Arsenic Absorption by Salvinia minima in Short and Long Times in Contaminated Waters and Its Possible Use for Phytoremediation

Arsenic (As) is a ubiquitous metalloid in nature, which represents a serious environmental impact due to its accumulation and difficult removal. The objective of this study was to evaluate whether Salvinia minima L., with great vegetative reproduction, serves as a bioremediator. The plants were washed with a 10 mM EDTA solution and grown in batch hydroponics, using a modified Hoagland solution (190 μE·s⁻¹·m⁻²), 16/8h photoperiod (artificial light/darkness) and temperature of 25 +/- 2ºC, for 7 days of adaptation. The exposure to As was carried out with raw water and the addition of 0.2 ppm of Na2AsO4. Uptake was analyzed over short periods of time, for 42h, by extracting triplicate samples every 6,12,18,24,30,36,42h from contaminated water and plant material. Uptake was analyzed over long periods of time, extracting triplicate samples every 48,96,144,192,240,288,336 and 384 h from contaminated water and plant material. Leaf and root homogenates were subjected to HNO3 mineralization by wet microwave procedure using hermetic teflon reactors with a pressure valve. Water samples were extracted at the same times and acidified with 1% HNO3. [As] was determined by ICP-Mass. Statistical analyses were performed by ANOVA followed by the Tukey test, with ***p≤0.001. The variation of As over short periods of time showed a significant decrease in culture solution at 42h with p **p≤0.01 and in S. minima a significant increase was observed at times 36 and 42h with ****p<0.0001. The variation of As over long periods in S.minima showed a very significant increase between 48 h and 384 h with a**** p<0.0001. The fresh weight showed a significant increase al 384 h with **** p<0.0001 and in dry weight there were no significant difference. S.minima is a promising species for water remediation.