Acute Toxicity of Mining Environmental Waste on Bulnesia retama and Plectrocarpa tetracantha Seedlings

P. DÍAZ; YOUNG, BRIAN JONATHAN; S. HRUBY; RIZZO, PEDRO; G. ROQUEIRO; B. HEREDIA

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

Native species of shrubs from arid environments disperse seeds in the surroundings of sites contaminated with mining waste. During the germination period and the first days of seedling development, numerous physiological processes occur in which the presence of toxic substances can interfere with the plant survival and normal development. The objective of this study was to evaluate the acute toxicity of soils contaminated with mining waste on seeds of Bulnesia retama (Br) and Plectrocarpa tetracantha (Pt), two native species from the Monte region (La Planta, San Juan, Argentina). Seeds were collected in the surroundings of La Planta and soil samples were taken in two sites: contaminated (S1) and reference sites (S2). Seeds were exposed to 6 increasing concentrations of soil mixtures from Site 1 and 2: 0, 10, 25, 50, 70, and 100% (v/v), where 0 corresponds to S2 soil and 100% to S1 soil. Experimental unit consisted of 20 seeds placed on wet soil into a Petri dish, reaching a total of 5 repetitions per treatment. A pre-germination treatment was applied to the seeds to ensure the seedling emergence. Toxicity tests were carried out in a germination chamber in darkness at 25±2 °C. Due to differences in germination time of each species, exposure of Br and Pt lasted 12 and 7 d, respectively. Mean Germination Time (MGT), Metal Tolerance Index (ITM), Germination Index (GI) and IC50 of root (r) and hypocotyl (h) length were estimated. For Br, a significant decrease was observed from 50% S1 concentration in ITMr, ITMh, and GI (p