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As one of the most abundant metals in heavy oils, Ni has suffered so notably increasing impacts from industrial and traffic activities that anthropogenic Ni emissions have altered natural geochemical processes. The coral Ni/Ca has become a reliable proxy for characterizing marine pollution, but this potential has been unexploited for highlighting oil pollution. Here, we utilized a high-resolution record of geochemical parameters (Ni/Ca, δ18O, and δ13C) in a Porites coral of an offshore island in the northern South China Sea to reconstruct of Ni distribution patterns in surface seawater from 1984 to 2015. The coral Ni/Ca ratios exhibit minor fluctuations, except for multiple mutation peaks (0.20 ± 0.42 μmol/mol) during the period from 1984 to 1993. The ratio was low and stable (0.10 ± 0.09 μmol/mol) from 1994 to 2008, and then increased rapidly with significant variations (1.60 ± 4.56 μmol/mol) from 2009 to 2015. The coral Ni/Ca ratios captured all significant Ni discharges, and this demonstrates its potential for recording oil spill episodes. The historical variations in the contributions of Ni indicate that industrial and traffic activities should be responsible for changes in the anthropogenic input. The leaks and consumptions of petroleum likely account for the primary Ni emission sources. [Display omitted] • Anthropogenic Ni input has altered the geochemical processes of oceanic Ni. • Coral Ni/Ca records have potentials to be novel proxies for surface winds. • Temporal emissions of anthropogenic Ni can be captured by coral Ni/Ca records. [ABSTRACT FROM AUTHOR]

Antibiotics have been the subject of much attention in recent years due to their widespread use and the potential ecological risks and resistance risks. In this study, we conducted an extensive survey of 19 antibiotics in a wide range of waters of the Beibu Gulf during summer and winter (154 samples). The total concentrations of the 19 antibiotics (Σ 19 ABs, ng/L) were significantly higher in winter (n.d.–364) than in summer (n.d.–70.1) and were mainly concentrated in areas of seagoing rivers (1.50–364). The primary route for antibiotics entering Beibu Gulf was through riverine input. Precisely, florfenicol (FF) (n.d.–278 ng/L) discharged from livestock and poultry farms upstream of Nanliu River, predominantly in swine farming, constitutes the main pollutant in Beibu Gulf throughout the year. The Nanliu River (988 kg/a) accounts for 85% of the gulf's total annual antibiotic emission flux. Source analysis identified livestock and poultry farming, particularly swine farming, as the primary pollution source, contributing 58% in summer. Risk assessment reveals that algae (0.51 ± 0.56) exhibited relatively high sensitivity to antibiotics, presenting a medium-high risk at specific sites in Nanliu River during winter. Additionally, FF discharged from swine farming demonstrates a certain level of antibiotic resistance risk. Therefore, reinforcing control measures for antibiotic discharges from livestock and poultry farming, especially upstream of Nanliu River, can effectively mitigate antibiotic-related risks in the water bodies of Beibu Gulf. [Display omitted] • Antibiotic levels in Beibu Gulf coastal water are higher in winter than summer. • The Nanliu River is the primary contributor of antibiotics through riverine inputs. • Livestock farming discharge is the primary source of antibiotics in Beibu Gulf. • Algae have a higher risk sensitivity to antibiotics than crustaceans and fish. [ABSTRACT FROM AUTHOR]

As emerging pollutants, the environmental geochemistry of organophosphate esters (OPEs) in the coastal zone with multiple functional areas are still less recognized. This study investigated spatiotemporal distribution, sources and risks of 11 widely used OPEs in surface waters from seagoing rivers and multiple coastal functional areas of the Beibu Gulf. The results indicated that significantly higher ∑ 11 OPEs (total concentrations of 11 OPEs, ng/L) occurred in summer (34.2–1227) than in winter (20.6–840), as a result of the high emission caused by climate reasons. In general, higher ∑ 11 OPEs occurred in rivers (41.2–1227) than in the coast (34.2–809) in summer, especially in the urban rivers, while in winter, higher ∑ 11 OPEs occurred in the coast (23.4–840 vs 20.6–319 in rivers) because of obviously higher ∑ 11 OPEs in marine fishery areas (99–840). Source identification revealed that fishery activity, especially fishing vessels, and urban rivers were the main sources of OPEs in the Beibu Gulf. For the individual OPE, only tri-n-butyl phosphate (TNBP) may have ecological risks to aquatic organisms in a few sites, but if considering the additive effects, the OPEs mixtures would pose a high risk to algae and low to medium threats to crustaceans and fish. [Display omitted] • OPEs' levels and sources were studied in the coastal water of Beibu Gulf (BG). • High temperature and rainfall may promote the release of OPEs to the environment. • Riverine discharge and fishery activities were the main sources of OPEs in the BG. • Ecological risk of OPEs at different trophic levels were assessed in BG. • They pose relatively high ecological risks to aquatic organisms, especially algae. [ABSTRACT FROM AUTHOR]