The study deals with the spatio-temporal distribution of heavy metals in the sediments of Chagan lake, Northeast China. The pollution history of heavy metals is studied simultaneously through the ²¹⁰Pb dating method by analyzing the characteristic of As, Hg, Cd, Cr, Ni, Cu, Pb, and Zn concentration-depth profiles. The potential ecological risk index (RI) and geo-accumulation index (I_geo) were used to evaluate the contamination degree. Principal component analysis (PCA), based on the logarithmic transformation and isometric log-ratio (ilr) transformed data, was applied with the aim of identifying the sources of heavy metals. The element concentrations show that the heavy metals are enriched in the surface sediment and sediment core with a varying degree, which is higher in the surficial residue. The results of I_geo indicate that the Cd and Hg in the surface sediment have reached a slightly contaminated level while other elements, uncontaminated. The results of RI show that the study area can be classified as an area with moderate ecological risk in which Cd and Hg mostly contribute to the overall risk. For the sediment core, the ²¹⁰Pb dating results accurately reflect the sedimentary history over 153 years. From two evaluation indices (RI and I_geo) calculated by element concentration, there is no contamination, and the potential ecological risk is low during this period. The comparative study between raw and ilr transformed data shows that the closure effect of the raw data can be eliminated by ilr transformation. After that, the components obtained by robust principal component analysis (RPCA) are more representative than those obtained by PCA, both based on ilr transformed dataset, after eliminating the influence of outliers. Based on ilr transformed data with RPCA, three primary sources could be inferred: Cr, Ni, As, Zn, and Cu are mainly derived from natural sources; the main source of Cd and Hg are associated with agricultural activities and energy development; as for Pb, it originated from traffic and coal-burning activities, which is consistent with the fact that the development of tourism, fishery, and agriculture industries has led to the continuous increasing levels of anthropogenic Pb in Chagan Lake. The summarized results and conclusions will undoubtedly enhance the governmental awareness of heavy metal pollution and facilitate appropriate pollution control measures in Chagan Lake.

Over the years, many geological exploration reports and considerable geological data have been accumulated during the prospecting and exploration of the Jiapigou gold metallogenic belt (JGMB). It is very important to fully utilize these geological and mineralogical big data to guide future gold exploration. This work collects the original textual data of different gold deposits in JGMB and constructs a knowledge graph (KG) for deposits based on deep learning (DL) and natural language processing (NLP). Based on the metallogenic geological characteristics of deposits, a visual construction method of a KG for deposits and a calculation of the similarity between deposits are proposed. In this paper, 20 geological entities and 24 relationship categories are considered. By condensing the key KG information, the metallogenic geological conditions and factors controlling the ore in 14 typical deposits in the JGMB are systematically analyzed, and the metallogenic regularity is summarized. By calculating the deposits’ cosine similarities based on the KG, the mineralization types of deposits can be divided into two categories according to the industrial types of ore bodies. The results also show that the KG is a cutting-edge technology that can extract the rich information of ore-forming regularity and prospecting criteria contained in the textual data to help researchers quickly analyze the mineralization information.

A total of 56 atmospheric deposition samples were collected on a yearly basis from the Baicheng-Songyuan areas, Jilin Province, Northeast China. Each sample was subdivided into wet (soluble) and dry (insoluble) fractions, and the concentrations of toxic trace elements including As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Se, and Zn in both fractions were analyzed. The bulk fluxes and ecological and human health risk of these toxic trace elements in atmospheric deposition were evaluated. The bulk deposition fluxes of toxic trace elements decreased in the order of Mn > Zn > Cr > Pb > Cu > Ni > As > Co >Mo > Cd > Se > Hg. The fluxes of toxic trace elements in dry fraction accounted for 74.7–99.9% of their bulk deposition fluxes, indicating that the atmospheric deposition of toxic trace elements in the study area is predominantly dry atmospheric deposition. The mean values of the geo-accumulation index (Igeo) and enrichment factor showed moderately heavy contamination with Cd via dry atmospheric deposition, but no contamination from other toxic trace elements; Cd and Hg in dry atmospheric deposition were in the moderate to considerable ecological risk levels, while other trace elements were at low ecological risk levels. The health risk assessment showed that the effects of toxic trace elements in dry atmospheric deposition via three exposure pathways were in the order of ingestion > inhalation > dermal contact for adults and children. The mean values of hazard quotient (HQ) and hazard index (HI) of toxic trace elements via three pathways were less than one, indicating that their non-carcinogenic risks in dry atmospheric deposition may be low or negligible for adults and children. The mean values of carcinogenic risk (CR) and total carcinogenic risk (TCR) of As and Cr via the three pathways for adults and children were between 10⁻⁶ and 10⁻⁴, indicating that the carcinogenic risk levels of As and Cr were tolerable or acceptable, and the mean TCR value of Cd through the three pathways for adult and children was less than 10⁻⁶, implying that the carcinogenic risk level of Cd was negligible. Mn, Ni, Cr, and Co in dry atmospheric deposition were mainly contributed from the crustal sources, while As, Cd, Cu, Hg, Mo, Pb, Se, and Zn in dry atmospheric deposition were derived from both crustal and anthropogenic sources. The results obtained in this study advocate the necessity for monitoring atmospheric deposition in some rural areas, and also provide a scientific basis for controlling contamination posed by toxic trace elements in dry atmospheric deposition.