Bitcoin has attracted a wealth of attention in the media and by investors alike and this paper investigates whether Bitcoin can act as a hedge or safe haven against world currencies. Contrary to previous studies, we assess the relationship between Bitcoin and currencies at the hourly frequency since Bitcoin experiences quite large volatility throughout the day. We employ an ADCC model and find that Bitcoin can be an intraday hedge for the CHF, EUR and GBP, but acts as a diversifier for the AUD, CAD and JPY. We also implement the non-temporal Hansen (2000) test to examine the safe haven properties of Bitcoin and find that Bitcoin is a safe haven during periods of extreme market turmoil for the CAD, CHF and GBP. Therefore our results indicate that Bitcoin does act as an intraday hedge, diversifier and safe haven for certain currencies, which will be of great interest to currency, cryptocurrency and high-frequency investors alike.

Bitcoin has attracted a wealth of attention in the media and by investors alike and this paper investigates whether Bitcoin can act as a hedge or safe haven against world currencies. Contrary to previous studies, we assess the relationship between Bitcoin and currencies at the hourly frequency since Bitcoin experiences quite large volatility throughout the day. We employ an ADCC model and find that Bitcoin can be an intraday hedge for the CHF, EUR and GBP, but acts as a diversifier for the AUD, CAD and JPY. We also implement the non-temporal Hansen (2000) test to examine the safe haven properties of Bitcoin and find that Bitcoin is a safe haven during periods of extreme market turmoil for the CAD, CHF and GBP. Therefore our results indicate that Bitcoin does act as an intraday hedge, diversifier and safe haven for certain currencies, which will be of great interest to currency, cryptocurrency and high-frequency investors alike.

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Seawater intrusion and brine water/freshwater interaction have significantly affected agriculture, industry and public water supply at Laizhou Bay, Shandong Province, China. In this study, a two-dimensional SEAWAT model is developed to simulate the seawater intrusion to coastal aquifers and brine water/fresh water interaction in the south of Laizhou Bay. This model is applied to predict the seawater intrusion and brine water/freshwater interface development in the coming years. The model profile is perpendicular to the coastal line with two interfaces, freshwater-saline water interface near the shore and inland brine water-saline water-seawater interface. The hydrogeological parameters in the SEAWAT-2000 model are calibrated by the head and salinity measurements. The precipitation infiltration coefficient, boundary conditions and thicknesses of aquifers are studied in a sensitivity analysis. The predicted results indicate that equivalent freshwater head in shallow freshwater-saline water area will decline 2.0 m by the end of the forecasting period, caused by groundwater over-pumping for farmland irrigation. The groundwater head in the brine-saline water area will also decrease about 1.8 m by the end of forecasting period, caused by excessive brine mining. Salinity finally decreases below 105 g/L in the brine area, but increases in other areas and contaminates fresh groundwater resources.

The aquifer in the coastal area of the Laizhou Bay is affected by salinization processes related to intense groundwater exploitation for brine resource and for agriculture irrigation during the last three decades. As a result, the dynamic balances among freshwater, brine, and seawater have been disturbed and the quality of groundwater has deteriorated. To fully understand the groundwater chemical distribution and evolution in the regional aquifers, hydrogeochemical and isotopic studies have been conducted based on the water samples from 102 observation wells. Groundwater levels and salinities in four monitoring wells are as well measured to inspect the general groundwater flow and chemical patterns and seasonal variations. Chemical components such as Na, K, Ca, Mg, Sr, Cl, SO, HCO, NO, F, and TDS during the same period are analyzed to explore geochemical evolution, water-rock interactions, sources of salt, nitrate, and fluoride pollution in fresh, brackish, saline, and brine waters. The decreased water levels without typical seasonal variation in the southeast of the study area confirm an over-exploitation of groundwater. The hydrogeochemical characteristics indicate fresh-saline-brine-saline transition pattern from inland to coast where evaporation is a vital factor to control the chemical evolution. The cation exchange processes are occurred at fresh-saline interfaces of mixtures along the hydraulic gradient. Meanwhile, isotopic data indicate that the brine in aquifers was either originated from older meteoric water with mineral dissolution and evaporation or repeatedly evaporation of retained seawater with fresher water recharge and mixing in geological time. Groundwater suitability for drinking is further evaluated according to water quality standard of China. Results reveal high risks of nitrate and fluoride contamination. The elevated nitrate concentration of 560 mg/L, which as high as 28 times of the standard content in drinking water is identified in the south region. In addition, the nitrate and ammonia data of the Wei River suggests decreasing nitrification rate in the study area from inland to estuary. High fluoride concentration, larger than 1 mg/L, is also detected in an area of about 50% of the study region. The saltwater intrusion is analyzed to be responsible for part of dissolution of minerals containing fluoride. Therefore, water treatment before drinking is needed in urgent to reduce the health expose risk.