Heavy Metal Levels and Ecological Risk in Crude Oil-Contaminated Soils from Okpare-Olomu, Niger Delta, Nigeria

Crude oil spills have inflicted extensive disruption upon the Niger Delta ecosystem, resulting in crop loss and severe environmental damage. Such spills exacerbate heavy metal concentration within soil due to the presence of metallic ions. The Okpare-Olomu community has borne the brunt of crude oil pollution from illicit bunkering, sabotage, and equipment malfunction. This study targets an evaluation of ecological hazards linked to heavy metals (HMs) in crude oil impacted agriculturally soils within Okpare-Olomu in Ughelli South LGA of Delta State. In this study, 24 topsoil samples were obtained from areas affected by crude oil pollution;the heavy metal content was evaluated through atomic absorption spectrometry. The concentration ranges for HMs (mg/kg) in soil were: 24.1 - 23,174 (Cu);0.54 - 37.1 (Cd);9.05 - 54 (Cr);12 - 174 (Ni);18.5 - 8611 (Pb);and 148 - 9078 (Zn) at a soil depth of 0 - 15 cm. Notably, metal concentrations were recorded to be above permissible World Health Organization limits. Predominantly, Zn and Pb recorded higher heavy metal concentration when compared to other heavy metals analysed, notably at sampling points PT7 through PT24. Zinc and Pb contamination exhibited highly significant contamination factors, and contamination severity was evidenced across all sample points, signifying a grave risk level. Pollution load indices indicated pervasive extreme pollution levels. Geoaccumulation indices signaled moderate to strong pollution, mainly by Pb and Zn. Ecological risk assessments revealed variable levels of heavy metal contamination, from low to very high, with potential ecological risk reflecting markedly elevated levels. This study underscores the imperative for soil remediation to rectify ecological imbalances in agriculturally affected soil constituents.

Autism spectrum disorder:difficulties in diagnosis and microRNA biomarkers

We performed a PubMed search for microRNAs in autism spectrum disorder that could serve as diagnostic biomarkers in patients and selected 17 articles published from January 2008 to December 2023,of which 4 studies were performed with whole blood,4 with blood plasma,5 with blood serum,1 with serum neural cell adhesion molecule L1-captured extracellular vesicles,1 with blood cells,and 2 with peripheral blood mononuclear cells.Most of the studies involved children and the study cohorts were largely males.Many of the studies had performed microRNA sequencing or quantitative polymerase chain reaction assays to measure microRNA expression.Only five studies had used real-time polymerase chain reaction assay to validate microRNA expression in autism spectrum disorder subjects compared to controls.The microRNAs that were validated in these studies may be considered as potential candidate biomarkers for autism spectrum disorder and include miR-500a-5p,-197-5p,-424-5p,-664a-3p,-365a-3p,-619-5p,-664a-3p,-3135a,-328-3p,and-500a-5p in blood plasma and miR-151a-3p,-181b-5p,-320a,-328,-433,-489,-572,-663a,-101-3p,-106b-5p,-19b-3p,-195-5p,and-130a-3p in blood serum of children,and miR-15b-5p and-6126 in whole blood of adults.Several important limitations were identified in the studies reviewed,and need to be taken into account in future studies.Further studies are warranted with children and adults having different levels of autism spectrum disorder severity and consideration should be given to using animal models of autism spectrum disorder to investigate the effects of suppressing or overexpressing specific microRNAs as a novel therapy.

Comparative Study of the Efficacy of Metal Removal from Contaminated Aqueous Solutions by Solid Bidentate Ligands&Liquid Plant Materials

Heavy metal contaminated water sources pose serious health risks for humans,animals,and plants.Exposure to and ingestion of heavy metals have been associated to liver,kidney,and brain function.Objective:The aim of this research is to comparatively examine the metal removal efficacy of three solid bidentate chemicals and four plant materials.Study Design&Methods:Standard solutions of zinc(II)and lead(II)ions with concentrations of 1,000 ppm were respectively treated with OA(Oxalic Acid),dibasic bidentate ligands(sodium hydrogen phosphate and sodium carbonate).Then,the solutions were placed on a shaker for 15 h,centrifuged,and the supernatant was analyzed using ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectrometry).Results:All the solid bidentate adsorbents were very effective in removing zinc and lead(>90%).However,more lead than zinc was removed across all adsorbents except for lemon where equal percent of zinc and lead(49%)were removed.OA and Na2HPO4 removed about equal amount of lead(>99%).The plant materials(SP(Spinach),bell pepper and GBP(Green Bell Pepper)),respectively and preferentially removed more lead(98.9%,98.3%,81.5%)than zinc(91.7%,46%,46%).Conclusion:Although plant materials have gained attraction for the remediation of heavy metal,however,some bidentate chemical ligands such as OA,sodium carbonate and sodium hydrogen phosphates are even more effective in removing these metals from contaminated water.Furthermore,heavier metals are preferentially removed than lighter metals.

Effects of Using Softwood Pellet Biochar Prepared at Different Temperatures with Grass Chippings on Retention of Heavy Metals in Contaminated Soils

Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining, industrial activities, improper usage of fertilizers and pesticides, and indiscriminate open waste disposal bring about an increase in the presence of heavy metals in the environment. In the Keffi Metropolis, different elements lead to land contamination which debilitates soil quality, plant survival, human well-being, and the environment as a result of extensive dispersion or quantity of heavy metals in the soil and water. In recent years, biochar has emerged as a promising soil amendment for mitigating heavy metal pollution due to its unique physicochemical properties. This paper provides the effects of softwood pellet biochar on the retention of heavy metals in contaminated soils. A microcosm experiment was carried out to investigate the effects of biochar on the retention of heavy metals in contaminated soils. This research aimed to give an overview of the effects of softwood biochar at different temperatures (550˚C and 700˚C) on the retention of heavy metals and metalloids released from the soil during water inundation. The results show that the addition of organic matter (grass chippings) minimizes heavy metal mobilization. Also, biochar at high temperatures is more effective than those at low temperatures. The expected outcome of the research analysis includes providing insights into the role of biochar in retaining heavy metal contamination and further understanding the use of biochar as a sorbent for the management of contaminated soil.

Effect of amendments on growth and metal uptake of giant reed(Arundo donax L.) grown on soil contaminated by arsenic,cadmium and lead

The effects of five amendments such as acetic acid（AA）, citric acid （CA）, ethylenediamine tetraacetic acid （EDTA）, sepiolite and phosphogypsum on growth and metal uptake of giant reed （Arundo donax L.） grown on soil contaminated by arsenic （As）, cadmium （Cd） and lead （Pb） were studied. The results showed that the shoot biomass of giant reed was enhanced by 24.8% and 15.0%, while superoxide mutase and catalase activities slightly varied when adding 5.0 mmol/kg CA and 2.5 mol/kg EDTA to soil as compared to the control, respectively. The concentrations of As, Cd and Pb in shoots were remarkably increased by the addition of 2.5 mmol/kg AA and CA, 5.0 mmol/kg EDTA, and 4.0 g/kg sepiolite as compared to the control. The accumulations of As and Cd were also significantly enhanced in the above condition, while the shoot Pb accumulation was noticeably enhanced by amending with 4.0 g/kg sepiolite and 8.0 g/kg phosphogysum, respectively. The results suggested that AA, CA and sepiolite could be used as optimum soil amendments for giant reed remediation system.

In-situ Elimination Effect on Heavy Metals in Contaminated Soil from the Mining Area by Ramie

[Objective] The aim was to study on in-situ elimination effect on heavy metals in soil of the mining area by ramie （Boehmeria nivea （L.） Gaud.）. [Methods] Based on Xiangzhu No.3 and Zhongzhu No.1, we conducted research on heavy metals contents of plants growing in soil of Qibao Mountain orefield in Liuyang, Hunan Province, and on characteristics of enrichment and transfer of heavy metals （Cu, Pb, Cd, Zn） under influence of the two ramie species. [Result] It was concluded that trend of Cu content in different parts of ramie was as follows： rootskinleafbone; trend of Pb was rootleafskinbone; trend of Cd was rootskinboneleaf; the trend of Zn was rootskinboneleaf. In farmland A （with low content of heavy metal）, for per square meter of plough horizon, effect of Zhong 1 on heavy metals transferring volume and the period for restoration of the soil into national standard one （Category Ⅲ of Environmental Quality Standard for Soil） have been concluded. Specifically, for Cu, the corresponding values were 3 404.44 mg and 8.59 y, respectively; for Pb, the values were 3 638.5 mg and 13.52 y; for Cd, the values were 720.48 mg and 1.49 y; for Zn, the values were 37 324.8 mg and 0.67 y. [Conclusion] Soil contaminated by Cu, Pb, Cd, and Zn in orefield can be rapidly restored by growing ramie.

Effects of Red Mud on the Remediation of Pb, Zn and Cd in Heavy Metal Contaminated Paddy Soil

[Objective] To study the remediation efficiency of red mud on Pb, Zn and Cd in the heavy metal contaminated paddy soil of mine area, to clarify its remediation mechanism and fertilizer efficiency on heavy metal contaminated soil. [Method] The soil incubation experiment was conducted to study the effect of red mud on the pH values and electrical conductivity （EC）, and the remediation efficiency of red mud on lead （Pb）, zinc （Zn） and cadmium （Cd） in heavy metal contaminated soil. [Result] Red mud addition reduced the content of exchangeable Pb, Zn and Cd in the soil significantly. Compared with the control, when incubated for 30, 60 and 90 d with the red mud dosage of 4% （W/W）, the exchangeable Pb content was decreased by 39.25%, 41.38% and 50.19%; exchangeable Zn content was decreased by 49.26%, 57.32% and 47.16%; and exchangeable Cd content was decreased by 19.53%, 24.06% and 25.70%, respectively. The application of red mud had significant impact on the share of Pb, Zn and Cd contents in five forms, and different amounts of red mud application all reduced the proportion of exchangeable Pb, Zn and Cd to the total Pb, Zn and Cd. In addition, the proportion of exchangeable Pb, Zn and Cd to total Pb, Zn and Cd decreased with the increasing amount of red mud addition. [Conclusion] The study provided references for reasonable application of red mud and reduction of heavy metal pollution in paddy soil.

Study Progress in Remediation of Soil Contaminated by Heavy Metals and Its Application Prospect

Flax is an ideal crop for remedying soil contaminated by heavy metals. It has high tolerance to heavy metals and strong adsorption to heavy metals. Through properly using or adjusting external conditions such as regulator, moisture, fertilizer, microorganisms, and pH value, it is able to improve ability of flax to absorb, trans- fer, and accumulate heavy metals. To improve the ability of flax in remediating heavy metal contaminated soil, it is recommended to strengthen cultivation of flax varieties and screening of germplasm resources, actively carry out studies on tech- nologies of fax remedying heavy metal contaminated soil, implement large-scale and mechanized planting of flax, and promote control of heavy metal contaminated soil.

Remediation of in-situ Leach Mining Contaminated Soil by Amendment-plant Synergism

This study aimed to remediate in-situ leach mining contaminated soil by amendment-plant synergism. The results showed that plant species exhibited ex-tremely significant effects on the concentration of nitrate nitrogen; to be specific, the concentration of nitrate nitrogen in soil planted with wheat was reduced from 692.19 mg/kg to lower than 100 mg/kg; when the mass ratio of amendment to soil reached 3：50 and the amendment particle size was 1-2 mm, the concentration of nitrate ni-trogen in soil planted with wheat was reduced to 43 mg/kg. The amendment type exhibited extremely significant effects on the concentration of ammonium nitrogen; to be specific, when the mass ratio of amendment to soil reached 10：50, the concen-tration of ammonium nitrogen in soil added with 2-3 mm zeolite was reduced from 23 593.75 to 3 300 mg/kg on day 15. Amendments and plants mainly exhibited desorption performance for sulfate radical in soil, and the amendment type extreme-ly significantly affected the concentration of sulfate radical; to be specific, the con-centration of sulfate radical in soil added with limestone increased from 370 mg/kg to 900 mg/kg on day 7.

Mechanical properties of anti-seepage grouting materials for heavy metal contaminated soil

Cement-based composite grouting materials were used to construct grouting cutoff wall for heavy metal contaminated soil in non-ferrous metal mining areas. Cement, fly ash, and slag as principal ingredients were mixed with water glass in different ways to produce three composite grouting materials. In order to investigate the effect of water glass mixing ratio, Baume degree, fly ash and slag contents on the mechanical properties of the composite grouting materials, particularly their gel time and compressive strength, the beaker-to-beaker method of gel time test and unconfined compressive strength test were conducted. In addition, the phase composition and microstructure of the composite grouting materials were analyzed by the X-ray diffraction（XRD） and scanning electron microscope（SEM） techniques. The test results show that their gel time increases when water glass mixing ratio and Baume degree increase. The gel time increases dramatically when fly ash is added, but decreases slightly if fly ash is partly replaced by slag. When the mixing ratio of water glass is below 20%, their compressive strength increases with the increases of the ratio; when the ratio is above 20%, it significantly decreases. The compressive strength also tends to increase as Baume degree increases, and improves if fly ash and slag are added.

血清SDC4、sOX40L水平与糖尿病肾病患者病情严重程度及预后的关系

目的分析血清SDC4、sOX40L水平与糖尿病肾病(DN)患者病情严重程度及预后的关系。方法以青岛市市立医院2019年5月—2021年11月收治的172例糖尿病患者为研究对象,其中DN患者84例(DN组),无肾病患者88例(单纯糖尿病组),另选取同期在我院体检的80例健康人群为对照组。比较三组血清SDC4、sOX40L水平;分析血清SDC4、sOX40L水平与DN患者临床指标的关系;Spearman相关性分析DN患者血清SDC4、sOX40L水平与肾脏病理损伤程度的关系;根据是否出现死亡或发展为终末期肾病(ESRD)将DN患者分为预后良好组和预后不良组,Logistic回归分析DN患者预后的影响因素。结果与对照组相比,糖尿病患者血清SDC4、sOX40L水平均显著升高(P<0.05),且DN组患者血清SDC4、sOX40L水平显著高于单纯糖尿病组(P<0.05);DN组患者血清SDC4、sOX40L水平与糖尿病病程、空腹血糖(FBG)、24 h尿蛋白定量、糖化血红蛋白(HbA_(1)c)、肾小球滤过率(eGFR)、血肌酐均相关(P<0.05),而与DN患者年龄、性别、BMI无关(P>0.05);DN组患者血清SDC4、sOX40L水平与肾小球分级、小管萎缩(IFTA)评分、间质炎症均相关(P<0.05),且随着肾脏损伤程度的加深,血清SDC4、sOX40L水平逐渐升高(P<0.05);Spearman相关性分析表明,DN组患者血清SDC4、sOX40L水平与肾小球分级、IFTA评分、间质炎症均呈显著正相关(P<0.05);预后不良组患者血清SDC4、sOX40L水平均显著高于预后良好组患者(P<0.05);Logistic回归分析结果表明,糖尿病病程、FBG、24 h尿蛋白定量、HbA1c、eGFR、血肌酐、SDC4、sOX40L是影响DN患者预后不良的独立危险因素(P<0.05)。结论DN患者血清SDC4、sOX40L表达水平与肾脏损伤程度及预后均具有相关性,血清SDC4、sOX40L表达水平越高,DN患者病情越严重,预后越差。

Study on the Remediation of Cd-contaminated Soil

[Objective] The remediation effect of the plant to Cd-contaminated soil was studied. [Method] By taking simulation test and field test, the ryegrass （Lolium perenne L.） was planted, and the remediation effect of the plant to contaminated sites was studied. [Result] The ryegrass was planted in the eluotropic soil for 0-60 d, Cd content in the soil showed a rapid decreasing trend; after 60 d, the enrich- ment ability of the plant to Cd gradually weakened over time; after 75 d of phytore- mediation, the Cd content in the soil decreased greatly, and the remediation effi- ciency was 90.66%. [Conclusion] Ryegrass remediation technology had good reme- diation effect to Cd-contaminated soil.

手机直连NGSO卫星业务中扩展L频段频率协调方案研究

在目前非对地静止轨道(NGSO)卫星移动业务用频越来越紧张的趋势下,针对手机直连NGSO卫星业务频率协调工作复杂的问题,首先对手机直连NGSO卫星系统的用频现状及趋势进行分析,其次重点对手机直连NGSO卫星业务在扩展L频段和其他同频空间业务的频率协调方案进行分析和研究。通过分析手机直连NGSO卫星业务在扩展L频段的频率协调态势确定需要与之开展频率协调工作的空间业务,基于和每一项空间业务的频率协调方案进行研究并给出协调方案建议,同时还对具体协调方案中涉及的干扰分析计算进行举例。以上研究均可作为手机直连NGSO卫星业务系统开展同频频率协调相关研究及下一步手机直连NGSO卫星关键技术研究等相关工作的参考。

线性Poisson-Boltzmann方程的虚单元L^(2)误差估计

针对一类线性Poisson-Boltzmann方程的虚单元L^(2)误差估计进行分析.首先引入正则化的线性Poisson-Boltzmann方程,将原问题转化为非奇性Poisson-Boltzmann方程.然后给出L^(2)范数的误差估计.最后在四边形和五边形混合多边形网格上进行数值实验,数值结果验证了理论分析的正确性.

Potential of weed species applied to remediation of soils contaminated with heavy metals

To screen out a series of ideal plants that can effectively remedy contaminated soils by heavy metals is the main groundwork of phytoremediation engineering and the first step of its commercial application on a large scale. In this study, accumulation and endurance of 45 weed species in 16 families from an agricultural site were in situ examined by using the pot-culture field experiment, and the remediation potential of some weed species with high accumulation of heavy metals was assayed. The results showed that Solanum nigrum and Conyza canadensis can not only accumulate high concentration of Cd, but also strongly endure to single Cd and Cd-Pb-Cu-Zn combined pollution. Thus 2 weed species can be regarded as good hyperaccumulators for the remediation of Cd-contaminated soils. Although there were high Cd-accumulation in Artemigia selengensis, Znula britannica and Cephalanoplos setosum, their biomass was adversely affected due to action of heavy metals in the soils. If the problem of low endurance to heavy metals can be solved by a reinforcer, 3 weed species can be perhaps applied commercially.

Removal of heavy metals from a contaminated soilusing tartaric acid

This study reports the feasibility of remediation of a heavy metal （HM） contaminated soil using tartaric acid, an environmentally-friendly extractant. Batch experiments were performed to test the factors influencing remediation of the HM contaminated soil. An empirical model was employed to describe the kinetics of riM dissolution/desorption and to predict equilibrium concentrations of HMs in soil leachate. The changes of HMs in different fractions before and after tartaric acid treatment were also investigated. Tartaric acid solution containing HMs was regenerated by chestnut shells. Results show that utilization of tartaric acid was effective for removal of riMs from the contaminated soil, attaining 50%-60% of Cd, 40%-50% of Pb, 40%-50% of Cu and 20%-30% of Zn in the pH range of 3.5-4.0 within 24 h. Mass transfer coefficients for cadmium （Cd） and lead （Pb） were much higher than those for copper （Cu） and zinc （Zn）. Sequential fractionations of treated and untreated soil samples showed that tartaric acid was effective in removing the exchangeable, carbonate fractions of Cd, Zn and Cu from the contaminated soil. The contents of Pb and Cu in Fe-Mn oxide fraciton were also significantly decreased by tartaric acid treatment. One hundred milliliters of tartaric acid solution containing HMs could be regenerated by 10 g chestnut shells in a batch reactor. Such a remediation procedure indicated that tartaric acid is a promising agent for remediation of HM contaminated soils. However, further research is needed before the method can be practically used for in situ remediation of contaminated sites.

Microbial changes in rhizospheric soils contaminated with petroleum hydrocarbons after bioremediation

Effects of bioremediation on microbial communities in soils contaminated with petroleum hydrocarbons are a scientific problem to be solved. Changes in dominate microbial species and the total amount of microorganisms including bacteria and fungi in rhizospheric soils after bioremediation were thus evaluated using field bioremediation experiments. The results showed that there were changed dominant microorganisms including 11 bacterial strains which are mostly Gram positive bacteria and 6 fungal species which were identified. The total amount of microorganisms including bacteria and fungi increased after bioremediation of microbial agents combined with planting maize. On the contrary, fungi in rhizospheric soils were inhibited by adding microbial agents combined with planting soybean.

Effects of field application of phosphate fertilizers on the availability and uptake of lead, zinc and cadmium by cabbage (Brassica chinensis L.) in a mining tailing contaminated soil

A field trial was conducted to evaluate the reduction of bioavailability of heavy metals including lead (Pb), zinc (Zn) and cadmium (Cd) in a soil contaminated by mining tailings in Shaoxing, Zhejiang, China. Three commercial phosphate (P) fertilizers including phosphate rock (PR), calcium magnesium phosphate (CMP), and single superphosphate (SSP) were applied to the plot at three P application rates, 50, 300, and 500 g/m2 with 9 treatments and control (CK). Plants, water soluble and exchangeable (WE) extra...

Characterization of recuperating talent of white-rot fungi cells to dye-contaminated soil/water

This study was purposed to explore the decolorization of dyes by fungi on either a soil or in a liquid medium and to determine the application through batch shaking system. Two commercial dyes were decolorized and studied with four fungal strains in three media. Fungal growth is the best in malt extract/glucose medium for all organisms. Decolorization of reactive blue 220 and methyl red was investigated in soil medium by Trametes versicolor. These dyes were removed 91% and 80% for methyl red and reactive blue 220 respectively(dye concentration; 100 mg·L^(-1)) by both organisms. Enzymatic activities were monitored. Laccase(Lac) and manganese peroxidase(Mn P) were detected. MnP enzyme had important role for the dye decolorization. This study demonstrates that it is possible to decolorize some synthetic dyes, which would be highly advanced for dye containing wastewater and soil. These applications could be used for dye bioremediation.

Phytoremediation Mechanisms of Heavy Metal Contaminated Soils: A Review

Phytoremediation is a green emerging technology used to remove pollutants from environment components. Mechanisms used to remediate soils contaminated by heavy metal are: phytoextraction, phytostabilisation, phytovolatilization and rhizofiltration. The two first mechanisms are the most reliable. Many factors influence the choice of the suitable phytoremediation strategy for soil decontamination. It depends on soil properties, heavy metal levels and characteristics, plant species and climatic conditions. The present review discusses factors affecting heavy metals uptake by plant species, the different phytoremediation strategies of heavy metal contaminated soils and the advantages and disadvantages of phytoremediation and each of its mechanisms.