Search

The presence of 14 organophosphate esters (OPEs) in surface sediments from a typical fishing port agglomeration in Dalian, North China was investigated for the first time. Tris(2-ethylhexyl) phosphate (TEHP), triphenylphosphine oxide (TPPO), and tris(2-chloroethyl) phosphate (TCEP) dominated 12 detectable OPEs (∑OPEs), with concentrations ranging widely from 0.56 to 352 ng/g (dry weight basis). The ∑OPE levels in sediments varied significantly across fishing harbors of various grades, and within the same grade, highlighting uneven distribution of OPE sources and inputs to harbors. The first- and second-class fishing harbors had higher geometric mean of ∑OPE contents compared to center and natural harbors, reflecting higher OPE pollution in these areas. Although there were significant correlations among the OPE congeners with high detection frequencies, the composition patterns of sediment OPEs varied considerably among fishing ports. The sediments in the center and first-class harbors had higher abundance of non-chlorinated OPEs (non-Cl-OPEs), suggesting heterogeneity in source strength and pollution characteristics of Cl- and non-Cl-OPEs in fishing ports. The distribution of OPEs in sediments was weakly associated with sediment organic carbon, but not socioeconomic variables, indicating complex controlling factors of their distributions in port sediments. The ecological risks of sediment OPEs were evaluated, and while OPE accumulations ranged broadly (7–684 ng/cm2), exposure hazards were negligible. The sediments in first- and second-class fishing harbors, which had greater OPE accumulation, were identified as reservoirs of OPEs in port aquatic environments. [Display omitted] • TEHP and TCEP dominated non-Cl- and Cl-OPEs in fishing port sediments, respectively. • OPE levels and compositions varied irregularly with fishing port grades. • Sediment organic carbon partially controlled OPE distributions among fishing ports. • The sediments of first- and second-class fishing ports were reservoirs of OPEs. [ABSTRACT FROM AUTHOR]

In the present study, the contamination level and spatial distribution of PFASs in the water dissolved phase and suspended particulate matter (SPM) phase of the Dalian Bay, and the SPM-water partition behavior were investigated. The total concentrations of PFASs (∑PFASs) in the water dissolved phase ranged from 6.9 to 17.1 ng L −1 , with perfluorooctanoic acid (PFOA), perfluorobutanoic acid, and perfluorobutane sulfonate (PFBS) as the predominant PFASs, while ∑PFASs in SPM ranged from 1.7 to 27.5 ng g −1 dw with higher contributions from PFBS, perfluorooctane sulfonic acid and PFOA. As for the pollution distribution, the concentrations of PFASs inside the Dalian Bay were higher than those outside the bay. For perfluoroalkyl carboxylic acid (PFCAs) and perfluoroalkane sulfonic acids (PFSAs), the suspended particulate matter-water partition coefficient (log K d ) values ranged from 2.62 to 3.76, and from 3.39 to 3.56, respectively. The log K d values of PFASs generally increased with the increasing perfluorinated carbon chain length. Short-chain PFCAs were mostly detected in the water dissolved phase, while long-chain PFCAs and PFSAs appeared to bind more strongly to SPM phase. The contamination level of long-chain PFCAs and PFSAs could be underestimated if only the water dissolved phase were measured. Therefore, further investigations should consider the role of SPM on the environmental behavior and fate of PFASs in the aquatic environment. [ABSTRACT FROM AUTHOR]

To date, the impact of air-sea exchange on spatial distribution of atmospheric methane (CH 4 hereafter) remains less understood in the coastal areas of China. Here we measured the dissolved and atmospheric CH 4 in the Dalian Bay and adjacent area in July and August 2014, respectively. Results showed that the study area was a net significant source of atmospheric CH 4 , with a mean sea-to-air CH 4 flux of 170.6 ± 149.5 μmol/(m2·day). We optimized a method to accurately quantify the elevated atmospheric CH 4 mole fraction (△CH 4 hereafter) caused by air-sea exchange. The calculated △CH 4 in the study area ranged from 15.4 to 102.1 nmol/mol, 1.5–10.2 nmol/mol, and 0.03–0.22 nmol/mol at the mixing height of 1, 10, and 471 m, respectively. The △CH 4 mole fractions caused by air-sea exchange were positive with sea-to-air CH 4 flux and in situ observed atmospheric CH 4 mole fraction, while negative with altitude. Under the standard conditions, we defined 50.8 μmol/(m2·day) as the criteria value of sea-to-air CH 4 flux which could result in a detectable elevation atmospheric CH 4 mole fraction at a height of 10 m. Image 106245 • Coastline is an intensive ventilated area for CH 4 in the study area. • A method was improved for quantifying the impact of air-sea exchange on atmospheric CH 4. • Air-sea exchange induced atmospheric CH 4 mole fraction decreasing with increasing altitude. • A criterion flux value was defined for studying the impact of air-sea CH 4 exchange. [ABSTRACT FROM AUTHOR]