Deep well injection for the waste brine disposal solution of potash mining in Northeastern Thailand.

Under the pressure of the existing world population growth trends, the dercreasing pastoral fields and the increasing duration and incidences of drought and heat stress, the potash fertilizers demand dramaticly increase to enhance the world food production. Asia currently consumes 40% of the world's potash market, yet 70% of world potash exports come from mines in Canada and Europe. Weak collective efforts to produce potassium fertilizers economically pose the risk of global shortages of potash goods and threatening global food security. While the Khorat Plateau in Northeastern Thailand is noted to contain active and promising regional potash deposits, developing a proper potash industry in the region has largely been unsuccessful due to major constraints such as the challenge of establishing a brine disposal solution. This study demonstrates the performance of deep well injection (DWI) as an environmentally friendly alternative to secure waste brine production from the potash mine. The groundwater numerical model demonstrates the movement and penetration of the concentrate during and after deep well injection. The boundary condition was utilized from the regional hydrogeology data. The waste brine injection is based on the waste products of the mine factory. Our simulation shows that the DWI can isolate waste brine with freshwater by injecting it into the deep formation based on the geologic structure and properties analysis. With high porosity and low specific yield, the Khok Kruat formation within Khrat Basin shows a high potential injection rate of 200,000 m3/day, which is 200 times higher than current water brine production rates. Moreover, the salinity can easily dissolve into the target domain with specific formation properties. Hence, the DWI not only boosts the potash industry's image in the long term but also enable sustainable potash mining development in the region. Finally, we recommend that government agencies with regulatory oversight over the DWI must promote further research associated with site characterization, well construction and injection technologies, and monitoring tools in the long term.

Characterizing the relationship between temperature and mortality in tropical and subtropical cities: a distributed lag non-linear model analysis in Hue, Viet Nam, 2009-2013.

BACKGROUND: The relationship between temperature and mortality has been found to be U-, V-, or J-shaped in developed temperate countries; however, in developing tropical/subtropical cities, it remains unclear. OBJECTIVES: Our goal was to investigate the relationship between temperature and mortality in Hue, a subtropical city in Viet Nam. DESIGN: We collected daily mortality data from the Vietnamese A6 mortality reporting system for 6,214 deceased persons between 2009 and 2013. A distributed lag non-linear model was used to examine the temperature effects on all-cause and cause-specific mortality by assuming negative binomial distribution for count data. We developed an objective-oriented model selection with four steps following the Akaike information criterion (AIC) rule (i.e. a smaller AIC value indicates a better model). RESULTS: High temperature-related mortality was more strongly associated with short lags, whereas low temperature-related mortality was more strongly associated with long lags. The low temperatures increased risk in all-category mortality compared to high temperatures. We observed elevated temperature-mortality risk in vulnerable groups: elderly people (high temperature effect, relative risk [RR]=1.42, 95% confidence interval [CI]=1.11-1.83; low temperature effect, RR=2.0, 95% CI=1.13-3.52), females (low temperature effect, RR=2.19, 95% CI=1.14-4.21), people with respiratory disease (high temperature effect, RR=2.45, 95% CI=0.91-6.63), and those with cardiovascular disease (high temperature effect, RR=1.6, 95% CI=1.15-2.22; low temperature effect, RR=1.99, 95% CI=0.92-4.28). CONCLUSIONS: In Hue, the temperature significantly increased the risk of mortality, especially in vulnerable groups (i.e. elderly, female, people with respiratory and cardiovascular diseases). These findings may provide a foundation for developing adequate policies to address the effects of temperature on health in Hue City.

Population-based cancer survival in sites in Viet Nam.

BACKGROUND: Very few population-based cancer survival studies have been performed in Viet Nam. The aim of the present study was to estimate observed and relative cancer survival rates in populations of Phu Tho, Hanoi and Hue city. METHODS: A retrospective-cohort study was performed for all 12 districts of Phu Tho province (semi-highland area in the north), eight districts of Hanoi city (Capital) and four districts of Hue city in central area). Seven indicators were collected for each case of cancer death: name, age, sex, date of the first diagnosis having cancer, date of death, the cause of death and full address. Two steps were done. Firstly, we collected name, age, sex, date of death, the cause of death and full address; secondly, we collected date of the first diagnosis having cancer by a household visit by trained interviewer. Survival time was calculated from the date of death minus the date of diagnosis for each case of cancer. Observed survival rates for 1-year, 2-years, 3-years, 4-years and 5-years were estimated by the form of survival number multiplied by 100 then corrected for the registered number of cancer cases. For relative survival rates, the observed survival rates were corrected for the general population survival rate. RESULTS: Males and females combined, for all cancer sites, 1-year, 2-year, 3-year, 4-year and 5-year observed and relative survival rates were 23.8%-23.9%, 8.5%-8.5%, 3.8%-3.8%, 2.6%-2.6%, 1.7%-1.7%, respectively. The highest one-year relative cancer survival rate was seen in the capital, Hanoi city (49,8%), followed by Hue city in the central area (24,7%), and the lowest in Phu Tho, north-semi-highland (21.8%). CONCLUSIONS: The better cancer survival in Hanoi than in Phu Tho province, as well as the results overall, point to a need for greater efforts in early detection and treatment, especially in rural areas.