التفاصيل البيبلوغرافية
| العنوان: |
Evaluation of chemical extractants to assess metals phytoavailability in Brazilian municipal solid waste composts. |
| المؤلفون: |
Asensio, Verónica, Abreu-Junior, Cassio H., da Silva, Fábio César, Chitolina, José Carlos |
| المصدر: |
Environmental Pollution; Dec2018:Part B, Vol. 243, p1235-1241, 7p |
| مصطلحات موضوعية: |
SOLID waste, ORGANIC fertilizers, PLANT nutrients, HEAVY metals, CHELATING agents |
| مستخلص: |
Abstract Municipal solid wastes (MSW) can be composted to become an organic fertilizer. However, besides plant nutrients, it can also contain high concentration of some toxic metals than can pollute agricultural soils, contaminate food, animals and human being. A greenhouse experiment was carried out for two purposes: i) to evaluate the concentrations of cadmium, copper, chromium, nickel, lead and zinc in four Brazilian MSW composts, and, ii) to know which is the best solution for extracting those metals in phytoavailable form from the composts. In order to evaluate the phytoavailability of metals, they were extracted with six chemical extractants: i) water, ii) 0.05 mol L−1 Ca(NO 3) 2 , iii) 0.1 mol L−1 HCl, iv) 0.005 mol L−1 DTPA at pH 7.3, v) 0.05 mol L−1 CaCl 2 and vi) Mehlich 3 solution. In addition, lettuces were cultivated as a test plant in pots containing 1.8 kg of MSW compost as substrate. Fifty-six days later, lettuce plants were harvested. New lettuces were then planted for a second cycle, and then harvested after fifty-six days. Semi-total concentration of metals in composts and total in plants was also determined through an extraction with nitric-perchloric acid. Semi–total concentration of Cd and Pb exceeded the intervention limits from Brazil in the four studied composts, and lettuce plants were polluted by those two elements. Therefore, compost made of MSW must be characterized before being used for agricultural soils. Copper and nickel in phytoavailable were effectively extracted with the strongest chelating agents used, HCl and Mehlich 3, probably because most metal is bound to organic matter in the compost. Cadmium, chromium, lead and zinc were no efficiently extracted with any of the tested extractants. Graphical abstract Image 1 Highlights • Six metals in phytoavailable form are studied in four urban solid waste composts. • Six chemical solutions were evaluated for extracting metals in phytoavailable form. • Concentration of all metals exceeded the intervention limits in the composts. • Lettuce plants growing in the used composts were polluted by Cd and Pb. • Cu and Ni in phytoavailable form were effectively extracted with HCl and Mehlich 3. HCl and Mehlich 3 are the most effective extractants from estimating the phytoavailable concentration of copper and nickel in municipal solid waste composts. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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