures containing all the metals concentrations expected by their respective legislative threshold. The effects of the mixture were class-specific: trends were comparable in dicots but different in monocots. The response induced by the mixture at high concentrations differed from that theoretically obtainable by summing the effects of the individual metals. This might be due to partial antagonism of the metals in soil or to the formation of complexes between the metals, which reduce the bioavailability of the pollutants for plants.
authors.affiliation: Laboratory of Environmental Chemistry and Toxicology, Department of Environmental Health Sciences, IRCCS Istituto di Ricerche Farmacologiche "Mario Negri", Via Giuseppe La Masa 19, 20156 Milano, Italy. Electronic address: diego.baderna@marionegri.it.
authors.forename: Diego
authors.initials: D
authors.lastname: Baderna
authors.affiliation: Laboratory of Environmental Chemistry and Toxicology, Department of Environmental Health Sciences, IRCCS Istituto di Ricerche Farmacologiche "Mario Negri", Via Giuseppe La Masa 19, 20156 Milano, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Lomazzi
authors.affiliation: Laboratory of Environmental Chemistry and Toxicology, Department of Environmental Health Sciences, IRCCS Istituto di Ricerche Farmacologiche "Mario Negri", Via Giuseppe La Masa 19, 20156 Milano, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Pogliaghi
authors.affiliation: Laboratory of Environmental Chemistry and Toxicology, Department of Environmental Health Sciences, IRCCS Istituto di Ricerche Farmacologiche "Mario Negri", Via Giuseppe La Masa 19, 20156 Milano, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ciaccia
authors.affiliation: Laboratory of Environmental Chemistry and Toxicology, Department of Environmental Health Sciences, IRCCS Istituto di Ricerche Farmacologiche "Mario Negri", Via Giuseppe La Masa 19, 20156 Milano, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Lodi
authors.affiliation: Laboratory of Environmental Chemistry and Toxicology, Department of Environmental Health Sciences, IRCCS Istituto di Ricerche Farmacologiche "Mario Negri", Via Giuseppe La Masa 19, 20156 Milano, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Benfenati
mesh_terms: D007558:Italy; D008670:Metals / Q000032:analysis / Q000633:toxicity*; D010944:Plants / Q000737:chemistry / Q000187:drug effects*; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D013054:Spectrophotometry, Atomic
chemical_list: D008670:Metals; D012989:Soil Pollutants
keywords: Environmental toxicology; Italy; Metals; Phytotest; Soil pollutants