Groundwater is an important source of water for human sustenance. The determination of groundwater quality at island sites is an urgent priority in China, but there are lacking systematic reports relating to them. Here, 63 groups of groundwater samples were collected and analyzed of Hainan Island. The groundwater in the study area is weakly alkaline, mainly comprising hard and soft freshwater. The predominant anions and cations are HCO₃⁻, and Ca²⁺ and Na⁺, respectively, and the main water chemistry types are HCO₃–Cl–Na and HCO₃–Cl–Na–Ca. The chemical evolution of groundwater is mainly affected by water–rock interactions, cation exchange, and human activity. The groundwater is mostly of high quality and, in most areas, is suitable for drinking and irrigation. Contrastingly, the water quality in the west of the island is relatively poor. The spatial distribution of the risk coefficient (HQ) is consistent with the spatial variation in the NO₃⁻ concentrations in the groundwater. Notably, there are unacceptable health risks for different groups of people, with infants having the greatest level of impact, followed by children, teenagers, and adults. This study provides a valuable reference for the development and utilization of groundwater resources, as well as the improvement of aquatic ecological conditions on Hainan Island and other island areas worldwide.

A generalized conceptual framework for regional carrying capacity evaluation along with its implementation approaches is introduced in this article, demonstrated by the case study in the Yangtze River Delta region, China. Following the data preprocessing, assimilative capacity, supportive capacity, and loading, the three essential aspects of regional carrying capacity, have been evaluated by principal components analysis and/or ecological footprint method. In terms of the characteristics of the results, sustainability criteria are established and used to determine the developmental states from 1997 to 2005 in the study area. Future states from 2006 to 2015 are predicted by a modified cellular automata model, into which an artificial neural network is incorporated to fit the transition rule. As revealed from the results of evaluation and prediction, the overall developmental states are worsening. For the sake of the sustainable development in this region, more attention should be paid to these results.

The study was aimed at exploring the effects of applying ordinary and nano zeolite on the soil pH, soil available cadmium (Cd) content, soil Cd speciation and Cd uptakes by tobacco using pot experiment with simulated Cd contaminated soil indoors. The results showed that soil pH increased and available Cd content reduced with the amount of ordinary and nano zeolite increasing. Compared with the control, the application of ordinary and nano zeolite increased soil pH at 0.47 - 1.05 and 0.73 - 1.57, respectively, and reduced the available Cd contents at 19.3% - 32.7% and 23.2% - 40.5%, respectively. In addition, soil pH had significantly negative correlation with available Cd content in each treatment (p<0.05). Nano zeolite could more effectively reduce Cd contents of all parts of tobacco than ordinary zeolite with the same amount treatments, and Cd content in all parts of tobacco plants was positively correlated with soil available Cd content. The content of exchangeable Cd (EXE) in soil decreased to some extent with different zeolite treatments, application of nano zeolite was better than that of application of ordinary zeolite in reducing Cd bioavailability and transferability. Overall, application of nano zeolite has an advantage over ordinary zeolite in reducing available Cd content in soil and Cd content in tobacco.

Ocean‐plate stratigraphy (OPS) refers to the lithostratigraphic column atop an ocean plate, which becomes scraped off during subduction and preserved in accretionary complex (AC). Herein, based on structural, stratigraphic, and geochronological studies of ACs from the Bangong‐Nujiang suture, we demonstrate that OPS can facilitate interpreting structural and compositional heterogeneities in ACs. Carefully correlated OPSs reveal that, on the overall sediment‐rich lower plate, different types of basement topography correspond to the accretion of distinct litho‐structural assemblages. In particular, subduction of the major, high‐relief Zhonggang seamount eroded the earlier margin and was subsequently accreted as coherent seamount slices. In contrast, subduction of the lower‐relief, Gaize seamount halted frontal accretion of trailing sediments, which were dragged downward to the seismogenic depth and underplated as pervasive, shear‐related broken formations. Such broken formations may fingerprint past lower‐relief‐seamount subduction in other fossil ACs.