Nonylphenol (NP) has attracted significant attention because of its widespread environmental presence, toxicity, and pseudo-estrogen properties. Photolysis is the main degradation pathway of many organic pollutants in water. In this study, the photodegradation mechanism of p-nonylphenol (p-NP) induced by OH in water was investigated using the density functional theory (DFT). Based on the calculations of charges using natural population analysis (NPA), the reaction of OH with NP included the carbon addition of a benzene ring and the hydrogen extraction of a phenolic hydroxyl group. The structures of all reactants, products, and intermediates were optimized at the B3LYP/6-31+G(d,p) level. Using vibrational frequency and intrinsic reaction coordinate analyses, the transition state and its reaction pathway were confirmed. Additionally, the solvent effect results showed the reaction preferably took place in water. Our results provide a theoretical basis for understanding the transformative process and assessing the potential risk of NP in the environment.

The concentration, constitution, distribution, possible sources, and associated consumption risks of polycyclic aromatic hydrocarbons (PAHs) in four marine fishes in the Zhoushan Archipelago were investigated. The concentrations of PAHs in the edible muscle of these four fishes ranged from 34.7 to 108 ng/g wet weight. Four-ring and six-ring PAH congeners constitute the most and least percentages of the total PAHs, respectively. The highest PAH concentrations were found in Mugil cephalus, followed by Sebastiscus marmoratus, Lateolabrax maculatus, and Collichthys lucidus. The highest PAH concentrations were found at the sampling island Liuheng, followed by Gouqi, Qushan, Dongji, and Zhujiajian. PAH concentrations in wet weight were remarkably different among these four fish species but not among different locations. High-molecular-weight congeners predominated the PAH composition pattern in most of the samples. Results showed that the consumption of M. cephalus might have potential carcinogenic risk. This study provided baseline data on PAH concentrations in seafood and consequent human consumption risk.

This study aims to investigate spatial distribution, contamination and origin of heavy metals (Pb, Zn, Cu, Ni, Co and Cr) in surface sediments of Jangsong tidal flat (JTF), Kangryong river estuary, DPR Korea, where has been affected by various mining activities. The spatial diverse of heavy metals are due to differences in their sources and sediment properties. Enrichment factor, geoaccumulation index and ecological risk indexes indicate that JTF is not polluted and has low ecological risk, although slight enrichments occur for some metals. Multivariate analyses revealed that Mn, Ni and Cr originated from lithogenic source, whereas other metals were of anthropogenic origin, among which Fe and Co originated from the iron mine settling pond near JTF, while Pb, Zn and Cu originated from AMD effluent by sulfide mining activity in catchment of JTF. The different transport mechanisms of heavy metals from AMD result in diverse distribution of the metals in JTF.

We examined the patterns of uptake and partitioning of metal(loid)s in Suaeda australis from three highly urbanised estuaries (Sydney Olympic Park, Hunter Wetlands and Lake Macquarie) in NSW, Australia. Of these, Sydney Olympic Park was found to be the most contaminated estuary in terms of combined sediment metal(loid) load, followed by Hunter Wetlands and lowest in Lake Macquarie (via PERMANOVA). Uptake in roots was greater for the essential metals Cu and Zn along with the non-essential metal Cd and the metalloid Se (root BCFs >1) and lower for Pb and As (root BCFs <1). Substantial barriers for translocation from roots to stems were identified for all metal(loid)s (stem TFs; 0.07–0.68). Conversely, unrestricted flow from stems to leaves was observed for all metal(loid)s at unity or higher (leaf TFs ≥ 1). Strong linear relationships between sediment and root for Zn and Pb were observed, indicating roots as a useful bioindicator.

Since 2007, the outbreak of green tides has become the most serious ecological problem in the Yellow Sea. In this study, a new method was used to identify green tides in multi-source satellite data from 2007 to 2020, and the relationship between the conditions necessary for green tide dissipation and other environmental factors was discussed. We found a “wavy” trend of green tide scales over the 14-year dissipation period. The dissipation direction was influenced by sea surface wind (SSW) and sea surface circulation (SSC). Under the action of northeast moving SSW and SSC, green tides move away from the shore and drift northward; under the action of northwest or southwest moving SSW and SSC, they moved towards the shore and drift southward. The date of dissipation was influenced by sea surface temperature (SST) and precipitation, and high SST accelerated the process of green tide dissipation, while precipitation slowed it down.

The resilience of coastal ecosystems and communities to poor environmental and health outcomes is threatened by cumulative anthropogenic pressures. In Kiribati, a developing Pacific Island country where human activities are closely connected with the ocean, both people and environment are particularly vulnerable to coastal pollution. We present a survey of environmental and human health water quality parameters around urban South Tarawa, and an overview of their impacts on the semi-enclosed atoll. Tarawa has significant water quality issues and decisions to guide improvements are hindered by a persistent lack of appropriate and sufficient observations. Our snapshot assessment identifies highest risk locations related to chronic focused and diffuse pollution inputs, and where mixing and dilution with ocean water is restricted. We demonstrate the importance of monitoring in the context of rapidly changing pressures. Our recommendations are relevant to other atoll ecosystems where land-based activities and ocean health are tightly interlinked.

The mercury (Hg) cycle in estuaries has been globally discussed, although Holocene deposition in mangrove sediments remains unknown. Herein, a sediment core from a mangrove system in southeastern Brazil was ¹⁴C-dated to evaluate millennial Hg deposition. The highest Hg concentrations (1010–2540 ng g⁻¹) in surface sediments were explained by emissions from a chlor-alkali industry (1964 CE). However, Hg levels were also high in pre-industrial periods, associated to fine grain-size and algal organic deposition. Less anomalous Hg concentrations in bottom sediments indicate Holocene ages (~1940–3324 cal yr BP), potentially associated to Serra do Mar mountains weathering. This study reveals the capacity of mangrove to retain Hg over millennial time scales, acting as significant and long-term Hg sinks. Therefore, the use of Hg as an Anthropocene marker must be considered cautiously in coastal systems that act as Hg sinks in times when environmental changes were not caused by human activities.

Organophosphorus derivatives are widely used in human health care and have been detected in aquatic ecosystems. These compounds may pose significant risks to non-target exposed organisms and only limited studies are available on bioconcentration and the effects of organophosphorus derivatives on marine organisms. The aim of this work was to evaluate the possible toxic effects of two concentrations (20 and 40 μg/L) of γ-oximo- and γ-amino-phosphonates and phosphine oxides in mediterranean clams Ruditapes decussatus exposed for 14 days using different biomarkers and the changes of filtration and respiration rate. The use of clams in ecotoxicity evaluation is thus mandatory to assess the feasibility of assessing oxidative stress on R. decussatus after being exposed to γ-oximo- and γ-amino-phosphonates and phosphine oxides. The oxidative status was analyzed by measuring oxidative stress biomarkers RNS and ROS production in mitochondria, superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferases (GSTs), lipid peroxidation (LPO) and acetylcholinesterase (AChE), whose alteration was indicative of organophosphorus exposure, in both gills and digestive gland of the clams. No significant alterations in RNS, ROS production, SOD, CAT and AChE activities and MDA content were observed in both organs of clams treated with γ-oximophosphine oxides. It was possible then to hypothesize that γ-oximophosphine oxides may have probably exerted an incomplete alteration of antioxidant defenses and damage, which was changed by the activation of defense mechanisms. On the contrary, oxidative stress parameters were changed after exposure to γ-amino-phosphonates and phosphine oxides. In addition, metals accumulation, filtration and respiration rates were altered following exposure to all the studied organophosphorus compounds.

Setiu Wetland is rapidly developing into an aquaculture and agriculture hub, causing concern about its water quality condition. To address this issue, it is imperative to acquire knowledge of the spatial and temporal distributions of pollutants. Consequently, this study applied combinations of hydrodynamic and particle tracking models to identify the transport behaviour of pollutants and calculate the residence time in Setiu Lagoon. The particle tracking results indicated that the residence time in Setiu Lagoon was highly influenced by the release location, where particles released closer to the river mouth exhibited shorter residence times than those released further upstream. Despite this fact, the pulse of river discharges successfully reduced the residence time in the order of two to twelve times shorter. Under different tidal phases, the residence time during the neap tide was longer regardless of heavy rainfalls, implying the domination of tidal flow in the water renewal within the lagoon.

When spilled oil collects at depth, questions as to where and when to dispatch response equipment become daunting, because such oil may be invisible by air, and underwater sensing technology is limited in coverage and by underwater visibility. Further, trajectory modeling based on previously recorded flow field data may show mixed results. In this work, the Bayesian model, SOSim, is modified to locate and forecast the movement of submerged oil, with confidence bound, by inferring model parameters based on any available field concentration data and the output of one or more deterministic trajectory models. Novel aspects include specification of a prior likelihood function, and generation of results in 3-D from data in the 2-D density space of the isopycnal layer containing oil. The model is demonstrated versus data collected following the Deepwater Horizon spill. This new inferential modeling approach appears complimentary to deterministic methods when field concentration data are available.