Recommended Safety Limits Research Articles

Assessment of Activity Concentration and Health Hazards of Radiation Exposure in Soil from Mamara Jidda and Waja Tin Mining Sites in Northern Nasarawa State, Nigeria

Natural background radiation exposure is an inevitable occurrence on Earth, and humans are exposed to radiation in their surroundings whether consciously or unconsciously. However, increased artisanal and illegal mining could harm the local environment and increase background radiation levels, affecting the community's overall health. This study assessed the activity concentration of primordial radionuclides (226Ra, 232Th, and 40K) from soil samples obtained from Mamara Jidda and Waja tin mine sites in Nasarawa State, Nigeria, and its risk to human health. The gamma spectroscopy using a Sodium iodide-thallium activated detector was used to measure the activity concentrations of primordial radionuclides in the surface soils/sediments samples. The activity concentrations of 226Ra, 232Th, and 40K for Mamara Jidda and Waja were found to be within the range of 4 - 18 Bq kg-1, 41 - 105 Bq kg-1, and 524 - 717 Bq kg-1; 13 - 40 Bq kg-1, 75 - 134 Bq kg-1, and 591 - 882 Bq kg-1 respectively. The average values show that 40K and 232Th concentrations are above the recommended limit set by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in Mamara Jidda and Waja mine sites. The annual gonadal dose equivalent (AGDE), annual effective dose rate (AEDE), radium equivalent (Raeq), absorbed dose rate (D), and external hazard index (Hex) for Mamara Jidda and Waja were found to be 0.56 mSv yr-1, 0.10 mSv yr-1, 588.58 Bq kg-1, 78.26 nGy hr-1 and 0.46; 0.73 mSv yr-1, 0.13 mS yr-1, 742.74 Bq kg-1, 103.72 nGy hr-1 and 0.61 respectively. The AEDE and Hex are below the recommended safety limits. However, the high values of AGDE in both mining sites and D in Waja mine demonstrate that with continuous exposure to radiation, a significant genetic impact is eminent to the miners and inhabitants of these areas. Also, the Raeq values for both mines suggest that their soils are unsafe for use as building materials.

Nitrate and nitrite quantification in U.S. vegetable-based baby foods and infant formula via ozone chemiluminescence

Determining nitrate (NO3-) and nitrite (NO2-) concentrations (“NN”) in infant diets is crucial due to their potential health implications and immature digestive systems. This study provides a comprehensive analysis of these ions in commercially available vegetable- and fruit-based baby foods and infant formulas in the United States. We evaluated 151 baby foods and 12 infant formulas to determine the NN quantity in these food items and to assess current exposure levels utilizing ozone chemiluminescence for sensitive detection. Our findings reveal notable variations in NN concentrations across different brands and types, with some exceeding recommended safety limits. The results underscore the necessity for regular assessment and monitoring of NN in these foods to inform development of regulatory standards to safeguard infant health. This research contributes to the discourse on dietary safety and highlights the importance of employing advanced methodologies for public health assurance and well-being of vulnerable populations.

Can metals and radionuclides in Shiveluch (Kamchatka) volcanic ash affect human health?

Volcanic eruption is associated with the release of large volumes of pollutants in the environment, which can pose a risk to humans and other living organisms. The elemental and radioisotope composition of ash released during the Shiveluch Volcano eruption in 2023 was analyzed using ICP-MS and low-background gamma spectrometry. The ash consisted of 59% SiO2, 16.7% Al2O3, 5.3% CaO, 4.6 % Na2O, 4.5% Fe2O3, 1.4% K2O, 0.48% TiO2, 0.17% P2O5, 0.15% S, 0.078% MnO and 44 trace elements. Hazard Quotient and Hazard Index were calculated in order to evaluate the potential health risks to children and adults due to exposure to contaminants via inhalation, ingestion, and dermal contact. All values were below the unit, indicating a low probability of non-carcinogenic and cancerogenic risk occurrence in target groups. The average activity concentrations of the natural radionuclides were 350, 12.4 and 4.84 Bq/kg for 40K, 226Ra and 232Th. Radiological indices, including external and internal risk assessment, radium equivalent activity, annual effective dose, gamma index, and excess lifetime cancer risk were calculated to estimate the radiological hazard for the population. The values of all indices were below the recommended safety limits, indicating a low level of hazard for the exposed population.

From Fields to Families: Understanding the Health Impacts of Excessive Soil Fertilization

Background: Fertilizers play a crucial role in modern agriculture, significantly boosting crop yields and global food production. However, their widespread use has unintended consequences that raise significant environmental and health concerns. Nitrogen-based, phosphorus-based, and potassium-based fertilizers contribute to nutrient replenishment in soils but can lead to soil and water contamination, posing risks to ecosystems and human health. Objective: This narrative review aims to comprehensively examine the health and environmental impacts of excessive soil fertilization, with a focus on understanding the mechanisms by which fertilizers affect soil and water quality and the subsequent implications for human health. Methods: An extensive literature search was conducted across multiple electronic databases, including PubMed, Web of Science, Scopus, and Google Scholar. Articles published between 2000 and 2023 were selected based on predefined inclusion criteria, focusing on studies that provided empirical data or substantial theoretical insights into the environmental and health impacts of fertilizer use. A qualitative analysis was performed to synthesize findings and identify common themes. Results: The review highlighted that nutrient runoff from excessive fertilizer use leads to significant water quality degradation, with nitrate concentrations in some regions exceeding recommended safety limits by 30-50%. Prolonged exposure to contaminated water is linked to various health issues, including a 20% increased risk of methemoglobinemia in infants and a 15-25% higher risk of gastric and colorectal cancers in adults. Additionally, heavy metal accumulation in crops due to fertilization practices raises concerns, with cadmium levels in some crops surpassing safe consumption limits by 40-60%. Conclusion: While fertilizers are essential for enhancing agricultural productivity, their excessive use poses significant environmental and health risks. A balanced approach integrating sustainable agricultural practices, effective water management, and comprehensive regulatory frameworks is imperative to mitigate these adverse effects. Continued research and collaboration among scientists, policymakers, and the agricultural community are necessary to promote a sustainable and health-conscious approach to fertilizer use.

Evaluation of heavy metal accumulation and associated human health risks in three commercial marine fish species from the Aegean Sea, Türkiye

This study investigates the presence and concentrations of ten specific heavy metals in the muscle tissues and gonads of three commercially important marine fish species: Garfish (Belone belone), European barracuda (Sphyraena sphyraena), and Anglerfish (Lophius piscatorius) collected from the Aegean Sea in Türkiye. The results indicate variations in metal accumulation, both between genders and among species. The fish species tend to accumulate higher levels of heavy metals in their gonads than in muscle tissues (p<0.05). While Cr, Cd, and Pb were not detected, Zn, Cu, and Fe are the predominant metals in muscle tissues due to their essential biological roles. However, within toxic elements, Hg was predominant, and L. piscatorius, a benthic fish, exceeded its recommended safety limits. A health risk assessment suggests that except for L. piscatorius, consuming these fish species from the Aegean Sea is generally safe, with estimated weekly intake (EWI) values below permissible limits. Total Hazard Quotient (THQ) values for most metals are below 1, indicating no significant non-carcinogenic health risks for consumers. This study emphasizes the critical need for regularly monitoring heavy metal levels in marine fish from the Aegean Sea, Turkiye. While overall safety in consuming these fish is highlighted, exceptions exist, notably concerning Hg levels in L. piscatorius. Therefore, persistent monitoring of heavy metal concentrations, especially in L. piscatorius, is advised to ensure ongoing safety and mitigate potential risks of metal accumulation.

Assessment of radionuclides content of dumpsites within Kaduna Metropolis

This study assessed the concentration of radionuclides (Ra-266, Th-232, U-238, and K-40) in selected dumpsites within some Local Government Areas of Kaduna State. Radiological analysis was carried out using a gamma spectrometer (HPGE) located at the Energy Research Center, University of Ibadan, Nigeria. The results of the concentration of Ra-266, Th-232, U-238 and K-40 in the study area were as follows: 196.12 – 239.14 Bq/kg, 126.79 – 171.32 Bq/kg, 84.96 – 115.96 Bq/kg, and 317.11 – 521.77 Bq/kg respectively for Chikun LGA; 213.84 – 268.98 Bq/kg, 102.17 – 122.90 Bq/kg, 110.89 – 137.80 Bq/kg, 407.64 – 486.38 Bq/kg respectively for Igabi LGA; 187.15 – 364.50 Bq/kg, 166.04 – 387.00 Bq/kg, 97.35 – 180.57 Bq/kg, and 541.72 – 801.08 Bq/kg respectively for Kaduna North LGA; and 128.98 – 293.45 Bq/kg, 139.43 – 182.96 Bq/kg, 70.57 – 132.02 Bq/kg and 526.19 – 707.42 Bq/kg respectively for dumpsites in Kaduna South. The results revealed that K-40 had the highest concentration in all the study areas and was found to be above the UNSCEAR (2000) recommended limit of 300 bq/kg. Ra-266, Th-232, and U-238 were found to be 37, 31, and 51 Bq/kg above the UNSCEAR (2000) recommended limits of 35, 30, and 50 Bq/kg, respectively. The annual effective dose was in the range of 1.23–2.30 mSvy^(-1) above the UNSCEAR (2000) recommended safety limit. The radioactivity level in the study areas was high; therefore, continuous exposure to these radionuclides and their progenies may pose a severe risk to public health. All the sampled radionuclides were found to be within the recommended standard of ≤1.0 WHO reference values.

Determination of Activity Concentration and Radiological Risks from Gold Mine Tailings around Ilahun-Ijesa in Obokun Local Government, Osun State, Nigeria

In this study, the activity concentrations and radiological risks associated with exposure to NORMS in soils around the gold mine tailings in Ilahun – Ijesa, Obokun Local Government, Osun State, Nigeria was evaluated. A Sodium Iodide (NaI) gamma spectroscopy was used to determine the activity concentrations of the natural radio nuclides in soil samples that were collected from the gold mine tailings. The mean activity concentration for 238 U, 232 Th and 40K were 14.50±2.40, 10.45±3.20 and 332.70±6.10 Bqkg-1 respectively. The average absorbed dose was calculated to be 26.4 nGy/h and the corresponding average annual effective dose was found to be 0.0031 mSv, which is less than the total annual effective dose of 1 mSv recommended by ICRP for public exposure control. Radiological hazard parameters were evaluated from activity concentrations and the average values were found to be lower than recommended safety limits.

Assessment of dosimetric approaches in evaluating radiation exposure for interventional cardiologists in Sri Lanka.

Interventional cardiologists face significant radiation exposure during interventional cardiology procedures. Therefore, this study focuses on assessing radiation exposure among interventional cardiologists during their procedures. Specifically, it aims to determine the effectiveness of both single and double dosimeter methods in estimating annual occupational radiation doses. This research holds pioneering significance as it represents the very first study undertaken in Sri Lanka. Thirteen interventional cardiologists performed 486 interventional cardiology procedures over three months in three different healthcare institutes. Active Hp(10) dosimeters were placed to measure radiation exposure. Effective doses were calculated using single and double dosimetric algorithms. Annual occupational doses were assessed on an operator basis. Statistical analyses were conducted to assess algorithmic differences and dose variations using the Kruskal-Wallis test and linear regression. The highest annual occupational dose for each dosimetric algorithm received as 2.00 ± 0.24 mSv, 2.29 ± 0.48 mSv, 3.35 ± 0.71 mSv, and 2.64 ± 0.42 mSv, respectively, and remained below the recommended safety limit of 20 mSv/year. The Kruskal-Wallis test revealed no significant differences in the effective doses among double dosimetric algorithms, as well as between single and double dosimetric algorithms (p > 0.05). Linear regression showed strong correlations among various algorithms, demonstrating consistency. The findings of this study hold significant effects on interventional cardiology practice in Sri Lanka, enhancing radiation safety and monitoring.

Evaluation of radiological health risk caused by the use of fly ash in cement and concrete production and its storage

ABSTRACT As a result of firing pulverized coal in thermal power plants, enormous amounts of fly ash (FA) are produced as industrial waste. The release into the atmosphere and storage of this industrial waste remains one of the major environmental problems that threaten human health by contributing to air, water, and soil pollution. The recovery and reuse of FA in the construction industry is the only economic solution to the existing problem. In this study, the potential radiological risk caused by the usage of FA in concrete and cement production as a main component and its storage in landfill sites was evaluated for people and works by estimating radiological parameters (activity concentration and alpha index, annual effective doses, and the corresponding excess lifetime cancer risks) based on activity concentrations of terrestrial radionuclides in FA. Also, the radiological risk to the workers working in the FA landfill site was evaluated using the Residual Radioactivity Onsite 7.2 code. The average activity concentrations of terrestrial radionuclides in FA samples from the Tunçbilek lignite coal-fired thermal power plant at Kütahya province of Turkey were measured as 417, 156 and 454 Bq kg−1 for 226Ra, 232Th and 40K, respectively. When using up to 35% by mass of FA in cement and concrete, the average values of the radiological parameters revealed that they were within the recommended safety limits. However, code estimations showed that a regular worker in FA storage would be exposed to a total effective dose rate greater than 3 mSv y−1.

Assessment of radioactivity levels and radiological hazard indices in phosphate and phosphate mine waste samples from Algeria.

Phosphate ore is the starting raw material for production of all phosphate products including fertilisers phosphate waste. It can be of sedimentary, volcanic or biological origin. Like any other geological material found in nature, it contains various amounts of naturally occurring primordial radionuclides, such as 238U series, 232Th series and 40K. Gamma-ray spectrometry was used to assess natural radioactivity levels and radiological hazard indices in phosphate samples. In this paper, the specific activity concentrations of 226Ra, 232Th and 40K of phosphate ores, merchant and mine waste samples were determined. Based on the activity concentrations, the radiation hazard indices (Raeq, Hex, Hin and I𝛾𝑟), and the radiation doses (D, AED and ELCR) were calculated. The results were discussed and compared with those from other studies as well as recommended safety limit values.

Measurements of natural radionuclide levels and hazards in the Lega Dembi gold mine, Oromia, Ethiopia

ABSTRACT This study aimed to evaluate natural radioactivity levels and hazards of radionuclides 232Th, 226Ra and 40K in soil samples taken from 15 locations in the Lega Dembi gold mining, Oromia, Ethiopia, using gamma-ray spectroscopy coupled with an HPGe detector. It was observed that the respective mean specific activities for 226Ra, 232Th and 40K determined in the mining site were 23.87 ± 0.7, 52.5 ± 1.8 and 391.62 ± 11.35 Bq/kg, and 8.89 ± 0.4, 13.83 ± 0.6 and 423.68 ± 9.5 Bq/kg in the living areas. The specific activity of 232Th was above the permissive limit in the mining site, while for 226Ra and 40K were within the limit. The specific activity of 40K in the living area was observed to be above the permissive limit. The calculated value of radiation hazards parameters; radium equivalent activity (Raeq), internal and external hazards indices (Hin) and (Hex), the mean annual effective dose (AED), and gamma representative indices (Iγ) were within permissively limit. The mean absorbed dose rate in the mining site was above the recommended safety limit. The total annual gonadal dose equivalent value was found to be 494.8 ± 8.7 µSv/a in the mining site. This value was also above the permissively.

Regulation of the nitrite, biogenic amine and flavor quality of Cantonese pickle by selected lactic acid bacteria

Nitrite and biogenic amines (BAs) are widely found in fermented vegetables, while there is no research about the nitrite and BAs of Cantonese pickle. Therefore, the nitrite and BAs contents of 20 commercial Cantonese pickles were analyzed. Among these Cantonese pickles, the nitrite levels of samples 9 (23.95), 11 (58.68) and 19 (46.64 mg/kg) exceeded the limit standard, and the total BAs concentration of sample 12 (1143.29 mg/kg) above the recommended safety limit. Then three lactic acid bacteria (LAB) with the higher abilities of degrading nitrite and BAs were selected from the pickle samples with low nitrite and BAs concentration, which were identified as Lactiplantibacillus plantarum S1, L. plantarum S14 and Limosilactobacillus fermentum G9, respectively. Furthermore, in order to evaluate the application potential of screened LAB in the control BAs and nitrite in Cantonese pickle, the influences of these three LAB on nitrite, BAs, organic acids, and volatile compounds of Cantonese pickles were investigated. Compared to natural fermentation group, the nitrite-peak of inoculation fermentation groups were smaller (<16 mg/kg), and their BAs contents were always at lower levels (<51 mg/kg). Moreover, these selected LAB could enrich the concentration and type of organic acids and volatile substances in Cantonese pickle. Therefore, it could be concluded that these three LAB were potential for controlling nitrite and BAs in Cantonese pickle.

Estimation of indoor gamma radiation dose rate from concrete blocks constructed from tin mine tailings

The use of building materials made from geological sources contributes greatly to the indoor radiation exposure of human. As a result, it is critical for public health that building materials be screened for elevated radionuclide concentrations. This research measures the primordial radionuclide content of concrete blocks derived from mine tailings and also estimates the indoor annual effective dose rate (AEDR) and associated parameters. Furthermore, it presents a simple empirical relationship for evaluating dose rate per unit specific activity due to radionuclides from a wall of arbitrary dimensions. Twelve concrete blocks constructed using tin mine tailings as fine aggregates were collected locally and analyzed for 235U, 232Th and 40K content using gamma spectrometry analysis. The concentration of 238U ranged from 86.29 to 197.73 Bq/kg with a mean of 120.93 Bq/kg. Also, the specific activity of 232Th and 40K is within the limits: 99.01–353.67 Bq/kg and 500.71–1021.77 Bq/kg with mean values of 248.31 Bq/kg and 635.10 Bq/kg, respectively. Obtained dose rate per unit specific activity agreed well with data from literature. Using the derived values of dose rate per unit specific activity, the annual effective dose rate (AEDR) obtained from a typical Nigerian room varies significantly from that obtained from equations in referenced documents where a different room configuration was used. The mean AEDR from the realistic Nigerian room (3.6 × 3.6 × 3 m3) was higher than the world average value but less than the recommended safety limit of 1 mSvy−1. Some of the blocks with AEDR more than the safety limits were recommended for use in superficial quantities for building construction. The model derived in this study can be applied to calculate dose rates within any room configuration.

Assessment of radiological health risk and radiogenic heat production changeability of different sedimentary rocks at Gabal Um Hamd, Southwestern Sinai, Egypt

Soil is a source of natural radionuclides and a source of natural radiation risk to humans. This study aims to measure the radioactivity concentrations, contributions, radiological hazards and to quantify the radiogenic heat productions in thirty two rock samples having different lithology from the middle member of Um Bogma Formation in Gabal Um Hamd, southwestern Sinai, Egypt. The concentration of natural radionuclides was determined using a p-type Hyper Pure Germanium (HPGe) detector. The average activity concentrations of uranium thorium and potassium in the interested area were found to be 4909.58 ± 54.34 5003.12 ± 17.56 79.04 ± 8.82 and 137.35 ± 8.64 respectively. Other hazard indices average values were measured, such as: annual effective dose equivalent, radium equivalent activity, external and internal indices, annual gonad equivalent dose, and excess lifetime cancer risk. The radiologic hazards results, obtained in this study shows that the radiation levels are higher than the internationally approved values and the recommended safety limits. Furthermore, the results show that the radiogenic heat value ranged from 3.58 to 402.45 μW m −3 with an average value of 60.11 ± 0.79μW m −3 in the studied area which is higher than previously reported averages.

Rare case of intraoperative LMA detachment.

Dear Editor, A 35-year-old female weighing 80 kgs was posted for abdominal liposuction. Patient was accepted under ASA (American Society of Anesthesiology) I and Mallampati score 1. After preoxygenation the patient was premedicated with intravenous midazolam 1 mg, ondansetron 4 mg, and fentanyl 100 mcg. Induction was done with intravenous propofol 120 mg and atracurium 30 mg. Bag mask ventilation was confirmed and classic LMA (Laryngeal Mask Airway) size 4 was placed in the prone position and patient was put on elective ventilation. Proper minute ventilation was achieved with peak airway pressure of 16 cm of water. After 45 min, posterior liposuction was completed and patient was placed in supine position for anterior abdominal liposuction but it was observed that the airway pressure started showing low volume of 4–5 mm of H2O and saturation was starting to fall. ETCO2 was not showing any reading and capnograph was not present. Monitors and ventilator settings were rechecked for any disconnection but everything was in place. There was no chest rise and saturation was starting to fall. LMA was pulled out immediately but only the shaft (airtube) came out and cuff remained inside. Laryngoscopy had to be performed and the cuff was removed with the help of Magill’s forceps. After ruling out any injuries to the airway, bag mask ventilation was done and a fresh LMA number 4 was placed again to complete the remaining procedure. Circuit was connected to the LMA and ventilation was started. All the parameters were normal thereafter. The procedure was completed properly without any difficulty. Patient was normal at the time of discharge. The LMA mask was carefully examined and detachment was confirmed as shown in Figures 1 and 2.Figure 1: Laryngeal mask airway detachmentFigure 2: Laryngeal mask airway detachmentThe cause of such a detachment could not be pinpointed but repetitive use and sterilization of the device may have been responsible for this malfunction. According to some researchers, the reusable LMA can be used for more than 40 times.[1] According to hospital records the LMA that we used during the procedure was sterilized by ethylene oxide and used for over 24 times before. Though this number lies within the recommended safety limit of 40 times, it raises a question on the accepted norm of reusability of LMA.[1] In spite of using correct techniques for cleaning and sterilizing the device, the probability of its deterioration over time with each use cannot be ruled out. It has been suggested that the cuff of the device should be deflated and dehydrated as much as possible before sterilization.[2] In conclusion, a thorough external examination of the LMA device preoperatively is obligatory along with following strict sterilization techniques including complete deflation and dehydration of the cuff before sterilization to avoid such incidences in future. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Determination of Activity Concentration of Natural Radionuclides and Radiation Hazards' Assessment of Building Materials in High Background Radiation Areas of Homa and Ruri, Kenya.

The areas around Homa and Ruri hills in Homa Bay County in Kenya are associated with high background radiation levels. The activity concentration of the natural radionuclides (226Ra, 232Th, and 40K) in earthen building materials used in the areas of Homa and Ruri hills has been measured using a NaI (Tl) detector in this work. The measured values of radioactivity concentrations are used to estimate the associated radiological risk. The earthen building material samples from Ruri registered relatively high 232Th concentration values averaging 1094 ± 55 Bq/kg, nearly three times those of the samples from Homa. 226Ra level was not significantly different in both regions with Homa reporting 129 ± 10 Bq/kg and Ruri 111 ± 6 Bq/kg. 40K was however higher in the samples from Homa by an approximate factor of 2 relative to those from Ruri where the activity concentration was 489 ± 24 Bq/kg. The radium equivalents for 226Ra, 232Th, and 40K in the samples from Ruri were 111 ± 9, 1564 ± 125, and 38 ± 3 Bq/kg, while in Homa, the values were 129 ± 10, 570 ± 46, and 69 ± 5 Bq/kg, respectively. The calculated value of total radium equivalent in Ruri was 1713 ± 137 Bq/kg which was two times higher than that of Homa. 232Th contributed about 74% and 91% to the total radium equivalent in Homa and Ruri, respectively; thus, it was the one with the largest contribution to radiation exposure in both regions. The average indoor annual effective dose rates were 1.74 ± 0.14 and 3.78 ± 0.30 mSv/y in Homa and Ruri, respectively, both of which were above the recommended safety limit of 1 mSv/y.

Evaluation of natural radioactivity levels and potential radiological hazards of common building materials utilized in Mediterranean region, Turkey.

Radiometric measurement of building materials is very important to assess the internal and external exposure caused by the ionizing radiation emitted from terrestrial radionuclides in building materials. The activity concentrations of 226Ra, 232Th, and 40K in fifty-eight samples of fifteen different structural and covering building materials commonly used in Osmaniye province located in the Mediterranean region of Turkey were measured by using gamma-ray spectroscopy. The activity concentrations of 226Ra, 232Th, and 40K varied from 2.5 ± 0.1 (marble) to 145.7 ± 4.4 (clay brick), 1.3 ± 0.1 (marble) to 154.3 ± 4.1 (marble), and 8.6 ± 0.2 (sand) to 1044.1 ± 70.3 (granite), respectively. Radiological parameters (activity concentration index, alpha index, indoor absorbed gamma dose rate and the corresponding annual effective dose rate, and excess lifetime cancer risk) were estimated to evaluate the health hazards associated with these building materials. Since the estimated values of these parameters are within the recommended safety limits or criteria values, the use of the studied building materials in the construction of dwellings can be considered to be safe for the residents of the region.

Rational Fabrication of Crystalline Smart Materials for Rapid Detection and Efficient Removal of Ozone

AbstractTraditional ozone sensing and removal materials still suffer from high energy consumption and low efficiency. Thus, seeking new ozone‐responsive materials with high efficiency and broad working conditions is of great significance. Herein, we first developed covalent organic frameworks (COFs) for smart sensing and efficient removal of ozone. Notably, imine‐based COFs possess dramatically fast optical responses (&lt;1 s) to ozone as low as 0.1 ppm under broad working conditions (e.g., in the presence or absence of moisture, room temperature). Moreover, we found that imine‐based COFs can also be applied as excellent ozone removers that can efficiently reduce the ozone concentration below the recommended safety limit (&lt;0.1 ppm) for humans. The mechanism for the performance of imine‐based COFs was unveiled in‐depth by various characterization techniques and analyses. This study not only provides a new type of advanced materials for ozone sensing and removal but also broadens the application scope of COFs.

Skyline Tensile Forces in Cable Logging

Skyline tensile forces have been shown to frequently exceed the recommended safety limits during ordinary cable logging operations. Several models for skyline engineering analyses have been proposed. Although skyline tensile forces assume a dynamic behaviour, practical solutions are based on a static approach without consideration of the dynamic nature of the cable systems.The aim of this study was to compare field data of skyline tensile forces with the static calculations derived by dedicated available software such as SkylineXL. To overcome the limitation of static calculation, this work also aimed to simulate the actual response of the tensile fluctuations measured in the real environment by mean of a finite element model (FEM).Field observations of skyline tensile forces included 103 work cycles, recorded over four different cable lines in standing skyline configuration. Payload estimations, carriages positions, and time study of the logging operations were also collected in the field. The ground profiles and the cable line geometries were analysed using digital elevation models. The field data were then used to simulate the work cycles in SkylineXL. The dynamic response of six fully-suspended loads in a single-span cable line was also simulated by a dedicated FEM built through ANSYS®. The observed data and the software calculations were then compared.SkylineXL resulted particularly reliable in the prediction of the actual tensile forces, with RMSE ranging between 7.5 and 13.5 KN, linked to an average CV(RMSE) of 7.24%. The reliability in predicting the peak tensile forces was lower, reporting CV(RMSE) of 10.12%, but still not likely resulting in a safety or performance problem. If properly set-up and used, thus, SkylineXL could be considered appropriate for operational and practical purposes. This work, however, showed that finite element models could be successfully used for detailed analysis and simulation of the skyline tensile forces, including the dynamic oscillations due to the motion of the carriage and payload along the cable line. Further developments of this technique could also lead to the physical simulation and analysis of the log-to-ground interaction and the investigation of the breakout force during lateral skidding.

EVALUATION OF HEAVY METALS CONCENTRATIONS IN SOIL AND WATER SAMPLES AROUND E-WASTE DUMPSITES IN OLABISI ONABANJO UNIVERSITY, AGO-IWOYE, SOUTH-WESTERN NIGERIA

In this paper, the health implications of electronic wastes (E-Wastes) on the inhabitants of the University site at AgoIwoye, Ogun State South Western Nigeria were reported. The main goal of this study was to evaluate heavy metals concentrations in the soil around e-wastes dumpsite in soil and water samples at Olabisi Onabanjo University, Ago-Iwoye Ogun State. The heavy metal concentrations in soil and water around the e-waste dumpsites were measured and compared with international standard limits. The values recorded for soil and water were below the recommended safety limit. This is an indication that the soil and water of Olabisi Onabanjo University can be used for drinking, agricultural purposes, and construction of buildings without causing any health hazard. The results of this study revealed that the presence of heavy metals in water was not significant and in the order of increased magnitude Cd &lt; As &lt; Ni &lt; Co &lt; Zn &lt; Pb &lt; Cr &lt; Cu. However, care must be taken to face the challenges in the future for health safety.