Carcinogenic Heavy Metals Research Articles

Characteristics and Health Risk Assessment of Heavy Metals in PM2.5 Under Winter Haze Conditions in Central China: A Case Study of Huanggang, Hubei Province

To explore the pollution characteristics and potential health risks of heavy metals in PM2.5 on haze days in Central China, PM2.5 samples were collected from the Huanggang monitoring station, a regional observation point in Central China, between January 13 and 24, 2018. The contents of Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Sn, and Pb in PM2.5 were analyzed by inductively coupled plasma mass spectrometry(ICP-MS), and the enrichment factor method was used to determine the potential risk based on the exposure model recommended by the Environmental Protection Administration(EPA). The results showed that during the observation period, the concentrations of Zn in PM2.5 were highest, and the concentrations of the carcinogens As and Cd were higher than the secondary standard limits of China's ambient air quality standard(GB 3095-2012), with 70% of these elemental concentrations accounting for the largest proportion in the middle haze period. The enrichment factor analysis showed that Cd, Sn, Co, Pb, and Zn were the most abundant elements, especially during the middle haze period, and were mostly derived from transportation and coal combustion. The results of the human health risk assessment showed that exposure via hand-mouth feeding was the main non-carcinogenic risk, and the exposure and non-carcinogenic risks of children were significantly higher than those of adults. Pb poses a non-carcinogenic risk to children, while heavy metals in PM2.5 pose no non-carcinogenic risks to adults and carcinogenic heavy metals pose no carcinogenic risks.

Evaluation of Health Risk from Concentrations of Heavy Metal in PM-10 and PM-2.5 particles at Sasang Industrial Complex of Busan, Korea

We investigated the distribution of hazardous heavy metals (As, Cr6+, Ni, Cd, Pb, and Mn) and estimated the health risk related to the heavy metals in fine dust (PM-10 and PM-2.5) of Sasang industrial complex, Busan, Korea. The concentration of fine dust in the industrial complex was 1.2 times higher than in a residential area, while harmful heavy metals showed a difference of at least 1.3 times (Cd) and up to 6.5 times (Ni). The concentration of fine dust and carcinogenic heavy metals in the industrial complex increased significantly compared to the residential area in spring (March to May) and winter (December to February) months. A risk assessment was performed using Monte-Carlo simulations containing a four-step procedure. During hazard identification, As, Cr6+ Ni, Cd, and Pb were categorized as human carcinogens and probable human carcinogens and evaluated for their levels of excess cancer risk. For concentrations of over 90% Cr6+ and As, the excess cancer risk was over 10-5 (1 person per 100,000). The non-cancer hazard index of As, Cr6+, Cd, and Mn was below the limit value of 1.

Applications of chromatography in giant complex drug-organism system

色谱是一门以分离分析为主,旨在追求复杂事物纯而净的分析化学的重要分支学科。其经过百余年的发展,理论与技术日臻完善,集科学、技术与艺术于一体。近年来,色谱及其与质谱、核磁共振波谱、原子发射光谱等联用技术极大推动了环境、食品、石油化工、生物医药等领域中所涉及复杂体系的研究进展。作为我国传统文化的核心代表,中医药为中国乃至世界人民的健康服务逾千年,从古至今历经上千年临床考验,疗效经久不衰。近年来,中国政府强调继承与创新,加大推进中医药的现代化与国际化。然而中药自身的多成分协同起效复杂性及其与机体时刻新陈代谢变化的复杂性往往相互作用,由此形成了药物-机体复杂巨系统。该复杂巨系统的分析研究是中医药现代化进程的关键瓶颈。色谱的优势在于复杂成分的分离与分析,此恰能为上述复杂巨系统提供技术支撑,色谱及其联用技术已成为推动中医药分子化、数字化、信息化乃至现代化的主流技术。该文综述了色谱及其联用技术在中药复杂体系、复杂生命过程及药物-机体复杂巨系统中的应用进展,介绍了笔者研究团队对中医药现代化的认识、研究思路和研究工作,最后笔者结合对于百年色谱与千年中医药文化之现代化交织的感悟,对色谱技术在此领域的前景做出了展望。

Reusable Polyacrylonitrile‐Sulfur Extractor of Heavy Metal Ions from Wastewater

AbstractMercury, lead, and cadmium are among the most toxic and carcinogenic heavy metal ions (HMIs), posing serious threats to the sustainability of aquatic ecosystems and public health. There is an urgent need to remove these ions from water by a cheap but green process. Traditional methods have insufficient removal efficiency and reusability. Structurally robust, large surface‐area adsorbents functionalized with high‐selectivity affinity to HMIs are attractive filter materials. Here, an adsorbent prepared by vulcanization of polyacrylonitrile (PAN), a nitrogen‐rich polymer, is reported, giving rise to PAN‐S nanoparticles with cyclic π‐conjugated backbone and electronic conductivity. PAN‐S can be coated on ultra‐robust melamine (ML) foam by simple dipping and drying. In agreement with hard/soft acid/base theory, N‐ and S‐containing soft Lewis bases have strong binding to Hg2+, Pb2+, Cu2+, and Cd2+, with extraordinary capture efficiency and performance stability. Furthermore, the used filters, when collected and electrochemically biased in a recycling bath, can release the HMIs into the bath and electrodeposit on the counter‐electrode as metallic Hg0, Pb0, Cu0, and Cd0, and the PAN‐S@ML filter can then be reused at least 6 times as new. The electronically conductive PAN‐S@ML filter can be fabricated cheaply and holds promise for scale‐up applications.

ALKBH5 promotes cadmium-induced transformation of human bronchial epithelial cells by regulating PTEN expression in an m6A-dependent manner

Cadmium is a carcinogenic heavy metal that poses a severe threat to human beings. The underlying mechanism, however, remains elusive. N6-methyladenosine (m6A) is the most abundant post-transcriptional modification in mRNA that regulates RNA metabolism. Emerging evidence shows that m6A is involved in the pathogenesis of various cancers. In this study, human bronchial epithelial BEAS-2B cells were transformed by exposing to 2 μM of cadmium for 20 weeks to investigate the role of m6A in cadmium carcinogenesis. We found the level of m6A in mRNA was significantly decreased in cadmium-transformed BEAS-2B cells, and this change was regulated by m6A demethylase ALKBH5. ALKBH5 was significantly upregulated in the middle and late stages of cell transformation at week 8, 12, 16 and 20. Knockdown of ALKBH5 in cadmium-transformed cells alleviated cell proliferation, migration, invasion, and anchorage-independent growth, but co-transfection with ALKBH5 siRNA and PTEN siRNA restored the inhibitory effects of ALKBH5 knockdown on those transformation properties. ALKBH5 decreased the m6A level of PTEN mRNA, resulting in its instability and reduction of PTEN protein expression. These results indicate that ALKBH5-mediated demethylation m6A at PTEN mRNA is involved in cadmium-induced cell transformation. Our study provides a new perspective for the involvement of m6A modification in cadmium carcinogenesis.

Environmental Cadmium Exposure and Odds of Residing in a Breast Cancer Hotspot in Kentucky

BACKGROUND AND AIM: Breast cancer is the most common invasive cancer diagnosed in US women. Cadmium is a carcinogenic heavy metal pollutant found in cigarettes and as an agricultural and industrial byproduct. Studies of cadmium exposure and breast cancer risk have produced mixed results depending upon methodology. We examined environmental cadmium exposure and risk of residing in a breast cancer hotspot in Kentucky. METHODS: Invasive breast cancer cases diagnosed between 1995-2018 were identified from the Kentucky Cancer Registry (n=66,413) and 68 of the 1,114 KY census-tracts were identified as breast cancer clusters using Getis-Ord Gi* for age-standardized rates. Census-tract cadmium concentrations from the 2014 National Air Toxics Assessment interpolated estimations were linked to cases’ residential addresses. Logistic regression was performed to assess the odds of residing in a hotspot across quartiles of cadmium exposure adjusted for individual-level (demographic, reproductive factors, Appalachian residence, insurance, tobacco use) and neighborhood factors (population density, poverty, and physical inactivity). Effect modification by smoking was assessed. RESULTS:4,134 women with breast cancer resided in hotspots (6.2%), which were located in major cities and southeast Kentucky. The mean age was 61 years. Hotspot cases were more likely than other cases to be black, single, uninsured or have public insurance, live in Appalachia, and reside in more densely populated neighborhoods with greater poverty. The odds of living in a hotspot were 4.2-times higher for those who resided in areas with the highest quartile of cadmium exposure compared to those in the lowest (95% CI: 3.6, 4.8; p-trend 0.0001). Results were similar (Q4 vs Q1: OR=4.4 95% CI 3.6, 5.4) among non-smokers. CONCLUSIONS:The observed associations of environmental cadmium exposure and residing in breast cancer hotspots in Kentucky warrant further research with more appropriate epidemiologic study designs. KEYWORDS: heavy metals, cancer and cancer precursors, environmental epidemiology, female, hotspot, air pollution

Cadmium exposure promotes activation of cerebrum and cerebellum ferroptosis and necrosis in swine

Cadmium(Cd) is a toxic and carcinogenic heavy metal pollutant leading to serious damage in various organs. Ferroptosis and necrosis as inflammation-related cell death are involved in several diseases of nervous system. In the present study, 10 weaning piglets with similar weight for 6 weeks were randomly divided into two groups. The daily grain containing 0 mg and 20 mg/kg of Cd chloride was fed in 20–26 ℃ environment, animals were sacrificed to collect cerebrum and cerebellum tissues after 40 days. Morphology and ultrastructure results were observed using HE and TEM. Moreover, molecular biological technologies western blot and qRT-PCR were used to detect the expression abundance of genes. Cerebrum and cerebellum injury was observed in Cd-exposed group, antioxidant capacity decreased significantly and oxidative stress increased; immunofluorescence, real-time quantification, and western blot results showed decreased necrosis genes and increased ferroptosis pathway genes abundance in cerebrum, whereas the results were reversed in cerebellum. These results indicated that Cd exposure can activated necrosis and ferroptosis pathways by increased oxidative stress, further resulting in cerebrum and cerebellum damage in pigs. These findings may provide a theoretical basis for early monitoring of Cd exposure in environment.

Targeting Cd coping mechanisms for stress tolerance in Brassica napus under spiked-substrate system: from physiology to remediation perspective

Cadmium (Cd) is a prevalent, non-essential, carcinogenic, and hazardous heavy metal that reduces plant productivity and capacity of arable land area around the globe. In the present substrate-based pot study, seedlings of Brassica napus 180015 were grown equidistantly in the spiked-substrate medium for 60 days under increasing concentrations of Cd (0, 10, 20, 30, 40, 50 mg kg−1). Following harvest, the morpho-physio-biochemical, antioxidative, and Cd-induced tolerance responses were evaluated in B. napus under an increasing Cd stress regime. Additionally, these parameters were also investigated to select the plant's threshold tolerance limit for Cd under the spiked-substrate system. B. napus showed dynamic behavior regarding morpho-physio-biochemical attributes, including agronomic features, biomass, photosynthetic pigments, relative water content under increased Cd toxicity. Cd stress-induced hydrogen peroxide (H2O2) production with high MDA contents and passive EL, followed by the orchestration of both enzymatic (SOD, POD, APX, CAT, and GR) and non-enzymatic antioxidants (flavonoids, TPC, TPA, proline, and total soluble protein) up to a certain limit. In addition, Cd-induced stress upregulated transcriptional levels of antioxidative enzyme SOD, POD, APX, GR, and MT encoded genes in B. napus. The increasing trend of Cd accumulation in different tissues at the highest Cd concentration was as follows: root > leaf > stem. In spiked substrate system, B. napus demonstrated improved metal extractability performance and a high potential for phyto-management of low to moderate Cd contamination, implying that this study could be used for integrative breeding programs and decontaminating heavy metals in real contaminated scenarios. Novelty statement This study provides an insight into Cd-coping mechanisms of oilseed rape involved in alleviating toxicity and simultaneous phyto-management of increasing Cd concentration under spiked substrate system. The current study is the first scientific evidence of using a Cd-spiked soilless substrate medium. The present study will further strengthen our understanding of Cd-instigated positive responses in B. napus. Furthermore, it will provide a useful basis for integrative breeding programs and decontaminating heavy metals in real contaminated scenarios.

Construction of three-dimensional MgIn2S4 nanoflowers/two-dimensional oxygen-doped g-C3N4 nanosheets direct Z-scheme heterojunctions for efficient Cr(VI) reduction: Insight into the role of superoxide radicals

Environmental crisis aroused from carcinogenic and mutagenic heavy metal Cr(VI)-containing wastewater has attracted great attention. Herein, a direct Z-scheme three-dimensional MgIn2S4 nanoflowers/two-dimensional oxygen-doped g-C3N4 nanosheets heterostructured composite photocatalysts were fabricated for Cr(VI) photoreduction. The crystalline structure, morphology, specific surface areas, chemical components, optical properties, as well as photoelectrochemical performance of the fabricated photocatalyst were systematically studied. All the hybrids photocatalysts exhibited superior Cr(VI) photoreduction performance than a single component. The optimal sample showed 2.0 and 343.7 times increasing than three-dimensional MgIn2S4 nanoflowers and two-dimensional oxygen-doped g-C3N4 nanosheets, respectively. The enhancement of the Cr(VI) photoreduction performance could be ascribed to the enhanced specific surface areas, the improved light absorption, and the Z-scheme charge carriers’ separation and migration pathway. Moreover, the role of superoxide radicals was investigated. It is speculated that this research would present a new sight toward photocatalytic Cr(VI) reduction.

Detection of Hexavalent Chromium Concentration in Aqueous Solution Using Lab Developed Colorimeter

The detection of hazardous carcinogenic heavy metals in aqueous solutions is important for biological health and environmental protection. There are various techniques to ascertain these oncogenic chemicals in an aqueous solution, like a potentiometric electrochemical sensor, spectrophotometer sensor, colorimeter sensor, and chemical sensors. As compared to other available methods, the colorimeter sensor has advantages such as low-cost instrument, qualitative sample detection, and higher precision. In this paper, the colorimeter is developed in the lab to detect hexavalent chromium [Cr (VI)] in the aqueous solution. Moreover, the absorbance principle is used to calibrate and measure the known sample concentration using amplified optical power light-emitting diodes (OP-LED). The estimation of Cr (VI) concentration in an aqueous solution is evaluated and programmed in a low-cost Arduino UNO development board. The concentration value is displayed on the touch screen. The readings displayed on the lab developed instrument annotates that the concentration percentage of the known sample can be used to determine the unknown concentration. The concentration of the known solution is determined and compared with commercially available colorimeters concerning the lab-developed colorimeter.

Removal of Hazardous Materials from Residential and Commercial Liquid Waste Using Solid Sorbents

Among various pollutants, wastewater consists of toxic or carcinogenic heavy metals such as lead (Pb), zinc (Zn), and copper (Cu). In this study, the contamination of heavy metals in residential (Domestic) and commercial (Car-wash centre) effluents from urban area of Quetta has been investigated using atomic absorption spectroscopy. The collected liquid effluent was passed through sorbents in vertical flow. The combined batch of Fly ash and Sawdust (adsorbents) showed high sorption capacity 0.0000424 mg·g -1 for lead (residential liquid waste) and 0.0000012 mg·g -1 for Cu (commercial liquid waste). The moderate partition coefficients were 0.001247 (Pb) and 0.000005 (Cu) mol·kg -1 ·Pa -1 for residential and commercial waste respectively. The highest removal efficiency of lead (99.763%) for residential effluent showed the breakthrough at 0.002. Thus, the sorbents used have significantly removal efficiency for Pb, moderate for Zn, and low for Cu. The effluent passed from designed filter media may be greatly effective for washing, cleaning and irrigation purpose.

Removal of Hazardous Materials from Residential and Commercial Liquid Waste Using Solid Sorbents

Among various pollutants, wastewater consists of toxic or carcinogenic heavy metals such as lead (Pb), zinc (Zn), and copper (Cu). In this study, the contamination of heavy metals in residential (Domestic) and commercial (Car-wash centre) effluents from urban area of Quetta has been investigated using atomic absorption spectroscopy. The collected liquid effluent was passed through sorbents in vertical flow. The combined batch of Fly ash and Sawdust (adsorbents) showed high sorption capacity 0.0000424 mg·g -1 for lead (residential liquid waste) and 0.0000012 mg·g -1 for Cu (commercial liquid waste). The moderate partition coefficients were 0.001247 (Pb) and 0.000005 (Cu) mol·kg -1 ·Pa -1 for residential and commercial waste respectively. The highest removal efficiency of lead (99.763%) for residential effluent showed the breakthrough at 0.002. Thus, the sorbents used have significantly removal efficiency for Pb, moderate for Zn, and low for Cu. The effluent passed from designed filter media may be greatly effective for washing, cleaning and irrigation purpose.

Health Risks and Source Analysis of Heavy Metal Pollution from Dust in Tianshui, China

The purpose of this study is to explore the degree and spatial distribution of dust heavy metal pollution in Tianshui City, the health risks, and the sources of heavy metals. The geoaccumulation index and health risk assessment are used to study pollution levels and human health risks, and Cu, Zn, and Pb pollution are found to be serious. The total exposure of children to dust and heavy metals is 8.329 × 10−3 mg·kg−1·d−1, which is 4.66 times that of adults. The effect of carcinogenic heavy metal exposure is more significant for adults than for children. The total non-carcinogenic risk quotient to children via multiple pathways is 2.1690, which is higher than that of adults. Children’s Pb non-carcinogenic risk quotient is 4.79 times that of adults, and children are more sensitive than adults to the health risks of Pb pollution. The GeoDetector and Unmix 6.0 models are used for source analysis, revealing that Zn, Pb, and As pollution originate primarily from urban transportation systems, V is sourced from soil-forming parent materials, and Mn, Ni, Cu, and Co arise from mixed sources. Therefore, the treatment of heavy metal pollution in cities needs to focus more on the urban transportation system.

The impact of vaping on ocular health: a literature review.

Vaping, or the use of electronic cigarettes, was initially introduced as a step toward smoking cessation, but has become an increasingly popular option for smokers. Though advertised as safer than conventional cigarettes, these devices have been found to contain carcinogenic chemicals, air pollutants, and heavy metals. The purpose of this article is to shed light on the known effects of vaping on the ocular setting and raise the discussion about additional potential effects that may call for further investigation. A comprehensive literature search was conducted for publications pertaining to the effects of vaping on the eye. Relevant studies and findings were summarized in this article. It was found that aldehydes and free radicals present in electronic cigarettes may induce a disturbance in tear film stability, and vape flavorings may damage the lipid layer through peroxidation. Corneal staining has been shown to appear following exposure to e-cigarette vapor, with nicotine and acrolein potentially inducing an inflammatory response in corneal epithelial cells. In addition, nicotine has been shown to induce nystagmus, exert vasoconstrictive effects on ocular blood flow, and may interfere with retinal light-adapted vision. Vape-related explosions, though unpredictable, may also result in decreased visual acuity along with long-term ocular trauma. Research discussing both the short-term and long-term effects of vaping on the eye is limited. However, the potential harms of substances such as nicotine and aldehydes warrant additional investigation and increased education about the detriment that electronic cigarettes may inflict on sensitive organs.

Pollution Characteristics and Health Risk Assessment of Heavy Metals in the Water of Lijiang River Basin

In order to clarify the pollution levels of heavy metals in the drinking water sources of the Lijiang River Basin, surface water samples were collected from 62 sites throughout the Lijiang River during May 2019. Heavy metals, including As, Cd, Cr, Mn, Cu, Zn, Hg, Co, and Sb, in the water samples were analysed. Health risk assessments associated with these nine heavy metals were conducted using the health risk assessment model from the US EPA. The results indicated that the order of the average concentrations of heavy metals in the water samples were Mn > Zn > As > Cr > Cu > Sb > Co > Cd > Hg. No heavy metals exceeded the limit values of the drinking water health standards in China (GB 5749-2006), and the concentrations were lower than the limitations of Grade Ⅰ level in the environmental quality standards for surface water (GB 3838-2002). According to the spatial distribution, the high contents areas of As, Cr, Zn, and Sb were predominantly distributed downstream of the Lijiang River, while the high contents areas of Cd, Cu, Hg, Co, and Mn were mostly distributed in the upper reaches. Multivariate analysis indicated that Cd, Mn, Cu, and Co were primarily from agricultural production; Cr, Zn, and Sb were mainly from tourism transportation; As was predominantly from the weathering of rock parent material and soil erosion; Hg was mainly from the improper disposal of domestic garbage and atmospheric deposition. The results of the health risk assessment indicated that children were more susceptible to the threat of heavy metal pollution than adults, and the average annual risk of carcinogenic heavy metals to human health through drinking water ingestion were higher than those of non-carcinogenic metals. The maximum personal average annual health risk of Cr was higher than the maximum allowance levels recommended by the International Commission on Radiological Protection (5×10-5 a-1). The average annual risk of non-carcinogenic heavy metals (10-14-10-9 a-1) decreased in the order of Co > Cu > Hg > Zn > Sb > Mn, which were far below the maximum allowance levels recommended by the ICRP.

A dual responsive probe based on bromo substituted salicylhydrazone moiety for the colorimetric detection of Cd2+ ions and fluorometric detection of F‒ ions: Applications in live cell imaging

A dual responsive probe based on bromo substituted salicylhydrazone moiety for the colorimetric detection of Cd2+ ions and fluorometric detection of F‒ ions: Applications in live cell imaging

Enhancement of chromate bioaccumulation by engineered Escherichia coli cells co‐expressing chromate reductase (YieF) and a rice metallothionein isoform (OsMT1)

AbstractBACKGROUNDHexavalent chromium Cr(VI) is a toxic and carcinogenic heavy metal. It is highly water soluble and one of the most widely used metals in industry, resulting in soil and water contamination. Nowadays engineering microbes provide new strategies for remediation of heavy metals.RESULTSIn the present work, a gene encoding E. coli chromate reductase (YieF) was cloned in pCDF‐1b and was transferred to both cells containing empty pET41a (control strain), and cells containing pET41a‐OsMT1 (R‐MT1) resulted in production of new strains R‐YieF and R‐YieF/MT1, respectively. Both proteins – YieF as His‐tag fusion protein and OsMT1 as glutathione‐S‐transferase fusion protein – appeared in the soluble fraction of R‐YieF/MT1 after induction with isopropyl‐d‐1‐thiogalactopyranoside . The strain R‐YieF/OsMT1 showed high tolerance to Cr6+ and accumulated significantly higher Cr6+ than R‐MT1 (5 mg L−1), R‐YieF (7 mg L−1) and control (2 mg L−1). The accumulation of Cr6+ was dependent on the initial concentration of Cr6+ in the medium, time and the presence of other toxic metals such as Ag+1, Hg+2 and Cd2+.CONCLUSIONThis study demonstrated that the co‐expression of YieF and OsMT1 could effectively enhance the accumulation of Cr(VI) by E. coli cells and opens new insights into bioremediation strategies. © 2020 Society of Chemical Industry

Chromium(VI) Heavy Metal Biosorption in Citarum River Water Sample Using Saccharomyces cerevisiae and Rhizopus oryzae Biomass

The Citarum River was regarded as the World’s dirtiest river in 2018, characterized by a Basin situated adjacent to several textile and electroplating industries. Hexavalent chromium metal (Cr6+) is a toxic, carcinogenic heavy metal found in the wastes of these industries. Furthermore, biosorption with biological adsorbents, including Saccharomyces cerevisiae and Rhizopus oryzae, is an alternative method for treating water polluted with heavy metals. This study therefore aims to adsorb Cr6 + heavy metals from Citarum River water using S. cerevisiae and R. oryzae biomass in two locations: Nanjung and Pangauban, with various biomass concentrations and stirring speeds. For this study, 0.25, 0.5, and 0.75 g of R. oryzae suspension, as well as 250, 500, and 750 µ of S. cerevisiae were used as adsorbent, while rotated at speeds of 250 rpm, 750 rpm and 1500 rpm. Subsequently, the Cr6 + metal content was measured using a UV-Vis spectrophotometer at a wavelength of 525 nm, and calculated based on a standard curve. The results showed S. cerevisiae and R. oryzae are able to reduce the levels of Cr6+ in Citarum river water. The most reduction was obtained with the highest concentration of the adsorbents, 750 µ for S. cerevisiae and 0.75 g for R. oryzae, at the speed of 1500 rpm. S. cerevisiae and R. oryzae have great potential as biosorbents for the in situ remediation of Citarum River contaminated with heavy metals.

Adsorption of Cr(VI) ions onto powdered activated carbon synthesized from Peganum harmala seeds by ultrasonic waves activation

Chromium is a toxic and carcinogenic heavy metal that is found in high concentrations in industrial liquid tanning wastewater. Therefore, the elimination of this element from the wastewater to prevent its entry into the aquatic environment, which is the objective of this study, is of prime importance. To start with, the powdered activated carbon (PAC) was prepared via activation of the Peganum harmala seeds (PPS) using ultrasonic waves. Subsequently, its ability, as an adsorbent, to capture Cr(VI) ions from the wastewater was examined at different conditions. The characterization study revealed the successful preparation of PAC with high activation of PPS. In addition, it was found that the prepared PAC possessed excellent adsorptive properties in terms of morphology, functional groups, surface area, and pore size. The kinetic and isotherm studies established that the adsorption process was simultaneously comprised of chemical and physical reactions of Cr(VI) ions on the multilayer and heterogeneous adsorption sites of the PAC. The removal efficiency of 20 mg/L Cr(VI) concentration by 10 g/L PAC concentration of > 99% was reached at pH = 3, mixing speed = 200 rpm, and contact time = 30 min. These results demonstrated the excellent ability of PAC for the removal of Cr(VI) ions from contaminated solutions via the adsorption process. Therefore, this study recommends that PAC that is prepared from the activation of PPS by ultrasonic waves be used as a highly efficient treatment agent in the adsorption process of Cr(VI)-loaded wastewater.

Differential cadmium translocation and accumulation between Nicotiana tabacum L. and Nicotiana rustica L. by transcriptome combined with chemical form analyses

Cadmium (Cd) is a severely toxic and carcinogenic heavy metal. Cigarette smoking is one of the major source of Cd exposure in humans. Nicotiana tabacum is primarily a leaf Cd accumulator, while Nicotiana rustica is a root Cd accumulator among Nicotiana species. However, little is known about the mechanisms of differential Cd translocation and accumulation in Nicotiana. To find the key factors, Cd concentration, Cd chemical forms, and transcriptome analysis were comparatively studied between N. tabacum and N. rustica under control or 10 μM Cd stress. The leaf/root Cd concentration ratio of N. tabacum was 2.26 and that of N. rustica was 0.14. The Cd concentration in xylem sap of N. tabacum was significantly higher than that of N. rustica. The root of N. tabacum had obviously higher proportion of ethanol extractable Cd (40%) and water extractable Cd (16%) than those of N. rustica (16% and 6%). Meanwhile the proportion of sodium chloride extracted Cd in N. rustica (71%) was significantly higher than that in N. tabacum (30%). A total of 30710 genes expressed differentially between the two species at control, while this value was 30,294 under Cd stress, among which 27,018 were collective genes, manifesting the two species existed enormous genetic differences. KEGG pathway analysis showed the phenylpropanoid biosynthesis pathway was overrepresented between the two species under Cd stress. Several genes associated with pectin methylesterase, suberin and lignin synthesis, and heavy metal transport were discovered to be differential expressed genes between two species. The results suggested that the higher accumulation of Cd in the leaf of N. tabacum depends on a comprehensive coordination of Cd transport, including less cell wall binding, weaker impediment by the Casparian strip, and efficient xylem loading.