Biological Accumulation Factor Research Articles

Improving vanadium removal from contaminated river water in constructed wetlands: The role of arbuscular mycorrhizal fungi

Industrial activities pose a significant ecological risk to water resources as they pollute surrounding waters with vanadium (V). Although the contribution of plants and substrates to V removal in constructed wetlands (CWs) has been reported, the role of arbuscular mycorrhizal fungi (AMF) is unclear. The aim of the present study was to investigate the role of AMF in V removal in CWs and to elucidate the underlying mechanisms. Reed plants (Phragmites australis) were inoculated with an AMF strain (Rhizophagus irregularis) in CW columns, creating AMF-inoculated (+AMF) and non-inoculated (-AMF) treatments. Three levels of influent V concentrations (low: 0.50 mg L−1, medium: 1.14 mg L−1 and high: 1.52 mg L−1) were examined. The + AMF treatment showed higher V removal (60%–98%) than the control (40%–82%) in all three conditions, although the difference was not significant in some cases. The mean mycorrhizal effects were 75%, 19%, and 28% for low, moderate, and high influent V concentrations, respectively. The +AMF treatment showed a higher GRSP-bonded V concentration (5.5 mg g−1) than the -AMF treatment (4.0 mg g−1). Furthermore, +AMF treatment showed larger plants with higher V concentrations in their tissues, accompanied by increased biological concentration factors and biological accumulation factors. Given the remarkable positive effect of AMF on V removal, our study suggests that treating AMF in CWs is a worthwhile approach.

Phytoremediation potential of native plants: Biomonitoring approach in contaminated soils

Phytoremediation has been used to remediate contaminated site. This study aims to investigate the potential of the selected native plants to accumulate and tolerate chemical pollutants. Two sites were selected in Southern Tunisia lands (Gabès), i) Gannouch located near the chemical industrial complex and ii) Zerkineis around 35 kilometres far from the industrial activities. Soil and plants were sampled and analysed for cadmium (Cd), lead (Pb), copper (Cu), zinc (Zn) and fluorine (F) concentrations. The native plants were Bassia indica and Chenopodium album, with no obvious morphological toxic symptoms. Results indicated that the upper soil layers were alkaline and salt affected with low organic matter content. The highest levels of fluoride and heavy metal were found in Ghannouch. The contents of Cd, Cu, Pb, Zn and F in the roots, stem and leaves of the native plants exceed the normal ranges and the phytotoxic level. Bioconcentration factor (BCF), translocation factor (TF), and biological accumulation factor (BAF) were determined for each element. Based on these factors the selected plants were classified as excluders, indicators, and accumulators for each element. The native plants, studied herein, seems to have significant potential for phytoremediation, thus they may be used as biomonitors in contaminated soils. Bassia indica identified as Cd, Cu and Pb accumulator, could be an excellent candidate for phytoextraction and phyto stabilization because of its F excluder performance.

Potentially harmful elements pollute soil and vegetation around the Atrevida mine (Tarragona, NE Spain)

Mining activity is one of the main sources to pollute soil, water and plants. An analysis of soil and plant samples around the Atrevida mining area in Catalonia (NE Spain) was preformed to determine potentially harmful elements (PHEs). Soil and plant samples were taken at eight locations around the mining area. The topsoil (0–15 cm) samples were analysed for physico-chemical properties by standard methods, by ICP-MS for Cd, Co, Cr, Cu, Fe, Ni, Pb and Zn, and were microwave-digested. Plant, root and shoot samples were digested separately, and heavy metals were analysed by AAS. Translocation factor (TF), biological concentration factor (BCF) and biological accumulation factor (BAF) were determined to assess the tolerance strategies developed by native species and to evaluate their potential for phytoremediation purposes. Soil pH was generally acid (5.48–6.72), with high soil organic matter (SOM) content and a sandy loamy or loamy texture. According to the agricultural soil values in southern Europe, our PHEs concentrations exceeded the toxicity thresholds. The highest root content of the most studied PHEs appeared in Thymus vulgaris L. and Festuca ovina L., while Biscutella laevigata L. accumulated more PHEs in shoots. The TF values were > 1 in B. laevigata L., but BAF obtained < 1, except Pb. B. laevigata L., and can be considered potentially useful for phytoremediation for having the capacity to restrict the accumulation of large PHEs amounts in roots and Pb translocation to shoots.

Inorganic versus organic fertilizers: How do they lead to methylmercury accumulation in rice grains

Both inorganic and organic fertilizers are widely used to increase rice yield. However, these fertilizers are also found to aggravate mercury methylation and methylmercury (MeHg) accumulation in paddy fields. The aim of this study was to reveal the mechanisms of inorganic and organic fertilizers on MeHg accumulation in rice grains, which are not yet well understood. Potting cultures were conducted in which different fertilizers were applied to a paddy soil. The results showed that both inorganic and organic fertilizers increased MeHg concentrations rather than biological accumulation factors (BAFs) of MeHg in mature rice grains. Inorganic fertilizers, especially nitrogen fertilizer, enhanced the bioavailability of mercury and the relative amount Hg-methylating microbes and therefore intensified mercury methylation in paddy soil and MeHg accumulation in rice grains. Unlike inorganic fertilizers, organic matter (OM) in organic fertilizers was the main reason for the increase of MeHg concentrations in rice grains, and it also could immobilize Hg in soil when it was deeply degraded. The enhancement of MeHg concentrations in rice grains induced by inorganic fertilizers (5.18–41.69%) was significantly (p < 0.05) lower than that induced by organic fertilizers (80.49–106.86%). Inorganic fertilizers led to a larger increase (50.39–99.28%) in thousand-kernel weight than MeHg concentrations (5.18–41.69%), resulting in a dilution of MeHg concentrations in mature rice grains. Given the improvement of soil properties by organic fertilizer, increasing the proportion of inorganic fertilizer application may be a better option to alleviate MeHg accumulation in rice grains and guarantee the rice yield in the agricultural production.

Vital evidence for arbuscular mycorrhizal fungi, bacteria and cattail plant to remove Pb-Cd heavy metals from contaminated soils

Phytoremediation is a low-cost but highly efficient and environmentally friendly technology for heavy metal soil remediation. However, its success in soils is dependent on the chosen plant and microbes. Moreover, the effect of mycorrhizal fungi and bacteria on CO2 release, mineralization rate, and metal translocation in cadmium and lead-contaminated cattails plant is unknown. The goal of the research was to look into the effects of bacteria, mycorrhiza, and cattails on CO2 release, mineralization rate, lead (Pb), and cadmium (Cd) removal from soil. The experiment used six different combinations (mycorrhiza, bacillus 10 mL, bacillus 100 mL, mycorrhiza + bacillus 10 mL, mycorrhiza + bacillus 100 mL, and control). The results showed that combining mycorrhiza with bacillus 100 mL resulted in greater increases in CO2 release, polysaccharides content and mineralization rate (2.84 mg CO2 g−1 in dry soil, 0.90 mg, 0.021 mg C g−1 dry soil day−1). More crucially, mycorrhiza + bacillus 100 mL roots had the greatest quantities of Cd and Pb (18.26 mg kg−1 and 155.22 mg kg−1), showing that bacteria had a prominent part in the phytoextraction process. Regarding Cd, the bacillus 100 mL had the highest translocation factor (TF) (3.99) and biological accumulation factor (BAF) (75.54), indicating effective translocation and excessive Cd accumulation in the plant. Bacillus 100 and mycorrhiza + bacillus 100 had the highest Pb TF (0.49) and BAF (6.08). Ultimately, the elimination of Cd and Pb was linked to the maximum bacterial cell density, mycorrhizal activity, and CO2 emission, resulting in a unique phytoremediation in Pb-Cd contaminated cattails rhizosphere soils.

Effect of biosorptive removal of cadmium ions from hydroponic solution containing indigenous garlic peel and mercerized garlic peel on lettuce productivity

One of the most harmful trace elements is cadmium (Cd) because of its persistence and high mobility. As Cd-contamination of soils increases worldwide, techniques to reduce the lettuce plant's Cd accumulation are required. The adverse effects of Cd can be reduced or eliminated using indigenous garlic peel (IGP) and, to a greater extent, mercerized garlic peel (MGP). In addition, the adsorption capacity of garlic peel after mercerization increased compared to indigenous garlic peel. This investigation explored the efficacy of IGP or MGP on the growth characteristics, Cd concentration, and biochemical processes in Cd-stress lettuce plants using a hydroponic growing system. The results demonstrated that IGP or MGP mitigated Cd's toxicity, improving lettuce growth, reducing Cd content, translocation factor, biological accumulation factor, tolerance index, malondialdehyde, and oxidative stress in both leaves and roots. In addition, the application of IGP and MGP significantly increased the non-enzymatic and enzymatic antioxidants in leaves and roots under Cd stress. Furthermore, all treated plants displayed high expression levels of certain regulatory defense genes, UBC21, LOX, and PAL.

Bacterial Endophytes of Spring Wheat Grains and the Potential to Acquire Fe, Cu, and Zn under Their Low Soil Bioavailability.

Simple SummaryUnmasking the overall endophytic bacteria communities from wheat grains may help to identify and describe the microbial colonization of bread and emmer varieties, their link to the bioactive compounds produced, and their possible role in mineral nutrition. The possibility of using microorganisms to improve the microelemental composition of grain is an important food security concern, as approximately one-third of the human population experiences latent starvation caused by Fe (anemia), Zn, or Cu deficiency. Four wheat varieties from T. aestivum L. and T. turgidum subsp. dicoccum were grown in field conditions with low bioavailability of microelements in the soil. Varietal differences in the yield, yield characteristics, and the grain micronutrient concentrations were compared with the endophytic bacteria isolated from the grains. Twelve different bacterial isolates were obtained that represented the genera Staphylococcus, Pantoea, Sphingobium, Bacillus, Kosakonia, and Micrococcus. All studied strains were able to synthesize indole-related compounds (IRCs) with phytohormonal activity. IRCs produced by the bacterial genera Pantoea spp. and Bacillus spp. isolated from high-yielding Oksamyt myronivs’kyi and Holikovs’ka grains may be considered as one of the determinants of the yield of wheat and its nutritional characteristics.Wheat grains are usually low in essential micronutrients. In resolving the problem of grain micronutritional quality, microbe-based technologies, including bacterial endophytes, seem to be promising. Thus, we aimed to (1) isolate and identify grain endophytic bacteria from selected spring wheat varieties (bread Oksamyt myronivs’kyi, Struna myronivs’ka, Dubravka, and emmer Holikovs’ka), which were all grown in field conditions with low bioavailability of microelements, and (2) evaluate the relationship between endophytes’ abilities to synthesize auxins and the concentration of Fe, Zn, and Cu in grains. The calculated biological accumulation factor (BAF) allowed for comparing the varietal ability to uptake and transport micronutrients to the grains. For the first time, bacterial endophytes were isolated from grains of emmer wheat T. turgidum subsp. dicoccum. Generally, the 12 different isolates identified in the four varieties belonged to the genera Staphylococcus, Pantoea, Sphingobium, Bacillus, Kosakonia, and Micrococcus (NCBI accession numbers: MT302194—MT302204, MT312840). All the studied strains were able to synthesize the indole-related compounds (IRCs; max: 16.57 µg∙mL−1) detected using the Salkowski reagent. The IRCs produced by the bacterial genera Pantoea spp. and Bacillus spp. isolated from high-yielding Oksamyt myronivs’kyi and Holikovs’ka grains may be considered as one of the determinants of the yield of wheat and its nutritional characteristics.

Heavy metal pollution status and health risk assessment vicinity to Barapukuria coal mine area of Bangladesh

Study related to pollution and subsequence health risk assessment adjacent to coal mining region is indispensable since coal mining and combustion have adverse impacts on the soil, subsoil, and plants in the surrounding area with a threat to human health and ecosystem. This study assesses the heavy metal pollution in water and soil as well as uptake in several parts of paddy plants over the three seasons around the year in the vicinity of the Barapukuria coal mine in Bangladesh, with the ultimate goal of estimating human health risks from eating the rice grown in this area. Enrichment factor (EF), pollution load index (PLI), geo-accumulation index (Igeo) and biological accumulation factor (BAF) were estimated for quantifying the pollution status in soils and plants. Collected samples were prepared and analysed by using USEPA recommended methods. PLI showed that soils irrigated by coal mine water were highly polluted by Ni, Fe, and Cr metals. The Igeo indicated that the soil in the study area was moderately contaminated by Cu, Zn and Ni. Amongst all types of samples, soil was found with the highest pollution followed by roots, stems, and grains; however, bioaccumulation was not evident. In the three varieties of rice grains tested, Zn and Fe were present with the highest concentrations. Through the rice grain, people in the area are ingesting Fe in the highest amounts and Cr with the lowest. Even though the concentration of Cr is low it is still above the oral intake level as recommended by USEPA.

Effect of irrigation water system's distribution on rice cadmium accumulation in large mild cadmium contaminated paddy field areas of Southwest China

There are large areas of moderately Cd-contaminated rice paddies (Cd content was less than risk intervention value) in southwest China, under natural conditions, the effect of irrigation water system's distribution on the Cd contamination in soil and rice is still less accurate. In this study, a survey of paired soil-rice (n = 1520) samples was conducted in a large paddy of about 7000 ha in southwest China that originated from the same parent material and grew with the same rice varieties. Specially, three representative characteristic regions (area A, B, C) were selected from north to south to thoroughly investigate the reasons for pollution characteristics. Background soil, irrigation water and sediment, atmospheric deposition, fertilizer were sampled to study the causes of pollution. Results showed the biological accumulation factor (BAF = C (rice Cd)/C (soil Cd)) of area C in the south reached 1.34, which was about 8 times higher than that of area A in the north. The uneven distribution of irrigation water due to geographical reasons was the most important factor leading to this pollution characteristics. The Cd content in soil of north was much higher than that in the south due to the history of Cd-contaminated irrigation and background content of Cd. During farmland formation, river impinges resulted in a gradual decrease in both Cd content and pH in the background soil from north to south. Both of historical polluters and major irrigation systems were distributed in area A. However, when sewage irrigation stopped about 30 years ago, long-term weakly alkaline irrigation increased the pH of the soil from acidic to neutral in area A. Meanwhile, flooding irrigation in area A reduced the absorption of Cd by roots compared area C where was rarely flooded during the rice planting process due to the lack of irrigation water.

Phytoremediation of Some Polluted Soils by Sudan Grass (Sorghum Sodanese L.)

A pot experiment was carried out in Soil Dep., College of Agric. Mans. Univ., to study the effect of using sudan grass for remediation of some polluted soils in Dakahlia governorate .Ten plant seeds per pot were sown on 25August,2014 and harvested on 10 October,2014. The experimental soils were taken from ten polluted locations to represent polluted soils in Dakahlia govrnorate from different sources i.e. (sewage, industry, traffic and agricultural drainage pollutions) as follows: Talkha fertilizer company adjacent area; El-Mansoura Sewage Station area; El-Mansoura Melting companies area; Town refuse - Sandob area; El-Mansoura Ratingat factory; El-Serw station Agric. Drainage; Gedilah road near El-Mansoura Institute; Sewage drainage - Meet El-Akrad area ; Sallant- Dekrnes road and El-Sallab Institute area. Data obtained from this investigation pointed out that the concentration of lead, nickel and cadmium were (6.00, 3.43 and 3.39 mg/kg) in sudan grass plant shoots which uptake and removed high values of lead, nickel and cadmium (192,122 and 104 mg/kg plant) shoots of Sudan grass plant than the roots (2.16, 2.78 and 2.13 mg/kg) and roots uptake (7.0, 9.0 and 7.0 mg/kg plant) from the studied polluted soils. It can be observed that; shoots of sudan grass extracted and absorbed more lead, nickle and cadmium than roots because this plant has a huge vegetative growth. Results, also showed that; translocation factor (2.77, 1.41 and 1.56) and biological accumulation factor were more than one (0.66,0.78 and0.72) for laed, nickle and cadmium, respectively. It can be concluded that; Sudan grass is more effective for remediation of these polluted soils in Dakahlia government and can be considered as a hyper accumulator for heavy metals.

Modulation of Cadmium Tolerance in Rice: Insight into Vanillic Acid-Induced Upregulation of Antioxidant Defense and Glyoxalase Systems.

Cadmium (Cd) is a toxic heavy metal that enters the human food chain from the soil via plants. Increased Cd uptake and translocation in plants alters metabolism andreduces crop production. Maintaining crop yield therefore requires both soil remediation andenhanced plant tolerance to Cd. In this study, we investigated the effects of vanillic acid (VA) on Cd accumulation and Cd stress tolerance in rice (Oryza sativa L. cv. BRRI dhan54). Thirteen-day-old rice seedlings treated with CdCl2 (1.0 and 2.0 mM) for 72 h showed reduced growth, biomass accumulation, and water and photosynthetic pigment contents, as well as increased signs of oxidative stress (elevated levels of malondialdehyde, hydrogen peroxide, methylglyoxal, and lipoxygenase) and downregulated antioxidant and glyoxalase systems. Cadmium-induced changes in leaf relative turgidity, photosynthetic pigment content, ascorbate pool size, and glutathione content were suppressed by VA under both mild and severe Cd toxicity stress. The supplementation of VA under Cd stress conditions also increased antioxidant and glyoxylase enzyme activity. Vanillic acid also increased phytochelatin content and the biological accumulation factor, biological accumulation co-efficient, and Cd translocation factor. Vanillic acid, therefore appears to enhance Cd stress tolerance by increasing metal chelation and sequestration, by upregulating antioxidant defense and glyoxalase systems, and by facilitating nutrient homeostasis.

Role of phosphorous mining in mobilization and bioaccessibility of heavy metals in soil-plant system: Abbottabad, Pakistan

Indiscriminate anthropogenic activities have considerably changed biogeochemical balance of naturally occurring heavy metals and posed serious threat to the environment. The phosphate rock (PR) mine is typically exploited for phosphorus fertilizers in Pakistan. It is mainly composed of phosphorous and minutely of many other elements like heavy metals (HM). This was the first attempt to evaluate the impacts of phosphate rock mining on soil and crop system adjoining PR mining near Abbottabad by growing maize plants due to mountainous nature of the study area. Exchangeable and water soluble forms of the HM were determined in phosphate rock. Results showed a significant increase in the concentration of HM in soil and plant samples. The heavy metal concentrations in soil samples varied in the order of Pb > Cr > Ni > Zn > Cd. The magnitude of metal species in soil samples decreased with the increasing distance from the mine irrespective of the kind of element. Maximum concentration of each metal was found at 20 m distance while minimum at 100 m distance from the mine. Phosphate mining enhanced HM concentrations in all parts of the maize plants. Plant parts differed in HM accumulation in the order: root > shoot > grain. The fields nearer to the PR site showed higher HM concentrations in plant parts. The results revealed that maize plants showed TF > 1.0 for Cd, while TF values for other heavy metals are Pb > Zn > Ni > Cr. Biological accumulation factor was higher for Cd, Pb, and Zn as compared with Cr and Ni. The results show that growing crops near PR mines is producing tangible impacts on soil-plant system thereby entering food chain and affecting the human and animal health.

Relationships between the properties of Spitsbergen soil, number and biodiversity of rhizosphere microorganisms, and heavy metal concentration in selected plant species

AimsThe aim of this study was to cross correlate data on physico-chemical parameters of soil with rhizosphere microorganisms and plant species in order to gain more knowledge about formation of soil and development of plants in the face of the changing climate on Spitsbergen and relations between them.MethodsWe investigated physico-chemical parameters of soil samples and the number and biodiversity of microorganisms, bacteria (oligotrophic and copiotrophic), and fungi. Moreover, heavy metal concentrations in 6 species of vascular plants collected in different areas were analysed.ResultsThe soil samples varied considerably in pH – from acid to alkaline, texture – from sand to loamy sand, and C:N ratio – from very low to high. In the soils, only partial Cd elevation expressed as the geoaccumulation index (Igeo) and the enrichment factor (EF) was detected. In the plants, the most significantly elevated concentrations of heavy metals expressed as Igeo and EF as well as the biological accumulation factor, bioconcentration factor, and translocation factor were detected in Salix polaris, Dryas octopetala, and Draba corymbosa. The high number of bacteria corresponded with an increase in the ecophysiological diversity index and the low colony development index, whereas a reverse relationship was found for fungi.ConclusionsThere was no significant impact of the geochemical properties on the total content of heavy metals in soil. The similar position of Cd and Pb in the order of heavy metal accumulation in the soil and plants was confirmed. TF showed that mainly these two metals were transported efficiently from roots to shoots. In the plants, the metals were distributed depending on the life form and their higher levels were detected in the woody perennials, e.g. S. polaris, D. octopetala, D. corymbosa, than in the herbaceous perennials. Very high numbers of culturable microorganisms were determined, regardless of the soil properties and plant species, which indicated that they were involved in the transformation of compounds containing C, N, and P and in the availability of heavy metals. The microorganisms and plants colonizing Spitsbergen soils showed great plasticity and adaptability to low temperatures and elevated Cd content.

Trace Metals in Water, Bottom Sediment, Shrimp and Dependent Human Blood in Ukwuani Local Government Area of Delta State, Nigeria

Trace metals (Fe, Mn, Zn, Cu, Pb, Cd and Cr) levels were investigated in the water, bottom sediment, shrimp (Macrobrachium vollenhovenii) of Okumeshi River using Atomic Absorption Spectrophotometer (ASS);and blood of individuals that feed on the shrimps using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS).The descriptive statistics such as the mean, range and standard error were for significant differences in the heavy metals, nutrients and total hydrocarbons in water and sediment samples was done using ANOVA (P < 0.05). Duncan Multiple Range (DMR) test was used to identify the source of variance using SPSS version 19.1.The order of accumulation in the matrices studied was bottom sediment > shrimp > water > human blood. High level of zinc and copper in human blood can be attributed to their high concentrations in all environmental matrices. It can also be attributed to the high biological accumulation factors of the metals in the shrimp. Copper also has a high essentiality in the respiratory pigment haemocyanin of shrimps. These facts are buttressed by the significant correlations of copper and zinc concentrations in the shrimp with their concentrations in human blood. The observed insalubrity of the shrimps is a prognostic of chronic health hazards to the consumers; which is also a function of the predominant oil exploration activities. Copper had an uninterrupted transit into the blood of the consumers from the aqueous phase. While zinc showed some significant level of biomagnification. The study provided an early signal of likely impending catastrophe; necessitating a proactive regulation of trace metals released into the aquatic system through the prevalent anthropogenic activities; mainly oil exploration.

The Characterization of Heavy Metals in the Grapevine (Vitis vinifera) Cultivar Rkatsiteli and Wild Blackberry (Rubus fruticosus) from East Serbia by ICP-OES and BAFs

ABSTRACTInductively coupled plasma optical emission spectroscopy, in combination with calculation of various biological factors, was used in this study not only for a simple illustration of the present status of some essential and non-essential metals such as copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), arsenic (As), and cadmium (Cd) in the grapevine cultivar Rkatsiteli and wild blackberry from East Serbia but also for the estimation of plant bioaccumulation potentials. Great majority of detected metal concentrations were in normal ranges except in few cases: Zn concentrations were at the level of deficiency in almost all plant parts, and some Cu and As concentrations were at the levels that could be considered phytotoxic. Biological accumulation factors provided very informative data on metal accumulation and translocation in both plants and pointed to low accumulation rates of metals except in the case of Cu, Zn, and As in some wild blackberry tissues.

Chemometric evaluation of trace metals in Prunus persica L. Batech and Malus domestica from Minićevo (Serbia)

The samples of spatial soils and different organs of Prunus persica L. Batech and Malus domestica were analyzed by methods such as inductively coupled plasma optical emission spectroscopy (ICP-OES), Hierarchical Cluster Analysis (HCA), One-way ANOVA, and calculation of biological accumulation factors (BAFs) with the aim of investigating whether these methods may help in the evaluation of trace metals in plants, as well as in the estimation of plant bioaccumulation potentials. ICP-OES provided accurate data on present concentrations of Cu, Zn, Pb, As, Cd, and Ni which showed that most concentrations were in normal ranges, except in some cases for Cu, Zn, and As. HCA illustrated nicely various specifics in the distribution of metals in both investigated systems plant-soil. One-way ANOVA pointed successfully on the existing statistical differences between metal concentrations. Calculated BAFs showed that both plants had very low accumulation rates for all elements; they acted as metal excluders.

Traffic-related heavy metals uptake by wild plants grow along two main highways in Hunan Province, China: effects of soil factors, accumulation ability, and biological indication potential.

This study was performed to investigate pollution of traffic-related heavy metals (HMs-Zn, Pb, Cu, Cr, and Cd) in roadside soils and their uptake by wild plants growing along highways in Hunan Province, China. For this, we analyzed the concentration and chemical fractionation of HMs in soils and plants. Soil samples were collected with different depths in the profile and different distances from highway edge. And leaves and barks of six high-frequency plants were collected. Results of the modified European Community Bureau of Reference (BCR) showed that the mobile fraction of these HMs was in the order of Cd > Pb > Zn > Cu > Cr. A high percentage of the mobile fraction indicates Cd, Pb, and Zn were labile and available for uptake by wild plants. The total concentration and values of risk assessment code (RAC) showed that Cd was the main risk factor, which were in the range high to very high risk. The accumulation ability of HMs in plants was evaluated by the biological accumulation factor (BAF) and the metal accumulation index (MAI), and the results showed that all those plant species have good phyto-extraction ability, while accumulation capacity for most HMs plants tissues was bark > leaf. The highest MAI value (5.99) in Cinnamomum camphora (L) Presl indicates the potential for bio-monitoring and a good choice for planting along highways where there is contamination with HMs.

Assessment of metallic pollution status of surface water and aquatic macrophytes of earthen dams in Ilorin, north-central of Nigeria as indicators of environmental health

The functional quality of an aquatic ecosystem is a reflection of the health of the environment. Therefore, the present study evaluates the trace metal contamination (Pb, Cd, Ni and Mn) of water and aquatic macrophytes in Asa, Agba, Unilorin and Sobi (Moro) earthen dams, north-central Nigeria to evaluate the level of anthropogenic impact on the immediate environment. The concentrations of trace metals in samples of water and available macrophytes from the earthen dams were determined by Atomic Absorption Spectrophotometry. Trace metal contamination of surface water in the earthen dams was assessed using metal index (MPI) and metal pollution index (HPI). The biological accumulation factor of trace metals in the aquatic macrophytes was extrapolated from trace metal concentrations in the water and macrophyte samples. The results of the MPI revealed gross metal contamination of the surface water by Pb and Cd (>6.0 for both metals) in the four earthen dams; while Agba and Sobi dams were slightly contaminated by Ni (MPIs=1.43 and 1.14 respectively). All the earthen dams were considered safe from Mn contamination (MPI<1.0). Considering the HPI, the four earthen dams fall within the critical pollution threshold for trace metals (HPI>100), but Asa dam (HPI=2682.4) was the most contaminated. The biological accumulation factor of Mn in the macrophytes indicated Ceratophyllum demersum, Pycreus lanceolatus and Pistia stratiotes as moderate accumulators of Mn, and can be used as bioindicators in monitoring Mn pollution of aquatic ecosystem. The obtained results in this study showed that the earthen dams are polluted by Pb, Cd and Ni which pose human health risks to the inhabitants through drinking water.

Feasibility of using tuberose (P. tuberosa L.) in horizontal subsurface flow constructed wetland for heavy metal removal from domestic wastewater

Constructed wetlands (CW) are well known for removal of organics, suspended solids, nutrients, and bacteria. However, the information on removal of heavy metals and their sequestration in plants especially, the ornamental plants is very limited. In this experimental study, efficiency of horizontal subsurface‐flow constructed wetland (HSCW) planted with an ornamental species Polianthus tuberosa L. was evaluated for heavy metal sequestration in the phytomass. The plants were harvested during the peak standing crop in early September, divided into leaves, inflorescence, roots, and rhizomes, and analyzed for six trace elements (Cu, Zn, Ni, Al, Pb, and Fe). Metal concentrations decreased in the order of roots &gt; rhizomes &gt; leaves &gt; inflorescence. The highest concentration in aboveground biomass were recorded for Al (3.66 mg kg−1) and Fe (1.35 mg kg−1), while the lowest concentration was recorded for Pb (0.06 mg kg−1). Belowground biomass also followed the same decreasing trend, the highest concentrations being recorded for Al (6.28 mg kg−1) with 5.78 mg kg−1 and 6.09 mg kg−1 concentration in rhizomes and roots, respectively. The lowest concentration in belowground biomass was recorded for Ni (0.28 mg kg−1) and Pb (0.17 mg kg−1). The belowground/aboveground concentration ratio ranged between 1.19 and 5.13 with an average value of 2.50. Due to average belowground/aboveground biomass ratio &lt; 1, the belowground/aboveground standing stock ratios for all the metals were &gt; 1 except Fe (0.79). The maximum values for bioconcentration factor (BCF) were found for Al and Zn 81.5 and 16.3, respectively. Biological accumulation factor (BAF) and transfer factor (TF) values were &gt; 1 and &lt;1, respectively for most of the heavy metals, which suggests their immobilization in the roots/rhizosphere and therefore, the species can be best suited for phytostabilization. The results of this study therefore provide the comprehensive information on sequestration of Cu, Zn, Ni, Al, Pb, and Fe in vegetation during domestic wastewater treatment in CW with horizontal subsurface flow. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 125–132, 2016

Heavy Metal Content in Acacia saligna and Acacia polyacantha on Slime Dams: Implications for Phytoremediation

Aims: To determine heavy metal content in A. saligna and A. polyacantha so as to ascertain their possible use in phytoremediation Place and Duration of Study: Bindura University of Science Education, Chemistry and Biological Sciences Dept, P. Bag 1020, Bindura, Zimbabwe. The study was carried out between December 2011 and January 2013. Methodology: Two sites which are the slime dams at a local gold mine in Bindura and a control site 10km outside the slimes were used in the study. A total of four sampling points each in the form of 5x5m quadrants were established after every 100m in transects, 700m long separately established on the control and slime dams. Soil samples at 5-10cm and 1015cm levels as well as roots, leaves and bark from five sampled plants were collected at each sampling point. The metals content was analyzed using Atomic Absorption Spectrometry and Inductively Coupled Plasma. The bioaccumulation factor and the shoot/root quotient were computed in Microsoft excel. Analysis of Variance was carried out using SPSS and Genstat Version 16. Research Article American Journal of Experimental Agriculture, 3(4): 871-883, 2013 872 Results: The present study shows that A. saligna and A. polyacantha accumulate heavy metals with biological accumulation factor (BAF) value results indicating significant differences between the slimes and control sites. Both species had BAF values for nickel, copper and iron greater than one except for zinc, lead and arsenic. The shoot/root quotients showed that nickel, copper and iron are translocated to the shoots in the species as compared to zinc, lead and arsenic. Conclusion: A. saligna and A. polyacantha showed evidence of accumulation of nickel, copper and iron and therefore may be used for phytoremediation and restoration purposes at mine slime dams.