Estuarine environments faced with contaminations from coastal zones and the inland are vital sinks of antibiotic resistance genes (ARGs). However, little is known about the temporal-spatial pattern of ARGs and its predominant constraints in estuarine environments. Here, we leveraged metagenomics to investigate ARG profiles from 16 China's estuaries across 6 climate zones in dry and wet seasons, and disentangled their relationships with environmental constraints. Our results revealed that ARG abundance, richness, and diversity in dry season were higher than those in wet season, and ARG abundance exhibited an increasing trend with latitude. The prevalence of ARGs was significantly driven by human activities, mobile gene elements, microbial communities, antibiotic residuals, physicochemical properties, and climatic variables. Among which, climatic variables and human activities ranked the most important factors, contributing 44% and 36% of the total variance of observed ARGs, respectively. The most important climatic variable shaping ARGs is temperature, where increasing temperature is associated with decreased ARGs. Our results highlight that the prevalence of ARGs in estuarine environments would be co-driven by anthropogenic activities and climate, and suggest the dynamics of ARGs under future changing climate and socioeconomic development.

Rivers can be sinks for potential toxic elements (PTEs) inputted in their systems by both natural and anthropic processes. Many indices have been proposed to assess the contamination degree of sediments and the environmental conditions of surficial water bodies. Above all, enrichment factor (EF) is the most used tool, but also it is the most debated for its limitations. The need for a reference element and for a background/baseline composition makes the EF method dependent on the researcher's expertise, implying that its repeatability may not be granted. Starting from the awareness that geochemical processes, bringing to compositional changes in the environmental matrices, involve multiple elements rather than individual variables, we developed a modified EF (mEF) based on the use of elemental associations. Different multivariate statistical methods (i.e. Robust Principal Component Analysis and Fuzzy Clustering), in a compositional data analysis (CoDA) perspective, were used to set all the terms of the mEF. The mEF was applied to 101 sediment samples collected from a 2 m-long core, covering a sedimentation period of about 150 years (1850–2007), located in the lower Changjiang River (China). The method resulted effective in recognizing most of the signals proceeding from the main natural and anthropogenic events which affected the lower river basin in the considered timespan. The largest geochemical variations recorded fit well the flooding events occurred; besides, the effects produced on the system by the recent socio-economic development (following the end of the civil war in 1949 and the beginning of economic reforms in 1978) and the start-up of the Three Gorges Dam (the world's largest power station since 2012) were also intercepted. The proposed method represents a step forward to enhance the effectiveness of the EF in discriminating geochemical anomalies that may be significant to assess the human historical impact on the environment.

During the last decades, the coastal areas of Morocco have witnessed an intense socioeconomic development associated with a continuous population growth and urban extension. This has led to an overexploitation of coastal aquifers leading to a degradation of their water quality. In order to obtain large scale overview on the quality status of Morocco's coastal aquifers (MCA) to assist national water managers to make informed decisions, a comprehensive scrutinization of the MCA against common indicators and using unified methods is essential. In this study, databases from thirteen MCA were analyzed, using multivariate statistical approaches and graphical methods in order to investigate the degree of mineralization in each aquifer and to identify the main salinization processes prevailing in groundwater. The results showed that the dominant groundwater types are Na–Cl, Ca–Mg–Cl, Ca–Mg–SO₄, Ca–Mg–HCO₃ and Ca–HCO₃–Cl. The Gibbs diagram and the seawater contribution (0–37%) indicate that the mineralization is mainly due to the seawater intrusion and water-rock interaction. The salinity degree diagram illustrates that almost all groundwater samples are located in the moderate to very saline zone, indicating that MCA are recharged by water from variable sources. The groundwater quality assessment shows a deterioration, particularly by seawater intrusion and significant nitrate pollution. The temporal evolution confirm that the MCA are influenced by seawater namely in the Atlantic part. The Wilcox and USSL diagram indicate that the majority of sampled water are unsuitable for irrigation uses. In addition, and by referring to the WHO and the Moroccan standards for water potability, large number of samples from the groundwaters of the MCA is not fully adequate for drinking purposes. A set of management actions (e,g., artificial recharge) are proposed in order to mitigate the effect of groundwater overexploitation and seawater intrusion to ensure the sustainability of MCA.

Urban heat island (UHI), an iconic consequence of anthropogenic activities and climate condition, affects air pollution, energy use, and health. Therefore, better understanding of the temporal dynamics of UHI is required for sustainable urban planning to mitigate air pollution under a changing climate. Here, we present the evolution of UHI intensity (UHIi) and its controlling factors in the Seoul metropolitan area, Korea, over the last 56 years (1962–2017), which has experienced unique compressed economic growth and urban transformation under monsoon climate. The analysis demonstrated an inverted U-shape long-term variation of UHIi with the progress of urban transformation and economic climate which has not been reported in Asian cities before. Meanwhile, short-term variations in UHIi are related to both diurnal temperature range and duration after rainfall event unlike previous studies, and the UHIi was exacerbated by heat waves. Our findings suggest that the UHIi will exhibit different temporal dynamics with future changes in the monsoon climate, and heat waves in the urban area will be reinforced if current rapid urbanization continues without a shift toward sustainable and equitable development. Asian cities that are likely to face the similar urbanization trajectory and the implications are that urban (re)development strategy considers changes in rainfall magnitude and timing due to monsoon system variation under changing climate and plans to mitigate synergy between heat wave and UHI in this area.

Africa's economy is growing faster than any other continent and it has been estimated that the middle class in Africa now exceeds 350 million people. This has meant a parallel increase in the importation of consumer goods and in the implementation of communication and information technologies (ICT), but also in the generation of large quantities of e-waste. However, inadequate infrastructure development remains a major constraint to the continent's economic growth and these highly toxic residues are not always adequately managed. Few studies have been conducted to date assessing the possible association between socioeconomic development factors, including e-waste generation, and blood levels of inorganic elements in African population. To disclose the role of geographical, anthropogenic, and socioeconomic development determinants on the blood levels of Ag, Al, As, Be, Cd, Co, Cr, Hg, Ni, Pb, Sb, and V —all of them frequently found in e-waste—, an immigrant population-based study was made including a total of 245 subjects from 16 countries recently arrived to the Canary Islands (Spain). Women presented higher levels of blood elements than men, and Northern Africans (Moroccans) were the most contaminated. People from low-income countries exhibited significantly lower blood levels of inorganic elements than those from middle-income countries. We found a significant association between the use of motor vehicles and the implementation of information and communication technologies (ICT) and the level of contamination. Immigrants from the countries with a high volume of imports of second-hand electronic equipment, telephone and internet use had higher levels of inorganic elements. In general terms, the higher level of economic development the higher the blood levels of inorganic pollutants, suggesting that the economic development of Africa, in parallel to e-waste generation and the existence of informal recycling sites, have directly affected the level of contamination of the population of the continent.

Polycyclic aromatic hydrocarbon (PAH) concentrations were determined in four dated sediment cores collected in mud depocenters of the southern Brazilian continental shelf. Core dating results covered the interval between 1925 and 2017. The total PAH concentrations (ΣPAHs) ranged from 44.69 ng g⁻¹ to 305.43 ng g⁻¹ and were similar between the analysed cores. Fine-grained sediments and total organic carbon (TOC) results did not correlate with the ΣPAHs, indicating that the variations in PAH concentrations are mostly related to variations in sources and emissions. PAH source appointment indicated a high input of a natural compound (perylene) and the predominance of anthropogenic PAHs from coal, biomass, and fuel combustion. Alkylated PAHs presented high contributions throughout all cores. The historical deposition of PAHs was associated with different periods of the socio-economic and industrial development of near coastal cities and reflected very well the history of coal production and consumption in the southern region of Brazil. The low levels of ΣPAHs before 1945 in all analysed cores may be related to the beginning of the industrialization process and the lower urbanization degree in the region. Between 1945 and 1965, the gradual ΣPAHs increase reflects the establishment and enlargement of the southern Brazilian industrial sector. The interval between 1965 and 1990 corresponded to the highest ΣPAHs in three of the four analysed cores. After 1990, a relative decrease in the ΣPAHs was observed in most cores and may be related the multiple cuts of incentives to the industrial usage of coal, as well as to Brazil's efforts in environmental regulation for coal extraction and consumption.

Based on the archival data on oil facilities, oil spill incidents, and environmental conditions, we researched the plausible causes of oil spill disasters in the Niger Delta of Nigeria between 2006 and 2019. The data were analyzed for geospatial and statistical patterns, using ArcGIS and R programming platforms, respectively. A fuzzy logic algorithm was employed to generate three oil spill disaster models (hazard, vulnerability, and risk). Ordinary Least Square algorithm was adopted to model the relationships between oil spill and two sets of predictor variables: oil facilities (oil well, flow station, and pipeline) and disaster models. We found that, during the 23 years, the Niger Delta experienced 7940 oil spill incidents, of which 67% occurred onshore. A total of 4,950, 501, 855 episodes were attributed to sabotage, corrosion, and equipment failure, with 87%, 62%, and 45% occurring onshore, respectively. Besides, 81% of the 5320 onshore oil spill cases were attributed to sabotage, while corrosion and equipment failure accounted for mere 6% and 7% of the incidents, respectively. The estimated average risk index (R = 0.20) shows that the risk of an oil spill disaster in the Niger Delta is low. Whereas, 5% of the region is characterized by a high risk of oil spill disaster. Furthermore, the regression model infers that the oil spillages exhibit a positive relationship with disaster models and oil facilities at α = 0.10. However, only 16% of the incidents were explained by disaster models, while the oil facilities account for 23% of the total cases, indicating the influence of other factors. To avert further socio-environmental damage in the Niger-Delta, oil theft and sabotage should be curbed, polluted areas are remediated, and an all-inclusive socio-economic development is prioritized.

Sediment records are widely used to infer impact of atmospheric metal deposition in alpine lakes, however, the legacy effect and catchment erosion of historical pollutants could potentially affect metal influx into lakes. Here, we collect data (including six trace metals and three lithogenic elements) from well-dated sediment cores of seven alpine lakes in southeast Tibet, which is adjacent to southwest China. This area has a documented history of preindustrial pollution. Metals such as cadmium (Cd), zinc (Zn) and arsenic (As) are found at relatively low concentrations until a clear increase is observed after 1950s across lakes. This result is consistent with accelerating atmospheric metal deposition due to socio-economic development in the region. We observe no synchronous trend across lakes in the changes of lead (Pb), copper (Cu) and silver (Ag), which show no significant increase after ∼1950 over the last two centuries in most of the study lakes. The historical trends of ²⁰⁶Pb/²⁰⁷Pb ratio reflect an important source of anthropogenic Pb associated with preindustrial mining and smelting in this study region, suggesting a substantial impact of legacy contamination from ancient mines. Furthermore, the temporal variations in these six anthropogenic metals are largely accounted for by terrigenous elements (e.g. aluminum (Al) and titanium (Ti)) in most of the study lakes, and to a lesser degree by sediment grain sizes and organic matter content, suggesting a significant role of catchment erosion in modulating sediment metal signals. In all, this study highlights the legacy effect of historical pollutants may have enhanced the forcing of catchment erosion in modulating the sediment signals of anthropogenic deposition in southeast Tibet.

Along with the rapid socioeconomic development, air pollution in China has become a severe problem. One component of air pollution, in particular, PM2.5 has aroused wide public concern because of its high concentration. In this study, data were collected from over 900 monitoring sites of the newly constructed PM2.5 monitoring network in China. The interpolation methods were used to simulate the PM2.5 exposure level of China especially in rural areas, thus reflecting the spatial variation of PM2.5 pollution. We calculated the health benefit caused by PM2.5 in China in 2014 based on Environmental Benefits Mapping and Analysis Program (BenMAP), assuming achievement of China National Ambient Air Quality Standard (No. GB3095-2012). By reducing the annual average concentration of PM2.5 to the annual Grade II standard (35 μg/m3), the avoided deaths for cardiovascular disease, respiratory disease and lung cancer could reach 89,000 (95% CI, 8000–170,000), 47,000 (95% CI, 3000–91,000) and 32,000 (95% CI, 6000–58,000) per year using long term health function, respectively. The attributable fractions of cardiovascular disease, respiratory disease and lung cancer to all cause were 42%, 22% and 15%, respectively. The total economic benefits for rolling back the concentration of PM2.5 to the level of 35 μg/m3 were estimated to be 260 (95%CI: (73, 440) billion RMB and 72 (95%CI: (45, 99) billion RMB using willingness to pay (WTP) and human capital (HC) methods, respectively, which account for 0.40% (95%CI: (0.11%, 0.69%) and 0.11% (95%CI: (0.07%, 0.15%) of the total annual Gross Domestic Product (GDP) of China in 2014.

The sedimentary history of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) over the past 140 years in a lake sediment core from Huixian karst wetland was reconstructed. The total PAHs and OCPs concentrations ranged from 40.0 to 210 ng g⁻¹ and 0.98 to 31.4 ng g⁻¹, respectively. The vertical distribution of PAHs and OCPs in different stages was great consistent with the history of regional socio-economic development and the usage of OCPs. As the indicators of socio-economic development, gross domestic product (GDP), population, energy consumption, highway mileage, and private vehicles correlated with the PAHs concentrations, indicating the impact of human activities on PAHs levels. The PAHs and OCPs concentrations were also affected by environmental changes in the wetland, as reconstructed by total organic carbon (TOC), sand, silt, clay, quartz, and calcite in sediments. Redundancy analysis (RDA) results showed TOC was the dominant factor to explain the concentrations of PAHs and OCPs with the explanation of 86.7% and 43.5%, respectively. In addition, TOC content had significantly positive correlation with PAHs (0.96, p < 0.01) and OCPs (0.78, p < 0.01). In particular, the significantly positive correlation (p < 0.05) between calcite and PAHs and OCPs inferred that karstification might play an important role in the migration of PAHs and OCPs in the karst area. Therefore, the lake in Huixian wetland tended to be a sink more than a source of PAHs and OCPs influenced by the increasing TOC content and karstification under climate warming.