Lakes are sensitive recorders of anthropogenic activities, as human society often develops in their vicinity. Lake sediments thus have been widely used to reconstruct the history of environmental changes in the past, anthropogenic, or otherwise, and radiocarbon dating provides chronological control of the samples. However, specific values of radiocarbon in different carbon reservoirs due to the different pathways of radiocarbon from the upper atmosphere to the lake, called the radiocarbon reservoir age, is always difficult to evaluate because of dynamic processes in and around lakes. There are few systematic studies on radiocarbon reservoir ages for lakes owing to the complex radiocarbon transfer processes for lakes. Here, we investigate lake waters of the Fuji Five Lakes with monthly monitoring of the radiocarbon reservoir effects. Radiocarbon from dissolved inorganic carbon (DIC) for groundwater and river water is also measured, with resulting concentrations (Δ 14 C) at their lowest at Lake Kawaguchi in August 2018 (–122.4 ± 3.2‰), and at their highest at Lake Motosu in January 2019 (–22.4 ± 2.5‰), despite a distance of 25 km. However, winter values in both lakes show similar trends of rising Δ 14 C (about 20‰). Our lake water DIC Δ 14 C results are compared to previously published records obtained from sediments in Lake Motosu and Lake Kawaguchi. These suggest that total organic carbon and compound-specific radiocarbon found in sediments are heavily influenced by summer blooms of aquatic organisms that fix DIC in water. Thus, future studies to conduct similar analyses at the various lakes would be able to provide further insights into the carbon cycle around inland water, namely understanding the nature of radiocarbon reservoir ages.

Widespread overuse and misuse of antibiotics has led to unintended consequences, and it is necessary to find effective ways to remove antibiotics. In this study, a visible-light-response photocatalyst zinc ferrite (ZnFe 2 O 4 ) was synthesized via a hydrothermal method. Meanwhile, the X-ray diffraction, Brunauer–Emmett–Teller, scanning electron microscope, X-ray photoelectron spectroscopy, and Fourier transform infrared spectra analysis were applied to characterize the structure, morphology, and physicochemical properties of the ZnFe 2 O 4 . The results indicated that the ZnFe 2 O 4 was circular granular morphology with a particle size of approximately 30–50 nm and the noticeable intergranular agglomeration. The specific surface area, pore volume, and pore diameter of the ZnFe 2 O 4 were determined to be 126.8655 m 2 /g, 0.2046 cm 3 /g, and 64.5190 Å, respectively, representing that the ZnFe 2 O 4 had a large specific surface area. Moreover, the enhancement of degradation efficiency of ofloxacin (OFL) by peroxymonosulfate (PMS) under the visible light (Vis) was systematically evaluated. The results exhibited that the ZnFe 2 O 4 achieved the relatively optimum catalytic activity with 80.9% of OFL degradation efficiency in 30 min at pH 6.0 under the PMS concentration of 100 mg/L and the corresponding pseudo-first-order kinetic constant of OFL degradation was 0.0438 min –1 . In addition, the effects of ZnFe 2 O 4 dosage, PMS concentration, initial OFL concentration, solution pH, and water matrix on the OFL degradation were comprehensively investigated in the Vis/PMS/ZnFe 2 O 4 process. Furthermore, the ZnFe 2 O 4 exhibited excellent stability and reusability for OFL degradation. The Vis/PMS/ZnFe 2 O 4 process would be a reliable alternative for the degradation of OFL-like antibiotics to solve the increasingly serious problem of antibiotic pollution.

Sun Moon Lake is the first dam reservoir constructed in Taiwan with the capability of generating hydroelectricity satisfying the whole Taiwan need during the Japanese colonial period since 1934 CE. Now, the Sun Moon Lake is one of the biggest hydropower stations in Taiwan and has become an important touring area. During World War II (1944–1945 CE), the hydroelectric power plant at Sun Moon Lake was bombed by the U.S. air force, which caused severe damage to the dam structure. More recently, the dam structure was also damaged during the 1999 CE Chi-Chi earthquake whose epicenter is nearby in the Nantou County. A suite of cores were taken from both Sun Lake and Moon Lake, and two selected cores, Sun 2–1 and SM 16 4–3, from Sun Lake were detailed studied with multiple analyses, including X-ray imaging, magnetic susceptibility, visible spectrophotometry, X-ray fluorescence (XRF) scanning, and mineral analysis. We discovered that the increase of Ca content in the sediments not only clearly indicates when the dam was constructed at Sun Moon Lake but also records evidence of structure repairs after both the World War II bombing and the Chi-Chi earthquake. Additionally, the yellow turbidite, X-ray image, and low-Ca signals in Core Sun 2–1 strongly correlate to the typhoon events that caused severe floods in the watershed of Zhuoshui River. The turbidite layers caused by the 1963 Gloria Typhoon are also characterized by conspicuous high peak of Fe/Mn in both cores. This study shows that XRF scanning results are useful for recognition of human activity and for high precipitation event correlation. Moreover, the appearance of charcoal layers shows evidence of forest burning and slash-and-burn activities by humans during the past 4,000 years back to the Middle Neolithic Age.

Heavy metal pollution is a serious concern in the urban area of China. Understanding metal pollution history is crucial for setting up appropriate measures for pollution control. Herein, we report a record of concentrations of 10 heavy metals (Fe, Mn, Cu, Zn, Ni, Cr, Cd, Pb, Co, and Sr) in Pinus massoniana tree rings from Fuzhou City over the past 168 years, which represents the longest tree-ring chronology of heavy metals in China. The studied metals displayed contrasting distribution patterns. Among them, Mn and Sr showed the strongest migration trend with peak concentrations at the pith. Co, Cd, and Pb also showed distinctively high concentrations near the boundary between heartwood and sapwood. Ni, Cu, Cr, and Fe showed an increasing trend possibly due to migration toward bark caused by physiological activities and increasing tourism activities and traffic pollution. The other elements (Cr, Fe, and Zn) with low migration revealed the historical pollution possibly discharged by the Fuzhou Shipping Bureau and other anthropogenic activities. Strong correlations between Cu content and temperature were found, which provides an alternative tree-ring proxy for climate reconstruction. This study provides a long-term perspective of the joint impacts of physiological, environmental, and climatological factors on the concentrations of heavy metals in southeastern China.

Single particle aerosol mass spectrometers (SPAMS) have created significant interest among atmospheric scientists by virtue of their ability to provide real-time size-resolved information on the chemical composition of aerosols. The objective of this study is to evaluate the newly developed single particle analysis technique in terms of chemical characterization and source apportionment of ambient aerosols by comparing it with traditional filter-based methods. In this study, an air quality monitoring campaign was conducted over a period of 25 days at an urban area in Yulin city, southern China, by employing both SPAMS and traditional filter-based measurements to establish the performance of SPAMS. It was observed that the chemical characterization of particles based on SPAMS did not agree well with the filter-based analysis. Based on the filter analysis, sulfate was the most abundant component in PM 2.5 (23.5%), followed by OC (18.1%), while for single particle analysis (number concentration), EC-containing particles showed the largest contribution to PM 2.5 (>40%), followed by OC (15.7%). In terms of source apportionment via positive matrix factorization, six sources were identified by each of the two approaches. Both the approaches showed relatively good agreements for secondary species, traffic, and dust sources; however, discrepancies were noted for industry, fossil fuel, and biomass burning sources. Finally, investigation of diurnal profiles and two specific emission episodes monitored during the Chinese New Year and traffic activities demonstrated the relative advantage of single particle analysis over filter-based methods. Overall, single particle analysis can provide source apportionment with a high time resolution, which is helpful for policy makers to analyze and implement emergency control strategies during air pollution episodes. However, SPAMS performs quantification of number concentration rather than mass concentration and is limited to particles larger than 200 nm, which leads to discrepancies between the two methods. SPAMS measurements can therefore not simply replace traditional filter-based analyses, which needs to be carefully considered in the selection of the monitoring implementation.

Trace element pollution derived from human activities in aquatic systems has raised widespread concerns due to its toxicity, persistence, and bioaccumulation. In this article, we presented a systematic investigation of the anthropogenic overprints on trace elements geochemistry in three streams of the human-impacted (agriculture, urban area, and abandoned mining), located at Lake Aha, Guiyang, Southwest China. Concentrations reported in the study demonstrated that the abandoned mining stream showed the highest trace elements (608.16 μg/L), followed by the urban stream (566.11 μg/L) and agricultural stream (457.51 μg/L). Nonmetric multidimensional scaling (NMDS), used to display sampling dates and trace elements, showed discernible temporal variation in trace element concentrations. Trace element concentrations in months (May, September, and October) with less rainfall were higher than in June, July, and August indicated by NMDS. Principal component analysis (PCA) had shown that As, Ba, Mo, and Zn were mainly impacted by the urbanized streams, and Fe and Sr influenced by the mine. Risk assessment of human beings to trace elements demonstrated that As may pose a detrimental health risk. The research found that trace elements were potential tracers for the presence of human activities and environmental changes.

Rainwater is an essential pathway to remove fine particulate matter and dissolved atmospheric pollutants (e.g., SO 2 , HNO 3 , and NH 3 ). Acid rain (pH < 5.6) has been a severe environmental issue in China since the 1970s, adversely impacting ecosystem health. This study focuses on the influence of anthropogenically induced anions (SO 4 2– and NO 3 – ) and alkaline cations (Ca 2+ and NH 4 + ) on acid rain in Chinese cities. In this review, cities with high population density east of the Hu Huanyong Line that divides China geographically according to its uneven economic development were studied. Coastal and central areas of China to the east of the line are characterized by a much faster developing economy and rapid urbanization. The observed trends and spatial variability of acidity and chemical composition in rainwater are discussed in relation to industrialization and environmental changes in China. Over the past 3½ decades, the precipitation pH in the urban regions has exhibited reduced acidity. A mixed nitric–sulfuric acid rain type has become prominent due to the significant decrease in SO 4 2– via desulfurization. Ca 2+ levels have decreased, while NH 4 + has increased slightly due to more vehicular transportation. In addition, the neutralization capacity of Ca 2+ and NH 4 + has decreased from north to south. Overall, the acid rain problem in Chinese cities has been alleviated in recent years.

The pyrite ores are strategic industrial resources which generally serve as raw material for producing sulfuric acid. However, during the mining and industrial processing activities, associated toxic elements of cadmium (Cd) and lead (Pb) could be released into the surroundings, posing a significant threat to local environment and human health. In this study, the Institute for Reference Materials and Measurement (IRMM) sequential extraction scheme was used to investigate the geochemical fractionation of Cd and Pb in pyrite ores from a mining area located in Yunfu, western Guangdong, China. The results showed that most of Cd and Pb (>90%) were predominantly found in the geochemically mobile fractions, indicating that Cd and Pb were readily bioaccessible thus easily assimilated and accumulated by organisms. FESEM-EDS results showed that the studied pyrite ores were mainly composed of O, S, and Fe, while the XRD characterizations suggested that FeS 2 and SiO 2 were the major minerals. The high-resolution transmission electron microscope and element mapping characterization further confirmed that FeS 2 was the main mineral of pyrite ores which contained relatively enriched toxic heavy metals (e.g., Pb and Cd). The findings highlight that an extremely large amount of geochemically mobile heavy metals can be released into the environmental media during the mining and utilization processes of pyrite ores based on IRMM sequential extraction protocol. Therefore, proper countermeasures against environmental risks of utilizing pyrite ores should be taken to mitigate the impacts on local ecosystem and human health.

Tidal marshes are important recycling areas for biogenic silica (BSi) and macro- and microelements at the land–sea interface and are key locations for examining the decomposition process of wetland plant litter. In this study, in situ decomposition experiments were conducted with Phragmites australis , Cyperus malaccensis , and Spartina alterniflora in the Min River estuary wetland. Litterbags of 0.2-mm mesh size were used to evaluate the litter decomposition process and residual values of BSi and macro- and microelements, including C, N, Cr, Cu, Cd, Zn, Pb, Al, Mn, and Fe over 520 days. The litter decomposition rate significantly differed among species in the following order: C. malaccensis (0.005 d –1 ) > S. alterniflora (0.004 d –1 ) > P. australis (0.003 d –1 ) with BSi release rates of 98.64%, 96.75%, and 97.23%, respectively. Although there were net releases of BSi, C, and N from the three litter species, continuous decrease in the BSi/(C, N) ratio indicated that BSi was removed from the litter much faster than C and N. The accumulation index results showed that Cu, Pb, Al, and Fe were net-accumulated in the litter, whereas Cd, Mn, Cr, and Zn were predominantly released during litter decay. Pearson’s correlation analysis results showed that the amounts of N, Cu, Cd, Pb, Al, and Fe in the litter restrained BSi release with a significant negative correlation. These findings in the Min River estuary have important implications for geochemical cycles within wetland systems and the transport processes of potential nutrients out of the system.

Agricultural practices such as fertilization considerably influence soil greenhouse gas fluxes. However, the effects of fertilization on greenhouse gases fluxes remain unclear in tea soil when soil nitrogen is low. In the present study, soil CO 2 and CH 4 fluxes under various fertilization treatments in tea soil were investigated during a 50-day period. The experiment consisted of five treatments: no fertilizer (CK), single nitrogen (urea, N), single oilseed rape cake fertilizer (R), nitrogen + cake fertilizer (2:1, NR1), and nitrogen + cake fertilizer (1:2, NR2). The fertilization proportion of NR1 and NR2 was determined by the nitrogen content of nitrogen fertilizer and cake fertilizer. The results revealed that the single application of nitrogen had no significant effect on soil CO 2 flux. However, the addition of cake fertilizer significantly increased CO 2 emissions through enhanced soil microbial biomass carbon (MBC). Additionally, CO 2 emissions were directly proportional to the amount of carbon (C) in the fertilizer. All treatments were minor sinks for CH 4 except for the treatment NR1. Specifically, the cumulative CH 4 fluxes of NR1 and NR2 were significantly higher than rest of the three treatments, which implies that application of urea and oilseed rape cake reduced the capability of CH 4 oxidation in tea soil. Structural equation models indicated that soil CO 2 flux is significantly and positively correlated with soil dissolved organic carbon, MBC and soil pH, while mineral nitrogen content was the main factor affecting CH 4 flux. Overall, the application of oilseed rape cake increased the oxidation of CH 4 and promoted soil C sequestration but inevitably increased the soil CO 2 emissions.

Human skeletal morphology is a dynamic system affected by both physiological and environmental factors, due to the functional adaptation and remodeling responses of bones. To further explore the adaptation of bone to the environment and the consequent subsistence strategies determined by the diverse natural contexts in the Anthropocene, this study presents a comparative study on the tibiae of seven ancient populations located in different regions of East Asia. Through the analysis of the tibial shaft morphology, a comparative analysis between the populations and genders was conducted to evaluate the differences in external morphology and sexual division of labor. The cnemic indices of the tibial shaft were selected to quantify the external shape. Results showed that different populations had different tibial morphology. Among males, those of Jinggouzi had the flattest tibia while those of Changle had the widest tibia. Among the females, females of Hanben had the flattest tibia, whereas tibia from females of Shiqiao, Changle, and Yinxu were among the widest. The sexual dimorphism was relatively larger in Shiqiao and Jinggouzi and smaller in Tuchengzi and Changle. Through a combination of previous archaeological findings, historical records, and ethnography of the aboriginal Taiwanese, it is concluded that the terrain and ecological environments laid basis for varied subsistence strategies. In addition, the mobility and social labor division under a particular subsistence strategy further contributed to the adaptation of the lower limb morphology to its context. The comparative analysis provides further insight on habitual activities, terrestrial mobility patterns, and subsistence strategies of the populations, which lived in different environmental contexts during the Bronze Age and early Iron Age, thus demonstrating the diverse interactions between human populations and natural environment in the Anthropocene.

Thallium (Tl) is a highly toxic trace metal widely distributed in water environments, which may threaten the water quality and aquatic organisms at excessive levels due to increased anthropogenic activities. This study investigated the changes in microbial communities of intestines and organs of zebrafish. The toxic response assessments include intestinal microbiota composition and the histopathology of zebrafish’s gill and liver tissues under exposure of Tl at environmental-relevant levels. The results support that the intestinal microbial community of zebrafish greatly changed under a relatively high Tl concentration (1000 ng/L). A significant increase of pathogenic intestinal bacteria such as Mycobaterium in the intestine of zebrafish exposed at Tl levels over 500 ng/L was found. Additionally, the gill and liver tissues displayed different degrees of damage under Tl exposure, which possibly leads to mating behavior changes and death of zebrafish. The results indicate that low doses of Tl in the aquatic environment induce high toxicity on zebrafish and may pose pathological threats to the gill and liver of zebrafish. In addition, Tl exposure gives rise to increasing abundance of pathogenic intestinal bacteria and changes the community structure of intestinal microorganisms.

During the past century, many lacustrine environments have changed substantially at the ecosystem level as a result of anthropogenic activities. In this study, the distributions of n-alkane homologues, carbon isotopes (δ 13 C org ), organic carbon, and the C/N atomic ratio in two sediment cores from Fuxian Lake (Yunnan, southwest China) are used to elucidate the anthropogenic impacts on this deep, oligotrophic, freshwater lake. The carbon preference index (CPI) of long-chain components, average chain length (ACL), proportion of aquatic macrophytes (Paq), and terrigenous/aquatic ratios (TAR) show different temporal patterns that reflect variations in biological production. Notably, the n-alkane homologues are shown to be more sensitive to environmental changes than δ 13 C org and the C/N ratio. Prior to the 1950s, minor variations in the sedimentary geochemical record were likely caused by climate changes, and they represent a natural stage of lake evolution. The onset of cultural eutrophication in Fuxian Lake occurred in the 1950s, when the n-alkane proxies collectively exhibited high-amplitude fluctuations but overall decreasing trends that coincided with population growth and related increases in land-use pressure. In the 21st century, Fuxian Lake has become even more eutrophic in response to human activities, as indicated by sharp increases in C/N ratio, Paq, δ 13 C org , ACL, CPI, and TAR. Our findings provide robust molecular sedimentary evidence confirming that the environmental evolution of lakes in the Yunnan–Guizhou Plateau over the past century was closely associated with enhanced anthropogenic activities.