Reducing chromium uptake through application of calcium and sodium in spinach

Pressmud Subdue Phytoremediation Indices in Lead-Contaminated Soils: A Human Health Perspective

Direct discharge of waste into water bodies and mining are two major sources of lead contamination in ecosystems. Water scarcity promoted the usage of industrial effluent-contaminated waters for crop production, mainly in peri-urban areas. These wastewaters may contain heavy metals and pollute crop ecosystems. These metals can reach the living cell via contaminated raw foodstuffs that grow under these conditions and cause various ill effects in metabolic activities. In this study, graded levels of pressmud (0, 2.5, 5, 10 g/kg) were applied on lead imposed soil with different contamination levels (0, 100, 150, 300 mg/kg) and metal dynamics was studied in spinach crop. Experimental results showed that the addition of pressmud upto 10 mg/kg had decreased different phytoremediation indices in spinach crop. Whereas, increasing Pb level enhanced the indices' values, indicating accumulation of significant amount of Pb in spinach biomass. However, application of pressmud (upto 10 mg/kg) reduced the bioconcentration factor (BCF) from 0.182 to 0.136, transfer factor (TF) from 0.221 to 0.191, translocation efficiency 66.11-59.34%; whereas, Pb removal enhanced from 0.063 to 0.072 over control treatment. These findings suggest that application of pressmud declined Pb concentration, the BCF and the TF in test crop which lead to less chances of adverse effect in human. These information are very useful for effectively managing wastewater irrigated agricultural crop production systems.

Pressmud overcome lead toxicity by improving spinach biomass in lead-contaminated soils

Lead (Pb) pollution is a severe problem that primarily affects food chain in developing countries. Continuous use of Pb containing effluent for growing food crops builds up measurable concentration of Pb in soils; and adversely affects the soil properties and crop produce quality. To reduce the Pb metal toxicity in contaminated soil, a pot experiment was conducted with graded doses of pressmud (PM) (0, 2.5, 5.0, and 10.0 g/kg) and Pb (0, 100, 150, and 300 mg/kg soil). Various metal dynamics parameters were computed after spinach crop was harvested. Result showed that higher doses of Pb (300 mg/kg) diminished the spinach root and shoot biomass during the study; whereas, application of PM improved the spinach biomass. However, increasing the pressmud reduced the Pb concentration in shoot from 6.16, 5.99, 4.94, and 3.39 µg/g. Maximum reduction was measured in highest PM applied treatment in shoot (44.92%) and root (57.33%). In this experiment, increasing level of Pb significantly uptake was recorded with higher application rate of Pb (150 and 300 mg/kg). However, elevated doses of PM from control initially enhanced the small chunk of Pb and drastically reduced the shoot Pb uptake (0.060 to 0.049 mg/pot) in maximum level of PM applied treatment. This study is very useful to improve the soil health by immobilizing the labile fraction of Pb by addition of PM in Pb-contaminated soils.

Immobilization of chromium bioavailability through application of organic waste to Indian mustard (Brassica juncea) under chromium-contaminated Indian soils

Industrialization results in production of large volume of wastewaters, and disposing of them become a serious problem. The wastewaters may have range of heavy metals, which have an impact on soil and plant health. The objective was to evaluate the influence of farm yard manure (FYM) and pressmud (PM) applications on Indian mustard growth and chromium (Cr) uptake in tannery effluent irrigated Cr-contaminated soil. Soil was collected from the tannery effluent irrigated fields (chromium contaminated) of Shekhpura village of Kanpur, India. A pot culture experiment was carried out by growing Indian mustard (Brassica juncea) var. RH 749 on the Cr-contaminated soil with application of different levels and combinations of FYM and PM (at 0, 2.5, and 5 g kg^-1 each). Biomass yield, Cr uptake, bioconcentration factor (BCF), transfer factor (TF), transfer efficiency (TE), and Cr removal indices were examined. Higher doses of FYM and PM resulted in reduction of Cr concentrations in shoot (6.60 to 2.50 µg g^-1) and root (27.27 to 9.43 µg g^-1); and absorption in plant tissues and had improved total dry matter yield (14.56 to 30.94 g pot^-1). The use of FYM and PM had a substantial (p ≤ 0.05) impact on phytoremediation parameters like BCF (0.128 to 0.045), TE (59.61 to 64.51%), and Cr removal (0.65 to 0.51%). Combined application of FYM (5 g kg^-1) and PM (5 g kg^-1) had enhanced the dry matter yield of shoot (12.51 to 26.40 g pot^-1) and root (2.05 to 4.54 g pot^-1) and reduced the Cr uptake (138.54 to 108.79 mg pot^-1) than the individual amendment addition of FYM (138.52 to 135.89 mg pot^-1) and PM (126.02 to 130.52 mg pot^-1). Combined application of FYM (5 g kg^-1) and PM (5 g kg^-1) could be beneficial for remediation of Cr-contaminated areas for cultivation of crops.

Reuse of poor-quality water for sustainable crop production in the changing scenario of climate

The availability of freshwater is limited for agriculture systems across the globe. A fast-growing population demands need to enhance the food grain production from a limited natural resources. Therefore, researchers and policymakers have been emphasized on the production potential of agricultural crops in a sustainable manner. On the challenging side, freshwater bodies are shrinking with the pace of time further limiting crop production. Poor-quality water may be a good alternative for fresh water in water scarce areas. It should not contain toxic pollutants beyond certain critical levels. Unfortunately, such critical limits for different pollutants as well as permissible quality parameters for different wastewater types are lacking or poorly addressed. Marginal quality water and industrial effluent used in crop production should be treated prior to application in crop field. Hence, safe reuse of wastewater for cultivation of food material is necessary to fulfil the demands of growing population across the globe in the changing scenario of climate.

Effects of lead, cadmium and zinc on protein changes in Silene vulgaris shoots cultured in vitro

In the present research, Silene vulgaris as a representative species growing on both unpolluted and heavy metal (HM) polluted terrains were used to identify ecotype-specific responses to metallic stress. Growth, cell ultrastructure and element accumulations were compared between non-metallicolous (NM), calamine (CAL) and serpentine (SER) specimens untreated with HMs and treated with Pb, Cd and Zn ions under in vitro conditions. Moreover, proteins' modifications related to their level, carbonylation and degradations via vacuolar proteases were verified and linked with potential mechanisms to cope with ions toxicity. Our experiment revealed diversified strategy of HM uptake in NM and both metallicolous ecotypes, in which antagonistic relationship of Zn and Pb/Cd ions provided survival benefits for the whole organism. Despite this similarity, growth rate and metabolic pathways induced in CAL and SER shoots varied significantly. Exposition to HMs in CAL culture led to drop in protein level by approximately 16% compared to the control. This parameter nearly correlated with the enhanced activity of proteases at pH 5.2 as well as possible glutamate changes to proline and reduced glutathione, resulting in intensified growth and first signs of cell senescence. In turn, SER shoots were characterized by growth retardation (to 53% of the control), although protein level and carbonylation were not modified, while a deeper insight into protein network showed its remodeling towards production of polyamines and 2-oxoglutarate delivered to the Krebs cycle. Contrary, an uncontrolled HM influx in NM shoots contributed to morpho-structural disorders accompanied by an increase activity of proteases involved in the degradation of oxidized proteins, what pointed to metal-induced autophagy. Taken together, S. vulgaris ecotypes respond to stress by triggering various mechanisms engaged their survival and/or death under HM treatment.