Heavy Metal Contamination in Oryza sativa L. at the Eastern Region of Malaysia and Its Risk Assessment

Paddy plants tend to accumulate heavy metals from both natural and anthropogenic sources, and this poses adverse risks to human health. The objective of this study was to investigate heavy metal contamination in paddy plants in Kelantan, Malaysia, and its health risk assessment. The bioaccumulation of heavy metals was studied by means of enrichment (EF) and translocation factors (TF). The health risk assessment was performed based on USEPA guidelines. The EF for heavy metals in the studied areas was in the descending order of Cu > As > Cr > Cd > Pb. Meanwhile, Cr and Pb exhibited higher TF values from stem to grain compared with the others. The combined hazard index (HI) resulting from five heavy metals exceeded the acceptable limit (HI >1). The lifetime cancer risk, in both adult and children, was beyond the acceptable limit (10−4) and mainly resulted from exposure. The total cancer risk (CRt) due to simultaneous exposures to multiple carcinogenic elements also exceeded 10−4. In conclusion, intake of heavy metal through rice ingestion is likely to cause both non-carcinogenic and carcinogenic health risks. Further research is required to investigate the extent of heavy metal contamination in agricultural soils and, moreover, to establish human exposure as a result of rice consumption.

Transfer accuracy of 3D-printed trays for indirect bonding of orthodontic brackets:

ABSTRACT Objectives To evaluate the transfer accuracy of 3D-printed indirect bonding trays constructed using a fully digital workflow in vivo. Materials and Methods Twenty-three consecutive patients had their incisors, canines, and premolars bonded using fully digitally designed and 3D-printed transfer trays. Intraoral scans were taken to capture final bracket positioning on teeth after bonding. Digital models of postbonding scans were superimposed on those of corresponding virtual bracket setups, and bracket positioning differences were quantified. A total of 363 brackets were evaluated. One-tailed t-tests were used to determine whether bracket positioning differences were within the limit of 0.5 mm in mesiodistal, buccolingual, and occlusogingival dimensions, and within 2° for torque, tip, and rotation. Results Mean bracket positioning differences were 0.10 mm, 0.10 mm, and 0.18 mm for mesiodistal, buccolingual, and occlusogingival measurements, respectively, with frequencies of bracket positioning within the 0.5-mm limit ranging from 96.4% to 100%. Mean differences were significantly within the acceptable limit for all linear dimensions. Mean differences were 2.55°, 2.01°, and 2.47° for torque, tip, and rotation, respectively, with frequencies within the 2°-limit ranging from 46.0% to 57.0%. Mean differences for all angular dimensions were outside the acceptable limit; however, this may have been due to limitations of scan data. Conclusions Indirect bonding using 3D-printed trays transfers planned bracket position from the digital setup to the patient's dentition with a high positional accuracy in mesiodistal, buccolingual, and occlusogingival dimensions. Questions remain regarding the transfer accuracy for torque, tip, and rotation.

Centralised and decentralised data communication scheme for voltage regulation in DC Microgrids

Voltage regulation is one of the main control issues in DC Microgrids (MGs). To achieve voltage regulation in MGs, exchange information between distributed generation units (DG) is inevitable. There are two types of data exchange proposed and discussed, centralised and decentralised data communication schemes. Many papers in the literature did not give attention to the type of data communication infrastructure that will have a significant impact on both centralised and decentralised schemes. This paper proposes centralised and decentralised data communication scheme and their impact on voltage regulation in DC MGs. The dynamic performance of a DC MG with loads fluctuations, operating with the proposed technique, is evaluated through simulation analyses, realized in MATLAB. Both the proposed centralised and decentralised methods are able to maintain the voltage within acceptable limit during loads fluctuations; however the centralised method is around five times faster than the decentralised method. The results show the superiority of the proposed method for the DC MGs operations during load demands fluctuations, loads varieties, communication delays and structures.

Determination of Zn, Fe, Cr and Cu in Marine Fish Commonly Consumed in Senegal

The content of four heavy metals (zinc, iron, chromium and copper) in muscles, liver and gonads has been studied for the five most consumed fish species (Cephalopholus taeniops, Scomber japonicus, Lagocephalus laevigatus, Pagellus bellottii and Pagrus caeruleostictus) in the Soumbedioune region. The samples were digested by acid digestion. The metal contents were quantified using a PF-11 type photometer. The results obtained show that metals such as zinc, iron and chromium are significantly higher (p <0.05) in the muscles of the four species than in the liver and gonads. However, the levels of heavy metals in the muscles, liver, and gonads of the five species are above the acceptable limit recommended by the FAO and WHO, with the exception of the copper levels in the gonads of the species Pagellus bellottii.

Some physicochemical parameters in the surface water of mini Whuo Stream in Port Harcourt, Rivers State, Nigeria

The levels of physicochemical properties of Mini Whuo Stream in Port Harcourt, Rivers State, Nigeria was evaluated. The physicochemical parameters were analyzed using standard conventional procedures. The average values recorded for the physicochemical parameters during the months of investigation were in the range; temperature; 30.00±0.42-30.26±0.83oC, with all-round mean of 30.14±0.47oC, pH; 6.22±0.33-6.42±0.25 (6.29±0.29), electrical conductivity; 146.01±74.04-147.26±75.13µS/cm (146.58±74.69 µS/cm), total alkalinity; 61.63±6.37-62.20±6.41mg/L (61.91±6.41 mg/L), sulphates; 109.67±51.34-110.67±51.88mg/L (110.22±51.81 mg/L), nitrates; 12.20±2.38-12.60±2.86mg/L (12.31±2.65 mg/L), turbidity; 49.32±1.49-50.18±2.02 NTU(49.83±1.55 NTU), TDS; 74.20±36.43-75.61±37.50 mg/L (75.00±36.81 mg/L), TSS; 27.14±2.12-28.37±0.78mg/L (27.64±1.89 mg/L), chlorides; 15.17±2.90-15.66±2.70mg/L (15.34±2.65 mg/L) and salinity; 24.36±4.83-24.82±4.97mg/L (24.66±4.78 mg/L). The evaluation of the physicochemical parameters showed that the Mini Whuo Stream has been contaminated due to human activities within the stream and therefore adequate measures should be taken to forestall the present situation of the stream in order to mitigate any possible increase in deterioration of the studied physicochemical parameters in the stream beyond acceptable limit.

Evaluation of Some Selected Heavy Metals in Groundwater from Samaru, North-western Nigeria

The chemical properties of selected heavy metals in groundwater from selected locations in Samaru, Zaria were determined and compared with Nigerian standards.Water samples were collected and chemical properties were determined. The Chemical properties such as Lead (Pb), Zinc (Zn), Copper (Cu), Cobalt (Co), Iron (Fe) Cadmium (Cd), Manganese (Mn), and Nickel (Ni) were determined. The chemical properties were determined following the American Public Health Association (APHA) procedure. The Data were analyzed using the World Health Organization (WHO) and the Nigerian Standard of Drinking Water Quality (NSDWQ). The findings showed that Pb, Zn, Cu, Co in all the samples and Fe in samples B, D, F, and G` were within the acceptable limit. While Cd, Mn, and Ni in all the samples and Fe in samples A, C, E, and H were more than the acceptable limit as presented in Table 2. Therefore the results show that the Samaru Groundwater is not totally good for consumption since Cadmium (Cd), Manganese (Mn), and Nickel (Ni) were more than the acceptable limit. Moreover, it is recommended that urgent prevention measures should be put in place to prevent increased concentrations of Cd, Fe, Mn, and Ni as a result of anthropogenic activities.Keywords: Concentration, Drinking water quality, Groundwater, Heavy metals.

Food Waste and Qualitative Evaluation of Menus in Public University Canteens—Challenges and Opportunities

Background: This study aims to evaluate food waste and menu quality in two canteens (A and B) from a Portuguese public university in order to identify challenges and opportunities to improve the food service. Methods: Food waste included the analysis of two canteens over 5 consecutive days by selective aggregate weighing. A qualitative evaluation of a 5-week menu cycle related to lunches was performed through the Qualitative Evaluation of Menus (AQE-d) method. Results: Both menus have “satisfactory” evaluations and lower adequacy to the dietary guidelines in criteria A, which evaluates general items from the dish, and in criteria B, which evaluates meat, fish and eggs. The calculated mean of food waste in both canteens exceeded the acceptable limit of 10%, except for the vegetarian (7.5%) dish in canteen A. The biggest waste was found in the vegetarian dish (16.8%) in canteen A. In meat dishes the conduit presents more waste (17.0%) than in fish and vegetarian dishes. Among these, the vegetables were the most wasted (25.3% and 27.9%, respectively). Conclusion: This work presents some insights to future interventions in the direction of a healthier and more sustainable foodservice.

Preliminary Results of Air Pollution Status in Selected Roadsides in Jalingo, Taraba State Nigeria

The rapid increase in vehicular activities in the past two centuries contributes vastly to air pollution levels. In as much as Social interactions and economic growth are well enhanced by vehicular transportation in many developing countries, it is unfortunate that exhausts from vehicles contribute immensely to ambient air quality especially in the urban areas. The concentrations of carbon monoxides (CO) and carbon dioxide (CO2) emissions in selected roadsides in Jalingo have been assessed. Four roads were used as sample locations where the concentration of CO2 and CO were measured using an air quality meter for four weeks. The mean concentration of CO2 and CO obtained were respectively as follows: 542.25 ppm and 7.49 ppm for the roadblock, 540.05 ppm and 5.55 ppm for Hammaruwa way, 598.81 ppm and 17.42 ppm for market road, and 463.80 ppm and 1.08 ppm for Nigerian Labour Congress (NLC) road (control). Based on the acceptable limit of CO2 (600 ppm), the Roadblock road, Hammaruwa way, and the NLC/control road are safe. Only the market road had value that exceeded the acceptable limit, and it may be attributed to high vehicular activities on the roadsides. Therefore, more alternative roads should be constructed in other to minimize traffic congestion and also, the use of nose masks should be encouraged. For the CO, all the sites are safe because they fall within the acceptable level of CO (1-70 ppm).

Spatial Variation Study of Heavy Metal in Ground Water of Southern Part of Upper Berach River

The present study was conducted to study heavy metal pollution in ground water of southern part of Upper Berach river. The water samples for the heavy metal analysis were collected from the open well of the 38 locations from Upper Berach river to find out concentration of different heavy metal such as Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn), Cadmium (Cd), Lead (Pb) and Nickel (Ni). The different heavy metals thematic maps of study area were prepared under GIS environment and the spatio-temporal variations of these parameters were analyzed. Results of the study indicates that about 57.94 per cent area shows Fe within BIS acceptable limit (< 0.3 mg/lit) and 42.06 per cent area show exceed Fe above acceptable limit of drinking purpose. About 42.03 per cent area shows Mn within BIS acceptable limit (< 0.1 mg/lit) and 57.97 per cent area shows Mn above permissible limit of drinking purpose.

Utilization of Arduino Control in Mitigating the Hybrid Harmonics of DC/AC Inverter

This Paper deals with the implementation of Harmonics distortion in distribution system by using the method of hybrid of active filter and passive filters. The active filter is used to reduce the distortion present in the output. Boost converter is used to increase the voltage level. This boost converter is connected to the inverter, which is designed by using the MOSFET as a switch. In practical application the pulses for the inverter is given by using the Arduino control. By using this hybrid method, the total harmonics distortion is reduced to below the acceptable limit. Simulation for this proposed method is done by using the MATLAB simulink. Initially, fast fourier transform may found to mitigate harmonics. But emerging technologies like Arduino control is proved to simple and economical in carrying out the same task effectively.