Phytoremediation efficiency of Portulaca tuberosa rox and Portulaca oleracea L. naturally growing in an industrial effluent irrigated area in Vadodra, Gujrat, India

Phytoremediation potential of monocotyledonous plants in the sediments of the Uben River, Gujarat, India

Phytoremediation is a basic eco-friendly technique that uses to treat contaminated water and soil. The plants that remediate the water and soil by their absorption process and improve the water and sediment fertility or decrease the contamination. Form this experiment our finding suggest that the contamination decrease in majority from starting point to end point, it means plants plays the most important role in clean-up the environment and its cost-efficient method to improve the quality of water and soil. This study was carried out on Uben River which is around 50kms long and we covered around 41.88kms of area which divided into six locations. in soil minerals (Ca2+, Mg2+, Na+ and K+) from Up-stream to Down-stream the concentration of minerals is in decreasing order but in heavy metals (Cu2+, Zn2+, Fe2+ and Mn2+) the concentration data is varying. We selected plants that grow around riverbanks belongs to family Cyperaceae, Poaceae, Typhaceae. Most of the plants accumulate high Fe2+ concentrations in their root while in the shoots have low concentration observed from our data. For the statistical validation of data, we perform Grouped Component Analysis (GCA) and Radial Cluster Hierarchy (RCH) analysis. Further we included pollution indices: Contamination factor (CF), Degree of contamination (Cd), Geo accumulation index (Igeo).

Insight to chromium homeostasis for combating chromium contamination of soil: Phytoaccumulators-based approach

Chromium (Cr) is a naturally occurring, carcinogenic heavy metal that has become a pressing concern in recent decades for environmentalists. Due to high anthropogenic activities, the concentration of Cr has crossed the environmental threshold levels and consequently contaminated soil and water. The high solubility of Cr ions in the groundwater results in its high uptake by the plants leading to phytotoxicity and yield loss. The dearth of efficient and cost-effective treatment methods has resulted in massive chromium pollution. However, some phytoaccumulators capable of accumulating Cr in high amounts in their shoots and then performing their metabolic activity typically have been identified. Chromium bioremediation using phytoaccumulators is very contemplative due to its eco-friendly and cost-effective outcome. These accumulators possess several mechanisms, such as biosorption, reduction, efflux, or bioaccumulation, naturally or acquired to counter the toxicity of chromium. This review focuses on the detoxification mechanism of Cr by the phytoaccumulator species, their responses against Cr toxicity, and the scope for their application in bioremediation. Besides, Cr bioavailability, uptake, distribution, impairment of redox homeostasis, oxidative stress, and phytotoxicity imposed on the plants are also summarized. Further, the knowledge gap and prospects are also discussed to fill these gaps and overcome the problem associated with the real-time applicability of phytoaccumulator-based bioremediation.

The potential of saltmarsh halophytes for phytoremediation of metals and persistent organic pollutants: An Australian perspective

Persistent organic and inorganic pollutants are among the most concerning pollutants in Australian estuaries due to their persistent, ubiquitous, and potentially toxic nature. Traditional methods of soil remediation often fall short of practical implementation due to high monetary investment, environmental disturbance, and potential for re-contamination. Phytoremediation is gaining traction as an alternative, or synergistic mechanism of contaminated soil remediation. Phytoremediation utilises plants and associated rhizospheric microorganisms to stabilise, degrade, transform, or remove xenobiotics from contaminated mediums. Due to their apparent cross-tolerance to salt, metals, and organic contaminants, halophytes have shown promise as phytoremediation species. This review examines the potential of 93 species of Australian saltmarsh halophytes for xenobiotic phytoremediation. Considerations for the practical application of phytoremediation in Australia are discussed, including mechanisms of enhancement, and methods of harvesting and disposal. Knowledge gaps for the implementation of phytoremediation in Australian saline environments are identified, and areas for future research are suggested.

Positive Effects and Optimal Ranges of Tea Saponins on Phytoremediation of Cadmium-Contaminated Soil

Confirming positive effects and offering optimal ranges of tea saponins on improving the efficiency of phytoremediation on cadmium is a prerequisite for applying tea saponins in field remediation. Existing studies qualitatively tested the feasibility of tea saponins on promoting the absorption of cadmium by hyperaccumulators in pots experiments, while this study investigated the effects of tea saponins on increasing the proportion of cadmium available fraction in contaminated soil quantitatively and confirmed tea saponins promoted the absorption by Portulaca oleracea in cadmium-contaminated water by independent soil experiments and hydroponic experiments. The results showed that for acquiring a higher proportion of cadmium available fraction, the concentration of tea saponins was negatively correlated with the concentration of cadmium contained in the soil, and the optimal treatment time of tea saponins was between 3–9 days depending on the cadmium concentration in contaminated soil. Using tea saponins could enhance the absorption of cadmium by Portulaca oleracea in a relatively short time to decrease the concentration of cadmium left in the contaminated water. The above findings help to deepen the understanding of tea saponins’ effects and use ranges on phytoremediation of cadmium both in soil and water and conduce studies on phytoremediation of other heavy-metal-contaminated soil and water with the help of tea saponins.

A review on bioactive phytochemicals and ethnopharmacological potential of purslane (Portulaca oleracea L.)

The Portulaca oleracea L. commonly known as purslane is distributed all over the world and easily grows in diverse soil and climatic conditions. It has been traditionally used as a nutritious and ethnomedicinal food across the globe. Various studies have shown that the plant is a rich source of various important phytochemicals such as flavonoids, alkaloids, terpenoids, proteins, carbohydrates, and vitamins such as A, C, E, and B, carotenoids and minerals such as phosphorus, calcium, magnesium and zinc. It is particularly very important because of the presence of a very high concentration of omega-3- fatty acids especially α-linolenic acid, gamma-linolenic acid and linoleic acid, which are not generally synthesized in terrestrial plants. Various parts of purslane are known for ethnomedicinal and pharmacological uses because of its anti-inflammatory, antidiabetic, skeletal muscle relaxant, antitumor, hepatoprotective, anticancer, antioxidant, anti-insomnia, analgesic, gastroprotective, neuroprotective, wound healing and antiseptic activities. Due to multiple benefits of purslane, it has become an important wonder crop and various scientists across the globe have shown much interest in it as a healthy food for the future. In this review, we provide an update on the phytochemical and nutritional composition of purslane, its usage as nutritional and an ethnomedicinal plant across the world. We further provide a detailed account on ethnopharmacological studies that have proved the ethnomedicinal properties of purslane.

Development of laser induced breakdown spectroscopy technique to study irrigation water quality impact on nutrients and toxic elements distribution in cultivated soil

This study is focused mainly on impact of irrigation water quality in cultivated soil on distribution of essentials nutrients (Al, Mg, Ca, Fe, S, Si, Na, P, and K) and relatively toxic metals (As, Ba, Cr, Cu, Ti, Sn, Mn, Ni, and Zn) using an elegant Laser induced breakdown spectroscopy (LIBS) technique. A pulsed Nd:YAG laser operating at 1064 nm in conjunction with suitable detector was applied to record soil emission spectra. The abundance of these elements were evaluated via standard calibration curve Laser Induced Breakdown Spectroscopy (CC-LIBS) and calibration free Laser Induced Breakdown Spectroscopy (CF-LIBS) approaches. Quantitative analyses were accomplished under conjecture of local thermodynamic equilibrium (L.T.E) and optically thin plasma. The average electron temperatures were estimated by Boltzmann plot method for cultivated soil samples in 7800 to 9300 K range. The electron number density was ~ 1.11 × 1017 cm − 3 to 1.60 × 1017 cm − 3. Prior to application on soil samples, the experimental setup was optimized at the following parameters: pulsed energy = 60 mJpulse-1, sample to lens distance of 9.0 cm, and the gate delay of 3.5 μs. It is noteworthy that nutritional elements content of cultivated soils were found strongly dependent upon the irrigation water quality. The cultivated soil from industrial area was found rich of toxins while the cultivated land using tube well water contains toxins in least amount. Our LIBS findings were also validated by comparing its results with contents measured using a standard inductively coupled plasma optical emission spectroscopy (ICP-OES) method and both were found in excellent agreement. The present study could be highly beneficial for agricultural applications and for farmers to produce safe food products and higher crops yield.

Portulaca oleracea L. for phytoremediation and biomonitoring in metal-contaminated environments

In phytoremediation and biomonitoring, plants are used to clean and monitor contaminated environments, respectively. Thus, scientists are searching for ideal plants, i.e., those that rapidly uptake and accumulate a considerable quantity of contaminants in their tissues, with or without toxicity symptoms. All these aspects are satisfied by the annual herbaceous plant Portulaca oleracea L. P. oleracea L. is ranked eighth as "most common plant in the world" and twelfth as "non-cultivating species well colonise[d] in new areas." Because of its fast regeneration of shoots and roots from leaves and roots and leaves from the stem and its tolerance capacity for metal stress, this plant has been used for phytoremediation and biomonitoring studies in the field, as well as in pot and hydroponics studies. The growth attributes of this plant in metal-stressed environments and the uptake of metals from its growth media (via the root), which is followed by the accumulation of the metals in its tissues, have been studied. Metal is translocated from the root into the shoot and is calculated as the translocation factor, TF; the metal taken from the soil into the plant is calculated as the bioaccumulation factor, BAF. These measures have been used to determine the hyperaccumulation (uptake and storage of unusually large amounts of metals) potential of the plant. This review article critically evaluates the literature studies to increase the practicability of phytoremediation and biomonitoring approaches using various life stages of P. oleracea.

Improvement of a Traditional Orphan Food Crop, Portulaca oleracea L. (Purslane) Using Genomics for Sustainable Food Security and Climate-Resilient Agriculture

Purslane (Portulaca oleracea L.) is a popular orphan crop used for its nutritional properties in various parts of the world. It is considered one of the richest terrestrial sources of omega-3 and omega-6-fatty acids (ω-3 and 6-FAs) suggesting its importance for human health. This ethnomedicinal plant is also an important part of traditional healing systems among the indigenous people. Many studies have indicated its tolerance against multiple stresses and found that it easily grows in a range of environmental gradients. It has also been considered one of the important biosaline crops for the future. Despite its huge nutritional, economic, and medicinal importance, it remains neglected to date. Most of the studies on purslane were focused on its ethnomedicinal, phytochemical, pharmacological, and stress-tolerance properties. Only a few studies have attempted genetic dissection of the traits governing these traits. Purslane being an important traditional food crop across the globe can be valorized for a sustainable food security in the future. Therefore, this review is an attempt to highlight the distribution, domestication, and cultivation of purslane and its importance as an important stress-tolerant food and a biosaline crop. Furthermore, identification of genes and their functions governing important traits and its potential for improvement using genomics tools for smart and biosaline agriculture has been discussed.

Translocation factor of heavy metals by elephant grass grown with varying concentrations of landfill leachate

The aim of this study is to obtain the translocation factor by application of landfill leachate (LL) diluted in public irrigation water (IW). Pennisetum purpureum Schum (elephant grass) was cultivated for 83 days in an experimental water reuse unit. The present work was developed at the Experimental Water Reuse Unit (UERA), on the UFERSA campus in Mossoró, RN, Brazil. Plot irrigation was based on water balance and crop evapotranspiration (ETc). The concentration in the plant tissue (root and leaf) of the following heavy metals was measured to determine the respective translocation factors: manganese (Mn), zinc (Zn), copper (Cu), nickel (Ni), cadmium (Cd), and lead (Pb). The experiment was set up in a randomized block design with five treatments (T1, plots irrigated only with IW; T2, 50% of LL dose plus IW; T3, 100% of LL dose plus IW; T4, 150% of LL dose plus IW; and T5, 200% of LL dose plus IW) and five replications. All treatments received LL plus IW depth of 491.02 mm for 83 days of P. purpureum cultivation. The data obtained were submitted to multivariate analysis plus the nonparametric Kruskal-Wallis test to compare the means. Pennisetum purpureum showed a potential to accumulate metals in its tissues, mainly Mn, Zn, and Cu. The treatments that most favored the extraction of these metals were T2 and T5; in this sense, P. purpureum was not efficient in translocating heavy metals, since the translocation factor observed in all treatments was below 1.0, indicating that the species used extract heavy metals from soil solution and keeps in yours roots. This suggests planting P. purpureum may not be a viable option to remediate environments highly contaminated with heavy metals.

Nitrogen Effect on Growth-Related Parameters and Evaluation of Portulaca oleracea as a Phytoremediation Species in a Cr(VI)-Spiked Soil

In a pot experiment, we assessed the potential of purslane (Portulaca oleracea) as a phytoremediation species in Cr(VI)-contaminated soils. We focused on the evaluation of phytotoxic Cr(VI) effects at concentrations reaching 150 mg Cr(VI) kg−1 and the possible stress amelioration effect of nitrogen on Cr(VI)-stressed plants. Treatments were T-0 (control), T-1 (25 mg Cr(VI) kg−1), T-2 = 50 mg kg−1, T-3 = 100 mg kg−1, and T-4 = 150 mg kg−1. We measured Cr(VI) concentration in aerial and root tissues, a series of parameters related to photosynthesis and plant growth, phosphorus aerial plant tissue content, and we also calculated indices (ratios) related to leaf growth and above ground tissue water content. Cr(VI) almost exclusively was found in root tissues; all physiological and growth parameters studied were severely affected and plants selectively accumulated phosphorus in aerial plant tissues with increasing Cr(VI) soil concentrations. On the other hand, N amendment resulted in improved plant features in some of the measured parameters: chlorophyll index was improved with added N at T-2, plant height was significantly higher at T-0, T-1, and T-2, and aerial dry weight and leaf area was higher at T-0; these effects indicate that added N did increase P. oleracea potential to ameliorate Cr(VI) toxic effects. We conclude that purslane showed a potential as a possible species to be successfully introduced to Cr(VI)-laden soils, but more research is certainly necessary.

Perspectives of future water sources in Qatar by phytoremediation: biodiversity at ponds and modern approach

Anthropogenic and industrial wastewater (IWW) could be an additional future source of water to support the needs of the people of the State of Qatar. New lagoons have been built using modern technologies to optimize water use and waste recycling, as well as increasing the green spaces around the country. To achieve successful development of these new lagoons, lessons should be learned from the old ponds by examining their biodiversity, ecology, and the roles played by aquatic plants and algae to remediate wastewaters at these ponds. The perspectives of using IWW (from oil and gas activities), that is currently pumped deep into the ground are presented. Instead of causing great damage to groundwater, IWW can be stored in artificial ponds prepared for ridding it of all impurities and pollutants of various types, organic and inorganic, thereby making it serviceable for various human uses. Phycoremediation, bioremediation, and phytoremediation methods adopted by algae, bacteria and aquatic native plants are discussed, and special attention should be paid to those that proved successful in removing heavy metals and degrading organic compounds. At least three native plants namely: Amaranthus viridis, Phragmites australis, and Typha domingensis should be paid special attention, since these plants are efficient in remediation of arsenic and mercury; elements found abundantly in wastewater of gas activities. Some promising modern and innovative experiences and biotechnologies to develop efficient transgenic plants and microorganisms in removing and degrading pollutants are discussed, as an important strategy to keep the ecosystem clean and safe. Novelty statementIndustrial wastewater (IWW) could be an alternative source of water at the Arabian Gulf region. Currently, IWW is pumped deep into the ground causing a great damage to groundwater; little information about this issue has been reported. Such IWW can be stored in artificial ponds designed for ridding them of all impurities of various types; various remediation methods can be used. Modern biotechnology to develop transgenic plants and microorganisms to enhance these remediation methods can be adopted.

Chronic dietary exposure to inorganic arsenic

Following an official request to EFSA from the European Commission, EFSA assessed the chronic dietary exposure to inorganic arsenic (iAs) in the European population. A total of 13,608 analytical results on iAs were considered in the current assessment (7,623 corresponding to drinking water and 5,985 to different types of food). Samples were collected across Europe between 2013 and 2018. The highest mean dietary exposure estimates at the lower bound (LB) were in toddlers (0.30 μg/kg body weight (bw) per day), and in both infants and toddlers (0.61 μg/kg bw per day) at the upper bound (UB). At the 95th percentile, the highest exposure estimates (LB-UB) were 0.58 and 1.20 μg/kg bw per day in toddlers and infants, respectively. In general, UB estimates were two to three times higher than LB estimates. The mean dietary exposure estimates (LB) were overall below the range of benchmark dose lower confidence limit (BMDL 01) values of 0.3-8 μg/kg bw per day established by the EFSA Panel on Contaminants in the Food Chain in 2009. However, for the 95th percentile dietary exposure (LB), the maximum estimates for infants, toddlers and other children were within this range of BMDL 01 values. Across the different age classes, the main contributors to the dietary exposure to iAs (LB) were 'Rice', 'Rice-based products', 'Grains and grain-based products (no rice)' and 'Drinking water'. Different ad hoc exposure scenarios (e.g. consumption of rice-based formulae) showed dietary exposure estimates in average and for high consumers close to or within the range of BMDL 01 values. The main uncertainties associated with the dietary exposure estimations refer to the impact of using the substitution method to treat the left-censored data (LB-UB differences), to the lack of information (consumption and occurrence) on some iAs-containing ingredients in specific food groups, and to the effect of food preparation on the iAs levels. Recommendations were addressed to improve future dietary exposure assessments to iAs.

Phytoremediation of polluted soils and waters by native Qatari plants: Future perspectives

Because pollution is predicted to worsen and sources of quality water for agriculture and other human activities are limited, many countries have been motivated to seek novel water sources. Qatar relies on groundwater and water desalinization to meet its water needs, and additional water resources will be needed to avoid unexpected crises in the future. Industrial wastewater (IWW) is an alternative water source, and much research activities should be focused on developing innovative and contemporary approaches to removing pollutants from IWW. Phytoremediation methods, shown to be efficient methods of removing and degrading contaminants of various kinds from polluted waters and soils, require knowledge of the native plants and associated microorganisms. In Qatar, many native plants (monocot and dicot, indigenous or introduced) have been shown to be greatly effective in remediating polluted areas. This article is a guide for Qatari scientists aiming to identify promising native plants and associated microbes for IWW phytoremediation. In it, we review the basic components of bioremediation and summarize the principle phytoremediation approaches and preferred recycling options. The multiple mechanisms and methods of phytoremediation for cleansing polluted soils and waters are also discussed as are details of the metabolic reactions degrading the organic components of oil and gas. Finally, heavy metal accumulation is addressed. Wastewater from industrial and domestic activities is currently being used to create green areas around Doha, Qatar, and such areas could be at risk of contamination. Many native Qatari plants and soil-dwelling microbes are efficient at removing organic and inorganic contaminants from polluted soils and waters, and some are promising candidates for achieving a clean environment free of contaminants.

Phytoremediation efficiency of Portulaca oleracea L. naturally growing in some industrial sites, Dakahlia District, Egypt

Phytoremediation is an economic process through exploitation of plants capacity to accumulate heavy metals in polluted habitats by their harvestable parts. In the present investigation, Portulaca oleracea was examined to estimate its role in the accumulation of Mn(II), Cu(II), Zn(II), Fe(III) and Pb(II) ions and recognize its persistence against the industrial effluent toxicity from different farmlands located beside these regions (S1:S9) in Dakahlia district, Egypt. The most recorded associate plants were; Amaranthus viridus, Malva parviflora, Chenopodium murale and Echinochloa colonum, which have high potentiality of heavy metals (HM) accumulation. The phytoremediation efficiency (bioconcentration factor (BCF), bioaccumulation factor (BF), translocation factor (TF), enrichment coefficient of shoot (ECS) and element accumulation index (EAI)) of P. oleracea were calculated. Considering the results, S7 showed the highest BCF value for Cu(II), 7.40; Fe(III), 2.06; and Zn(II), 4.33, while Mn(II), 2.06 at S1 and Pb(II), 3.89 at S3. BF and TF values were less than unity 1.0 for most of the sites. However, ECS values showed small variations among the investigated HM at the nine sites. EAI values were higher in shoots out of all the sites except S2 > EAI of roots of the same sites. Also, there was positive correlation between the soil HM concentrations in most sites. Moreover, total protein was estimated quantitatively and qualitatively. The protein profile showed 16 bands of molecular weight ranged from 30.9 to 240.6 KDa. Finally, P. oleracea can be used for decontamination of soils with heavy metals due to the high ecological amplitude and phytoremediation characteristics.

Heavy metals in contaminated environment: Destiny of secondary metabolite biosynthesis, oxidative status and phytoextraction in medicinal plants

Contamination of soils, water and air with toxic heavy metals by various human activities is a crucial environmental problem in both developing and developed countries. Heavy metals could be introduced into medicinal plant products through contaminated environment (soil, water and air resources) and/or poor production practices. Growing of medicinal plants in heavy metal polluted environments may eventually affect the biosynthesis of secondary metabolites, causing significant changes in the quantity and quality of these compounds. Certain medicinal and aromatic plants can absorb and accumulate metal contaminants in the harvestable foliage and, therefore, considered to be a feasible alternative for remediation of polluted sites without any contamination of essential oils. Plants use different strategies and complex arrays of enzymatic and non-enzymatic anti-oxidative defense systems to cope with overproduction of ROS causes from the heavy metals entered their cells through foliar and/or root systems. This review summarizes the reports of recent investigations involving heavy metal accumulation by medicinal plants and its effects on elicitation of secondary metabolites, toxicity and detoxification pathways, international standards regarding in plants and plant-based products, and human health risk assessment of heavy metals in soil-medicinal plants systems.

Portulaca grandiflora as green roof vegetation: Plant growth and phytoremediation experiments

Finding appropriate rooftop vegetation may improve the quality of runoff from green roofs. Portulaca grandiflora was examined as possible vegetation for green roofs. Green roof substrate was found to have low bulk density (360.7 kg/m³) and high water-holding capacity (49.4%), air-filled porosity (21.1%), and hydraulic conductivity (5270 mm/hour). The optimal substrate also supported the growth of P. grandiflora with biomass multiplication of 450.3% and relative growth rate of 0.038. Phytoextraction potential of P. grandiflora was evaluated using metal-spiked green roof substrate as a function of time and spiked substrate metal concentration. It was identified that P. grandiflora accumulated all metals (Al, Cd, Cr, Cu, Fe, Ni, Pb, and Zn) from metal-spiked green roof substrate. At the end of 40 days, P. grandiflora accumulated 811 ± 26.7, 87.2 ± 3.59, 416 ± 15.8, 459 ± 15.6, 746 ± 20.9, 357 ± 18.5, 565 ± 6.8, and 596 ± 24.4 mg/kg of Al, Cd, Cr, Cu, Fe, Ni, Pb and Zn, respectively. Results also indicated that spiked substrate metal concentration strongly influenced metal accumulation property of P. grandiflora with metal uptake increased and accumulation factor decreased with increase in substrate metal concentration. P. grandiflora also showed potential to translocate all the examined metals with translocation factor greater than 1 for Al, Cu, Fe, and Zn, indicating hyperaccumulation property.

Biosynthesis of gold nanoparticles using green roof species Portulaca grandiflora and their cytotoxic effects against C6 glioma human cancer cells

Leaf and stem extracts of popular green roof vegetation, Portulaca grandiflora, were used for the synthesis of gold nanoparticles. The synthesized gold nanoparticles were characterized using UV–visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. FTIR results indicated the presence of proteins and polyphenols in plant extracts which were responsible for the reduction and stabilization of gold nanoparticles. SEM and TEM images confirmed the formation of spherical, rhombus, triangular, tetragonal, pentagonal, rods and hexagonal shaped gold nanoparticles. The size of the particles was in the range of 8 and 72 nm. The antiproliferative effects of synthesized gold nanoparticles were assessed using C6 glioma human cancer cells. Results indicated that gold nanoparticles synthesized using leaf extracts (150 µg/mL) and stem extracts (200 µg/mL) of P. grandiflora decreased the viability of C6 glioma cell lines up to 50%. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1732–1740, 2016

Alternative Strategies in Response to Saline Stress in Two Varieties of Portulaca oleracea (Purslane)

Purslane (Portulaca oleracea) is a globally-distributed plant with a long history of use in folk medicine and cooking. We have developed purslane as a model system for exploring plant responses to stress. We exposed two varieties of purslane to saline stress with the objective of identifying differences between the varieties in the plasticity of morphological and physiological traits. The varieties responded to saline stress with significantly different changes in the measured traits, which included inter alia biomass, flower counts, proline concentrations and betalain pigment concentrations. The alternative responses of the two varieties consisted of complex, simultaneous changes in multiple traits. In particular, we observed that while both varieties increased production of betalain pigments and proline under saline stress, one variety invested more in betalain pigments while the other invested more in proline. Proline and betalain pigments undoubtedly play multiple roles in plant tissues, but in this case their role as antioxidants deployed to ameliorate saline stress appears to be important. Taken holistically, our results suggest that the two varieties employ different strategies in allocating resources to cope with saline stress. This conclusion establishes purslane as a suitable model system for the study of saline stress and the molecular basis for differential responses.

Tolerance of Portulaca grandiflora to individual and combined application of Ni, Pb and Zn

In the present study, metal accumulation capacity and tolerance of Portulaca grandiflora were investigated. Plants were grown under greenhouse conditions in pots on soil amended with Ni, Pb and Zn to the final concentration of 2 mmol kg(-1) for each metal. Results show considerable accumulating capacity and translocation of Ni and Zn, as well as significant accumulation of Pb in roots. A slight decrease of biomass with Zn and of chlorophyll content with Zn and Ni were observed, as well as an increase of proline content with each of the metals. Combinations of metals revealed mutual interference affecting both the uptake and translocation of the metals and their impact on physiological parameters. Results suggest that Portulaca grandiflora, although not a hyperaccumulator, shows a good tolerance and accumulation capacity for Ni, Pb and Zn, but, for the purposes of remediation, interference of the metals must be taken into account.

Effect of Co-planted Purslane (Portulaca Oleracea L.) on Cd Accumulation by Sunflower in Different Levels of Cd Contamination and Salinity: A Pot Study

Heavy metal bioaccumulation can be affected by various crop-weed interactions that potentially exist in agroecosystems. A pot experiment was conducted to evaluate the role of rhizosphere interaction of sunflower and purslane (Portulaca oleracea L.) weed on cadmium (Cd) uptake and its allocation to sunflower grains. The experimental treatments consisted of two cropping systems (mono and mixed culture), two adjusted salinity levels (0 and 0.5% NaCl) and three artificial levels of Cd in soil (Control, 3 and 6 mg kg(-1)). The results showed that the growth of sunflower in the presence of purslane in comparison to mono culture of sunflower led to change of total Cd content and Cd allocated to grains only in saline conditions. Promoting effects of salinity on Cd concentration of grain were alleviated where sunflower was co-planted with purslane. Besides, supply of Zn in grains of co-planted sunflower was strongly affected by salinity. Results of this study revealed that although co-planted purslane could alter conditions in the shared rhizosphere, it had no effect on enhancing Cd uptake by neighboring sunflower directly.

Contamination of soil with heavy metals from industrial effluent and their translocation in green vegetables of Peshawar, Pakistan

Heavy metal pollution is a serious problem in countries like Pakistan, claiming soil, water and food resources due to negligence and no treatment.

Olive mill wastewater treatment using a simple zeolite-based low-cost method

Olive mill wastewater (OMW), a liquid by-product of the olive oil industry, represents a severe environmental problem owing to its high pollution load. In this study, successive columns containing different types of natural materials were investigated for their OMW treatment efficiency. Passing OMW through three columns of gravel, fine sand, and a mixture of acidified cotton and zeolite (weight:weight ratio of cotton:clinoptilolite of 2:1), followed by treatment with activated charcoal (AC) and lime, was the best treatment in terms of the quality of water obtained. This treatment decreased concentrations of [Formula: see text] , B, K, P, and total fat in OMW by mean percentages of 78.0, 92.4, 66.6, 48.3, and 93.3%, respectively. Furthermore, it decreased OMW turbidity and electric conductivity (EC) by 96.8 and 48.4%, respectively. Most contaminants were removed from the OMW in the cotton/clinoptilolite column owing to the high sorption affinity of clinoptilolite on its active sites. The AC was efficient for organic particle removal; meanwhile, lime was used to raise the pH of the treated OMW (TOMW) from 2.9 to 5.1. This simple method enables us to obtain environmentally friendly TOMW that can be safely used for irrigation.

Remediation of organochlorine pesticides (OCPs) contaminated site by successive methyl-β-cyclodextrin (MCD) and sunflower oil enhanced soil washing - Portulaca oleracea L. cultivation

An innovative ex situ soil washing technology was developed in this study to remediate organochlorine pesticides (OCPs)-contaminated site. Elevated temperature (50 °C) combined with ultrasonication (35 kHz, 30 min) at 25 g L(-1) methyl-β-cyclodextrin and 100 mL L(-1) sunflower oil were effective in extracting OCPs from the soil. After four successive washing cycles, the removal efficiency for total OCPs, DDTs, endosulfans, 1,2,3,4,5,6-hexachlorocyclohexanes, heptachlors, and chlordanes were all about 99%. The 4th washed soil with 3 months cultivation of Portulaca oleracea L. and nutrient addition significantly increase (p<0.05) the number, biomass carbon, nitrogen, and functioning diversity of soil microorganisms. This implied that the microbiological functioning of the soil was at least partially restored. This combined cleanup strategy proved to be effective and environmental friendly.

Heavy metals in vegetables and respective soils irrigated by canal, municipal waste and tube well waters

Heavy metal contamination in the food chain is of serious concern due to the potential risks involved. The results of this study revealed the presence of maximum concentration of heavy metals in the canal followed by sewerage and tube well water. Similarly, the vegetables and respective soils irrigated with canal water were found to have higher heavy metal contamination followed by sewerage- and tube-well-watered samples. However, the heavy metal content of vegetables under study was below the limits as set by FAO/WHO, except for lead in canal-water-irrigated spinach (0.59 mg kg(-1)), radish pods (0.44 mg kg(-1)) and bitter gourd (0.33 mg kg(-1)). Estimated daily intakes of heavy metals by the consumption of selected vegetables were found to be well below the maximum limits. However, a complete estimation of daily intake requires the inclusion of other dietary and non-dietary exposure sources of heavy metals.

Characterization of Cd-, Pb-, Zn-resistant endophytic Lasiodiplodia sp. MXSF31 from metal accumulating Portulaca oleracea and its potential in promoting the growth of rape in metal-contaminated soils

The aim of this study was to characterize the features of a Cd-, Pb-, and Zn-resistant endophytic fungus Lasiodiplodia sp. MXSF31 and to investigate the potential of MXSF31 to remove metals from contaminated water and soils. The endophytic fungus was isolated from the stem of Portulaca oleracea growing in metal-contaminated soils. The maximum biosorption capacities of MXSF31 were 3.0 × 10(3), 1.1 × 10(4), and 1.3 × 10(4) mg kg(-1) for Cd, Pb, and Zn, respectively. The biosorption processes of Cd, Pb, and Zn by MXSF31 were well characterized with the pseudo-second-order kinetic model. The biosorption isotherm processes of Pb and Zn by the fungus were fitted better with the Langmuir model, while the biosorption processes of Cd was better fitted with the Freundlich model. The biosorption process of MXSF31 was attributed to the functional groups of hydroxyl, amino, carbonyl, and benzene ring on the cell wall. The active biomass of the strain removed more Cd, Pb, and Zn (4.6 × 10(4), 5.6 × 10(5), and 7.0 × 10(4) mg kg(-1), respectively) than the dead biomass. The inoculation of MXSF31 increased the biomass of rape (Brassica napus L.), the translocation factor of Cd, and the extraction amount of Cd by rape in the Cd+Pb-contaminated soils. The results indicated that the endophytic fungus strain had the potential to remove heavy metals from water and soils contaminated by multiple heavy metals, and plants accumulating multiple metals might harbor diverse fungi suitable for bioremediation of contaminated media.

Responses of Portulaca oleracea Linn. to selenium exposure

The present study was investigated to evaluate the uptake and accumulation of selenium (Se) by the stem cuttings of Portulaca oleracea L. grown in alfisol amended with various concentrations of Se. P. oleracea accumulated a maximum of 63.4 µg g−1 dry weight in a short growth period of 42 days. The order of accumulation of Se among the plant parts was leaves (31.5 μg g−1) > stems (16.4 μg g−1) > roots (15.5 μg g−1). The accumulation potential was fourfold higher than the plant available concentration of 15.2 μg g−1 of Se g−1 of soil (diethylenetriaminepentaacetic acid extracted). Although the plant was able to accumulate Se in their tissues, increase in Se concentrations in soil caused a concentration-dependent decrease in the growth rate of plants (regeneration of leaves, number of leaves, number of roots, root length, stem length and biomass).

Arsenic accumulation in native plants of West Bengal, India: prospects for phytoremediation but concerns with the use of medicinal plants

Arsenic (As) is a widespread environmental and food chain contaminant and class I, non-threshold carcinogen. Plants accumulate As due to ionic mimicry that is of importance as a measure of phytoremediation but of concern due to the use of plants in alternative medicine. The present study investigated As accumulation in native plants including some medicinal plants, from three districts [Chinsurah (Hoogly), Porbosthali (Bardhman), and Birnagar (Nadia)] of West Bengal, India, having a history of As pollution. A site-specific response was observed for Specific Arsenic Uptake (SAU; mg kg(-1) dw) in total number of 13 (8 aquatic and 5 terrestrial) collected plants. SAU was higher in aquatic plants (5-60 mg kg(-1) dw) than in terrestrial species (4-19 mg kg(-1) dw). The level of As was lower in medicinal plants (MPs) than in non-medicinal plants, however it was still beyond the WHO permissible limit (1 mg kg(-1) dw). The concentration of other elements (Cu, Zn, Se, and Pb) was found to be within prescribed limits in medicinal plants (MP). Among the aquatic plants, Marsilea showed the highest SAU (avg. 45 mg kg(-1) dw), however, transfer factor (TF) of As was the maximum in Centella asiatica (MP, avg. 1). Among the terrestrial plants, the maximum SAU and TF were demonstrated by Alternanthera ficoidea (avg. 15) and Phyllanthus amarus (MP, avg. 1.27), respectively. In conclusion, the direct use of MP or their by products for humans should not be practiced without proper regulation. In other way, one fern species (Marsilea) and some aquatic plants (Eichhornia crassipes and Cyperus difformis) might be suitable candidates for As phytoremediation of paddy fields.

Concentration levels of metals in vegetables grown in soils irrigated with river water in Addis Ababa, Ethiopia

Samples of vegetables, water and soil were collected from four vegetable farms in Addis Ababa to evaluate the extent and trend of metal accumulation in these systems and health risk concerns to consumers. Vegetable samples were digested in HNO(3) and HClO(4), soil samples in Aqua Regia and water samples were pre-concentrated with methyl isobutyl ketone (MIBK) using the chelating agent ammonium pyrrolidine dithiocarbamate (APDC). All the samples were analyzed for Co, Cr, Cu, Mn, Ni, Zn, Cd and Pb with flame atomic absorption spectrophotometer. The concentrations of Cd (0.12-1.13 mg kg(-1)) and Pb (0.11-0.89 mg kg(-1)) in the vegetables surpassed the maximum recommended levels. The total metal concentrations in soils were (mg kg(-1)): Cr, 9.9-22.8; Co, 28.0-47.3; Cu, 25.1-51.4, Mn, 1000-1054; Ni, 16.4-55.8; Zn, 146-149; Cd, 1.4-1.8 and Pb, 22.0-50.7. The trace metals Cd, Co, Cu, Mn and Ni in most of the water samples collected from Goffa, Kera and Akaki farms also surpassed irrigation water guideline limits, which might be a case for high accumulation of metals in the soils. However, the soil pH (6.5-7.6) and high cation exchange capacity (CEC), 38.41-50.18, coupled with high clay content, 37-51%, of the soil seemed to limit metal uptake by the vegetables. The physical parameters, pH (7.43-7.89) and electrical conductivity (0.33-1.54 dS/m) of irrigation waters measured at 25°C were found within the acceptable range.

Metal contamination of soil and translocation in vegetables growing under industrial wastewater irrigated agricultural field of Vadodara, Gujarat, India

The present investigation was carried out to evaluate metals concentration in ten vegetable crops growing in mixed industrial effluent irrigated agricultural field near Vadodara, Gujarat, India. Differential accumulation and translocation of various metals in selected vegetables plant species was observed. A higher concentration of metals were found in order of Fe>Mn>Zn>Cd>Cu>Pb>Cr>As in soil irrigated with industrial effluent than soil irrigated with tube well water; however, the concentration of As, Cr and Pb found below detection limit in tube well water irrigated soil. Metal accumulation in root and top of vegetables varied significantly both in relations to metal concentration in the soil and the plant genotype. Among ten vegetable species studied five vegetable species, i.e. Spinach, Radish, Tomato, Chili and Cabbage growing in mixed industrial effluent irrigated agricultural field showed high accumulation and translocation of toxic metals (As, Cd, Cr, Pb and Ni) in their edible parts, thus, their cultivation are unsafe with respect to possible transfer in food chain and health hazards. However, it is suggested that vegetable crops restricting toxic metal in non-edible port may be recommended for cultivation in such metal contaminated agricultural field.