Phytoremediation Potentials of Sunflowers (Tithonia diversifolia and Helianthus annuus) for Metals in Soils Contaminated with Zinc and Lead Nitrates

Abstract

Two species of sunflower, i.e., Tithonia diversifolia and Helianthus annuus, were investigated for their potential to remove heavy metals from contaminated soils. Dried and mature T. diversifolia (Mexican flower) seeds were collected along roadsides, while H. annuus (sunflower) seeds were sourced from the Department of PBST, University of Agriculture Abeokuta, Nigeria. The contaminants were added as lead nitrate (Pb (NO 3 ) 2 ) and zinc nitrate (Zn (NO 3 ) 2 ) at 400 mg/kg which represents upper critical soil concentration for both Pb and Zn. The results indicated that T. diversifolia mopped up substantial concentrations of Pb in the above-ground biomass compared to concentrations in the roots. The concentrations in the leaf compartment were 87.3, 71.3, and 71.5 mg/kg at 4, 6, and 8 weeks after planting (AP), respectively. In roots, it was 99.4 mg/kg, 97.4 mg/g, and 77.7 mg/kg while 79.3, 77.8, and 60.7 mg/kg were observed in the stems at 4, 6, and 8 weeks AP, respectively. Observations with H. annuus followed the pattern found with T. diversifolia, showing significant (p<0.05) accumulation of Pb in the above-ground biomass. Results obtained from Zn contaminated soils showed significant (p<0.05) accumulation in the above-ground compartments of T. diversifolia and H. annuus compared with root. However, the highest accumulation of Zn was observed in the leaf. The translocation factor and enrichment coefficient of Pb and Zn with these plant species are greater than 1, indicating that these metals moved more easily in these plants. However, this result also showed that the translocation of Zn from root to the shoot of the two plants was higher than Pb. In conclusion, this experiment showed that these plants accumulated substantial Pb and Zn in their shoots (leaf and stem) at 4 weeks AP which diminished with time. This implies that the efficiency of these plants in cleaning the contaminated soils was at the early stage of their growth.

Phytoremediation Using Microbial Communities: II

“…The aboveground plant parts rich in accumulated metal can be easily and safely processed by drying, ashing or composting. The plants used in a phytoextraction scheme should ideally have large biomass production and accumulate high concentration of metals in the aboveground portions (Adesodun et al 2010 ). Over 500 plant species (101 families) and approximately 0.2 % of angiosperms have been reported to possess metal hyperaccumulation ability (Krämer 2010 ).…”

“…Soil fungi, for example, improve phytoremediation ability of plants by increasing the absorptive area of the roots of plants. The effi ciency of Tithonia diversifolia and Helianthus annuus in remediating soils contaminated with zinc and lead nitrates could be improved by introducing mycorrhizal fungi in order to increase the absorptive area of the roots of these plants ( Adesodun et al 2010 ). Plants on the other hand play a key role in determining the size and health of soil microbial populations.…”

Application of treated wastewater on yield and heavy metals content of seeds in sunflower cultivars

“…Sunflower (Helianthus annuus L.) is an increasingly important source of vegetable oil and biomass, usefully employed for food, chemical, energy, and industrial purposes (Riva and Calzoni, 2004). It is believed that the plant had the capacity to absorb heavy metals (Madejon et al, 2003;Vamerial et al, 2012), but these components probably accumulated in the roots rather than shoot and plant seeds (Madejon et al, 2003;Marchiol et al, 2007;Adesodum et al, 2010). The objectives of this study were to evaluate the effects of treated municipal wastewater on the yield and heavy metals content of the sunflower seed.…”

Absorción de plomo de suelos altamente contaminados en especies vegetativas usadas para consumo animal y humano

“…Estudios realizados por (Adesodun et al, 2010;Agudelo et al, 2009;Babula et al, 2012;Chinmayee et al, 2012;DeSouza et al, 2012), entre otros, señalan que los procesos de fitorremediación utilizan variedades de plantas que sirven para consumo humano y animal como el maíz (Zea mays) (Suthar et al, 2014), mostaza parda (Brassica juncea) (López y Torija, 2006), nabo (Brassica rapa) (Mateo, 2008), amaranto (Amaranthus hybridus) (Salas y Boradonenko, 2009;Peralta, 2009;Chinmayee et al, 2012), girasol (Helianthus annuus) (Flores, 2010), entre otras especies alimenticias.…”