Levels Of Manganese Research Articles

Transcriptome profiling uncovers differentially expressed genes linked to nutritional quality in vegetable soybean.

Vegetative soybean (maodou or edamame) serves as a nutrient-rich food source with significant potential for mitigating global nutritional deficiencies. This study undertook a thorough examination of the nutritional profiles and transcriptomic landscapes of six soybean cultivars, including three common cultivars (Heinong551, Heinong562, and Heinong63) and three fresh maodou cultivars (Heinong527, HeinongXS4, and HeinongXS5). Nutrient analysis of the seeds disclosed notable differences in the levels of protein, fat, soluble sugars, vitamin E, calcium, potassium, magnesium, manganese, iron, and zinc across the cultivars. Through comparative transcriptome profiling and RNA sequencing, distinct variations in differentially expressed genes (DEGs) were identified between fresh and traditional maodou cultivars. Functional enrichment analyses underscored the involvement of DEGs in critical biological processes, such as nutrient biosynthesis, seed development, and stress responses. Additionally, association studies demonstrated robust correlations between specific DEG expression patterns and seed nutrient compositions across the different cultivars. Sankey diagrams illustrated that DEGs are strongly linked with seed quality traits, revealing potential molecular determinants that govern variations in nutritional content. The identified DEGs and their relationships with nutritional profiles offer valuable insights for breeding programs focused on developing cultivars with improved nutritional quality, tailored to specific dietary needs or industrial applications.

Hygiene dan Sanitasi Desa Wisata: Peningkatan Kualitas Air Sumur Melalui Media Filterisasi, Pangkajene dan Kepulauan

Poor well water quality is a problem often faced by rural communities in Indonesia. This community service activity aims to improve the quality of well water in Taraweang Village through the use of simple filtering equipment. Through training and demonstrations, the community of Taraweang Village managed to improve their understanding and skills in managing well water using filtering technology. The results of this activity showed a significant improvement in well water quality, including a decrease in iron, manganese and bacteria levels in the water. The success of this program opens up opportunities for replication in other villages experiencing similar problems, with a note that continuous monitoring and support are needed to ensure the sustainability of the use of this technology

MAPO-5 molecular sieves from alkylimidazolium bromide ionic liquids

The ionic liquids diisopropylimidazolium bromide (DIPI) and diisobutylimidazolium bromide (DIBU) were used both as solvents and structure-directing agents (SDAs) to obtain AlPO4-5 and MnAPO-5 (Mn-AFI) molecular sieves. For increasing level of manganese, DIBU always yielded pure-phase Mn-AFI whereas DIPI led to amorphous product when more than 0.13 eq of Mn was added. Varying amounts of water, HF and metal led to AFI, cristobalite or tridymite phases. We also explored the use of nickel as the metal dopant, and although AFI phase were obtained under certain conditions, no framework incorporation of the metal was observed. Because of the vanishingly low vapor pressure of the ILs, the synthesis does not carry the risk of pressure build-up. The ILs were easily and fully recyclable and used for multiple syntheses. The MnAPO-5 material was characterized with powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), electron paramagnetic resonance (EPR), multinuclear solid-state nuclear magnetic resonance (SS-NMR) and X-ray absorption fine structure (XAFS). These findings provide new insight into the ionothermal synthesis of metal-doped AFI frameworks with possible implications in catalytic applications.

GmSTOP1-3 Increases Soybean Manganese Accumulation Under Phosphorus Deficiency by Regulating GmMATE2/13 and GmZIP6/GmIREG3.

Mineral nutrient deficiencies and metal ion toxicities coexist on acid soils. Phosphorus (P) deficiency in plants is generally accompanied with significant levels of leaf manganese (Mn) accumulation. However, the molecular regulatory mechanisms underpinning remain unclear. The present study found that P-deficient soybean plants accumulated more Mn compared to P-sufficient ones on acid soils in both field and greenhouse experiments. Meanwhile, both P deficiency and Mn toxicity enhanced the expression of GmSTOP1-3. Over-expressing GmSTOP1-3 enhanced Mn accumulation in transgenic soybean hairy roots, but RNA-interference did not show obvious differences. Moreover, transgenic soybeans with GmSTOP1-3-overexpression showed enhanced root citrate exudation and augmented Mn accumulation. RNA-sequence identified four downstream genes of GmSTOP1-3, including multidrug and toxic compound extrusion (GmMATE2/13) and metal transporter genes (GmZIP6/GmIREG3), which encode plasma membrane proteins. GmSTOP1-3 activated the transcription of these four genes by directly binding to their promoter regions. In addition, both GmZIP6 and GmIREG3 functioned in Mn uptake as manifested by the higher Mn concentration and decreased growth of soybean hairy roots with their overexpression. Taken together, it is suggested that upregulation of GmSTOP1-3 by low P stress on acid soils activates transcripts of GmMATE2/13 and GmZIP6/GmIREG3, which consequently result in enhanced Mn accumulation in soybean.

Manganese inhibits HBV transcription and promotes HBsAg degradation at non-toxic levels

Chronic hepatitis B virus (HBV) infection continues to pose a significant global health challenge. However, therapeutic measures for a cure are lacking in clinical practice. Manganese, an essential trace element, has garnered attention due to its potential to activate innate immune pathways and its significant role in antiviral and antitumor immunity. Yet, the specific impact of manganese on chronic hepatitis B has been largely unexplored. Our research reveals that manganese substantially inhibits HBV replication in hepatocellular carcinoma cells at non-toxic levels. This suppression occurs independently of well-known anti-HBV innate immune pathways, such as the cGAS-STING pathway. Mechanistically, manganese decreases HBV transcription by diminishing the levels of liver-specific transcription factors. Furthermore, it activates the mTOR pathway, enhancing HBsAg ubiquitination through the upregulation of the ubiquitin ligase β-TrCP and increasing proteasome activity via the augmentation of its subunits, leading to a ubiquitin-dependent degradation of HBsAg. Significantly, our study also uncovers a notable clinical correlation between manganese levels and chronic hepatitis B infection. These findings position manganese as a critical element in diminishing HBV replication, offering a new direction in the management of chronic hepatitis B.

Study of excess manganese stress response highlights the central role of manganese exporter Mnx for holding manganese homeostasis in the cyanobacterium Synechocystis sp. PCC 6803.

Cellular levels of the essential micronutrient manganese (Mn) need to be carefully balanced within narrow borders. In cyanobacteria, a sufficient Mn supply is critical for ensuring the function of the oxygen-evolving complex as the central part of the photosynthetic machinery. However, Mn accumulation is fatal for the cells. The reason for the observed cytotoxicity is unclear. To understand the causality behind Mn toxicity in cyanobacteria, we investigated the impact of excess Mn on physiology and global gene expression in the model organism Synechocystis sp. PCC 6803. We compared the response of the WT and the knock-out mutant in the Mn exporter (Mnx), ∆mnx, which is disabled in the export of surplus Mn and thus functions as a model for toxic Mn overaccumulation. While growth and pigment accumulation in ∆mnx were severely impaired 24 h after the addition of tenfold Mn, the WT was not affected and thus mounted an adequate transcriptional response. RNA-seq data analysis revealed that the Mn stress transcriptomes partly resembled an iron limitation transcriptome. However, the expression of iron limitation signature genes isiABDC was not affected by the Mn treatment, indicating that Mn excess is not accompanied by iron limitation in Synechocystis. We suggest that the ferric uptake regulator, Fur, gets partially mismetallated under Mn excess conditions and thus interferes with an iron-dependent transcriptional response. To encounter mismetallation and other Mn-dependent problems on a protein level, the cells invest in transcripts of ribosomes, proteases and chaperones. In the case of the ∆mnx mutant, the consequences of the disability to export excess Mn from the cytosol manifest in additionally impaired energy metabolism and oxidative stress transcriptomes with a fatal outcome. This study emphasizes the central importance of Mn homeostasis and the transporter Mnx's role in restoring and holding it.

Evaluation of Heavy Metal Contamination in Amaranthus hybridus (Spinach)

Heavy metals contamination in edible plants poses significant risks to human health and environmental sustainability. This study evaluates heavy metal contamination in Amaranthus hybridus L. (spinach) collected from three sites: Nyabunkaka River, Kogin Sarki, and Mayo-Gwoi River in Jalingo, Taraba State, Nigeria. The study aimed to determine the levels of lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), copper (Cu), nickel (Ni), manganese (Mn), and cobalt (Co) in spinach samples using Atomic Absorption Spectrophotometry (AAS). Results revealed that Pb concentration in spinach from Nyabunkaka slightly exceeded the FAO permissible limit, while Cd, Cr, Zn, Cu, Ni, Mn, and Co levels in all samples were below FAO reference values, indicating minimal contamination risks. These findings highlight the potential environmental pollution near Nyabunkaka River and suggest that spinach from the selected areas remains largely safe for human consumption, except for slight Pb contamination. The study emphasizes the need for continuous monitoring to ensure food safety.

Bioaccumulation Patterns of Trace Elements in Jellyfish (Crambionella orsini and Cassiopea andromeda) from Northwestern Coastal Waters of the Persian Gulf

Trace element pollution in the Persian Gulf originates from industrial activities, urbanization, shipping, and oil extraction, leading to accumulation in sediments, water, and marine life such as jellyfish. This study investigated trace element bioaccumulation in two jellyfish species, Crambionella orsini and Cassiopea andromeda, across different locations. Jellyfish samples were collected from the Mahshahr and Dilam ports, and their trace element concentrations were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The study revealed no significant differences in trace element concentrations between C. orsini and C. andromeda. However, levels of copper, iron, manganese, and nickel were significantly higher in specimens from Mahshahr compared to those from Dilam. No significant differences were observed for cadmium, mercury, vanadium, tin, magnesium, and selenium across sites. Lower concentrations of lead, arsenic, zinc, and cobalt were found in C. orsini from Dilam compared to Mahshahr. Additionally, the study found no significant correlation between trace element concentrations in the water and their accumulation in jellyfish bodies. These findings offer valuable insights into the distribution and bioaccumulation of trace elements in jellyfish populations across different marine environments in the Persian Gulf.

Assessment of the adaptive ability of regenerant and original oat genotypes to soil stressors

The aim of the research is a comparative analysis of the response to soil stressors according to the biochemical and productive characteristics of the initial genotypes of oats (line 2h15) and regenerative forms (RA, RAAl, RAMn, RACd) in the framework of evaluating the effectiveness of applied cell selection schemes. In the vegetation experiment, the effect of soil stressors on plants was studied – increased acidity (pH = 4.3), toxicity of manganese ions (65.2 mg/kg, pH = 5.2) and cadmium (2.87 mg/kg, pH = 5.2). The Arkhan variety was used as a standard. The control was soil with a neutral pH (7.2). Regenerants were previously obtained in vitro on artificial media without stress (RA) and with selective agents: alumina acid (RAAl), increased Mn2+ (RAMn) and Cd2+ (RACd). On soil with stressors, the pigment content in regenerant leaves exceeded the baseline values by 1.4…1.6 times. In control, the differences between RA and the baseline are unreliable. All regenerative lines, regardless of growing conditions, were characterized by significantly lower levels of polyphenols in grain (11.2…12.4 mg/g dry weight), compared with the baseline and the standard by 1.2…1.3 times. On backgrounds with artificial addition of metals, an excess of the manganese level in the grain was noted: 1.7 times in RAMn (256.1 mg/kg), compared with the baseline, and there were no differences between them in the cadmium content in RACd (1.82…1.67 mg/kg). On the control background, RA and the baseline significantly lagged behind the standard in terms of grain weight from the plant: in regenerants – 1.29 g; baseline – 1.38 g; standard – 1.65 g. With increased acidity and cadmium, all genotypes decreased productivity relative to the control, but to a lesser extent regenerants (1.6 and 1.4 times, respectively), the baseline – 2.8 and 2 times, the standard – 2.4 and 1.9 times.

ZIP8 Is Upregulated in the Testis of Zip14-/- Mice.

Manganese is an essential nutrient involved in various biological processes, including reproductive health, yet the mechanisms regulating its homeostasis in the testis remain poorly understood. In this study, we investigated the expression and regulation of key manganese transporters-ZIP8, ZIP14, and ZnT10-in mouse testes. Immunoblotting analyses revealed that ZIP8 is expressed in the testes, while ZIP14 and ZnT10 were undetectable. Using Zip14 knockout (Zip14-/-) mice, which exhibit systemic manganese overload, we discovered a significant increase in manganese levels in the testis, accompanied by an upregulation of ZIP8. Importantly, the levels of other essential metals, such as iron, zinc, and copper, remained unchanged. Our findings suggest that ZIP8 plays a critical role in manganese transport in the testis, and its increased expression may contribute to manganese accumulation in the absence of ZIP14. This study advances our understanding of manganese homeostasis in the testis and its potential impact on male reproductive health.

Association between trace elements and cognitive function among hemodialysis patients in Turkey.

Cognitive impairment is common among patients with hemodialysis. Hemodialysis patients have theoretical risks for both deficiency and accumulation of trace elements. We aimed to investigate the relationship between cognitive dysfunction and whole blood levels of trace elements in hemodialysis patients. We also aimed to examine the effect of baseline trace element status and cognitive dysfunction on mortality. Maintenance hemodialysis patients and age-and sex-matched controls were included. The whole blood levels of trace elements were measured by inductively coupled plasma mass spectrometry. Cognitive impairment was defined as a score of ≤24 points on the Montreal Cognitive Assessment test. Executive dysfunction was also defined as Trails A score of more than 75 s and Trails B score of more than 180 s. Forty-two patients and 35 controls were included. Cognitive impairment was detected in 69% of the patients and 45.7% of the controls (p = 0.039). Cognitively impaired patients had lower education years (p = 0.003) and higher whole blood levels of manganese (Mn) and lead (Pb) (p = 0.026, p = 0.019, respectively) compared to patients without cognitive impairment. Mn levels were also found statistically higher in patients with executive dysfunction compared to patients without executive dysfunction (p = 0.005). Lower education years and higher Pb levels were independent risk factors for cognitive impairment in hemodialysis patients (odds ratio [OR] 0.589 [95% confidence interval, CI 0.400-0.866, p = 0.007] and OR 1.047 [95% CI 1.001-1.096, p = 0.047, respectively]). Cognitive impairment, especially impaired executive function, is common among patients with hemodialysis patients. Cognitive impairment is not found to be associated in cross-sectional analysis with several modifiable end-stage renal disease- and dialysis-associated factors. The accumulation of trace elements especially Mn and Pb might exacerbate the cognitive dysfunction in hemodialysis patients.

Advanced chelate technology-based trace minerals reduce inflammation and oxidative stress in Eimeria-infected broilers by modulating NF-kB and Nrf2 pathways

This study investigated the effects of substituting inorganic trace minerals (ITM) with advanced chelate technology-based TM (ACTM) in broiler chicken feed on productive performance, metabolic profile, humoral immunity, antioxidant status, and modulation of NF-kB and Nrf2 signaling pathways in mixed Eimeria species exposure. The study involved 480 newly hatched male broiler chickens, which were divided into 5 treatment groups, each with 6 replicate cages and 16 chickens per replicate. The experimental treatments included an uninfected negative control group fed a basal diet with recommended inorganic TM levels (NC), an infected positive control group fed the same diet (PC), a PC group supplemented with salinomycin (SAL), and two PC groups in which the basal diet was replaced with 50% and 100% ACTM instead of inorganic TM (ACTM50 and ACTM100, respectively). All groups, except for the NC group, were orally challenged with mixed Eimeria species oocysts on day 14. According to the results, the PC group showed lower feed intake, breast yield, low-density lipoprotein-cholesterol concentration, lactobacillus spp. counts, and serum IgG levels, but higher jejunal TGF-β expression versus the NC group. The broilers in the NC, SAL, and ACTM100 groups showed higher body weight gain, carcass yield, and TGF-β expression, but lower serum alkaline phosphatase activity, ileal E. coli count, and jejunal expression levels of IL-1β, IL-6, IFN-γ, Nrf2, and SOD1 compared to the PC group, with the NC group having the highest body weight gain and lowest IL-1β and Nrf2 expression levels. Furthermore, the administration of ACTM100 treatment improved feed efficiency, increased serum iron, zinc, manganese, and copper levels, enhanced total antioxidant capacity and different antioxidant enzyme activities, and reduced malondialdehyde concentration. In conclusion, complete replacement of ITM with ACTM effectively protects broilers from Eimeria infection, with similar positive effects to SAL treatment in terms of productive performance and anti-inflammatory responses and better antioxidant responses and mineral availability.

Hexavalent chromium exposure induces lung injury via activation of NLRP3 and AIM2 inflammasomes in rats

Hexavalent chromium (Cr(VI)) has been identified as a Class I human carcinogen, but its carcinogenic mechanism is currently unclear. There is still a lack of understanding of its associations with early pulmonary inflammatory damages. Inflammation is an important stage before the occurrence of tumors, and under the long-term stimulation of inflammation, it can promote the development of tumors. In this study, the aim is to explore the effect of Cr(VI) exposure on pulmonary inflammation and its relationship with the mechanism of inflammation cancer transformation. We established a Cr(VI) exposure model in SD rats using tracheal instillation of potassium dichromate solution, and collected samples at the time of cessation of exposure and 14 days after cessation of exposure. Analyzing the experimental results, it was found that the lung index increased after exposure to Cr(VI), promoting the occurrence of apoptosis in lung tissue cells and exacerbating lung tissue damage. The damage situation improved after exposure termination; Inductively coupled plasma mass (ICPRQ) spectrometer detection found that the exposed group had significantly increased levels of blood chromium, blood manganese, blood copper, blood arsenic, urine chromium, urine copper, and urine lead; After two weeks of repair, blood chromium and blood manganese levels were significantly lower than those in the same dose group of the exposure group, while blood copper levels were significantly higher than those in the same dose group of the exposure group. There was no significant difference in blood arsenic levels between the exposure group and the exposure group. Urine chromium and urine lead levels were significantly lower than those in the same dose group of the exposure group, while urine copper levels only increased. At the same time, it was found that Cr(VI) exposure caused disruption of oxidative stress levels in rat lung tissues. After 14-day exposure, Cr(VI) significantly decreased and oxidative stress levels significantly decreased. Further investigation revealed that Cr(VI) induces activation of inflammasomes NLRP3, AIM2, and their signaling pathways in lung inflammatory injuries, but this condition persists even after cessation of exposure. The study suggested that in hexavalent chromium induced lung tissue injuries in rats, NLRP3 and AIM2 inflammasomes and their signaling pathways activation. Furthermore, the characteristic of sustained activation after cessation of exposure was also indicated. These results provide new ideas and references for further elucidating the mechanisms of Cr(VI), lung inflammation and inflammation cancer transformation.

Manganese: From Soil to Human Health—A Comprehensive Overview of Its Biological and Environmental Significance

Background: Manganese is an essential micronutrient that plays a pivotal role in environmental systems, plant physiology, and human health. This review comprehensively examines the manganese cycle in the environment, its absorption and transport mechanisms in plants, and the implications of manganese exposure to human health. Objectives: The objectives of this review are to (i) analyze the environmental cycling of manganese and its bioavailability, (ii) evaluate the role of manganese in plant metabolism and disease resistance, and (iii) assess the impact of manganese toxicity and deficiency on human health. Conclusion: This review highlights that while manganese is crucial for photosynthesis, enzyme activation, and resistance to plant diseases, both its deficiency and toxicity can have severe consequences. In plants, manganese deficiency can lead to impaired growth and reduced crop yields, while toxicity, particularly in acidic soils, can inhibit photosynthesis and stunt development. In humans, manganese is necessary for various physiological processes, but overexposure, especially in occupational settings, can result in neurodegenerative conditions such as manganism. The conclusion emphasizes the importance of managing manganese levels in agriculture and industry to optimize its benefits while minimizing health risks. A multidisciplinary approach is advocated to enhance agricultural productivity and ensure public health safety.

Evaluating water, sanitation, and hygiene in schools of Bangladesh: progress toward SDG compliance

ABSTRACT The availability of safe water, sanitation, and hygiene (WASH) facilities in schools is essential for a healthy learning environment and achieving sustainable development goals (SDGs) 4 and 6. Despite its importance, comprehensive studies on drinking water quality, sanitation, and hygiene in schools are scarce. This study explicitly assessed the WASH services and gaps in 43 educational institutions, located in Tongi, Bangladesh, through field and laboratory investigations. Thirteen physicochemical and bacteriological parameters were analyzed, and water quality was classified using an Integrated Water Quality Index (IWQI). Hygiene and sanitation were evaluated through observations and data from school administrators on water sources, toilets, handwashing facilities, and solid waste management. Results showed that WASH services exceeded the national average, but all schools had dangerously high Escherichia coli levels (mean: 43.95 CFU/100 mL) in drinking water, posing health risks. Additionally, 89.72% of samples showed elevated manganese levels, 35% had high iron, and 41.86% had increased conductivity. About 35% of water was unsuitable for drinking based on IWQI. Schools lacked the capacity to monitor WASH quality, especially drinking water. A strategic framework for safe WASH facilities is recommended. The findings can lead the policymakers to prioritize the improvements in WASH facilities for attaining SDG 6.

Quality and Influences of Natural and Anthropogenic Factors on Drinking Water in Rural Areas of Southern Chile

Water quality is a fundamental aspect of public health and environmental sustainability. In rural areas, the physicochemical and microbiological quality of drinking water depends not only on hydrogeological conditions but also on anthropogenic activities carried out on the surface of the basin. This study aimed to identify natural and anthropogenic influences related to the quality of drinking water in rural areas of southern Chile. In order to perform this, six rural drinking water systems were evaluated. A total of two types of catchment sources (groundwater and surface water) that were located in a longitudinal gradient were used, where coverage and sequences of rocks and soils could be differentiated. The results show that the water delivered by the majority of rural drinking water systems studied was of good quality, meeting the standards of Chilean and international regulations. No fecal coliforms or Escherichia coli were recorded. In addition, we recorded that turbidity, color, pH, concentration of total dissolved solids and fecal coliforms showed significant differences between groundwater and surface water. We also recorded that in two groundwater systems, iron and manganese levels slightly exceeded the regulations, endangering the acceptability of the water. These increases can be related to the natural origins of the metals, linked to the presence of oxides in Andisol- and Utisol-type volcanic soils.

The tolerable upper intake level of manganese alleviates Parkinson-like motor performance and neuronal loss by activating mitophagy

Manganese (Mn2+) is among the indispensable trace elements required by the human body, but high-dose Mn2+ exposure can lead to Mn poisoning. Therefore, the tolerable upper intake level (UL) for Mn2+ has been established for normal individuals in different countries. However, whether the UL of Mn2+ is suitable for the patients of Parkinson's disease (PD) is unclear.Here, we found unexpectedly that the dietary UL of Mn2+ supplement enhanced mitophagy through the PINK1/parkin-mediated ubiquitin-dependent pathway in MPTP- induced mice and cells. Mn2+ promoted mitochondrial biogenesis and dynamics, thereby increased the activity of the mitochondrial respiratory chain with restored mitochondrial function. Additionally, Mn2+ directly elevated the activity of mitochondrial superoxide dismutase (MnSOD), which contributed to the clearance of reactive oxygen species (ROS), restored dopaminergic and motor functions in the MPTP-induced PD mouse model. Similar results were also observed in SH-SY5Y cells, whereas knockdown parkin using siRNA or application of mitophagy inhibitors (Mdivi-1 or cyclosporine A), abolished the neuroprotective effects of Mn2+.These findings demonstrate that the dietary UL of Mn2+ is protective for the MPTP-induced Parkinson-like lesions with the mechanisms involving the activation of mitophagy, suggesting potential intervention of PD by moderately increasing dietary Mn2+ intake.

Assessment of Essential Trace Elements Cu, Zn, Mn, and Ni in Mediterranean Mussels (Mytilus galloprovincialis) from the Algerian Coast.

The aim of this study was to determine the levels of essential trace elements copper, zinc, manganese, and nickel in two size groups of mussels, Mytilus galloprovincialis, sampled from three sites along the Algerian coast with different levels of pollution. The results of this work are very interesting for determining the effect of mussel size on the variation of contaminant levels in environmental monitoring studies. Thirty individuals from 2 size groups, less than 4-cm and more than 4-cm shell length, were collected over 4 seasons at each site studied. The samples were dissected, and copper, zinc, manganese, and nickel were measured in the whole soft tissues by inductively coupled plasma mass spectrometry (ICP-MS). The maximum concentrations of copper, zinc, manganese, and nickel expressed in mg/kg dry weight at the three sites were 54.01, 146.25, 20.69, and 8.85, respectively. A clear distribution pattern of the studied elements was observed in the two size classes. In fact, significantly higher concentrations (P < 0.05) were found in individuals with a shell length of less than 4 cm. Significantly, higher concentrations (P < 0.05) were found in individuals with a shell length of less than 4 cm due to their high filtration and low excretion activities compared to long individuals. In addition, metal pollution index (MPI) values were higher in small bivalve individuals. The trace element contents found in the mussel samples of the present study showed large spatial and temporal variations among the different sites studied, highlighting the typical exposure of marine sites to different marine pollutants. Notably, elevated concentrations of copper were observed in the port of Zemmouri, likely due to port activities. Conversely, the highest levels of manganese and nickel were recorded at Boudouaou El Bahri, potentially attributable to the use of fertilisers by agricultural activities. Some shellfish samples had exceeded the permissible concentration levels of copper and manganese, thereby posing a danger to bivalve consumers.

Evaluation of Heavy Metal Concentration in Sediments of Rupingazi River, Kenya

Heavy metal concentration (Cu, Zn, Fe, Mn, Ni) was evaluated in sediment samples of Rupingazi river during the wet and dry seasons. In this study, the sediment samples were collected from twenty sampling points along the river. The heavy metal levels were evaluated using Atomic Absorption Spectrphotometer.The obtained data was analyzed using one-way analysis of variance. The range of the concentration of copper was found to be 4.68- 12.69 mg/kg for the wet season and 0.98-24.10mg/kg for the dry season. The mean values of the concentration of iron was found to be 1422-6145.33 mg/kg for the wet season and 1254-5866.67 mg/kg for the dry season. The range of the concentration of Nickel was found to be 0.72- 30.73 mg/kg for the wet season and 2.63-12.48 mg/kg for the dry season. Concentration of manganese was found to be 48.03-411.20 mg/kg for the wet season and 6.15-248.35 mg/kg for the dry season Zinc concentration was found to be 26.29-167.10 mg/kg for the wet season and 4.82-28.39 mg/kg for the dry season. The Zinc, Manganese, Nickel Iron and Copper levels were not beyond the USEPA recommended limits.

Properties of biocoal briquettes from mesoporous coals and rice husk and their effects on environmental pollution

This work assessed some properties and effects of biocoal briquettes on environmental pollution compared with utilising coal alone. A mixture of coal fines and rice husks was prepared, with cassava starch gel as a binder, before compaction in a briquetting machine and drying with a solar dryer. Samples of the coal fines, rice husk, cassava flour and briquettes were analysed for their elemental and oxide concentrations via an energy-dispersive X-ray fluorescence analyser. The heat fuels were analysed for their thermal behaviour via thermogravimetric analyser (TGA), whereas the specific surface area, pore size and pore volume were determined using a Brunner–Emmett–Teller (BET) analyser. The conversion of the tested coals to biocoal briquettes resulted in a reduction in the level of arsenic in the briquettes. Additionally, the sulphur level decreased from 1.96 to 1.11% in the Okobo-Enjema briquettes and from 1.78 to 0.90% in the Onyeama briquettes. However, the levels of manganese increased from 0.04 to 0.22% in the Okobo-Enjema briquettes and from 0.04 to 0.21% in the Onyeama briquettes. Thermogravimetric analysis at different heating rates revealed that derivative weight loss increased with increasing heating rate, from 4.4% at 10 °C/min to 5.5% at 20 °C/min. BET analysis revealed that the briquettes had larger pore diameters, volumes and specific surface areas than did the coal samples. The coal samples have greater propensity to pollute the environment as the amount of potentially hazardous elements in the samples is greater than in their biocoal briquettes.