Bao Xiang

Coastal wetlands are important sinks for heavy metals, yet the linkage between vertical redistribution, quantitative source contributions, and ecological–health risk drivers remain insufficiently understood. This study collected the stratified sediment samples from three depth intervals (0–20, 20–40, and 40–60 cm) from 28 representative sites in the coastal wetlands of western Bohai Bay, and evaluated the spatial distribution, vertical variation, pollution status, potential sources, and ecological–human health risks of eight heavy metals (Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb). The mean concentrations were below the Class I limits of the Marine Sediment Quality Standard. Most metals were close to or slightly below regional background values, whereas Cu and As showed mild enrichment and Cr was higher than values reported for Bohai Bay and Hangzhou Bay. Vertical profiles were generally homogeneous, with weak enrichment of specific metals, probably due to sediment resuspension, tidal disturbance, and bioturbation. Pollution assessment based on the geoaccumulation index (Igeo), Nemerow pollution index (P_N), and pollution load index (PLI) consistently indicated low contamination levels, with Hg and Pb as the main contributors to the regional pollution load. Source apportionment indicated that heavy metals were jointly influenced by lithogenic background (38.9%), atmospheric deposition (31.1%), and local anthropogenic activities (30.0%). Ecological risk assessment showed that the integrated risk index (RI) remained within the low-risk category, although Hg consistently fell within the moderate-risk range and Cd approached the moderate-risk threshold. Health risk assessment showed that both non-carcinogenic and carcinogenic risks were within acceptable limits for all receptor groups. Children had higher risks in core residential areas, whereas adults showed higher risks in non-core industrial–agricultural zones because of increased exposure frequency. The source–risk analysis indicates that non-carcinogenic risk is mainly associated with background-derived Cr, whereas carcinogenic risk is primarily linked to anthropogenic As inputs. These findings indicate that source contributions and risk contributions are not necessarily consistent, highlighting the need for source-oriented risk management in industrialized coastal wetlands.

As an important link to realize intelligent discipline inspection and supervision, the term “case characterization and discipline measurement” refers to the automatic extraction of material facts from case description and the conclusion of conformity and nonconformity after comparison in accordance with legal norms. In response to the problem that there was no special method for the task of case characterization and discipline measurement, the paper combined the practical case handling process of the staff and proposed a method of case characterization and discipline measurement based on discipline inspection and supervision knowledge graph. The method uses the knowledge graph as auxiliary information and aligns the entities of regulations and cases using knowledge fusion technology to construct the discipline inspection and supervision knowledge graph. For the newborn case descriptions, named entity recognition technology is used to extract the key elements that determine the verdict outcome. Similar cases were identified with the same discipline breach nature. Then, text classification technology is used to predict the severity of case circumstances. Combined with the disciplinary violation facts, the disciplinary result is given according to the party discipline rules. Experiments were carried out with a dataset of typical cases notified by the discipline inspection and supervision. According to the experimental results, the proposed method shows its validity, which improves the interpretability of case characterization and discipline measurement and fills the field gap.

This study focused on the Chao River and Baimaguan River located upstream of the Miyun Reservoir in Miyun District (Beijing, China). Soil and sediment samples were collected from the river and drainage basin. Total nitrogen, total phosphorus, and six potentially toxic elements including cadmium, zinc, lead, chromium, arsenic, and copper, were analyzed in terms of concentration, potential ecological risk, and human health risk. The average concentrations of the six potentially toxic elements were all below the soil environmental quality standards for China. Cadmium was the most serious pollutant in both soils and sediments, at 2.58 and 3.40 times its background values. The contents of Cd and Pb were very closely related (p < 0.01) to total nitrogen concentrations in both soil and sediment samples. The potential ecological risks posed by Cd in the Chao and Baimaguan River soils were considerable and moderate, respectively. The historical iron ore mining and agricultural activity were identified as the primary sources of potentially toxic element pollution of soil and sediment in the Chao-Bai River in Miyun District. Human health risk assessment indicated that non-carcinogenic risks all fell below threshold values. The total carcinogenic risks due to Cr and As were within the acceptable range for both adults and children. This conclusion provides a scientific basis for the control of potentially toxic element pollution and environmental protection of the Miyun Reservoir in Beijing.

This study assessed literature-based data for the period 2006–2016 regarding heavy metal (As, Cd, Cr, Cu, Pb, Ni, Zn, and Hg) concentrations in soils from 32 Chinese cities and the associated human health risks. The mean concentrations of the eight metals were lower than the soil environmental quality standards in China, but were much higher than the background values for most cities. The enrichment factor (EF) and geoaccumulation index (I_geo) values showed moderate pollution levels, possibly influenced by anthropogenic activity for Cd, Hg, Pb, and Zn. The pollution levels in eastern cities were much higher than those in western cities, and heavy metals concentrations in different types of cities followed the order: industrial based cities > more developed cities > metropoles > underdeveloped cities. The human health risk assessment for heavy metals in most cities indicated that non-carcinogenic risks were within threshold values (HI < 1). The total carcinogenic risk due to As, Cr, and Ni in most urban areas was in excess of 1 × 10⁻⁵, but was lower than 1 × 10⁻⁴. However, in some cities (e.g., Baoji City, Tiyuan City, and Xuzhou City), Ni and Cr have potential cancer risks for both adults and children. Compared to adults, children could be more seriously threatened by heavy metal contamination in soils. In general, we recommend that Cd, Hg, and Pb are selected as priority heavy metals pollutants that require control in Chinese cities.

A total of 128 surface soil samples were collected, and eight heavy metals, including As, Cd, Cr, Cu, Pb, Ni, Zn, and Hg, were analyzed for their concentrations, potential ecological risks, and human health risks. The mean concentrations of these eight metals were lower than the soil environmental quality standards in China, while they were slightly higher than the background values in Shanxi Province. The enrichment factor, coefficient variation, and potential ecological risk index were used to assess the pollution and eco-risk level of heavy metals, among which, Cd and Hg showed higher pollution levels and potential risks than the others in the studied area. Moreover, multivariate geostatistical analysis suggested that Hg originated mainly from point sources such as industrial emissions, while agricultural activity is the predominant factor for Cd. The human health risk assessment indicated that non-carcinogenic values were below the threshold values. The total carcinogenic risks due to As, Cr, and Ni were within the acceptable range for adults, while for children, they were higher than the threshold value (1.0E−04), indicating that children are facing higher threat to heavy metals in soils. These results provide basic information on heavy metal pollution control and human health risk assessment management in the study regions.

Vegetation plays an important role in regulating the terrestrial carbon balance and the climate system, and also overwhelmingly dominates the provisioning of ecosystem services. Therefore, it has significance to monitor the growth of vegetation. Based on AVHRR GIMMS NDVI and MODIS NDVI datasets, we analyzed the spatiotemporal patterns of change in NDVI and their linkage with climate change and human activity from 1982 to 2012 in the typical arid region, Xinjiang of northwestern China, at pixel and regional scales. At regional scale, although a statistically significant positive trend of growing season NDVI with a rate of 4.09 x 10⁻⁴· a⁻¹ was found during 1982-2012, there were two distinct periods with opposite trends in growing season NDVI before and after 1998, respectively. NDVI in growing season first significantly increased with a rate of 10 x 10⁻⁴· a⁻¹ from 1982 to 1998, and then decreased with a rate of -3 x 10⁻⁴· a⁻¹ from 1998 to 2012. The change in trend of NDVI from increase to decrease mainly occurred in summer, followed by autumn, and the reversal wasn't observed in spring. At pixel scale, the NDVI in farmland significantly increased; the NDVI changes in the growing season and all seasons showed polarization: Areas with significant change mostly increased in size as the NDVI record grown in length. The rate of increase in size of areas with significantly decreasing NDVI was larger than that with significantly increasing NDVI, which led to the NDVI increase obviously slowing down or stopping at regional scale. The vegetation growth in the study area was regulated by both climate change and human activity. Temperature was the most important driving factor in spring and autumn, whereas precipitation in summer. Extensive use of fertilizers and increased farmland irrigated area promoted the vegetation growth. However, the rapid increase in the proportion of cotton cultivation and use of drip irrigation might reduce spring NDVI in the part of farmlands, and the increase in stocking levels of livestock might lead to a decrease in NDVI in some grasslands.

This article investigated the spatiotemporal variation of landscape ecological risk in Dantu District of Zhenjiang City with statistical method based on the ETM remote sensing data in 2000 and 2005, and the TM remote sensing data in 2010, and quantitative index of regional ecological risk assessment was established with the employment of landscape index, so as to enhance the ecosystem management, prevent and reduce the regional ecological risk in southern Jiangsu with rapid economic development. The results showed that the fragmentations, divergence, and ecological losses of natural landscape types, such as forestland, wetland, waters, etc., were deteriorated with the expansion of built-up lands from 2000 to 2010. The higher ecological risk zone took up 5.7%, 9.0%, and 10.2% of the whole region in 2000, 2005, and 2010, respectively, which mainly distributed in the plain hilly region. During the study period, the area aggravating to the higher ecological risk zone was approximately 296.2 km2, 48% of the whole region. The ecological risk rose up in most of the region. The interference of rapid economic development to landscape patterns was even more intensive, with obvious spatial differences in ecological risk distribution. The measures of exploiting resources near the port, utilizing natural wetlands, constructing industrial parks, and rapid urbanization, etc., intensified the ecological risk and accelerated the conversion rate. Prompt strategies should be established to manage the ecological risk of this region.

Fluorescence characterization of soil dissolved organic matter (DOM), which is one of the most important indexes concerning study on soil organic matter, can be effected by freezing and thawing cycles. In this paper, the fluorescence characterization of black soil DOM under the effect of freezing and thawing cycles was studied, using three-dimensional excitation-emission-matrix fluorescence spectroscopic (EEM). Based on the transformation of fluorescence characterization, the influences of humification degree and active humus in black soil were analysed. The result showed, compared with untreated by freezing and thawing cycles, (1) The phenomena red-shift of UV fulvic-like was found in soil DOM. It meant that the aromatization and humification degree increased. (2) Protein-like fluorescence peak was observed in some soil samples, which meant microbial activity was enhanced. (3) Active humus and humification degree are the indexs of soil fertility. The content of TOC in the active humus rose, just the same as the value of humification degree. It meant that soil fertility was improved. (4) Compared with the ratio of UV: visible humic-like fluorescence (r(a,c)), there were positive correlations with the active humus and humification degree. It meant that r(a, c) of soil DOM was one of the indexs on active humus, humification degree and soil fertility effected by freezing and thawing cycles.