Embargo until 23 November 2019 | China's coastal environment has been heavily affected by the loading of terrestrial pollutants in recent decades, and quantitative risk assessment is urgently needed to assess the ecological risks of China's coastal environment. We assessed the ecological risks induced by five heavy metals (including Cu, Zn, Pb, Hg and As) in China's coastal waters for three groups of marine organisms (including crustacean, fish and mollusc) based on data obtained from a nationwide unified coastal environment monitoring program consisting of 301 sampling sites. The results show that higher heavy metal concentrations occurred more frequently in the Bohai Sea and in the estuaries of major sea-going rivers. The ecological risks decreased in the following order: Bohai Sea > Yellow Sea > South China Sea > East China Sea. There was generally low ecological risk, but certain hotspots existed near Tianjin and Jinzhou, which had relatively high ecological risks caused by Cu and Zn. | acceptedVersion

China's coastal environment has been heavily affected by the loading of terrestrial pollutants in recent decades, and quantitative risk assessment is urgently needed to assess the ecological risks of China's coastal environment. We assessed the ecological risks induced by five heavy metals (including Cu, Zn, Pb, Hg and As) in China's coastal waters for three groups of marine organisms (including crustacean, fish and mollusc) based on data obtained from a nationwide unified coastal environment monitoring program consisting of 301 sampling sites. The results show that higher heavy metal concentrations occurred more frequently in the Bohai Sea and in the estuaries of major sea-going rivers. The ecological risks decreased in the following order: Bohai Sea>Yellow Sea>South China Sea>East China Sea. There was generally low ecological risk, but certain hotspots existed near Tianjin and Jinzhou, which had relatively high ecological risks caused by Cu and Zn.

A combination of local (i.e. firefighting training facilities) and remote sources (i.e., long-range transport) are assumed to be responsible for the occurrence of per- and polyfluoroalkyl substances (PFASs) in Svalbard (Norwegian Arctic). However, no systematic elucidation of local PFASs sources have been conducted yet. Therefore, a survey was performed aiming at identifying local PFASs pollution sources on the island of Spitsbergen (Svalbard, Norway). Soil, fresh water (lake, draining rivers), sea water, melt-water run-off, surface snow and coastal sediment samples were collected from Longyearbyen (Norwegian mining town), Ny-Ålesund (research facility) and the Lake Linnévatnet area (background site) during several campaigns (2014-2016) and analysed for 14 individual target PFASs. For background site (Linnévatnet area, sampling during April to June 2015), ∑PFAS levels ranged from 0.4 – 4 ng/L in surface lake water (n = 20). PFAS in melt water from the contributing glaciers showed similar concentrations (~4 ng/L, n = 2). The short chain perfluorobutanoate (PFBA) was predominant in lake water (60-80% of the ∑PFASs), meltwater (20-30 %) and run-off water (40 %). Long range transport is assumed to be the major PFAS source. In Longyearbyen, 5 water samples (i.e. 2 seawater, 3 run-off) were collected near the local firefighting training site (FFTS) in November 2014 and June 2015, respectively. The highest PFAS levels were found in FFTS melt water run-off (118 ng/L). PFOS was the most abundant compound in the FFTS meltwater run-off (53 – 58 % PFASs). At the research station Ny-Ålesund, sea water (n = 6), soil (n = 9) and fresh water (n = 10) were collected in June 2016. Low ∑PFAS concentrations were determined for sea water (5 - 6 ng/L), whereas high ∑PFAS concentrations were found in run-off water (113 – 119 ng/L) and soil (211 – 800 ng/g dry weight (dw)) collected close to the local FFTS. In addition, high ∑PFAS levels (127 ng/L) were also found in fresh water from lake Solvatnet close to former sewage treatment facility. Overall, at both FFTS affected sites (soil, water), PFOS was the most abundant compound (60 – 69% of ∑PFASs). FFTS and landfill locations were identified as major PFASs sources for Svalbard settlements. | Elucidation of contamination sources for poly- and perfluoroalkyl substances (PFASs) on Svalbard (Norwegian Arctic) | acceptedVersion

A combination of local (i.e. firefighting training facilities) and remote sources (i.e., long-range transport) are assumed to be responsible for the occurrence of per- and polyfluoroalkyl substances (PFASs) in Svalbard (Norwegian Arctic). However, no systematic elucidation of local PFASs sources have been conducted yet. Therefore, a survey was performed aiming at identifying local PFASs pollution sources on the island of Spitsbergen (Svalbard, Norway). Soil, fresh water (lake, draining rivers), sea water, melt-water run-off, surface snow and coastal sediment samples were collected from Longyearbyen (Norwegian mining town), Ny-Ålesund (research facility) and the Lake Linnévatnet area (background site) during several campaigns (2014-2016) and analysed for 14 individual target PFASs. For background site (Linnévatnet area, sampling during April to June 2015), ∑PFAS levels ranged from 0.4 – 4 ng/L in surface lake water (n = 20). PFAS in melt water from the contributing glaciers showed similar concentrations (~4 ng/L, n = 2). The short chain perfluorobutanoate (PFBA) was predominant in lake water (60-80% of the ∑PFASs), meltwater (20-30 %) and run-off water (40 %). Long range transport is assumed to be the major PFAS source. In Longyearbyen, 5 water samples (i.e. 2 seawater, 3 run-off) were collected near the local firefighting training site (FFTS) in November 2014 and June 2015, respectively. The highest PFAS levels were found in FFTS melt water run-off (118 ng/L). PFOS was the most abundant compound in the FFTS meltwater run-off (53 – 58 % PFASs). At the research station Ny-Ålesund, sea water (n = 6), soil (n = 9) and fresh water (n = 10) were collected in June 2016. Low ∑PFAS concentrations were determined for sea water (5 - 6 ng/L), whereas high ∑PFAS concentrations were found in run-off water (113 – 119 ng/L) and soil (211 – 800 ng/g dry weight (dw)) collected close to the local FFTS. In addition, high ∑PFAS levels (127 ng/L) were also found in fresh water from lake Solvatnet close to former sewage treatment facility. Overall, at both FFTS affected sites (soil, water), PFOS was the most abundant compound (60 – 69% of ∑PFASs). FFTS and landfill locations were identified as major PFASs sources for Svalbard settlements. | Elucidation of contamination sources for poly- and perfluoroalkyl substances (PFASs) on Svalbard (Norwegian Arctic)

Biodegradation of chemically dispersed oil at low temperature (0–2 °C) was compared in natural seawater from Arctic (Svalbard) and a temperate (Norway) fjords. The oil was premixed with a dispersant (Corexit 9500) and small-droplet oil dispersions prepared. Faster biotransformation of n-alkanes in the Arctic than in the temperate seawater were associated with the initially higher abundance of the alkane-degrading genus Oleispira in the Arctic than the temperate seawater. Comparable transformation of aromatic hydrocarbons was further associated with the late emergences Cycloclasticus in both seawater sources. The results showed that chemically dispersed oil may be rapidly biodegraded by microbial communities in Arctic seawater. Compared to oil biodegradation studies at higher seawater temperatures, longer lag-periods were experienced here, and may be attributed to both microbial and oil properties at these low seawater temperatures. | acceptedVersion

Biodegradation of chemically dispersed oil at low temperature (0–2 °C) was compared in natural seawater from Arctic (Svalbard) and a temperate (Norway) fjords. The oil was premixed with a dispersant (Corexit 9500) and small-droplet oil dispersions prepared. Faster biotransformation of n-alkanes in the Arctic than in the temperate seawater were associated with the initially higher abundance of the alkane-degrading genus Oleispira in the Arctic than the temperate seawater. Comparable transformation of aromatic hydrocarbons was further associated with the late emergences Cycloclasticus in both seawater sources. The results showed that chemically dispersed oil may be rapidly biodegraded by microbial communities in Arctic seawater. Compared to oil biodegradation studies at higher seawater temperatures, longer lag-periods were experienced here, and may be attributed to both microbial and oil properties at these low seawater temperatures.

Subsea blowouts have the potential to spread oil across large geographical areas, and subsea dispersant injection (SSDI) is a response option targeted at reducing the impact of a blowout, especially reducing persistent surface oil slicks. Modified Weber scaling was used to predict oil droplet sizes with the OSCAR oil spill model, and to evaluate the surface oil volume and area when using SSDI under different conditions. Generally, SSDI reduces the amount of oil on the surface, and creates wider and thinner surface oil slicks. It was found that the reduction of surface oil area and volume with SSDI was enhanced for higher wind speeds. Overall, given the effect of SSDI on oil volume and weathering, it may be suggested that tar ball formation, requiring thick and weathered oil, could possibly be reduced when SSDI is used. | acceptedVersion

Subsea blowouts have the potential to spread oil across large geographical areas, and subsea dispersant injection (SSDI) is a response option targeted at reducing the impact of a blowout, especially reducing persistent surface oil slicks. Modified Weber scaling was used to predict oil droplet sizes with the OSCAR oil spill model, and to evaluate the surface oil volume and area when using SSDI under different conditions. Generally, SSDI reduces the amount of oil on the surface, and creates wider and thinner surface oil slicks. It was found that the reduction of surface oil area and volume with SSDI was enhanced for higher wind speeds. Overall, given the effect of SSDI on oil volume and weathering, it may be suggested that tar ball formation, requiring thick and weathered oil, could possibly be reduced when SSDI is used.

Oil-related aggregates (ORAs) may contribute to the fate of oil spilled offshore. However, our understanding about the impact of diatoms and associated bacteria involved in the formation of ORAs and the fate of oil compounds in these aggregates is still limited. We investigated these processes in microcosm experiments with defined oil dispersions in seawater at 5 °C, employing the Arctic diatom Fragilariopsis cylindrus and its associated bacterial assemblage to promote ORA formation. Accumulation of oil compounds, as well as biodegradation of naphthalenes in ORAs and corresponding water phases, was enhanced in the presence of diatoms. Interestingly, the genus Nonlabens was predominating the bacterial communities in diatom-supplemented microcosms, while this genus was not abundant in other samples. This work elucidates the relevance of diatom biomass for the formation of ORAs, microbial community structures and biodegradation processes in chemically dispersed oil at low temperatures relevant for Arctic conditions. | acceptedVersion

Oil-related aggregates (ORAs) may contribute to the fate of oil spilled offshore. However, our understanding about the impact of diatoms and associated bacteria involved in the formation of ORAs and the fate of oil compounds in these aggregates is still limited. We investigated these processes in microcosm experiments with defined oil dispersions in seawater at 5 °C, employing the Arctic diatom Fragilariopsis cylindrus and its associated bacterial assemblage to promote ORA formation. Accumulation of oil compounds, as well as biodegradation of naphthalenes in ORAs and corresponding water phases, was enhanced in the presence of diatoms. Interestingly, the genus Nonlabens was predominating the bacterial communities in diatom-supplemented microcosms, while this genus was not abundant in other samples. This work elucidates the relevance of diatom biomass for the formation of ORAs, microbial community structures and biodegradation processes in chemically dispersed oil at low temperatures relevant for Arctic conditions.

The objective of this paper is to provide a simple extension of the much-used gravity spreading model for oil on calm water to account for the spreading behavior of waxy crude oils in cold waters – including the observed retardation and eventual termination of spreading at certain oil film thicknesses. This peculiar behavior is not predicted by traditional spreading models for oil on calm water (i.e. viscous-gravity spreading models), but may occur due to non-Newtonian oil properties caused by precipitation of wax at low temperatures. To clarify the spreading behavior of such oils, SINTEF has conducted a series of laboratory experiments with a range of waxy oil mixtures. The present paper contains analyses of data from these experiments, including favorable comparisons with calculations by a proposed improved surface spreading model. | Spreading of waxy Crude Oils on calm weather | acceptedVersion

The objective of this paper is to provide a simple extension of the much-used gravity spreading model for oil on calm water to account for the spreading behavior of waxy crude oils in cold waters – including the observed retardation and eventual termination of spreading at certain oil film thicknesses. This peculiar behavior is not predicted by traditional spreading models for oil on calm water (i.e. viscous-gravity spreading models), but may occur due to non-Newtonian oil properties caused by precipitation of wax at low temperatures. To clarify the spreading behavior of such oils, SINTEF has conducted a series of laboratory experiments with a range of waxy oil mixtures. The present paper contains analyses of data from these experiments, including favorable comparisons with calculations by a proposed improved surface spreading model.