Heavy Metal Uptake Research Articles

Enhanced selective adsorption capacity of lead (II) from complex wastewater by aminopropyltriethoxysilane-functionalized biochar grafted on the MXene based on anion-synergism

The simultaneous elimination of dyes and metal ions from wastewater is essential for industrial wastewater treatment. In the current work, a novel adsorbent, aminopropyltriethoxysilane-functionalized biochar grafted on MXene (APTES/BC/MXene composite), was synthesized and utilized to increase the selectivity of the uptake of lead from a complex multi-metal solution based on anion-synergism. The surface area of the APTES/BC/MXene composite (164 m2/g) was higher as compared to the BC (90 m2/g), APTES (87 m2/g), and APTES/BC (151 m2/g). The outcomes of selective adsorption of metal ions were altered by the composite before (APTES = 52.98 mg/g, APTES/MXene = 58.65 mg/g, and APTES/BC = 313.86 mg/g) and after grafting aminopropyltriethoxysilane-functionalized biochar on the MXene (APTES/BC/MXene = 323.17 mg/g). In this investigation, the composite showed remarkable selectivity for the adsorption of lead. The adsorption capacity of composite for Pb2+ (323.17 mg/g) was superior compared to Cd (16.45 mg/g), Sr (10.99 mg/g), Zn (25.37 mg/g), Ni (7.82 mg/g, Ca (20.79 mg/g), and Ag (58.47 mg/g). Interestingly, the selective uptake of lead by the composite was enhanced from 446.85 to 1072.04 mg/g as coexisting methyl blue dosages increased from 0 to 100 mg/L at a pH value of 6.0. In the lead-methyl blue complex binary system, lead and methyl blue indicated synergistic phenomena, in which the existence of methyl molecules generated new unique sites for lead adsorption, while methyl blue uptake was also increased by the existence of lead. The experiment's findings demonstrate that the prepared APTES/BC/MXene exhibited excellent stability and regeneration capabilities (96.2% and 95.1% adsorption efficacy after 5th cycles for Pb2+ and MB respectively), suggesting it can be employed as a quick and efficient uptake adsorbent for the elimination of MB and Pb2+ in a single pollutant system. Hydrogen bonding, electrostatic interaction, synergistic penetration, and ion exchange processes were primarily involved in the uptake of lead and methyl blue. This investigation offers useful insights for the development of composite that indicate outstanding performance and easy recovery for the synergistic and simultaneous uptake of heavy metal ions and organic dyes. The results also reveal the remarkable enhancement of selective heavy metal uptake from complex wastewater by utilizing anion-bye interactions.

Interactive Suitability of Rice Stubble Biochar and Arbuscular Mycorrhizal Fungi for Improving Wastewater-Polluted Soil Health and Reducing Heavy Metals in Peas

Arable soils irrigated with wastewater (SIWs) cause ecological and human health issues due to the presence of heavy metals (HMs). Burning rice stubble (RS) poses severe environmental and human health hazards. Converting RS into rice stubble compost (RSC) and rice stubble biochar (RSB) can overcome these issues. Here, we considered the role of RS, RSC, and RSB as individual soil amendments and combined each of them with arbuscular mycorrhiza fungi (AMF) to observe their effectiveness for HM immobilization in SIW, their uptake in pea plants, and improvements in the physicochemical properties of soil. The results revealed that adding RSB and AMF reduced the bioavailable concentrations of Pb, Cd, Ni, Cu, Co, and Zn in SIW by 35%, 50%, 43%, 43%, 52%, and 22%, respectively. Moreover, RSB+AMF treatment also reduced Pb, Cd, Ni, Cu, Co, and Zn concentrations in grain by 93%, 76%, 83%, 72%, 71%, and 57%, respectively, compared to the control. Improvements in shoot dry weight (DW) (66%), root DW (48%), and grain yield (56%) per pot were also the highest with RSB+AMF. RSB+AMF treatment enhanced soil health and other soil attributes by improving the activity of urease, catalase, peroxidase, phosphatase, β-glucosidase, and fluorescein diacetate by 78%, 156%, 62%, 123%, 235%, and 96%, respectively. Interestingly, RSB+AMF also led to the strongest AMF–plant symbiosis, as assessed by improved AMF root colonization (162%), mycorrhizal intensity (100%), mycorrhizal frequency (104%), and arbuscular abundance (143%). To conclude, converting RS into RSB can control air pollution caused by RS burning. Moreover, adding RSB with AMF to SIW can reduce HM uptake in plants, improve soil health, and thus minimize ecological and human health issues.

Co-applications of Rhizobium and arbuscular mycorrhizal fungi synergistically alleviate heavy metal uptake and toxicity in lentil plants (Lens culinaris Medik.) grown in sewage sludge amended soil

Reusing sewage sludge as a mode of nutrients and an organic amendment may be a viable choice for the appropriate treatment of organic waste. This study examined the impact of symbiotic microbes such as Rhizobium and two selected arbuscular mycorrhizal fungi (AMF), Funneliformis caledonius (Nicolson & Gerd.) and Glomus bagyarajii (Mehrotra), on the growth, photosynthetic pigments, biochemical content, microbial population, and heavy metal uptake in lentil plants grown in soil mixed with 20 % sewage sludge. Lentil seeds were inoculated with Rhizobium prior to sowing and with either of the AMF (Funneliformis caledonius or Glomus bagyarajii) in pots filled with soil-sewage sludge mixture. The results showed that the tested microbial inoculum enhanced the growth and productivity of lentil plants. Lentil plants inoculated with Rhizobium and AMF had better nodulation and root colonization, leading to an increase in the nitrogen, phosphorus and potassium (NPK) content and a decrease in the stress marker, proline, in plant parts. In addition, the inoculated microbes also improved the photosynthetic and biochemical contents of the plant. Lentil plants grown in sewage sludge-amended soil when inoculated with Rhizobium and either of AMF were found to be more effective in accumulating Cd, Cr, Pb, Ni, and Zn in the roots, while restricting their translocation to the above-ground parts of the plant, thereby improving plant health. Overall, the study outcomes provide evidence that Rhizobium and AMF have the potential to tolerate heavy metal stress caused by the addition of sewage sludge to soil, which has important implications for sustainable agriculture practices. The study also highlights the importance of microbial inoculants, such as Rhizobium and AMF in enhancing growth and yield, particularly under heavy metal stress in economically important lentil.

Efficient organic-MgO matrix as adsorbent for heavy metal uptake: Spectroscopic, adsorption isotherms, kinetic and thermodynamic analysis

Efficient organic-MgO matrix as adsorbent for heavy metal uptake: Spectroscopic, adsorption isotherms, kinetic and thermodynamic analysis

Understanding the bacterial community structure associated with the Eichhornia crassipes rootzone.

Plant microbiome acts as an interface between plants and their environment, aiding in the functioning of the ecosystem, such as protection against abiotic and biotic stress along with improving nutrient uptake. The rhizosphere is an essential interface for the interaction between plants and microbes and plays a substantial part in the removal as well as uptake of heavy metals and antibiotics from contaminated locations. Eichhornia crassipes is a promising plant that contains a rich community of microbes in its rhizosphere. Microorganism's association with plants embodies a crucial pathway via which humans can also be exposed to antibiotic-resistant genes and bacteria. In our earlier study enhanced removal of ciprofloxacin was observed by plant growth-promoting Microbacterium sp. WHC1 in the presence of E. crassipes root exudates. Therefore, the V3-V4, hypervariable region of the 16S rRNA gene was studied to assess the bacterial diversity and functional profiles of the microbiota associated with plant roots. Using the QIIME software program, 16S rRNA data from the Next Generation Sequencing (NGS) platform was examined. Alpha diversity including Chao1, Observed Shannon, and Simpson index denote significantly higher bacterial diversity. Proteobacteria (79%) was the most abundant phylum which was present in the root samples followed by Firmicutes (8%) and Cyanobacteria (8%). Sulfuricurvum (36%) is the most abundant genus belonging to the family Helicobacteraceae and the species kujiense in the genus Sulfuricurvum is the most abundant species present in the root sample. Also, the bacterial communities in the rhizoplane of Eichhornia crassipes harbor the genes conferring resistance to beta-lactams, tetracycline, fluoroquinolones, and penams. Metagenomic studies on the E. crassipes microbiome showed that the bacterial communities constituting the root exudates of the Eichhornia aid them to survive in a polluted environment.

Phytoextraction potential of herbaceous plant species and the influence of environmental factors – A meta-analytical approach

Heavy metals account for a notable share of soil and water body contaminations. For restoring contaminated soils, phytoremediation is considered an eco-friendly and sustainable practice. However, the implementation in the field requires a well-thought-out plant selection and comprehensive knowledge of the influence of various environmental factors. Therefore, a quantitative evaluation of 330 studies was done using a meta-analytical approach. The systematic assessment included the calculation of bioconcentration factors for roots and shoots (BCFROOT, BCFSHOOT) and translocation factors (TF) of 48 herbaceous species, as well as the identification of the most important soil and plant factors that regulate the heavy metal uptake into plant tissues. The results showed substantial variations in roots' and shoots' heavy metal uptake capacity among the diverse plant species. The uptake also varied depending on the type of heavy metal. Most species revealed a higher accumulation of heavy metals in roots than shoots, indicating a limited heavy metal transport from below-ground into above-ground plant parts. Among the different heavy metals, Cd showed the highest median BCFSHOOT and BCFROOT, followed by Zn, Cu, Ni, Cr, and Pb, which can partly be explained by the solubility and plant availability of the elements. The strongest significant and positive correlations of heavy metal contents in plant tissues were found with the total and available soil content. Clay and silt content showed a weak negative, and sand content a slight positive correlation. Further, root, shoot and total biomass revealed weak negative correlations to the plants' heavy metal contents. Overall, this study forms a basis for the minimum accumulation capacities of various species and thus makes an essential contribution to the planning and practical application of phytoremediation projects.

Evaluation of Accumulation Potency of Arka Plant Varieties for Metals and Nutrients through Natural Biological Treatment

This study aims to evaluate the effectiveness of a natural biological treatment system for wastewater using Red soil, Arka Darshan, Arka Tilak, Arka Nirantara, and Arka Prajwal plants. The system employs clay as a natural nanomaterial for adsorption of substances such as nitrates, phosphates, potassium, and heavy metals. The soil contains numerous microorganisms that decompose organic matter into simpler compounds, while the plants use phytoremediation to uptake heavy metals and nutrients. The study measured the system’s efficiency in reducing Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Phosphate, Magnesium, Zinc, Nitrate, Sodium, and Potassium. The results showed that the system had an average efficiency of 98% in COD and 96% in BOD removal, and contributed an efficiency of 99% TSS and 46% TDS. The system also removed nitrates and phosphates, which cause eutrophication in water bodies, by 76% and 72%, respectively. Additionally, heavy metals like chromium, Nickel and Zinc were reduced by up to 81%, 71% and 59%. The study suggests that the natural biological treatment system is a sustainable and effective alternative to conventional wastewater treatment, particularly in sparsely populated rural areas. Therefore, we can conclude that this system has potential for wider adoption in treating wastewater.

Eco-friendly management of Meloidogyne incognita in cadmium-contaminated soil by using nematophagous fungus Purpureocillium lavendulum YMF1.683: Efficacy and mechanism

Root-knot nematodes (RKNs) are distributed globally, including in agricultural fields contaminated by heavy metals (HM), and can cause serious crop damages. Having a method that could control RKNs in HM-contaminated soil while limit HM accumulation in crops could provide significant benefits to both farmers and consumers. In this study, we showed that the nematophagous fungus Purpureocillium lavendulum YMF1.683 exhibited a high nematocidal activity against the RKN Meloidogyne incognita and a high tolerance to CdCl2. Comparing to the P. lavendulum YMF1.838 which showed low tolerance to Cd2+, strain YMF1.683 effectively suppressed M. incognita infection and significantly reduced the Cd2+ uptake in tomato root and fruit in soils contaminated by 100 mg/kg Cd2+. Transcriptome analyses and validation of gene expression by RT-PCR revealed that the mechanisms contributed to high Cd-resistance in YMF1.683 mainly included activating autophagy pathway, increasing exosome secretion of Cd2+, and activating antioxidation systems. The exosomal secretory inhibitor GW4869 reduced the tolerance of YMF1.683 to Cd2+, which firstly demonstrated that fungal exosome was involved in HM tolerance. The up-regulation of glutathione synthesis pathway, increasing enzyme activities of both catalase and superoxide dismutase also played important roles in Cd2+ tolerance of YMF1.683. In Cd2+-contaminated soil, YMF1.683 limited Cd2+-uptake in tomato by up-regulating the genes of ABCC family in favor of HM sequestration in plant, and down-regulating the genes of ZIP, HMA, NRAMP, YSL families associated with HM absorption, transport, and uptake in plant. Our results demonstrated that YMF1.683 could be a promising bio-agent in eco-friendly management of M. incognita in Cd2+ contaminated soils.

A first field evaluation of heavy metals uptake by innovative artificial mussel (AM) technology versus live mussel (LM) from inshore of the Bay of Bengal, Bangladesh and the application of AM technology for global pollution study

The comparative application of innovative artificial mussel (AM) technology together with live mussel (LM) has yet to be performed in the coastal waters of Bangladesh. Here, we report the accumulation of targeted metals (Cd, Cu, Fe, Mn, Ni, Pb, U and Zn) in both AM and LM (Perna viridis) from inshore of the Bay of Bengal, Bangladesh. AMs and LMs were deployed in two sites (MaheshKhali Channel and Reju Khal mouth, Cox’s Bazar district), in the Bay of Bengal, Bangladesh for this research study. Our data suggest that the uptake of Cu, Pb and Ni have correlated positively between AM and LM. The first equilibrium phase of metal uptake in AMs was achieved around day 7 for most of the metals, and the kinetics of uptake from day 0 to day 7 is descended as follows: Zn>Fe>Mn>Ni>U>Cu>Cd>Pb. In contrast, the concentration of metals in LM has not been changed a lot from its background level and found highly enriched in Fe, Pb and U compared to AMs. The overall uptake patterns show that AM can provide precise and time-integrated metal concentrations without any biological influence associated with LMs. Based on our research, AM technology can be a good replacement for bioindicator (live mussel) to monitor heavy metals in waterways since a) all of our targeted metals were accumulated in both AM and LM; and b) both AM and LM show a similar metal uptake, in particular, the uptake of Cu, Pb, and Ni in AM was found positively correlated with LM.

Applicability of the sigmoid model to estimate heavy metal uptake in maize and sorghum as affected by organic acids.

Although assisted phytoremediation using chemical treatments is a suitable technique for the removal of heavy metals (HMs), the estimation of this process using simple models is also crucial. For this purpose, a greenhouse trial was designed to evaluate the effectiveness of citric, oxalic, and tartaric acid on Cd, Pb, Ni, and Zn phytoremediation by maize and sorghum and to estimate this process using sigmoid HMs uptake model. Results showed that mean values of root and shoot dry weight and metals uptake, translocation factor (TF) of Pb and Zn, and uptake efficiency (UE) of Cd in maize were higher than sorghum but the TF of Cd and the phytoextraction efficiency (PEE) and UE of Pb in sorghum were higher than maize. Citric, oxalic, and tartaric acid significantly increased the UE of Pb by 17.7%, 22.5%, and 32.5%, respectively. Tartaric acid significantly increased the mean values of shoot dry weight, shoot Cd, Pb, and Ni uptake, and PEE of Pb and Ni, but decreased TF of Zn. The R2, NRMSE, and KM values indicated the ability of sigmoid HM uptake model in estimating HMs uptake in maize and sorghum treated with organic acids. Thus, tartaric acid was more effective than citric and oxalic acids to enhance phytoremediation potential. Sigmoid HM uptake model is suitable to estimate the HMs uptake in plants treated with organic acids at different growth stages.

Assessment of heavy metals availability and its health risk on Zea mays and Sorghum grown on agricultural soil, Southern Borno, Nigeria

Heavy metals are deleterious due to their long biological half-lives, non-biodegradable nature, and their ability to accumulate in different body parts. Heavy metals emanating from anthropogenic sources are more dangerous because of their instability and solubility leading to high bioavailability. Heavy metals uptake by plants is generally the first step of their entry into the agricultural food chain. The present study aimed at assessing the availability of heavy metals on cereals crops (Zea mays and Sorghum) grown on agricultural soil hence their health risk index. Soil and cereals crops were digested analyzed for Cr, Cd, Cu, Pb, Ni and Zn using Atomic Absorption Spectroscopy (Buck scientific model 210GP) while transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were evaluated. The concentration of Cd in all the three soil samples had mean values of 10.7±2.32 mg/kg while Zea mays and Sorghum had mean values of 2.12±0.09 and 2.75±0.03 mg/kg respectively. The decrease in concentrations of the metals in Zea mays and Sorghum samples across sampling locations followed this order Cd > Cu > Cr > Pb > Ni > Zn. The trend of heavy metal transfer factor from soil to Zea mays and Sorghum grown in Askira Uba, Southern Adamawa were in the order of Cd > Ni > Cu > Pb > Cr > Zn. The HRI values of Cd (1.00, 2.70) in both zea mays and sorghum were higher than other studied heavy metals. The finding of this study with respect to DIM and HRI showed that the consumption of Zea mays and Sorghum grown in Askira Uba, Southern Borno were nearly free of risks at all sites for all assessed heavy metals except Cd. Even though the values of HRI for other metals were nearly one, the long term consumption of these crops may lead to serious health risk.

Lanthanum promotes Solanum nigrum L. growth and phytoremediation of cadmium and lead through endocytosis: Physiological and biochemical response, heavy metal uptake and visualization

Rare earth elements (REEs) are important to enhance agricultural productivity. The utilization of phytoremediation as a green technology for addressing heavy metal (HMs) contamination in soil and wastewater has gained significant attention. In our research, we conducted indoor hydroponic experiments to examine the impacts of lanthanum (La) on the growth and enrichment capacity of Solanum nigrum L. (S. nigrum). S. nigrum was cultivated in 10 mg·L−1 of cadmium (Cd), 25 mg·L−1 of lead (Pb), and a mixture of both (5 mg·L−1 Cd + 15 mg·L−1 Pb). Additionally, S. nigrum were subjected to foliar spray or hydroponic supplementation of La(III). The treatment with La(III) significantly increased total fresh weight by 17.82 % to 42.20 %, compared to the treatment without La(III). Furthermore, La(III) facilitated the endocytosis of roots and enhanced Cd2+ flux ranging from 15.64 % to 75.99 % when compared to the treatment without La(III). Foliar and hydroponic application of La(III) resulted in an increase in the translocation factors (TF) in plants of Cd and Pb compared to treatments without La(III). These findings can offer valuable insights into the potential of La(III) to enhance the phytoremediation of soil or wastewater polluted with compounds.

Amino-functionalized SiO2 microbeads optimize photosynthetic performance, gene expression, ROS production and antioxidant status in chromium and copper-exposed Zea mays

The objective of the current study was to assess the potential of the amino-functionalized SiO2 microbeads (S) in improving the tolerance of maize to chromium and/or copper toxicity. For this purpose, Zea mays L. cv. DKC5685 was grown by exposure at different S concentrations (100–500 mg L-1) alone and with 200 µM chromium (Cr stress) and 100 µM copper (Cu stress) for 7 days. The photosynthesis-related parameters (Fv/Fm, Fv/Fo), relative growth rate (RGR), and relative water content (RWC) levels were suppressed under Cr and/or Cu stresses. In addition, stress altered antioxidant activities and gas exchange parameters. S applications abolished the negative impacts of stress on the physiological state of the photosynthetic system, potential photochemical efficiency and chlorophyll fluorescence. S increased the performance index by reversing the detrimental effects on the electron flow rate through the PSII electron transport flux and electron transfer from the decreased plastoquinone pool to the PSI reaction center. Following exposure to S, the effects of stress on photosystem I-associated reaction center proteins were rearranged by induced expression levels of PsaA and PsaB genes. S treatments had potent ROS scavengers in maize leaves. In the Cr+S groups, the AsA-GSH cycle was regulated by increasing the activities of all the responsible enzymes mentioned above, such as SOD, CAT, APX and GR, and the accumulation of H2O2 and TBARS effectively removed. CAT and POX activities in Cu+S groups were not effective in these adjustments. In Cr+Cu+S applications, although H2O2 and TBARS contents were reduced as evidenced by ROS visualization using fluorescence of dye, AsA regeneration could not be achieved, and low tAsA/DHA levels were detected. Our results show that amino-functionalized SiO2 microbeads have significant promise to offer resistance to maize by minimizing oxidative damage brought on by heavy metal uptake and preserving the metabolic processes involved in photosynthesis.

Phytoremediation of heavy metals from industrially contaminated soil using sunflower (Helianthus annus L.) by inoculation of two indigenous bacteria

The phytoremediation technique is gaining excessive consideration as a promising method to remediate industrially contaminated soils with heavy metals. In this study, a pot experiment was performed in which the ornamental plant Helianthus annus L. was grown in the pots with three concentrations i.e., 0, 5, and 10 % of contaminated soil amended with compost (2 %) in all pots of the experiment following three treatments of bacteria i.e., Co, Stutzerimonas stutzeri and Pseudomonas sundara. After sixty days of the experiment, the plants were harvested and morphological, physiological, antioxidants and pollution parameters were investigated. The plant height and biomass of the sunflower were increased by the inoculation of S. stutzeri and P. sundara. Pigments e.g., chlorophyll a, b, carotenoids and proteins of the plants were enhanced. There was an increase in antioxidants e.g., catalase, peroxidase, ascorbate peroxidase and proline content and a decrease in hydrogen peroxide content of plants by inoculation of S. stutzeri and P. sundara. The bacteria boosted the uptake of heavy metals (cadmium, chromium and lead) in parts of plants. Post-harvested soil analysis indicated decreased electronic conductivity, total dissolved solids, bicarbonates and heavy metals in the soil. In the future, the combination of H. annus and bacteria could be a better technique to remediate the heavy metals in industrially polluted soils.

Accumulation of livestock manure–derived heavy metals in the Hexi Corridor oasis agricultural alkaline soil and bioavailability to Chinese cabbage (Brassica pekinensis L.) after 4-year continuous application

Hexi Corridor is one of the most important base of vegetable producing areas in China. Livestock manure (LM) applied to agricultural field could lead to soil heavy metal (HM) pollution. Previous studies have focused on HM pollution following LM application in acidic polluted soils; however, fewer studies have been conducted in alkaline unpolluted soils. A 4–year field vegetable production experiment was conducted using pig manure (PM) and chicken manure (CM) at five application rates (0, 15, 30, 45, and 60 t ha−1) to elucidate potential risks of HMs in an alkaline unpolluted soil in the Hexi Corridor oasis agricultural area and HM uptake by Chinese cabbage. The results showed that LM application caused a significant build–up of Cu, Zn, Pb, Cd, and Ni content in topsoil by 30.6–99.7%, 11.4–51.7%, 1.4–31.3%, 5.6–44.9%, 14%–40.8%, respectively. The Cd, Cu, Zn could potentially exceed the soil threshold in next 8–65 years after 15–60 t ha−1 LM application. Under LM treatment, the soil DTPA–extractable Cu, Zn, Fe, the acid–extractable fraction of Cu, Zn, Fe, Cd, Ni, and the Oxidable fraction of Cu, Zn, Fe, Mn, Cd, Ni significantly increased, but the DTPA–extractable Pb, Cd, the acid–extractable fraction of Pb, and the reducible fraction of Cd significantly decreased. Cu and Zn could migrate to the deeper soil and relatively increase in DTPA–extracted Cu, Zn were found in 20–40 cm soil depth after LM application. The pH and SOM could influence the bioavailability of HMs in soil. The bioaccumulation factor and transfer factor (TF) values were <1 except Mn (TF > 1). HMs in leaf did not approach the threshold for HM toxicity due to the “dilution effect”. Recommend the type of manure was the PM and the annual PM application rate was 30 t ha−1 to ensure a 20–year period of clean production in alkaline unpolluted Fluvo–aqiuc vegetable soils.

Increasing phosphorus plant availability from P-rich ashes and biochars by acidification with sulfuric acid

Biochars and ashes derived from thermal treatment of P-rich wastes could be used as bio-based fertilizers to improve P recycling. However, thermal treatments often result in low plant P availability. Acidification of these materials before soil application could potentially increase plant P availability. Based on the water-extractable P levels obtained in titration experiments, sulfuric acid concentrations between 2.5 M and 10 M were applied to digestate solids char and ash (DS-C, DS-A), poultry litter ash (PL-A), insect frass char (IF-C), sewage sludge char and ash (SS-C, SS-A) and meat and bone char (MB-C). Acidified and untreated materials were applied in a pot experiment with maize in 33P labeled soil to determine fertilizer P uptake. The acidification resulted in a significant increase in P solubility. The amount of acid required depended on the materials’ buffer capacity and P speciation. Based on XRD analysis, we assume that mainly Ca-associated P was solubilized. In the pot experiment, acidified materials outperformed untreated materials and the unfertilized control in terms of biomass and P uptake. The P recovery from the acidified materials ranked in the order DS-C > SS-A > PL-A > IF-C > DS-A > SS-C > MB-C. The acidification did not significantly decrease soil pH, nor was there an effect on plant heavy metal availability. In conclusion, acidification increased plant growth and P uptake without affecting plant heavy metal uptake and soil pH. Therefore, acidification to increase the P fertilizer value of ashes and chars is a promising approach to facilitate P recycling.

Comparative Study of Whole-Body Proximate Composition, Dressing Losses and Bioaccumulation of Heavy Metals in Muscle Tissues of Wild and Farm-Raised Labeo Rohita

The muscle tissues of wild and farm-raised rohu were analyzed for proximate composition (Crude protein, crude fat, ash, and dry matter) and uptake of heavy metals (Cd, Ni, Pb, and Cr) using the standard protocols. For this purpose, wild fish samples were collected from the Khanpur Canal, Sheikhupura, and farmed fish samples from a local fish market in Lahore. The results showed that the concentration (%) of protein (17.92±0.36), ash (06.54±0.13), and moisture (76.50±1.53), was observed to be higher in the wild when compared to protein (16.90±0.34), ash (5.07±0.10) and moisture (73.50±1.47) of farm-raised rohu. In contrast, crude fat contents were observed to be higher (4.02±0.08) in farm-raised rohu than wild (03.65±0.07). In terms of dressing losses, wild fish showed higher (26.37%) losses as compared to farm raised (25.83%). Results showed that in wild and farm fish’s muscles, the trend of the heavy metals was Pb &gt; Cd &gt; Ni &gt; Cr. The findings demonstrated that in comparison to Cd, Ni, and Cr, Pb concentration (ppb) was greater in both wild (128.32.82) and farm-raised (111.42.16) rohu. When compared to wild rohu, farmed rohu showed a higher bioaccumulation tendency for Cr and Ni, but Cd and Pb showed the reverse pattern. The findings of this study suggest that fish proximate composition, dressing losses, and bioaccumulation of heavy metals are certainly impacted by the aquatic life of freshwater fish like Labeo rohita both in wild and farmed conditions and these results will be helpful for the aquaculturists as well as the local consumers of the fish.

Effect of vermicompost and biochar amendments on uptake of heavy metals, micro and macroelements by Sedum Plumbizincicola

Comparative research on the impact of organic amendments on the uptake of heavy metals and micro and macroelements of Sedum Plumbizincicola has been carried out. Experiments have been implemented in controlled conditions. The soil used in this experiment was sampled from the vicinity of the Non-Ferrous Metals Work near Plovdiv, Bulgaria. The pot experiment was a randomised complete block design containing five treatments and three replications (15 pots). The treatments consisted of a control (no organic amendments) and vermicompost and biochar amendments (added at 5% and 10%, respectively, recalculated based on dry soil weight). Applying organic additives to the soil influences the physicochemical properties. It leads to increased organic matter, electrical conductivity and content of macroelements (P, K, Ca and Mg) and microelements (Fe, Mn, Zn) in the soil. Applying organic additives to the soil affects the uptake of heavy metals and micro and macro elements by Sedum Plumbizincicola. Organic additives affect yield, influenced by the type of additive and dose. Cd and Zn yields were up to 3 times higher in the variant with 10% vermicompost application. Application of 10% biochar resulted in a negligible increase. Keywords: phytoextraction, organic amendments, contaminated soils, Sedum Plumbizincicola

Industrial wastewater irrigation increased higher heavy metals uptake and expansins, metacaspases, and cystatin genes expression in Parthenium and maize.

Industrial wastewater irrigation of agricultural crops can cause a lot of environmental and health problems in developing countries due to heavy metals deposition in agricultural soils as well as edible plant consumption by human beings. Therefore, this study was conducted to find out the heavy metals concentration in industrial wastewater and soil irrigated with that wastewater. In addition, the aim was to determine the impact of industrial wastewater irrigation on Parthenium hysterophorus and Zea mays genes involved in growth improvement and inhibition. For this purpose, plant samples from agriculture fields irrigated with wastewater from Hattar Industrial Estate (HIE) of Haripur, Pakistan, and control plants from non-contaminated soil irrigated with tape water were collected after 15 and 45 days of germination. Heavy metals concentration in the collected plant samples, wastewater, and soil was determined. The results revealed that the soil of the sample collection site was predominantly contaminated with Cr, Pb, Ni, Cu, Co, Zn, and Cd up to the concentrations of 38.98, 21.14, 46.01, 155.73, 12.50, 68.50, and 7.01 mg/kg, respectively. The concentrations of these heavy metals were found to surpass the permissible limit in normal agricultural soil. Expansins, cystatins (plant growth enhancers), and metacaspases (plant growth inhibitor) gene expression were studied through reverse transcription polymerase chain reaction. The results showed that the expression of these genes was higher in samples collected from wastewater-irrigated soils as compared to control. The expression of these genes was observed in 45 days old samples, 15 days old samples, and control. Taken together, this study suggests the use of Parthenium and maize for phytoremediation and that they should not be used for eating purposes if irrigated with industrial wastewater.

CO-RECYCLING OF SEWAGE SLUDGE AND GARDEN WASTE BIOCHAR: AS A GROWING MEDIUM FOR LANDSCAPE PLANT

Urban greening produces a large amount of garden waste, and the pyrolysis of garden waste into biochar is an effective waste management technology. Biochar has a large specific surface area and soil remediation ability. However, the knowledge about the co-recycling of sewage sludge and garden waste biochar to improve the growth of Monstera deliciosa needs to be highlighted. Therefore, we conducted a pot experiment by applying Ficus altissima litter-derived biochar (FB) at rates of 0, 1.5, and 3.0% (w/w, CK, FB1.5, and FB3) in soil amended with sewage sludge at 50% (w/w), to improve the soil properties, and further analyzed the effects of FB on growth and heavy metals (HMs) uptake of landscape plant M. deliciosa. Results showed in comparison with control setups, the addition of 3% FB treatment in sewage sludge amended soil improved the soil properties and significantly increased M. deliciosa dry weight (86.75%), root: shoot ratio (73.23%), N (99.44%), P (116.13%), K (124.40%), Pb (78.81%), and Cu (159.01%) accumulation respectively. In summary, FB3 treatment achieved the best effects in promoting plant growth and soil remediation. These findings revealed that sewage sludge and garden waste biochar could be recycled as amendments for poor acid soils under restoration, a sustainable development path for urban waste disposal.