High Heavy Metal Research Articles

Soil contamination with cadmium and potential risk around various mines in China during 2000–2020

Cadmium (Cd) pollution in mining areas is the most important challenge for soil environment management in China. Assessing the actual Cd pollution risk in various mining areas and identifying the core areas requiring supervision can provide a basis for government departments and industries to carry out detailed further investigations in key areas. In this study, we collated published data on metal mine circumjacent soil contaminated by Cd in China from 2002 to 2020 to conduct a comprehensive study on soil cadmium pollution and ecological and health risks in mining areas. The temporal and spatial variations of Cd concentrations and the pollution source were investigated. Results indicated that the Cd concentration in soil was strongly associated with the types of mining area. The Cd pollution in the circumjacent soil of lead-zinc and tungsten mines with high heavy metal pollution discharging coefficient was more serious than the soil around other mines. Identification of temporal and spatial variations for soil Cd in China indicated that the high Cd concentrations were found in the central, southern, and southwestern regions of China, and the distribution of mining activities in these regions are relatively concentrated. Meanwhile, a temporal turning point in the mean soil Cd concentration occurred in these regions in 2012, which indicated that the heavy metal control management policy implemented by the government was effective. The ecological risk of soil Cd pollution around mining areas was moderate to high. Health risk assessment showed that some regions adjacent mining areas had a high non-carcinogenic risk, notably, lead-zinc and tungsten mining areas were more serious. Supervision should focus on reducing ecological risks and protecting the safety of agricultural products rather than concentrating on health risks. The research results provide a reference for the priority management of contaminated soil in mining areas.

Comprehensive Genome Analysis of Halolamina pelagica CDK2: Insights into Abiotic Stress Tolerance Genes

Halophilic archaeon Halolamina pelagica CDK2, showcasing plant growth-promoting properties and endurance towards harsh environmental conditions (high salinity, heavy metals, high temperature and UV radiation) was sequenced earlier. Pan-genome of Halolamina genus was created and investigated for strain-specific genes of CDK2, which might confer it with features helping it to withstand high abiotic stress. Pathways and subsystems in CDK2 were compared with other Halolamina strain CGHMS and analysed using KEGG and RAST. A genome-scale metabolic model was reconstructed from the genome of H. pelagica CDK2. Results implicated strain-specific genes like thermostable carboxypeptidase and DNA repair protein MutS which might protect the proteins and DNA from high temperature and UV denaturation respectively. A bifunctional trehalose synthase gene responsible for trehalose biosynthesis was also annotated specifying the need for low salt compatible solute strategy, the probable reason behind the ability of this haloarchaea to survive in a wide range of salt concentrations. A modified shikimate and mevalonate pathways were also identified in CDK2, along with many ABC transporters for metal uptakes like zinc and cobalt through pathway analysis. Probable employment of one multifunctional ABC transporter in place of two for similar metals (Nickel/cobalt and molybdenum/tungsten) might be employed as a strategy for energy conservation. The findings of the present study could be utilized for future research relating metabolic model for flux balance analysis and the genetic repertoire imparting resistance to harsh conditions can be transferred to crops for improving their tolerance to abiotic stresses.

Enrichment Evaluation of Heavy Metals from Stormwater Runoff to Soil and Shrubs in Bioretention Facilities

Bioretention facilities with different inflow concentrations, growing media and plants were examined to determine whether the soil in these facilities was polluted with heavy metals and whether runoff had obvious toxic effects on plants. Using Beijing soil background value as the standard, the soils were evaluated by bioaccumulation index and single factor index. The results show that stormwater runoff containing Cu caused slight pollution in soils, and stormwater runoff containing Zn and Pb was not polluted. Nemerow comprehensive index evaluation revealed that the heavy metals content in the facilities containing vermiculite (a yellow or brown mineral found as an alteration product of mica and other minerals, used for insulation or as a moisture-retentive medium for growing plants) and perlite (a form of obsidian characterized by spherulites formed by cracking of the volcanic glass during cooling, used as insulation or in plant growth media) were higher than the standard. High influent concentration caused significantly higher heavy metals content in plants. While Pb accumulation in the two studied plants was the highest, Cu and Zn accumulation, which are essential for plant growth, was relatively low. The contents of the three heavy metals in the studied plants also exceeded their corresponding critical values.

Metallophores production by bacteria isolated from heavy metal-contaminated soil and sediment at Lerma-Chapala Basin.

Environmental pollution as a result of heavy metals (HMs) is a worldwide problem and the implementation of eco-friendly remediation technologies is thus required. Metallophores, low molecular weight compounds, could have important biotechnological applications in the fields of agriculture, medicine, and bioremediation. This study aimed to isolate HM-resistant bacteria from soils and sediments of the Lerma-Chapala Basin and evaluated their abilities to produce metallophores and to promote plant growth. Bacteria from the Lerma-Chapala Basin produced metallophores for all the tested metal ions, presented a greater production of As3+ metallophores, and showed high HM resistance especially to Zn2+, As5+, and Ni2+. A total of 320 bacteria were isolated with 170 strains showing siderophores synthesis. Members of the Delftia and Pseudomonas genera showed above 92 percent siderophore units (psu) during siderophores production and hydroxamate proved to be the most common functional group among the analyzed siderophores. Our results provided evidence that Lerma-Chapala Basin bacteria and their metallophores could potentially be employed in bioremediation processes or may even have potential for applications in other biotechnological fields.

Ti3C2TX-Ethylenediamine nanofiltration membrane for high rejection of heavy metals

In a situation in which a huge amount of industrial wastewater is being generated worldwide, developing technology to effectively remove various types of heavy metal ions in wastewater is crucial. To achieve this goal, in this study, a material functionalized with ethylenediamine on Ti3C2TX is used as the active layer of a nanofiltration membrane to provide excellent rejection against six types of heavy metal ions (Mn2+, Zn2+, Cd2+, Cu2+, Ni2+, and Pb2+). When this Ti3C2TX-EDA membrane is applied to the nanofiltration system, a heavy metal rejection of greater than 93% is demonstrated, regardless of the heavy metal type with high pure water permeance of 21.1 LMH bar−1 at optimized operating conditions. In particular, for Mn2+, the Ti3C2TX-EDA membrane demonstrates a high heavy metal rejection of 99.8%. In addition, this membrane exhibit excellent continuous nanofiltration performance for various heavy metal solutions. Because this material can be deposited onto various support membranes, using it as an active layer provides a very efficient approach to achieving heavy metal removal from industrial wastewater.

Algae and cyanobacteria in soils polluted with heavy metals (Northwest Russia, Murmansk region)

The analysis of algae and cyanobacteria in Albic Podzols affected by emissions of the copper–nickel plant Pechenganikel in the forest-tundra of the Arctic region was carried out. The main pollutants contained in the emissions and entering the soil are sulfur compounds and heavy non-ferrous metals. Algae and cyanobacteria were identified in soil samples collected in three zones differing in their distance from the pollution source: the zone of strong pollution (at a distance of 3 km southwest from the source of the emission), the zone of medium pollution (5-7 km), and the zone of weak pollution (16-25 km). In total, 61 species of eukaryotic algae and 2 species of cyanobacteria were found. In the studied soils, several species of algae were found with a high frequency, apparently resistant to unfavorable natural and anthropogenic factors: Chloromonas sp., Neocystis brevis, Parietochloris alveolaris, Pseudococcomyxa simplex, Stichococcus bacillaris, Interfilum terricola, Leptosira cf. obovata, Myrmecia bisecta, Nostoc muscorum. Algae from the Chlorophyta division predominated in all soils studied. Yellowgreen algae and diatoms were found only in the zone of strong pollution and were represented by a very small number of species. The presence of Microthamnion kuetzingianum, which is resistant to high acidity and heavy metals concentration, can be useful as an indicator of severe heavy metal contamination. Our study confirmed sensitivity of Vischeria magna to soil contamination with heavy metals. In long-term aspect, the species diversity of algae has increased by 35% in the soils influenced by the Pechenganikel plant in comparison with the data obtained 30 years ago, which probably indicates a certain decrease in anthropogenic load on the adjacent territories.

Soil amendment with a humic substance and arbuscular mycorrhizal Fungi enhance coal mine reclamation

Coal mine sites covered by sandy soils often have low nutrient and high heavy metal concentrations, making reclamation for agricultural uses challenging. Although the combined use of humic substances and soil biota has generated considerable research interest, little information is available regarding their synergistic effects. In a two year field study, we assessed the effects of sole and combined applications of a humic substance product called nano humus (150 g/m2 in soils), arbuscular mycorrhizal fungi (250 g inocula/m2 in soils), and fertilizer (37 g/m2 in soils) on soil chemical properties, soil heavy metals, and growth of alfalfa (Medicago ruthenica L.) and barley (Hordeum vulgare L.). Application of arbuscular mycorrhizal fungi with nano humus exhibited greatest effects in year two. Relative to untreated soils, they increased soil cation exchange capacity by 38%, total organic carbon by 36%, and available nitrogen, phosphorus, and potassium by 20 to 92%; they reduced concentrations of soil cadmium by 25% and of arsenic by 9%. Mycorrhizal colonization rate and soil heavy metal concentrations were significantly negatively correlated, suggesting an inhibition effect of metals on colonization. The combination of arbuscular mycorrhizal fungi and nano humus showed greatest impact on root and shoot biomass of alfalfa, which increased 18 and 12 times, respectively. Barley responded most positively to combinations of arbuscular mycorrhizal fungi, nano humus, and fertilizer; root biomass increased 4 times, and shoot biomass and seed production increased 3 times. Combined applications generally provided greater benefits than sole applications, which could be a useful practice in heavy metal contaminated reclamation sites.

Comparative analytical study of landfill soil and soil from sanitary protection zone of the solid municipal waste landfill of the Irkutsk city for 2014 and 2019

The largest SMW landfill in the Irkutsk region is that in the Irkutsk city. In 2014, high heavy metal contents were registered in landfill soil samples taken at the landfill site, and it was proposed to perform monitoring outside the landfill in 2019 and determine the pollution distribution area. In this article, the comparative analysis of the degree of heavy metal pollution of the landfill soil and soil from sanitary protection zone is presented. It was established that the studied landfill soil refers to extremely hazardous soils with heavy metal contents that are up to 68 times higher than TLV. Soil samples from the landfill-affected area also contain heavy metals in high concentrations. The manufacturing supervision of the SMW landfill should include the continuous observation of the soil, water, and air condition in the zone of possible impact of the landfill for taking timely environmental protection measures and preventing further negative impact of the landfill on the ecosystem.

Assessment of the Heavy Metal Contamination of Roadside Soils Alongside Buddha Nullah, Ludhiana, (Punjab) India.

The present study was carried out to determine the physico-chemical characteristics and heavy metal contents in roadside soil samples collected during 2 sampling periods (September 2018 and April 2019) from 8 different roadside sites lying parallel to the Buddha Nullah, an old rivulet, flowing through Ludhiana, (Punjab) India. The contents (mg/kg) of seven metals (cadmium, chromium, cobalt, copper, lead, nickel and zinc) were estimated using a flame atomic absorption spectrophotometer. Among the metals analyzed, the contents of Cd, Co, Cu, Pb and Zn were found above the permissible limits. The results of the index of geoaccumulation (Igeo), contamination factor (CF), contamination degree (Cdeg), modified contamination degree (mCdeg), the Nemerow pollution index (PI) and pollution load index (PLI) indicate a moderate to high heavy metal contamination of the analyzed soil samples. The results of the potential ecological risk factor (ERi) and potential ecological risk index (RI) indicate a low to moderate risk of heavy metals in the studied soil samples. The Pearson correlation analysis revealed that most of the variables exhibited a statistically significant correlation with one or more variables during the two samplings. Multivariate analysis demonstrates that contents of heavy metals in the study area are influenced by anthropogenic and geogenic factors.

Use of Solar Still in Heavy Metals Removal from Kitchen Wastewater

Indiscriminate discharge of wastewater into the environment can lead to environmental pollution. Heavy metals present in wastewater can infiltrate into the ground to cause groundwater contamination. In this study, a solar still was employed in the removal of heavy metals from domestic wastewater. Five wastewater samples with high heavy metal contents were kept in a solar still and subjected to heat from the sun. The solar still was constructed using locally available materials. The concentration of Iron (Fe), Zinc (Zn), Manganese (Mn), Chromium (Cr) and Cadmium (Cd) in the untreated and treated wastewater samples were determined. The study revealed a drastic reduction in the heavy metal content of the treated wastewater, however, the heavy metal content of most of the treated wastewater samples did not fall within World Health Organization (WHO) limit for potable water. Remarkably, The Zn content of four out of the five treated wastewater samples fell within WHO limit for potable water except for sample 2 which witnessed a drastic reduction from 13.9 to 3.28 mg/L but still did not meet up with WHO limit of 3 mg/L. The treated wastewater can be safely discharged into the environment; however, further treatment is required to make the water safe for human consumption.

Bee pollens as biological indicators: An ecological assessment of pollution in Northern Turkey via ICP-MS and XPS analyses.

In this study, pollens were collected from 25 different locations of Northern Turkey to investigate pollution monitoring. Surface chemistry of pollen samples was characterized by X-ray photoelectron spectroscopy (XPS). Then the concentrations of certain elements (Li, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Ba, and Pb) in pollen samples were determined by inductively coupled plasma mass spectrometry (ICP-MS) for the evaluation of environmental pollution. The levels of elements were detected in the following ranges (minimum-maximum, mg/kg dry pollen): Li (0.18-0.39), Al (24.98-308.04), V (6.18-98.58), Cr (1.05-6.81), Mn (13.85-95.91), Fe (52.20-326.26), Co (0.15-0.34), Ni (1.66-10.79), Cu (8.61-19.01), Zn (20.47-70.02), As (1.22-2.65), Se (0.39-0.67), Cd (0.05-0.74), Ba (0.73-16.30), and Pb (0.00-0.26). It has been concluded that there is a correlation between the pollen samples with high heavy metal concentrations and traffic density as these regions are closer to the road in the northern region. It is exposed to pollution from various sources such as intensified urbanization and tourism activities carried out on land and sea; industrial activities are increasing rapidly due to the opportunities offered by the coastal areas, sea transportation, and agricultural, domestic, and industrial pollution coming from the inner regions through rivers and streams. In this sense, pollens can be used as potential bio-indicators for monitoring heavy metal pollution and gives an idea about how we can use them for future assessing purposes.

Use of Solar Still in Heavy Metals Removal from Kitchen Wastewater

Indiscriminate discharge of wastewater into the environment can lead to environmental pollution. Heavy metals present in wastewater can infiltrate into the ground to cause groundwater contamination. In this study, a solar still was employed in the removal of heavy metals from domestic wastewater. Five wastewater samples with high heavy metal contents were kept in a solar still and subjected to heat from the sun. The solar still was constructed using locally available materials. The concentration of Iron (Fe), Zinc (Zn), Manganese (Mn), Chromium (Cr) and Cadmium (Cd) in the untreated and treated wastewater samples were determined. The study revealed a drastic reduction in the heavy metal content of the treated wastewater, however, the heavy metal content of most of the treated wastewater samples did not fall within World Health Organization (WHO) limit for potable water. Remarkably, The Zn content of four out of the five treated wastewater samples fell within WHO limit for potable water except for sample 2 which witnessed a drastic reduction from 13.9 to 3.28 mg/L but still did not meet up with WHO limit of 3 mg/L. The treated wastewater can be safely discharged into the environment; however, further treatment is required to make the water safe for human consumption.

Toxicological Indices of Wistar Rats Fed Formulated Chaw of Telfairia occidentalis Planted on Crude Oil Contaminated and Remediated Soil

Toxicological indices of wistar rats fed formulated chaw of Telfairia occidentalis planted on crude oil contaminated and bioremediated soil was studied. Farmland, measuring 18 m2 was divided into three lots of 4 m2 and 2 m space was allowed between each lot (A, B and C). Two lots were polluted, subjected to 16 weeks of bioremediation and viable seeds of T. occidentalis were planted and grown for 28 days. The harvested vegetable leaves were analyzed. Leaves from natural attenuated soil showed high concentration of both aliphatic and polycyclic aromatic hydrocarbons with values of 9.34+0.03 mg/kg and 9.18+0.05 mg/kg for C36 and Fluoranthene respectively, while the bioaugmented soil had Lead as the highest heavy metal with a value of 0.10+0.02 g/100g. Four groups, of 9 rats each (totalling 36 rats) of adult males and females, wealing males and females were subsequently sub-grouped into 3 and allowed to acclimatize for a period of 1 week. These animals were fed formulated rat chaw of 50% dry weight of T. occidentalis, from the three lots (control, bioaugmented and natural attenuated soil) for a period of 28 days. Assay of animals’ toxicological index showed elevated concentrations of alkaline phosphatase, alanine and aspartate aminotransferases, urea and creatinine in their sera. A slight increase in serum amylase activity was recorded, while concentrations of their haemoglobin and Packed Cell Volume (PCV) reduced. The obtained results from these biomarkers were confirmed by the histopathological sections of the animal organs.

A global perspective of the current state of heavy metal contamination in road dust.

Heavy metals are persistent and bio-accumulative, and pose potential risk to human health and ecosystem. We reviewed the current state of heavy metal contamination, the ecotoxicological and human health risk of heavy metals reported in urban road dust from various cities in different continents (Asia, Europe, Africa, America, and Australia). We compared and synthesized the findings on the methods related to sample collection, extraction, analytical tools of heavy metals, their concentrations, level of contamination, ecological risk, non-carcinogenic risk, and carcinogenic risk in road dust. Concentrations of Pb, Zn, Cu, Ni, Cd, Cr, Mn, and Fe were found to be higher than their background values in soil. As expected, the contamination levels of the heavy metals varied extensively among cities, countries, continents, and periods. A high level of contamination is observed for Pb and Cd in road dust due to operating leaded gasoline and the old vehicle population. The highest Zn contamination was observed from road dust in Europe, followed by Asia, Africa, Australia, and America (North America and South America). Cu contamination and the pollution load index (PLI) is found to be the highest in Europe and lowest in Africa, with in-between values of PLI in American and African cities. The potential ecological risk on different continents was observed highest in Asia, followed by Europe, Australia, America, and Africa. A comparative assessment of non-carcinogenic risk for children indicated that Australia is the most susceptible country due to high heavy metal exposure in road dust, followed by Asia. However, there is no susceptible risk in European, African, and American cities. We did not observe any potential risk to adults due to non-carcinogenic metals. Carcinogenic risk to all age groups was within the threshold limit range for all the regions worldwide.

METHOD OF INCREASING MEAT PRODUCTIVITY AND ENVIRONMENTAL SAFETY OF BROILER MEAT BY FEEDING ADSORBENT AND ANTIOXIDANT

In recent years, the use of adsorbent and antioxidant preparations in the formulation of feed with a high content of heavy metals is a promising direction in the industrial production of broiler meat. The study aims to study the consumer and hygienic properties of broiler meat when including adsorbent Ferrotsin and antioxidant Selenopyran in diets with high heavy metals and aflatoxin B 1 content. The authors experimentally established the necessity of containing the adsorbent Ferrotsin in the dose of 300 g/t feed and the antioxidant Selenopyran in the quantity of 300 g/t feed into the composition of mixed fodder with excessive concentration of heavy metals. This inclusion of adsorbents and antioxidants in the compound feed composition is necessary to increase the nutritional properties and protective properties of poultry meat. Group 3 broiler chickens significantly exceeded (P < 0.05) the control counterparts by 18.88 % by weight of half-gutted carcass and 18.26 % by weight of the gutted carcass. Also, broiler chickens of the 3rd experimental group exceeded the content of solids in the thoracic and thigh muscles by 1,40 and 0,60, and protein by 0,67 % and 0,67 %. Group 3 broilers significantly (P < 0.05) exceeded the control in protein quality index (PQI) of meat by 18.86 %. In broilers of experimental group 3, there was a reliable (P < 0.05) decrease in the level of zinc by 3.07, cadmium by 2.25 and lead by 3.24 times in the samples of breast muscle relative to the control counterparts. The highest final score was obtained by boiled white poultry meat of the 3rd experimental group. This sample of meat reliably (P < 0.05) exceeded the total sum of organoleptic parameters of the control sample by 0.81 points. In broilers of experimental group 3 in examples of breast, thigh muscles and meat homogenate, the level of selenium was significantly higher than in control due to the presence of this substance in Selenopyran.

Attention deficit among preschool and school-aged children living near former metal-processing plants in Romania

Industrial areas affected by high and long-term heavy metal pollution have a great impact on health of the resident population. Children represent a group at high-risk with an increased susceptibility to chronic heavy metal intoxication.Our work included the assessment of attention particularities through a case-control study in pre-school and school-aged children (4–6 years and 8–11 years) from two study areas, Copşa Mică and Zlatna, compared to a non-polluted locality with no history of heavy metal pollution. Copşa Mică and Zlatna are two of the most polluted heavy metals regions in Romania due to non-ferrous metallurgy for a long period of time. Recruitment of participants was made by a random selection of an entire class for each age within the schools and kindergartens from the study areas (Copşa Mică and Zlatna) and from the non-polluted region. Interpretation of data was performed using statistical analysis (ANOVA and Student's t-test). Preschool children (4–6 years) were tested using Wechsler Preschool and Primary Scale of Intelligence (WPPSI) tests, Animal House and labyrinth samples. The results of the attention tests applied to pre-school children were lower in the study areas compared to the control group, but no statistical differences were found. The results of the attention tests applied to children aged between 8 and 11 years (Toulouse-Pieron test and Traffic light test) indicate lower average scores within the study groups from polluted areas, compared to the control group. Differences with statistically significance were registered for the 8 years age group (p = 0.037).In these areas efficient strategies and precise intervention measures are needed in order to limit or remove the heavy metal exposure and protect the human health, especially the groups exposed to a high level of risk.

КАЧЕСТВЕННЫЕ И КОЛИЧЕСТВЕННЫЕ ХАРАКТЕРИСТИКИ ПОЧВ И СВАЛОЧНОГО ГРУНТА ПОЛИГОНА ТВЕРДЫХ КОММУНАЛЬНЫХ ОТХОДОВ

The largest SMW landfill in the Irkutsk region is that in the Irkutsk city. In 2014, high heavy metal contents were registered in landfill soil samples taken at the landfill site, and it was proposed to perform monitoring outside the landfill in 2019 and determine the pollution distribution area. In this article, the comparative analysis of the degree of heavy metal pollution of the landfill soil and soil from sanitary protection zone is presented. It was established that the studied landfill soil refers to extremely hazardous soils with heavy metal contents that are up to 68 times higher than TLV. Soil samples from the landfill-affected area also contain heavy metals in high concentrations. The manufacturing supervision of the SMW landfill should include the continuous observation of the soil, water, and air condition in the zone of possible impact of the landfill for taking timely environmental protection measures and preventing further negative impact of the landfill on the ecosystem.

Bioaccumulation of Trace Metals for Daily Fish Consumption from Selected Former Tin Mining Ponds in Peninsular Malaysia: A Review on Safety of Fish Consumption

Tin mining was the predominate mining industry in Malaysia, especially during the mid-19th century. Most of the former mining areas have been reused for aquaculture purposes. Fish produced from former mining areas have been misunderstood as a high health risk if consumed due to their likelihood of containing high heavy metal content in their tissue. Therefore, we review national information on trace metals levels in the tissue of fish from selected former mining ponds in Peninsular Malaysia, together with background concentration of trace metals in their surroundings and food security and human health implications. Seven trace metals (Cu, Zn, As, Cd, Pb, Cr, and Ni) were observed in the water column and sediment. Various reports showed that background trace metal concentrations in the former mining area are mostly lower than several established limits (which were used as the main reference), except for the areas that were being treated for secondary use. Trace metal concentrations in the fish tissue also showed the same trend of high concentrations due to improper or unfinished treatment of former mining ponds. In the context of food safety, various local reports have shown that the consumption of aquaculture products from former mining areas over a lifetime is unlikely to cause any harmful effects and hence may be regarded to be safe. However, these findings are restricted due to the limited studies in Peninsular Malaysia. Therefore, extensive study regarding this particular issue is highly recommended

A Large-Scale Multiple Genome Comparison of Acidophilic Archaea (pH ≤ 5.0) Extends Our Understanding of Oxidative Stress Responses in Polyextreme Environments.

Acidophilic archaea thrive in anaerobic and aerobic low pH environments (pH < 5) rich in dissolved heavy metals that exacerbate stress caused by the production of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), hydroxyl radical (·OH) and superoxide (O2−). ROS react with lipids, proteins and nucleic acids causing oxidative stress and damage that can lead to cell death. Herein, genes and mechanisms potentially involved in ROS mitigation are predicted in over 200 genomes of acidophilic archaea with sequenced genomes. These organisms are often be subjected to simultaneous multiple stresses such as high temperature, high salinity, low pH and high heavy metal loads. Some of the topics addressed include: (1) the phylogenomic distribution of these genes and what this can tell us about the evolution of these mechanisms in acidophilic archaea; (2) key differences in genes and mechanisms used by acidophilic versus non-acidophilic archaea and between acidophilic archaea and acidophilic bacteria and (3) how comparative genomic analysis predicts novel genes or pathways involved in oxidative stress responses in archaea and likely horizontal gene transfer (HGT) events.

Assessment of Heavy Metals in Agricultural Soils and Plant (Vernonia amygdalina Delile) in Port Harcourt Metropolis, Nigeria

This study assessed the concentration of heavy metal, such as lead (Pb), cadmium (Cd), Chromium (Cr), iron (Fe), Nickel (Ni), and Silver (Ag), in Vernonia amygdalina Delile and agricultural soils of three university farms located in Port Harcourt, Nigeria. The soils and plants were taken randomly to form composite samples and analyzed for heavy metals by the use of atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF). The study stations were agricultural soils and Vernonia amygdalina Delile from the Ignatius Ajuru University of Education (I), River State University (R) and University of Port Harcourt (U). The soil samples recorded mean concentration ranges for Fe as 19.71 ± 1.77 (I)–27.24 ± 3.56 mg/kg (R) in soils and 12.95 ± 1.68 (R)–18.18 ± 2.02 mg/kg (U) for the bitter leaf samples. The mean range for Pb concentration in the soil and bitter leaf were 4.35 ± 0.87–6.80 ± 0.86 mg/kg and 0.24 ± 0.64–2.19 ± 0.74 mg/kg, while Cd concentration in the soil and bitter leaf were 0.46 ± 0.28–1.42 ± 0.40 mg/kg and 0.17 ± 0.22–0.42 ± 0.08 mg/kg, respectively. The respective mean ranges for Cr concentration in the soil and bitter leaf were 5.91 ± 1.14–8.77 ± 0.88 mg/kg and 4.04 ± 0.64–5.92 ± 0.69 mg/kg, while Ni in soil and bitter leaf were 0.54 ± 3.38–10.26 ± 3.50 mg/kg and 0.042 ± 1.42–3.30 ± 0.88 mg/kg, while Ag was negligible. Heavy metal levels in soils and Vernonia amygdalina followed the order Fe &gt; Cr &gt; Pb &gt; Ni &gt; Cd and Fe &gt; Cr &gt; Ni &gt; Pb &gt; Cd, respectively, and were lower than WHO/FAO and EPA, except Cd, which was higher in soil and in Vernonia amygdalina. The ecological risk factor (ErF) was comparatively lower in soils than in the plant, while pollution load index (PLI) showed high heavy metal retention capacities in Vernonia amygdalina due to more anthropogenic influences. The metal transfer factor (TF) was highest in Fe, followed by Cr &gt; Cd &gt; Ni &gt; Pb, while Pb had the highest chances of cancer risks from the incremental lifetime cancer risk (ILCR), especially in both soil and plant (mean ILCR, 2.07 × 10−2 and 2.45 × 10−3), while Cd had the least (mean ILCR, 9.64 × 10−5 and 3.36 × 10−5). Anthropogenic activities must be regulated and monitored by government relevant agencies to reduce heavy metal inputs into soils and avoid excessive accruals in food chain.