Simulation and optimisation of magnetic and experimental study of magnetic field coupling constructed wetland.

This study developed a novel constructed wetland (CW) coupled with a magnetic field for treating domestic wastewater, and the magnetic field distribution was solved and optimised by the finite element method. Herein, we investigated the effects of optimising magnetic field optimisation and studied its impact on CW treatment performance and the responses of a microbial community. The optimisation results showed that the average magnetic field strength of the CW unit increases from 3 to 8 mT, and the proportion of areas with magnetic field strength greater than 5 mT also increases from 30% to 74%. The water quality analysis results showed that the removal of chemical oxygen demand (COD) and NH4+-N (p < 0.01) was significantly increased by the magnetic field (average 3 mT), increasing by 12.2% and 8.49%, respectively. Moreover, the removal of COD and NH4+-N (p < 0.01) was more significantly increased by M-VFCW(O) (average 8 mT), increasing by 15.58% and 49.1%, respectively. The magnetic field application shifted significantly the abundance of dominant bacteria in CWs. Relative abundance of dominant bacteria such as Proteobacteria (63.3%), Firmicutes (4.72%) and Actinobacteria (2.11%) that played an important role in organics removal and nitrification and denitrification-related bacteria such as Nitrospirae (1.48%) and Planctomycetes (9.58%) significantly promoted in M-VFCW(O). These results suggest that introducing a magnetic field into CWs may improve organics and nitrogen removal via the biological process, and the optimisation of the magnetic field was significant in enhancing the performance of VFCWs.

Estimation of work-related injury and economic burden attributable to heat stress in Guangzhou, China.

BACKGROUND: Climate change has exacerbated the health effects of high ambient temperatures on occupational health and safety; however, to what extent heat stress can induce workplace injuries and economic costs is poorly studied. This study aimed to quantify the attributable fractions of injury claims and subsequent insurance payouts using data from work-related injury insurance system in Guangzhou, China. METHODS: Individual workers' injury claims data were collected for the period of 2011-2012, including demographic characteristics and work-related information. Daily maximum wet bulb globe temperature (WBGT, °C) was calculated from meteorological data. To examine the association between WBGT index and work-related injury, we fit a quasi-Poisson regression with distributed lag non-linear model. Then we calculated the numbers of injury claims and costs of insurance compensations attributable to days with WBGT above the heat stress limit according to the national occupational health standards. RESULTS: There were 9550 work-related injury claims, resulting in an insurance payout of 282.3 million Chinese Yuan. The risks of injury claims increased with rising WBGT. 4.8% (95% eCI: 2.9%-6.9%) of work-related injuries and 4.1% (95% eCI: 0.2%-7.7%) of work-related injury insurance payouts were attributed to heat exposure for WBGT threshold above the heat stress limit. Male workers, those in small enterprises and with low educational attainment were especially sensitive to the effects of heat exposure. CONCLUSIONS: Heat stress can contribute to higher risk of work-related injury and substantial economic costs. Quantified the impacts of injuries and related economic costs should be considered to develop targeted preventive measures in the context of climate change.

Does hot weather affect work-related injury? A case-crossover study in Guangzhou, China.

BACKGROUND: Despite increasing concerns about the health effects of climate change, the extent to which workers are affected by hot weather is not well documented. This study aims to investigate the association between high temperatures and work-related injuries using data from a large subtropical city in China. METHODS: We used workers' compensation claims to identify work-related injuries in Guangzhou, China during 2011-2012. To feature the heat effect, the study period was restricted to the warm seasons in Guangzhou (1 May-31 October). We conducted a time-stratified case-crossover study to examine the association between ambient outdoor temperatures, including daily maximum and minimum temperatures, and cases of work-related injury. The relationships were assessed using conditional Poisson regression models. RESULTS: Overall, a total of 5418 workers' compensation claims were included over the study period. Both maximum and minimum temperatures were significantly associated with work-related injuries, but associations varied by subgroup. One °C increase in maximum temperature was associated with a 1.4% (RR = 1.014, 95%CIs 1.012-1.017) increase in daily injury claims. Significant associations were seen for male and middle-aged workers, workers in small and medium-sized enterprises, and those working in manufacturing sector. And 1 °C increase in minimum temperature was associated with 1.7% (RR = 1.017, 95%CIs 1.012-1.021) increase in daily injury claims. Significant associations were observed for female and middle-aged workers, workers in large-sized enterprises, and those working in transport and construction sectors. CONCLUSIONS: We found a higher risk of work-related injuries due to hot weather in Guangzhou, China. This study provides important epidemiological evidence for policy-makers and industry that may assist in the formulation of occupational safety and climate adaptation strategies.

[Establishment and validation of an indicator system of risk assessment for mechanical cuts].

OBJECTIVE: To establish an indicator system of risk assessment for mechanical cuts, and to validate the system using examples. METHODS: An indicator system was proposed by the expert investigation method. The index weight, expert authority coefficient, and degree of coordination were determined. The reasonability and stability of the expert questionnaire were evaluated by the reliability analysis. Some on-site examples were given to validate the indicator system. RESULTS: An indicator system containing 3 first-class indicators, 10 second-class indicators, and 34 third-class indicators was obtained by screening indicators using the boundary value method and the assignment transformation method. The average expert authority coefficient was 0.79. The average expert coordination coefficient was 0.47. The overall reliability coefficient was 0.884. The scores obtained using the indicator system were significantly correlated with the actual injury results in six workplaces (r=0.866, P<0.01). CONCLUSION: The indicator system of risk assessment for mechanical cuts proposed in this study is reasonable and highly consistent with the actual injury results. However, this indicator system still needs further validation and optimization.

Effectiveness of participatory training on improving occupational health in small and medium enterprises in China.

BACKGROUND: Participatory training on occupational health is widely used in the world. Evaluations of local experiences are necessary to its successful performance. OBJECTIVES: The project evaluated the effectiveness of participatory training on occupational health improvement in small and medium enterprises of China, and explored local practice experiences. METHODS: Participatory training was provided to 525 welding workers from 25 small and medium enterprises in ship building and machinery manufacturing industries. This training consisted of interactive learning, worksite assessment and group discussion on laws/regulations, safety of machine operation, prevention of slips and trips, fire/explosion prevention, ergonomics, and recognition and prevention of other workplace hazards. Workers completed knowledge, attitude, and practice and worksite assessment questionnaires before and 3 months after intervention. RESULTS: Knowledge, attitude, and practice scores were significantly increased through the training. An inventory of workplace safety modifications was proposed by participants and many were fixed by workers and employers. Health management and personal protective equipment provision/use were most often improved, but improvements in engineering control and health-related accommodations remained unsatisfactory. CONCLUSIONS: Workers could recognize and fix workplace hazards after the participatory training. More efficient measures in China are to be explored to improve implementing solutions, especially on preventive engineering and human ergonomics.