Temporal-Spatial Evolution of Groundwater Nitrogen Pollution Over Seven Years in a Highly Urbanized City in the Southern China.

Understanding the temporospatial variation in nitrogen pollution in groundwater and the associated controlling factors is important to establish management practices that ensure sustainable use of groundwater. In this study, we analyzed inorganic nitrogen content (nitrate, nitrite, and ammonium) in 1164 groundwater samples from shallow, middle-deep, and deep aquifers in Zhanjiang, a highly urbanized city in the southern China. Our data span a range of 7 years from 2005 to 2011. Results show that shallow aquifers had been heavily contaminated by nitrate and ammonium. Temporal patterns show that N contamination levels remained high and relatively stable over time in urban areas. This stability and high concentration is hypothesized as a result of uncontrolled, illicit sewer discharges from nearby business facilities. Groundwater in urban land and farmland displays systematic differences in geochemical characteristics. Collectively, our findings demonstrate the importance of continuously monitoring groundwater quality and strictly regulating sewage discharges in Zhanjiang.

Distribution of Nitrate in Different Aquifers in the Urban District of Zhanjiang, China.

The study of NO3 (-) contamination in groundwater is becoming increasingly significant as high concentrations of NO3 (-) in groundwater can do damage to public health. Nitrate pollution in the shallow, middle-deep and deep aquifers in the urban district of Zhanjiang was studied using the ordinary Kriging interpolation method combined with hydrochemical and correlation analyses in 2011. The results showed NO3 (-) pollution was present in the shallow groundwater, with average concentrations of 47.43 mg/L and standard deviation of 50.92. Nitrate concentrations were lower in middle-deep and deep aquifers, with average concentrations of 2.36, 0.80 mg/L, and standard deviation of 6.23, 0.93, respectively. Nitrate was correlated with Na(+) + K(+), Mg(2+), Cl(-) and SO4 (2-) in the shallow aquifer, and the spatial distributions of NO3 (-) exhibited a same pattern with TDS in the shallow aquifer, the NO3 (-) pollution in the middle-deep and deep aquifers is less serious.

Reevaluation of the effect of Dianxianning on seizure rate of refractory epilepsy as additive treatment in clinical practice.

We observed the effect of Dianxianning, which was used as additive treatment to treat 206 epilepsy patients, on the epilepsy seizure rate. Based on a multicenter, prospective, randomized, and controlled clinical trial design, we used the seizure rate of epilepsy as the main index. For the treatment group comprising 137 patients, we combined Dianxianning with chemical medicine, which is the basic treatment. For the control group with 69 patients, we added placebo. The results showed that 1) Effect on seizure rate: After a three-month treatment, the seizure rate of the treatment group decreased by 37.84% on average, whereas that of the control group decreased by 13.18% on average. Statistically comparing the two groups, there was a significant difference between these groups (P < 0.05). 2) Effect on seizure frequency: As time passed, the frequency in each group gradually decreased. After a three-month treatment, there was a significant difference between the two groups (P < 0.05). 3) Comparison between the before and after treatment of each group: There was a very significant difference between the two groups (P < 0.0001). The results indicated that, as an additive treatment, Dianxianning has a good effect on controlling the epilepsy seizure rate and frequency management. It is more effective than using chemical medicine alone.