The frequent occurrence of extreme hydrological events (EHEs) poses a serious threat to human living environment. Magnetic profiles of deltaic sediments contain high-resolution EHE records, and magnetic minerals could be finally altered to pyrite by reductive diagenesis. Till now, the preservation of EHEs in the pyrite-bearing layers that formed through diagenesis is poorly known. In this study, systematic magnetic tests were conducted on Holocene deposits from core S23 (3.00-18.00 m, spanning the past 7.60 ka) in the East River Delta, southern China. Pyrite was widely discovered within the core, while magnetite, hematite, and greigite were the main magnetic contributors. An abrupt increase in magnetic mineral content along with the occurrence of coarse magnetic grains were observed in the intervals of similar to 0.70-0.60, 0.87-0.78, 1.07-0.94, 1.18-1.12, 1.40-1.33, 1.58-1.45, 1.92-1.82, 2.09-2.02, 2.62-2.48, 3.44-3.36, 3.90-3.62, 6.14-6.00, 6.74-6.67, and 7.42-7.36 cal. ka BP. These changes, consistent with the EHE sediment records in the nearby peat, indicate the regional EHE deposits. We propose a model in which EHEs promoted the quickly input of coarse, clastic materials (including magnetic minerals), which inhibit the sulfidation progress of greigite to pyrite, and enable the preservation of greigite. The occurrence of EHEs was mainly controlled by the El Nino-Southern Oscillation activity, while their frequency between 2.10-0.50 cal. ka was partly caused by the intensification of the anthropogenic activities in the basin. The continuous weakening of the Asian Summer Monsoon during 7.60-0.50 cal. ka BP led to a long-term increase in the frequency of EHEs in South China. This study provides a new approach for reconstructing ancient EHEs in South China deltas.

Human-driven soil erosion is a signal of the widely debated "Anthropocene". There is widespread controversy regarding the time consistency and time transgression of human-driven soil erosion in the Late Holocene. In this study, three well-dated cores, B10, B14 and W20 from west to east, spanning the past 4-6 ka from the Pearl River Estuary (PRE) shelf, southern China, were selected for elemental tests. Principal component analysis divides the elements into four components. The first principal component (PC1) includes TFe2O3, Al2O3, V, Cs, Rb, Ga, TiO2, K2O, Ta, Nb, MnO, Th, LOI, and Cl, being the proxy for fine-grained terrigenous input and watershed soil erosion. The PC1 variations in B10 and B14 reveal that erosion enhanced at similar to 2.2 ka BP, and less erosion occurred at similar to 1.5 ka BP but has intensified since similar to 1.2 ka BP, which is consistent with the simulated cropland area of the Pearl River Basin and lake records in the upper West River, southwestern China. However, the records from the W20 reveal a continuous increase in terrestrial input since 2.2 ka BP, which is consistent with the soil erosion changes recorded by the South China coast lakes at its provenance region. Hence, differences in the initial age of the signals of human activities were revealed in the PRE shelf system. Our study not only reveals the time transgression of the "Anthropocene" boundary but also updates the sediment source-to-sink model of the PRE shelf system.

Studies of land-sea transitions during the Holocene can provide valuable insights for predicting future trends of coastal evolution. However, the land-sea transition process during the Holocene evolution of the Pearl River Delta remains controversial. This study uses the magnetic properties of a Holocene sediment core from the Pearl River Delta, combined with an accurate chronological framework, to elucidate the land-sea transition process. Based on stratigraphic variations in magnetic properties, four sedimentary stages were identified. From 8700 to 7800 cal yr BP, the sediments were characterized by a relatively high hematite content, while the magnetic susceptibility was dominated by superparamagnetic (SP) magnetite. Between 7800 and 5500 cal yr BP, the total magnetic mineral content decreased, accompanied with an increasing proportion of fine-grained magnetite. From 5500 to 2800 cal yr BP, coarse-grained magnetite increased rapidly and then gradually decreased, while the relative proportion of magnetite showed an opposite trend. During 2800 to 1800 cal yr BP, both the content and relative proportion of coarse-grained magnetic particles increased substantially. These stages document the transition from terrestrial deposition to a marine transgression, subsequent sea-level fluctuations and regression, and a final return to terrestrial sedimentation. These results are consistent with sequential changes in transgression-regression shorelines across the delta plain and offer a new approach to high-resolution investigations of Holocene sea-level changes. Future research on coastal evolution should be comprehensively explored for regional land-sea changes and their intrinsic evolutionary mechanisms.

Inner shelf sediment properties are sensitive indicators of Holocene environmental changes; however, magnetic records can be altered by reductive dissolution. To refine our understanding of magnetic mineral dissolution, we conducted detailed analyses of three sediment cores from the inner shelf of the northern South China Sea. AMS14C dating, grain-size, magnetic parameters, mineral composition, organic carbon, and sulfur content were examined. The cores, composed uniformly of clayey silt and spanning the past 4-6 ka, were divided into three zones: (1) a suboxic surface layer (40-88 cm thick), (2) an intermediate zone with moderate magnetic properties, and (3) a basal zone characterized by intense magnetic mineral dissolution. Identified minerals include magnetite, hematite, and iron-sulfide phases such as pyrite. The depth of the suboxic-sulfate boundary (Zones 1-2) was inversely correlated with sedimentation rate and water depth. The magnetic dissolution front (Zones 2-3 boundary) coincided with a sharp increase in sedimentation over the past 1-2 ka, likely linked to intensified human activity. These results suggest that anthropogenic environmental changes may have influenced magnetic mineral reductive dissolution, warranting further investigation.

During the past decades, agricultural soil heavy metal pollution has been becoming increasingly severe due to urbanization and industrialization. However, the impact of externally input heavy metals on deep soils remains unclear because most previous relevant research only focused on surface soils. In the present study, Concentrations of eight heavy metals (Cu, Zn, Ni, Pb, Cr, Cd, As, and Hg) were determined for 72 pairs of surface and deep soil samples collected from an agricultural region close to the Pearl River estuary. Subsequently, heavy metal pollution and potential health risks were assessed using the Geo-accumulation Index and Potential Ecological Risk Index, a dose response model and Monte Carlo simulation, respectively. Principal component analysis (PCA) and the positive matrix factorization (PMF) receptor model were combined to analyze heavy metal sources. The results indicated that average concentrations of all heavy metals exceeded their corresponding background values. Cd was identified as the main pollutant due to its extremely high values of Igeo and Er. Unacceptable potential heavy metal non-carcinogenic and carcinogenic risks indicated by respectively calculated HI and TCR, higher than thresholds 1.0 and 1.0 × 10−4, mainly arose from heavy metals As, Cd, Cr, and Ni through food ingestion and dermal absorption. Anthropogenic sources respectively contributed 19.7% and 38.9% for soil As and accounted for the main contributions to Cd, Cu, and Hg (Surface: 90.2%, 65.4%, 67.3%; Deep: 53.8%, 54.6%, 56.2%) within surface and deep layers. These results indicate that soil heavy metal contents with deep layers were also significantly influenced by anthropogenic input. Therefore, we suggest that both surface and deep soils should be investigated simultaneously to gain relatively accurate results for soil heavy metal pollution and source apportionments.

Magnetic parameters of river sediments are commonly used as end-members for source tracing in the coasts and shelves. The eastern continental shelf area of China, with multiple sources of input, is a key region for discussing sediment sources. However, magnetic parameters are influenced by grain size, and the nature of this influence remains unclear. In this study, the Jiulong River was selected as a case to analyze the magnetic parameters and mineral characteristics for both the coarse (>63 μm) and fine-grained (<63 μm) fractions. Results show that the magnetic minerals mainly contain detrital-sourced magnetite and hematite. In the North River, a tributary of the Jiulong River, the content of coarse-grained magnetic minerals increases from upstream to downstream, contrary to fine-grained magnetic minerals, suggesting the influence of hydrodynamic forces. Some samples with abnormally high magnetic susceptibility may result from the combined influence of the parent rock and human activities. In the scatter diagrams of magnetic parameters for provenance tracing, samples of the <63 μm fractions have a more concentrated distribution than that of the >63 μm fractions. Hence, magnetic parameters for the <63 μm fraction are more useful in provenance identification.

Stratigraphic determination of the Anthropocene, the "Great Acceleration", requires more key globally synchronous stratigraphic markers which reflect the significant human impacts on Earth. Lacustrine sediment magnetic characteristics are of considerable importance in Anthropocene studies because they respond sensitively to environmental changes. There are many shallow lakes in the Songnen Plain (SNP) in northeast China, which are conducive to obtaining Anthropocene sedimentary records. This study explored magnetic materials in lacustrine sediment responses to environmental evolution impact by human activities on the SNP by measuring magnetic parameters in dated sediment cores from 5 shallow lakes in the SNP, northeast China. The results revealed that detrital magnetite and hematite dominated the magnetic minerals in lake sediments. The persistently low value of magnetic susceptibility might be caused by the low content of natural ferrimagnetic minerals in Quaternary fluvial deposits and humus-rich black soil in the catchment, and the loss of magnetic materials during the transport process. In Lake Longjiangpao (LJP), the magnetic concentrations significantly responded to regional precipitation, whereas in the other 4 lakes in the center of the plain, the parameters tended to reflect complex human activities. However, the isothermal remanent magnetization ratio (S-300), which is indicative of the ratio of hematite to magnetite, exhibited relatively consistent variations in the 5 studied lakes. After 1950, the "Great Acceleration", the increase of S-300 indicated a relative proportion of magnetite in sediments, and was positively correlated with the growth of human-activity proxies (Gross Domestic Product (GDP) and population). Thus, this proxy can be regarded as a useful indicator of the beginning of the Anthropocene in the studied region. This study provides new insights into the estimation of local human activities in history and possible evidence for the global definition of the Anthropocene.

Abstract The Cuo E (CE) core contains the entire Quaternary stratigraphy of the CE Lake (31°24′–31°.32′ N, 91°28′–91°33′E, Tibetan Plateau, China). Here, we study the magnetic properties of 1,748 samples from the CE core, combined with scanning electron microscopy and X‐ray energy dispersive spectrometer analysis on selected samples. The main magnetic minerals appear to be magnetite and greigite. To further quantify the presence of greigite in CE core, 84 samples were analyzed using rock magnetism in more detail including: susceptibility (χ) versus temperature, coercivity component analysis of acquisition curves of the isothermal remanent magnetization (IRM), and principal component analysis of the first‐order reversal curve (FORC) diagrams. The greigite content and saturation IRM over susceptibility (SIRM/χ) appear to be exponentially related. SIRM/χ can be used as greigite concentration indicator. We also propose a rapid way to identify greigite in the CE core: When SIRM/χ increases and anhysteretic remanent susceptibility (χARM) increases only slowly, the sample contains greigite. Samples with SIRM/χ < 15 kA/m also follow this relation. This greigite detection method has a lower limit of detection than the traditionally used SIRM/χ parameter. It is also faster than FORC analysis and thus particularly suitable for analysis of large sample collections. Twenty greigite‐bearing layers were identified in the CE core using this method. The location of the Jaramillo subchron in the CE core is controversial in the currently available magnetostratigraphy, possibly related to the presence of greigite in this core interval.

As a crucial “sink” for terrigenous material entering the ocean, provenance of sediments within the coastal zone and continental shelf sea regions holds significant scientific importance in the investigation of global material cycling. Environmental magnetism was proved as an effective and rapid approach for sediment source identification. Detail and systematic magnetic measurements were performed for surface sediment samples collected from the mega Pearl River, local small rivers (Tan, Moyang and Jian rivers) of west Guangdong, coastal zone (CZ) and continental shelf (CS) to analyze the contribution of local small watersheds to marine sediments. The results indicate that detrital river input magnetite and hematite are coexisted in both CZ and CS sediments. Compared to CZ sediments, relatively higher concentration of hematite and finer grain size of magnetite are appeared at CS sediments. By comparing of magnetic parameters, it was inferred that magnetic minerals from the Pearl and Tan rivers are transported and deposited on the coastal zone by Guangdong longshore current. Meanwhile, sediment magnetic parameters in the Moyang and Jian Rivers are similar to the CS sediments, implying the two rivers-sourced materials were directly transported and deposited at the CS due to their narrow and restricted estuaries, and/or the CS preserves the residual deposits from the two rivers formed during the Last Glacial. Except for the Pearl River, sources of local small rivers significantly contribute to marine sediments at the coastal zone and continental shelf.

Microplastic is an emerging pollutant and a technical fossil in Anthropocene sediments. Typhoon frequency and intensity have increased due to climate change, which has a major effect on the distribution patterns of microplastics. It is still unknown, though, how the topography of the peninsula affects the reconstruction of the distribution of microplastic in typhoons. Due to frequent typhoons, the Leizhou Peninsula (LZP) in the north part of the South China Sea is an ideal place to study the impact of topographic variations on microplastic distribution during typhoon events. This study investigated microplastics ranging in size from 50 mu m to 5 mm in sediment. Microscopic inspection and mu-FTIR tests were used to identify microplastic characteristics from offshore surface sediments before and after typhoons. The average microplastic abundance in offshore sediments decreased from 18 +/- 17 items/kg to 15 +/- 15 items/kg after typhoons. Results show that typhoons only increase the microplastic abundance in topographically protected areas along the northeast coast of LZP, with no significant difference observed in other regions. The influence of typhoon on the morphological characteristics of microplastics in sediments is more pronounced and widespread, as evidenced by a shift in the predominant shape of microplastics from fibers to fragments and a decrease in size accompanied by an increased abundance within the 100 mu m-1 mm fraction. The color of microplastics remained similar before and after typhoons, and the polymer composition of microplastics became more uniform. The alteration of microplastic morphology may be attributed to the enhancement of wave intensity induced by typhoons. This study enhances the comprehension of typhooninduced impacts on pollutant redistribution, specifically microplastics, thereby providing essential empirical evidence and theoretical foundations for pollution regulation.

Between 1958 and 1999, notable lithic localities recorded prehistoric activities in Xiqiao Town of Nanhai District, Foshan City, Guangdong Province, from which double-shouldered and microlith-stone artefacts were uncovered. Currently, the "Xiqiaoshan site" is recognized as a substantial Neolithic quarry and processing location, dating back to 4‒7 ka B P. Subsequently, from 2011 to 2022, we conducted multiple geological environmental surveys and analyses on Xiqiaoshan Mountain. A well-preserved Quaternary stratigraphic profile was discovered north of Fuxian village in the southeast foothills of Xiqiaoshan Mountain. The sedimentological, geochemical, and geochronological results indicate the presence of two primary sedimentary strata in the Fuxian locality. The upper unit comprises the Holocene swamp facies, with a calibrated AMS14C dating range from 5052‒5409 a B P; whereas, the lower unit comprises the late Pleistocene alluvial-diluvial strata, with a calibrated AMS14C dating range from 38420‒40502 a B P, and an optically stimulated luminescence (OSL) dating range of 41.977‒43.796 ka B P. Late Pleistocene strata yielded two sand-gravel layers containing Paleolithic artefacts, which are marked as layers A1 and A2. The predominant artefacts in lower layer A1 include larger scrapers, pointed tools, tongue-shaped edged tools, and small flake tools, such as various scrapers, denticulates, notches, knives, utilized flakes, and cores, including tanged axe-shaped knives. In the upper layer A2, backed or tanged knives appear more frequently. The other small flake tools from this layer (A2) were not significantly different from those in lower layer A1. One bifacially prepared core for producing small elongated flakes is of particular interest for this artefact. Based on the average deposition rate, the computational age of the A1 layer was 46.511‒47.325 ka B P, whereas that of the A2 layer was 41.977‒42.167 ka B P. Although the number of artefacts within the Holocene sediments (>5 ka B P) overlying the late Pleistocene strata is limited, the characteristics of inheritance and development are still evident in the types of artefacts. The discovery presented in this study has completely updated and extended the connotation of Xiqiaoshan National Geopark and "Xiqiaoshan culture,"breaking through the late Pleistocene Paleolithic remains records with exact dating in the Pearl River Delta region for the first time. Therefore, a ground-breaking discovery can accurately trace the footsteps of modern humans in the coastal areas of South China from 40‒50 ka. It also reveals the rich features of lithic industry and the developmental characteristics and evolution of its cultural connotations during this period. The present study shows that during the relatively warm and humid conditions of marine isotope stages 3 (MIS3) interglacial period and the subsequent cold and arid stage of MIS2, human population in the Fuxian locality encountered environmental challenges and adopted new subsistence strategy, which is of great significance for understanding modern human responses and adaptations to global and regional environmental and climate change.

Data for the paper of "Impact of typhoon events on microplastic distribution in offshore sediments in Leizhou Peninsula of the South China Sea"

With the intensification of global climate change, floods caused by typhoons and heavy rainfall occur frequently. It is important to effectively identify flood events within sedimentary records to study the flood frequency patterns. Currently, grain size analysis is the commonly applied method for flood event identification. The hydrodynamic conditions and sediment sources identified from the grain size parameters are used to distinguish flood events. However, identification results from a single index can easily lead to inaccuracies due to complex river sedimentation processes. Therefore, it is necessary to select the most suitable proxy and, in combination with the implications of different types of indicators, identify flood events in study areas. In addition to grain size analysis, the technology of environmental magnetism has been widely applied in the sedimentology research of flood sediments owing to its advantages of sensitivity, rapidity, economy, and non-destructiveness. In this study, a longitudinal floodplain sediment profile collected from a small watershed in northern Guangdong was selected as the research object. Both grain size and magnetic characteristics of the entire profile were determined in detail. Based on the flood event records identified by sediment grain size characteristics, an in-depth analysis of the magnetic characteristic differences between the flood sedimentary layers and normal sedimentary layers, was performed. We aimed to establish a set of suitable magnetic parameters for identifying flood events in this region. Consequently, a new approach can be used to identify paleofloods within sedimentary records. The results indicate the following. 1) The sediment particle size composition is primarily composed of silt, which accounts for more than 70% of the total. Moreover, the sediment particle size tended to become finer from the flood sedimentary layer to the normal sedimentary layer. Three sublayers characterized by relatively high peak values of sand content and mean grain diameter were identified as flood event sediments within the flood sedimentary layer. 2) The composition and sources of magnetic minerals within the sediments from different sediment layers are similar. The predominant magnetite and some hematite within the sediments are from the natural weathering of parent materials within the watershed. Exogenous input from the tailings pond of the Dabaoshan mine is another source of magnetic particles. 3) As deposition is dominated by suspended sedimentation in the study area, sediment sorting is sufficient under the influence of a continuous long-term high-water level. As a result, the magnetic particles within the flood sedimentary layer are relatively fine. With the enhancement of hydrodynamic conditions, the grain size of the magnetic particles and the concentration of fine-grained magnetite and hematite became coarser and increased in the three identified flood event sublayers within the flood sedimentary layer (from the middle to the top of the sedimentary profile). Therefore, a combination of environmental magnetic parameters and magnetic mineral composition analysis can be used for the accurate identification of flood events recorded by sediments. In the study area, the magnetic characteristics of the relatively high contributions of fine-grained magnetite and hematite and the relatively low contribution of coarser magnetite to saturation isothermal remanent magnetization can be regarded as proxies for identifying flood events and strong hydrodynamic conditions.

Variations in the extent of glaciated areas are among the most distinct natural responses to climate change. To explore the response mechanism of sediment magnetic properties to glacial-area variation, detailed environmental magnetism investigations were performed on a sediment core from Lake Heihai, an alpine lake located on Haba Snow Mountain in Yunnan Province. We discuss the changes in sediment magnetic properties in the past century and their response mechanism to variations in glacial area caused by climate change, especially air-temperature change, based on the published chronological data. Results of magnetic mineralogy showed that single- and multi-domain magnetite and a small amount of high coercivity magnetic minerals dominated the sediment magnetic properties throughout the core. Magnetic particles within the sediments of Lake Heihai mainly originated from the terrigenous input of the lake basin discharged by glacial meltwater. Significant positive correlations were found among the annual average air temperature in the study area and concentration-dependent magnetic parameters (χ lf ) while negative correlations occurred among the annual average air temperature and particle size-dependent magnetic parameters (χ ARM /SIRM), indicating that the sediment magnetic properties of alpine lakes were sensitive to glacial-area variations caused by air-temperature change. Increased input of coarse magnetic particles was a result of glacial-area shrink, while decreased coarse-grain input and occurrence of finer magnetic particles corresponded to glacial-area expand. In addition, we identified three glacial-area shrink and expand cycles based on the variations in sediment magnetic properties in the study area. We propose that the sediment magnetic properties of alpine lakes can be used for monitoring variations in glacial area caused by climate change.

Fixed-station sampling design was widely used in fishery-independent surveys because of its characteristics of convenient sampling station setting, but the non-probabilistic (fixed) nature made it more uncertainty of drawing inferences on population. The performance of fixed-station sampling design for multispecies survey has not been evaluated, and we are uncertain if the design could detect the temporal trends of different populations in multispecies fishery-independent survey. In this study, spatial distribution of abundance indices for three species with different spatial distribution patterns including small yellow croaker (Larimichthys polyactis), whitespotted conger (Conger myriaster) and Fang's blenny (Enedrias fangi) were simulated using ordinary kriging interpolation as the "true" population distribution. The performance of fixed-station sampling design was compared with simple random sampling design by resampling the simulated "true" populations in this simulation study. The results showed that the fixed-station sampling design had the power to detect the seasonal trends of species abundance. The effectiveness of fixed-station sampling design were different in different species distribution patterns. When the species had even distribution, fixed-station sampling design could get high quality abundance data; when the distribution was uneven with heterogeneity or patchiness, fixed-station sampling design tended to underestimate or overestimate the abundance. Evidently, the estimates of abundance index based on the fixed- station sampling design must be calibrated cautiously while applying them for fisheries stock assessment and management. This study suggested that fixed-station sampling design could catch the temporal dynamics of population abundance, but the abundance estimates from the fixed-station sampling design could not be treated as the absolute estimates of populations.

Magnetic minerals within fluvial sediments are affected by a variety of natural and anthropogenic factors, limiting the capability of sediment magnetism in tracing provenance, assessing pollution, and other environmental or geological fields. Twenty-three samples were collected from Liuxi River, a river influenced by complex natural and human processes, in southern China to conduct the analysis of magnetism, particle size, and geochemical elements. The micromorphology of magnetic particles was directly observed by scanning electron microscope and energy dispersive spectrometer. The following are the factors affecting the sediment magnetic properties: (1) There is a sampling site in the upper reach with over 100 times magnetic susceptibility than other sites. This sampling site is close to the areas having documented iron ore mining and smelting activities in the past few hundred years, and the sample contains the very high concentrations of metals (e.g., Fe, Mn, Ni, Pb, Sn, V, Cr, Cu, and Bi), implying the ancient mining activity could pose environmental risks in modern sediments. (2) In a downstream direction, magnetic concentration shows a decreasing tendency and magnetic grain size becomes finer. The contributions of superparamagnetic particles and high-coercivity minerals (e.g., hematite) to the total magnetism increase, and technogenic magnetic particles appear downstream of urban areas. In general, the upstream magnetic minerals are controlled by weakly weathered coarse-grained particles produced by granite denudation, while the downstream magnetic minerals are affected by the sedimentary rocks and the human activity. (3) Magnetic minerals become coarse after the river flows over barrages in response to the hydrodynamic changes. The investigation reveals the natural and anthropogenic influences according to the analysis of the sediments in Liuxi River, and further research related to the sediment magnetism in complex river should be conducted.

The river environment is complex and receives a variety of contaminants from numerous sources that are persistent, bioaccumulative, and toxic. The distribution, source, contamination, and ecological risk status of Zn, Pb, Cu, Ni, Cr, and Cd were evaluated in the surface sediments at 45 sites on the Moyang and Jian rivers in Western Guangdong, China. Single pollution indices, including contamination factor (CF) and enrichment factor (EF), revealed that Zn, Pb, Ni, Cu, and Cd showed moderate to significant enrichment. To overcome the limitation of the single element indices, a range of sediment quality indices, including modified contamination index (mCd), pollution index (PI), and modified pollution index (MPI), were utilized to ascertain the sediment quality. The sediment in the study area is deemed to be slightly to extremely polluted. The sediment quality guidelines (SQGs), potential ecological risk index (RI), and modified ecological risk index (MRI) were used to assess possible ecological risks. According to the SQGs, Pb, Ni, and Cu have the potential to induce biological effects. The RI indicated that the sediment poses a low ecological risk. However, the MRI indicated that the ecological risk of the sediment was moderate to very high. The accuracy of the single and multi-element indices and ecological risk assessment were evaluated in the river using the principal component analysis (PCA) and cluster analysis (CA), showing an anthropogenic impact. Results demonstrate the need to pay attention to the ecological environment of small rivers, which are sensitive to their surroundings.

The southern China coast areas are often invaded by typhoons, probably causing the redistribution of heavy metals in sediments. The knowledge of the influence of typhoons on the redistribution of heavy metals along the coasts is limited. The sea-floor sediments from the Leizhou Peninsula (LP) coast, southern China, were sampled to test the spatial distribution of the heavy metal before and after typhoons Barijat and Mangkhut in 2018. Results indicated that the coast suffered from varying levels of As contamination, while only minor enrichments were found in a few locations for other heavy metals. The pollution level on the western LP coast seemed to be higher than on the eastern coast. All heavy metals were mainly provided by terrigenous materials from the natural processes and were less affected by grain sizes. After the typhoon landings, more oxidation conditions promoted the deposits of As and the adsorption of Mo by MnO2.

Major elements and Sr-Nd isotopes data for the core PC338 from South China Sea.