Heavy metal exposure from cooked rice grain ingestion and its potential health risks to humans from total and bioavailable forms analysis

Heavy metal in rice studies has attracted a greater concern worldwide. However, there have been limited studies on marketed rice samples although it represents a vital ingestion portion for a real estimation of human health risk. This study was aimed to determine both total and bioaccessible of trace elements and heavy metals (Cd, Cr, Cu, Co, Al, Zn, As, Pb and Fe) in 22 varieties of cooked rice using an inductively coupled plasma-optical emission spectroscopy. Both total and bioaccessible of trace elements and heavy metals were digested using closed-nitric acid digestion and Rijksinstituut voor Volksgezondheid en Milieu (RIVM) in vitro digestion model, respectively. Human health risks via Health Risk Assessment (HRA) were conducted to understand exposure risks involving adults and children representing Malaysian population. Zinc was the highest while As was the lowest contents for total and in their bioavailable forms. Four clusters were identified: (1) Pb, As, Co, Cd and Cr; (2) Cu and Al; (3) Fe and (4) Zn. For HRA, there was no any risks found from single element exposure. While potential carcinogenic health risks present for both adult and children from single As exposure (Life time Cancer Risk, LCR > 1 × 10−4). Total Hazard Quotient values for adult and children were 27.0 and 18.0, respectively while total LCR values for adult and children were 0.0049 and 0.0032, respectively

Bioavailability of heavy metal in rice using in vitro digestion model

Rice is a carbohydrate, one of the plant-based foods that can accumulate heavy metal from soil and the irrigation water. Since total heavy metal always overestimates the amount of heavy metal available in rice, bioavailability of heavy metal is always preferred. Many studies have been done and found that in vitro methods offer an appealing alternative to human and animal studies. They can be simple, rapid, low in cost and may provide insights which not achievable in the in vivo studies. In vitro digestion model for rice may differ from other in vitro digestion models applied in soil or other type of foods studies. This review aims to provide an overview of in vitro digestion model used to determine bioavailability of heavy metal in rice, summarize health risk assessment application of heavy metal in rice studies and highlight the importance of health risk assessment to be included in the studies. Future exploration of in vitroNdigestion model and health risk assessment application on the bioavailability of heavy metal in rice was also suggested

Bioavailability of Heavy Metal in Cooked Rice and Health Risk Assessment Using in Vitro Digestion Model

Rice ingestion is one of major pathway for heavy metal bioaccumulation in human. This study has employed an in vitro digestion model to determine non-carcinogenic health risk assessment (HRA) from bioavailability of heavy metal concentrations in cooked rice. Totally, 22 varieties of marketed rice samples were purchased to assess bioavailability of heavy metal (Cd, Cu, Cr, Fe and Zn) using in vitro digestion model. Bioavailability of heavy metal concentrations in were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Outputs showed bioavailability of heavy metal concentrations were decreased from Zn > Fe > Cu > Cr > Cd. Zinc was found as the most abundant bioavailability of heavy metal concentration in the cooked rice samples and Thai fragrant rice has the highest Zn content. Hazard Quotient (HQ) values for bioavailability of heavy metal studied were less than 1 for adult and children indicating that there were no any non-carcinogenic health risks present. The application of in vitro digestion model in determining bioavailability of heavy metal produces a more realistic estimation of human health risks exposure

Ergonomic interventions: comparisons between footrest and anti-fatigue mat in reducing lower leg muscle discomforts during prolonged standing

Ergonomics is a science focusing on the study of human fit, decreasing human fatigue and discomfort through the design of new product. Prevention related to workers injury and illness such as muscle discomfort is part of the main goals in ergonomics interventions. Thus, this present study investigates the effectiveness of ergonomic interventions such as footrest and floor conditions in reducing workers lower leg muscle discomforts during prolonged standing. The main objective of this study was to determine and compare the lower leg muscles discomfort (exertion percentage (%)) of Gastrocnemius and Tibialis Anterior among the respondents using the two ergonomic interventions (footrest and anti-fatigue mat). About 60 healthy subjects were recruited to stand for 2 hours (120 minutes) while using the two interventions in different session with one week interval between each test session. During standing, lower leg muscle discomfort of Gastrocnemius and Tibialis Anterior muscles were continuously monitored. Changes in lower leg muscle discomforts over standing time were measured using the surface Electromyography (sEMG). In this study, the sEMG readings showed that the percentage of exertion (%) were increasing with time (within 120 minutes) on muscles for both legs with the usage of the interventions (footrest and anti-fatigue mat). However, the percentage of exertion (%) from the sEMG readings were lower compared to previous studies. The independent t-test was used to find the mean changes on exertion percentage (%) between each muscles of both legs for the two interventions. Results found that there were significant exertion percentage at certain time with 15 minutes time period within the 120 minutes standing. This study showed that the ergonomic interventions (anti-fatigue mat and footrest) gives a low number of exertion percentage (%), showing a reduced muscle discomfort to the lower leg muscles compared to previous studies and interventions. In comparisons with footrest, this study showed that anti-fatigue mat is more applicable for the assembly workers in the industrial factory. The data produced by the comparisons between the two interventions can be useful especially to the Department of Occupational Safety and Health Malaysia (DOSH) in enhancing the safety and wellbeing of industrial workers in Malaysia

Effect of footwear interventions on muscle discomfort and lower leg muscle fatigue among industrial workers

Introduction: Prolonged standing has been recognized as one of the factors which contributes about83% of MSDs among industrial workers (Zander, King and Ezenwa, 2004). Many ergonomics interventions have been recommended to reduce the effects of prolonged standing andvibration massage was found as an effective solution to delayed onset of muscle pain and discomfort. Objective: Thus, main objective of this study was to study the effect of prototype insole built-in massager on lower leg muscle discomfort among industrial workers during prolonged standing. Methodology: The study was conducted in a controlled room at a selected manufacturing company in Selangor which involved 110 male respondents. First phase of study involved the identification of characteristics in Product Design Specification (PDS) for an ideal prototype insole built-in massager. Then, second phase involved the experimental study design in which the prototype insole built-in massager being compared with other interventions (footrest and anti-fatigue mat) and control group (normalshoe). The respondents evaluated their discomfort rating using Borg’s Scales Questionnaire for every 15 minutes. At the same time, sEMG electrodes were attachedDuring the 2-hours standing, all respondents would do a task which were sorting the mixed items at the workstation provided. Results and discussion: Results indicated that respondents do experience mild discomfort on all their body parts during the experimental study especially at the lower body parts. Interventions (prototype insole built-in massager, footrest and anti-fatigue mat) groups had showed reductions in discomfort rating for all body parts compared to control group.The sEMG results indicated that prototype insole built-in massager gave the lowest percentage of exertion (22.38 – 42.2%) for all muscles studied compared to other interventions (anti-fatigue mat and footrest). There was a positive effect of discomfort level on both left and right Tibialis anterior and Gastrocnemius with the usage of prototype insole built-in massager compared to control group.There was a significant difference of discomfort rating between control and prototype insole built-in massager shoe group at ankle and feet, knee and calf part(p<0.05).Besides, there were significant differences of means for sEMG level (p<0.001) of the prototype built-in massager with other interventions (anti-fatigue mat and footrest). Conclusion and recommendations: Overall, there were positive indicator that the prototype insole built-in massager reduced the muscle discomfort of lower leg muscles to the workers compared to other interventions.Vibration massager in the insoles increase the blood circulation by relaxing foot muscles and decrease the discomfort level of the feet. However, this study recommended a much bigger population and more variation in measurement was needed. This prototype insole built-in massager can also serve as the reference required for the future interventions of prolonged standing among industrial workers

Total and bioavailability concentrations of heavy metals in varieties of cooked rice, and health risk assessment

Rice in the global market is increasing over the years similarly with the rice demand. Metal contamination in rice is a rising problem recently. However, limited information regarding the bioavailability of metals contamination and its health risks after rice ingestion was known. This study aimed to determine both total and bioavailability concentrations of metals (As, Cd, Cu, Cr, Co, Al, Fe, Zn and Pb) in varieties of cooked rice samples. Moreover, this study aimed to compare bioavailability concentrations of \\etals with the rice varieties, rice grain size and origin. This study also aimed to calculate Bioaccumulation Factor (BAF) of heavy metal in varieties of cooked rice samples and assess relationships between different bioavailability metals in varieties of cooked rice. In addition, this study also identified the similarity of chemical properties among the bioavailability metals using Cluster Analysis (CA). Lastly, this study hasassessed human carcinogenic and non-carcinogenic health risks using Health Risk Assessment (HRA). About 1 kg of rice for 22 rice varieties were purchased from local groceries and supermarket based on the convenience sampling. Total metal digestion was determined by using nitric acid while bioavailability metal digestion was done using RIVM in vitro digestion model. The metal concentrations were then analysed by using Inductively Coupled Optical Emission Spectrometry Pelkin Elmer Optima 8300. Results found that Zn concentration was the highest while As was the lowest metals concentration in both total and bioavailability concentrations. All total and bioavailability concentrations of metals were below the maximum permitted levels stated by Malaysian Food Regulation (1985), FAO/WHO CAC (1984) and FAO/WHO CAC (1989). Mann-Whitney U test results (Z values) show that there was a significant difference between total and bioavailability of metals concentration (p <0.05). Kruskal walis tests results (X2 values) also show that there was a significant differences between bioavailability concentrations of metals and rice varieties (p<0.05), except for As. However, Kruskal Walis Test (X2 values) shows no significant difference between bioavailability concentrations of metals with type of rice grains size (p>0.05). Nevertheless, Mann-Whitney U results (Z values) show no significant difference between bioavailability concentrations of metals with the rice origin (p>0.05). The bioaccumulation factor (BAF) values were found in the order of Fe>Cu>Al>Zn>Cd>Co>As>Pb>Cr with parboiled rice has the highest BAF values for Fe (BAF values>1). Spearman Correlation Coefficient results (rs values) show strong positive relationships between the bioavailability metals; FeB and AlB (rs=0.83) and between AsB with PbB (rs =0.88). From Cluster Analysis (CA) results, four clusters were identified, which were Cluster 1 (Pb, As, Co, Cd, and Cr), Cluster 2 (Cu and Al), Cluster 3 (Fe), and Cluster 4 (Zn). As for HRA determination, there was no non carcinogenic health risks found (Hazard Quotient, HQ<1) for adult and children through individual heavy metal exposure. However, there was non carcinogenic health risk present among adult via the combination of these heavy metal exposures (HI > 1). On the other hand, there were potential carcinogenic health risks present for adult and children via individual intake of As (Lifetime Cancer Risk > 1x10-4). Furthermore, the values for Total Cancer Risk (TCR) for Pb and As in both adult and children were above the acceptable range (TCR > 1 x 10-4). As conclusion, this study shows that Zn was the highest metal found in 22 varieties of rice with a significant difference between total and bioavailability metal concentrations. There was also a significant difference between bioavailability metal concentration and the rice varieties. Besides, non-carcinogenic and carcinogenic health risks may posed by adult and children through their combined metal exposure in the rice