Toxicity and Bioaccumulation of Heavy Metals in Spinach (Spinacia oleracea) Grown in a Controlled Environment

Abstract

The impact of heavy metal toxicity on the shoot and root lengths, total protein, fiber characteristics, moisture content and nutrient composition of spinach (Spinacia oleracea) was evaluated. Plants were grown in pots containing soil and treated with different concentrations (mg/kg) of lead (Pb; 300, 400 and 500), cadmium (Cd; 0.5, 1 and 1.5) and zinc (Zn; 250, 500, and 700) as well as mixtures of Cd and Pb (0.5/300, 1/400, 1.5/500), Cd and Zn (0.5/250, 1/500, 1.5/700), and Pb and Zn (300/250, 400/500, 500/700). Soil contaminated by long-term irrigation with wastewater containing heavy metals was simulated. An increase in concentrations of heavy metals both individually and as mixtures significantly (p < 0.05) reduced the growth parameters and nutrient contents of S. oleracea. The uptake patterns of heavy metals in mixtures showed antagonistic impacts on each other. The toxicities of the mixtures Cd and Pb, Cd and Zn as well as Pb and Zn were higher than those observed in separate heavy metal applications but less than their additive sums. The toxicity caused by individual heavy metals was the highest for Cd followed by Pb and Zn. The highest toxicity was observed in plants grown in soil contaminated by Cd and Pb.

Accumulation pattern of trace metals in Spinacia oleracea harvested from soil treated with urine in comparison with other soil amendments in Pretoria, South Africa

“…The order of the Zn concentration in S. oleracea was leaves [ roots [ -stalks for all the amendments and this is in agreement with the study conducted by Farooq et al (2008) where S. oleracea stalks recorded the least concentration of Zn. Even though the concentration of Zn in the stalks harvested from soil treated with urine was below the recommended value of 200 lg/g (Alia et al 2015;Jung 2008) the leaves harvested from the soil treated with urine was above this recommended value.…”

“…According to Dingkwoet et al (2013), S. oleracea has been shown to be an excellent source of Mn in food. In plants, Mn plays a role in the splitting of water molecules which are essential for photosynthesis (Alia et al 2015). In the human body, Mn is important for the manufacturing of enzymes even though in excess it has a negative impact on the enzyme activity, translocation, absorption and consumption of other mineral elements resulting in oxidative stress (Lion and Olowoyo 2013).…”

“…Zn is essentially required by plants in minute quantities (25-150 lg/g) in dry tissue (Jung 2008) and the level of Zn in agricultural products should be below 200 lg/g and the dietary intake of Zn should not be above 150 lg/g (Alia et al 2015;Jung 2008). In humans, excess amounts of Zn may cause metal poisoning and retardation of growth especially in young children (Sithole et al 2016) and in plants it may inhibit plant growth, cause damage and chlorosis in leaves resulting in a reduction in chlorophyll (Alia et al 2015). Mn concentration varied between 30.09 ± 0.57 and 446.00 ± 46.15 mg/kg.…”

Effects Research of Environmental Hormone BPA and PAEs on the Expression of HSP70-9 Gene in Spinacia oleracea

“…Current researchers who study EHs impact on organisms continue to increase, and have mainly focused on the influence of heavy metals on aquatic animals and plants [9][10][11][12], pesticides on insects [11], and EHs on organism genotoxicity [5]. The plasticizers, BPA for clear plastics and PAEs in hard plastics, have some estrogenic activity and anti-androgenic activity [4].…”

“…Among these families, HSP70 family is the highly conserved and the most researched gene family [11,15,17,[20][21][22][23][24]. Studies have demonstrated that heat stress [15,[18][19][20][24][25][26][27][28][29][30][31][32], Cold stress [15,24,26,29,30], water stress [22,25,26,33,34], oxidative stresses [19,20,22], heavy metals [9,12,13,35], salt stress [13,19,20,22,34], light stress [27], and chemical contaminants [11,15,18,19,25,[35]…”