[Mercury Distribution Characteristics and Its Mass Balance in a Multifunctional Urban Wetland].

The distribution characteristics and the source-sink relationship of total mercury (THg) and methyl mercury (MeHg) were studied in a wastewater treatment area and in a lake deep purification area of a multifunctional urban wetland that integrates domestic sewage treatment plant effluent, water purification, and leisure entertainment in Chongqing. The results showed that the THg concentration ranged from 1.98 ng·L-1 to 38.03 ng·L-1[average concentration was (9.10±5.84) ng·L-1] and MeHg concentration ranged from 0.09 ng·L-1 to 0.84 ng·L-1[average concentration was (0.34±0.08) ng·L-1] in an outlet of wastewater treatment area. In the deep purification zone, the THg concentration ranged from 0.37 ng·L-1 to 85.69 ng·L-1[average concentration of (6.76±2.29) ng·L-1] and the MeHg concentration ranged from 0.04 ng·L-1 to 1.47 ng·L-1[average concentration of (0.35±0.17) ng·L-1]. The interference of human activities on mercury concentration is prominent. The vertical distribution of THg in the water is consistent with that of MeHg, the surface layer has lower values than the deep layer. Material balance suggested that THg in the wetland system decreases by 155.50 g per year, and MeHg decreases by 1.65 g per year, which has a protective effect on the downstream water.

[Distribution Characteristics of Mercury in Different Urban Constructed Wetlands].

To explore the spatial and temporal distribution and the methylation characteristics of mercury in different constructed wetlands in cities, and to understand the potential ecological exposure of mercury in urban wetlands, four artificial wetlands in Chongqing were studied from March 2017 to March 2018. The water samples were collected separately in four quarters, and the mass concentration of total mercury (THg) and methyl mercury (MeHg) was researched for one year. The results showed that the THg concentration in the four wetland waters is higher than the background value of the world's lakes and reservoirs for dam construction, but it is far lower than the waters with pollution history. The THg mass concentration of the water inside the wetlands is slightly higher than in the inlet and outlet. In addition, the THg mass concentration in the aquatic plant growing area, the construction area, the cruise ship parking area, and the frequent play area has an increasing trend, indicating that urban wetlands have a trapping and converging effect of the water's THg, so human activities influence total mercury a lot. The mass concentration of MeHg in the four wetland waters was slightly higher than that in other water bodies. With the exception of the Caiyun Lake, where the mass concentration of MeHg at the outlet was higher than that of the water inlet, the other three wetlands showed lower MeHg mass concentration in the outlet than the inlet. The mass concentration of MeHg in the wetland water increased with increasing water depth. The ratio of MeHg concentration to THg mass concentration (MeHg/THg) was higher than in other waters, indicating that urban wetlands have effect on net mercury methylation from waters. The photoreduction of mercury and its absorption by aquatic plants can reduce the mercury load from urban wetlands to downstream watersheds. The THg mass concentration of the four urban wetland water bodies was high in the spring and autumn, with a slight decrease in the summer, and lowest in the winter. The mass concentration of MeHg was the lowest in winter, and in the other three seasons it was basically flat, about three times higher than in winter. This study clarifies the temporal and spatial distribution and methylation of mercury in urban wetlands. It explores the degree of disturbance of human activities on wetlands and the response characteristics, as well as the impact of wetland mercury on downstream watersheds. To avoid potential mercury exposure, measures need to be established for the construction of artificial wetlands.

Differentiation of Internet addiction risk level based on autonomic nervous responses: the Internet-addiction hypothesis of autonomic activity.

How high-risk Internet addiction (IA) abusers respond to different autonomic nervous activities compared with low-risk subjects may be a critical research goal with prevention and treatment implications. The aim of the present study was to address this issue by observing differences between high- and low-risk IA abusers in four physiological assessments when surfing the Internet: blood volume pulse (BVP), skin conductance (SC), peripheral temperature (PTEMP), and respiratory response (RESPR). Forty-two male and ten female participants aged 18-24 years were screened with the Chen Internet Addiction Scale (CIAS, 2003), and then separated into high- and low-risk IA groups. Using psychophysiology equipment, participants encountered a 3-minute adaptation period followed by a 6-minute testing period for surfing the Internet on baseline and testing phases. The present results indicate that: (a) the CIAS scores were positively and negatively correlated with the RESPR and the PTEMP; (b) the PTEMP and RESPR of high-risk IA abusers were respectively weaker and stronger than those of low-risk IA abusers; the BVP and SC of high-risk IA abusers were respectively augmented and decreased relative to low-risk IA abusers. Thus we suggest that four autonomic responses may be differentially sensitive to abusers' potency in terms of the IA hypothesis of autonomic activity. The stronger BVP and RESPR responses and the weaker PTEMP reactions of the high-risk IA abusers indicate the sympathetic nervous system was heavily activated in these individuals. However, SC activates parasympathetic responses at the same time in the high-risk IA abusers. The paradoxical responses between the sympathetic and parasympathetic actions are addressed in the discussion.