Increased health threats from land use change caused by anthropogenic activity in an endemic fluorosis and arsenicosis area.

Urbanization is conducive to promoting social development and improving living standards. However, the changing land use attributed to urbanization has placed both the environment and humans at risk. Based on the long-term monitoring and the land use change during 2010-2017, we investigated the exposure of fluoride (F) and arsenic (As) in groundwater. We analyzed the temporal and spatial variation of F and As from different land use changes. The study assessed health risk for children by calculating carcinogenic risk and non-carcinogenic risk. Furthermore, we mapped the distribution pattern of F and As using GIS. For the 768 water samples collected from 2010 to 2017, F concentrations ranged between 0.10 and 5.70 mg L-1 (M = 0.68 ± 0.02 mg L-1), As concentrations ranged between 0.50 and 71.50 µg L-1 (M = 4.28 ± 0.28 µg L-1). A concerning result showed that 6.77% of F concentrations larger than 1.5  mg L-1 and 11.46% of As concentrations larger than 10 µg L-1 based on the recommendation by WHO, respectively. Results proved that land use change caused by human activity increased groundwater pollution and placed human health at risk. High F and As risk were found in southern Taiyuan City. In particular, the groundwater of industrial land suffered from more severe pollution, especially at the frontier of urban and suburban areas in the southern part of Taiyuan City. Land use change attributed to industrial land resulted in major increases in the F and As concentrations in groundwater across 2010-2017. Both carcinogenic risk and non-carcinogenic risk in 2016-2017 were higher than that in 2010-2015. Rational land use planning, strict groundwater protection policies and the regular monitoring of pollution levels are necessary in order to prevent the adverse health of residents.

Analysis of Adaptive Evolution and Coevolution of rbcL Gene in the Genus Hildenbrandia (Rhodophyta).

The adaptive evolution and coevolution of the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) gene in the genus Hildenbrandia were studied based on phylogenetic tree construction and the physicochemical properties and the secondary structures of protein encoded by rbcL (Rubisco large subunit) were analyzed. The amino acids compositions and grand average of hydropathicity of freshwater H. rivularis and marine H. rubra were similar. Rubisco large subunit of Hildenbrandia was hydrophilic and the secondary structure was primarily composed of α-helixes and ß-sheets, revealing the relatively stable structure of this protein. The predicted phosphorylation sites in H. rivularis and H. rubra were 33 and 36, respectively. No positive selection sites were detected in the genus Hildenbrandia, implying that rbcL gene evolved either neutrally or under purifying selection. A total of 41 coevolutionary groups were detected in the Rubisco large subunit of Hildenbrandia and the coevolving sites are in closer proximity in 3-dimensional structure of the protein. Despite the long evolutionary history, rbcL gene in genus Hildenbrandia under different environments is rather conservative.

Optimized preparation of Phragmites australis activated carbon using the Box-Behnken method and desirability function to remove hydroquinone.

In this study, preparation of Phragmites australis activated carbon (PAAC) was optimized and applied for the removal of hydroquinone from aqueous solution. The Box-Behnken surface design (33) was used to statistically visualize the interactions among microwave power (A), microwave radiation time (B) and the ingredient ratio (C) (H3PO4: P. australis powder, in g). The desirability function was utilized to simultaneously optimize the multi-response indicators. A regression analysis showed that the experimental data of BBD optimization experimental results fit well to a quadratic model. PAAC was characterized according to its morphology, structure and composition. Dynamic adsorption data showed that the best fit was obtained by a pseudo-second-order model and the Freundlich isotherm model. The maximum adsorption capacity for hydroquinone adsorption onto PAAC was 156.25 mg/g at 30 ℃ and the adsorption mechanism may be attributed to multi-layer surface and chemisorption via donor-acceptor and coupling interaction of the electron. The present study showed that PAAC has the potential for use as a biosorbent for the adsorption treatment of water pollutants.