We used a section-segment method to determine the copper (Cu) fluxes from the Yangtze River to the East China Sea during 2012–2016 in this study, including the maximum, minimum and mean annual fluxes of dissolved and suspended Cu. The Cu fluxes exhibited a pronounced inter-annual variability. June was characterized with the highest monthly dissolved and suspended Cu fluxes, while the lowest monthly Cu fluxes was in February. The monthly Cu concentration and Cu fluxes both increased from January to June and decreased from July to December. The monthly Cu fluxes showed a positive correlation with the water flux and monthly mean Cu concentration; however, it had a negative correlation with the ratio of tidal flux to river runoff flux. Both natural (53%) and anthropogenic inputs (32.8%) were the main sources of Cu. The discharges of industrial and domestic sewage wastewater were the main anthropogenic factors affecting the entry of Cu.

Calvo et al. (2020) criticize a new seagrass rehabilitation method proposed by Alagna et al. (2019) and inspired by the Posidonia oceanica spontaneous recovery observed at Capo Feto (Sicily), were recolonization was detected almost exclusively on rubbles deployed to fill a pipeline trench. Calvo et al. (2020) claim that natural recovery occurred consistently also on dead matte along the eastern side of the trench, weakening the assumption on which the method is based. Here we show that the P. oceanica patches reported by these authors as new establishments were already documented in 2003 (Vega Fernandez et al., 2005) and are attributable to the fragmentation of the pristine meadow caused by altered sedimentation rate after an extensive dredging operation. Moreover, we outline the area of applicability of the method tested in Alagna et al. (2019) and provide a point-by-point rebuttal to the complaints of imprecise and misleading contents of the paper.

Aluminum smelter-derived polycyclic aromatic hydrocarbons (PAHs) in outmigrant juvenile Chinook salmon were evaluated in Kitimat Arm, British Columbia, Canada from 2000 to 2004, and in 2015. Decades of continual smelter operations by Rio Tinto resulted in PAH contamination of marine sediments at levels associated with adverse effects in juvenile salmon. Recently, smelter operations have undergone process changes to reduce PAH input to the environment. The PAH concentrations in juvenile Chinook salmon observed in 2000 to 2004, at sites nearest the smelter were comparable to salmon in other urban areas where reduced disease resistance was observed; the levels were lower in 2015 than 2000–2004 suggesting that the recent process changes were effective. Further, these data establish a benchmark for assessing any future changes affecting PAH input and the potential risks to the receiving environment.

This study highlights plastics occurrence in five demersal fish species from the Southern Tyrrhenian Sea: the Red mullet Mullus barbatus barbatus, the Piper gurnard Trigla lyra, the Blackmouth catshark Galeus melastomus, the Lesser spotted dogfish Scyliorhinus canicula and the Brown ray Raja miraletus. Overall, 125 fish were examined: 21 Red mullets, 16 Piper gurnards, 75 Blackmouth catsharks, 72 Dogfish and 1 Brown ray. The percentage of fish with ingested plastics was 14.4% with 0.24 items per specimen. The majority of the debris were fibers and the application of infrared and Raman spectroscopy allowed the identification and discrimination of plastic and non-plastic fibers. The plastic debris isolated were mainly microplastics (94.1%), while macroplastics occurrence was very low (5.9%). The plastics were identified as polypropylene, Teflon, nylon, kraton G (triblock copolymer) and polyethylene. Also cellulose was detected. S. canicula was the species with the highest number of plastic pollutants.

Ostreopsis is a benthic dinoflagellate genus comprising eleven species including seven that are toxigenic. Ostreopsis lenticularis was first described from French Polynesia and is widely distributed in many insular locations from the Pacific Ocean. The current study presents morphological and molecular evidence of the presence of O. lenticularis at the Fernando de Noronha Archipelago, South Atlantic. Light microscopy and scanning electron microscopy of field cells showed morphological features in agreement with the description of O. lenticularis. Cells were broadly oval, 66.0–117.5 μm in dorso-ventral diameter, 50.0–92.5 μm in width, with thecal plates presenting two kinds of pores. Phylogenetic analyses based on LSU (D1-D3) and ITS sequences from field cells from Fernando de Noronha clustered with O. lenticularis sequences from elsewhere. The species was present in low to high abundances. The current study expands the distribution of O. lenticularis to Fernando de Noronha Archipelago in the South Atlantic Ocean.

During the expedition 908 survey in 2007, 539 seafloor surface sediment samples and two cores were collected over a narrow sector of the northeastern Beibu Gulf, South China Sea. Currently, three dynamic sedimentological processes prevail in the study area: circulation-controlled sand deposition, mud deposition under weak sediment dynamics, and fluvial input. Core A233 from the circulation-controlled sand area, with a 60 cm mixed layer, provides evidence of dynamics disturbance since the mid-Holocene. To reconstruct the anthropogenic heavy metal pollution history, we selected core A146 from the stable mud sector influenced by fluvial input. The dating of core A146 was based on ²¹⁰Pb activity analysis, showing an ~90-year historical record in the upper 40 cm. The heavy metal contamination results showed a generally low pollution level. Nonetheless, increased pollution has happened since the 1950s, especially after 1978 A.D., corresponding to the beginning of China's reform and opening up.

We investigated the source, composition, and reactivity of particulate organic carbon (POC) in two contrasting Korean estuary systems, a closed estuary (Geum) (i.e., with an estuary dam at the river mouth) and an open (Seomjin) estuary. A dual isotope (δ¹³CPOC and Δ¹⁴CPOC) approach was applied to surface water samples collected along a salinity gradient in August 2016. Our results indicate that phytoplankton-derived POC was the main contributor to the total POC pool in the reservoir of the Geum estuary, while terrestrial-derived POC predominated the upper Seomjin estuary. A simple binary mixing model using Δ¹⁴CPOC revealed a higher modern POC contribution (87–90%) in the Geum estuary reservoir than that (77%) of the upper Seomjin estuary. Accordingly, it appears that an estuary dam can alter the source and reactivity of POC in a reservoir, which can be transferred to the adjacent coastal ecosystem.

To investigate the sediment quality of Fudu Estuary waters in East Liaodong Bay, the grain size, concentrations of total organic carbon (TOC) and heavy metal (Cr, Cu, Zn, As, Cd, Pb) of 25 surface sediments were tested. The concentration of heavy metals was found to be higher in the Southwest of Yingkou Port and outside the Fudu Estuary. Cd is the principal contaminant with mild pollutant and moderate ecological risk. Cr may cause negative biological effects. The abnormal enrichment of Cu and TOC may respectively be caused by riverside industrial activities and mariculture. The abnormal enrichment of Pb in Moon Bay Beach and the Lagoon was suggested to be caused by the mooring of boats or excessive tourist activities. Grain size dominates the concentrations of heavy metals in the study area. The impact of coastal engineering on sediment quality through changing sedimentary dynamics should also be given particular attention.

DDTs were detected in yellowfin tuna (Thunnus albacares, 92.1–221.8 ng‧g⁻¹ lipid weight) and their prey (54.9–93.5 ng‧g⁻¹ lipid weight) from the South China Sea (SCS). DDT levels reported in this study were lower than those of the previous studies indicated the recent mitigation of DDT contamination in the SCS. Higher DDT levels were observed in fat abdominal muscle than lean dorsal muscle in adult yellowfin tuna. Meanwhile, DDT levels in adult yellowfin tuna were higher than the young ones. The composition profiles of DDT and its metabolites suggested DDTs in fish in the SCS were mainly derived from the historical use of technical DDTs. DDTs were biomagnified through food chains with the trophic magnification factor of 2.5. Risk assessment results indicated that dietary exposure to DDTs through lifetime fish consumption from the SCS would pose little cancer and noncarcinogenic risk to coastal residents.

Arsenic (As) is a toxic metalloid associated with various negative human health impacts including cancer, skin lesions, cardiovascular diseases, and diabetes. Arsenic contamination of groundwater and soil is a major human health issue, particularly in South and Southeast Asia. Use of As-contaminated groundwater from shallow tube wells for irrigation of paddy rice, the staple food for people in this region, is one of the causes of As-related health impacts. The anaerobic growing conditions of flooded rice paddies and the unique physiology of the rice plants lead to increased As levels in rice. The World Health Organization (WHO) has set advisory levels of As in polished (i.e., white) rice grain at 0.2 mg/kg, but the EU and USA are yet to set legal standards for As in rice and rice-based products. Strategies for lowering As accumulation in rice revolve around two approaches—agronomic and biotechnological. Agronomic approaches, such as mineral supplementation of soil using iron, phosphorus, sulfur, silicon, water management, soil aeration practices, and the use of biological agents, are designed to lower As solubility, and uptake by rice. Rotation of the rice crop with As accumulating plants could also result in lowering soil As. Biotechnological approaches involve producing transgenic rice varieties by altering the expression of genes involved in As uptake, translocation, and sequestration in the plant. These approaches, combined with proper diet management and creating public awareness on potential health risks resulting from chronic exposure to As in rice, could play a key role in risk reduction.