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Hydrocarbons emitted by human activities probably constitute the largest class of contaminants that are present in coastal areas, because of widespread use of fossil fuels for power generation and logistics, and accidental spillages. The chemical composition of hydrocarbon mixtures found in the marine environment allowed the identification of relative contributions of different natural and anthropogenic sources. Identification of these hydrocarbons, especially n -alkanes, could act as tracers for the possible sources. To evaluate n -alkanes concentrations with emphasis on source analysis, surface water without visible oil was collected from the cruise in April 2016. Determination and quantification were performed by solvent extraction and gas chromatography-mass spectrometry. Various molecular diagnostic parameters were used to assess the contribution of different sources and origin of n -alkanes in surface seawater of Jiaozhou Bay. Concentrations of total dissolved n -alkanes(C 11 -C 37 ) were between 1.756-39.09 μg·L -1 with a high carbon number predominance profile without odd-even carbon number preference. The n -alkane concentrations varied spatially depending on the distance away from main input sources and the ability of water exchange. It was at a higher concentration in the northeast and west coastal areas, as well as the mouth of Jiaozhou Bay. And concentrations were relatively lower in the inner area and outside of Jiaozhou Bay. In the sea area with strong water exchange, concentrations of total n -alkanes were around 2.196 μg·L -1 , which could be considered as the environmental background level of n -alkanes in Jiaozhou Bay. Those n -alkanes were dominated with C 24 , with a slightly odd carbon number preference in low carbon n -alkanes and an even carbon number preference in high carbon n -alkanes. The values of CPI for the whole range of n -alkanes series, low carbon n -alkanes, and high carbon n -alkanes were 0.949, 1.026, and 0.980, respectively. Diagnostic indices and curves indicated that the dominant inputs of those n -alkanes were from marine biogenic input such as algae and marine bacteria. The concentration profiles of n -alkanes in other areas were characterized by no odd-even predominance in the range of C 21 -C 33 with peaks center at C 24 which were indicative of anthropic contributions as emission sources. N -alkanes dominating with anthropic sources comprised a high proportion(83.7%) of total n -alkanes. Activities of harbors and ships were the main contributors of Jiaozhou Bay n -alkanes. Physical processes, such as evaporation and dilution, were the principal weathering mechanisms. Because of its sufficient environmental capacity, Jiaozhou Bay was still moderately contaminated with petroleum.

The radionuclides contents in the surface sediments and sediment cores were determined by gamma spectrometry method. The distribution of radionuclides and its indication to material sources, human activities and other sedimentary environmental evolution events were discussed and the sedimentation rate was estimated. The results showed that the average activity concentrations of 238 U, 232 Th, 226 Ra and 40 K in the surface sediment were (54.4±11.7), (57.9±9.7), (28.6±4.3) and (542±21) Bq·kg -1 , respectively. Regional differences of radioactivity level reflected the material sources and influences of human activities on the sediment characteristics. According to the vertical distribution of excess 210 Pb, the sedimentation rate of high tidal areas was estimated at 0.23 cm·a -1 . In the sediment core, the variable coefficients of 238 U, 232 Th and 226 Ra contents were high. According to the vertical profiles of 238 U, 226 Ra and 238 U/ 226 Ra ratio, the process of sedimentation could be divided into four periods: period of slow deposition, period of dramatic change in sedimentary environment caused by great migration of the Yellow River channels, period of stable deposition after the Yellow River ran into one single channel, and period of alternate degradation and growth under the influence of human activities. The vertical variation of radionuclides in the sediment core could serve as an effective environmental indicator since it could record the environmental evolution processes of the coastal wetland.

Occurrence level, geochemical distribution of dissolved bismuth and its coupling relationship to eco-environment were investigated in the Yellow Sea and East China Sea to explore the source and influencing factors. The results showed that the concentration of dissolved bismuth was within the range of 0-0. 029 microg x L(-1) at the surface and 0.001-0.189 microg x L(-1) at the bottom, with the averages of 0.008 and 0.016 microg x L(-1), respectively. Horizontally, low value of dissolved bismuth exhibited the bidirectional extension feature, indicating that it could trace the path of Changjiang Diluted Water. High value of dissolved bismuth was observed where the Subei Costal Current and Yellow Sea Warm Current flowed and the Changjiang Diluted Water and Zhejiang-Fujian Coastal Current met, suggesting that it was controlled by the cycle of current system. Vertically, the coastal water was fully mixed by water convection and eddy mixing, and was divided from the stratified water by strong tidal front, which blocked the transport of dissolved bismuth to the open sea. Thus, the concentration in front area was significantly higher than that in the open sea. Diurnal variation of dissolved bismuth was related to the hydrodynamic conditions (tide, suspension and thermocline) instead of the environmental factors (temperature and salinity). Positive relationship to SPM (suspended particulate matter) clarified that bismuth was prone to release from solid phase to liquid phase. Furthermore, conditions with temperature ranging 22-27 degrees C, salinity ranging 28-31 and pH ranging 7.9-8.1 were shown to be optimal for the release process.

The contents of Cu, Pb, Zn, Cr, As and Hg in surface sediment from 14 sampling sites in the Huanghe estuary during July-August, 2011 were measured to investigate environmental geochemical characteristics of heavy metals related to multiple factors. The distribution, relationship with fine fraction and TOC, and sediment quality assessment concerning heavy metals were analyzed. The results showed that average concentrations of Cu, Pb, Zn, Cr, As and Hg in the Huanghe estuary were (16.5 +/- 2.7), (16.0 +/- 3.4), (21.0 +/- 3.3), (17.4 +/- 3.1), (6.5 +/- 1.2), (0.0444 +/- 0.0307) mg x kg(-1), respectively, which were lower than those in other typical areas along the coast of China. The distribution of metals displayed higher profiles in south than that in north of the Huanghe estuary, with a trend of increase seaward, especially for stations in southwest of the Laizhou bay. The insignificant correlation among metals indicated the complex sources of heavy metals in flood season. Pearson correlation was also conducted between metal contents and percentage of fine particulates and TOC, which was also insignificant, suggesting heavy metal concentration and distribution in the study region were also controlled by other factors except grain size and TOC. There was a good correlation between clay fraction and TOC (r = 0.724, P < 0.05), indicating TOC tends to accumulate in clay. Compared with variety of background values and an internationally used consensus-based sediment quality guidelines (CBSQGs) for saltwater ecosystem, heavy metals in surface sediments from the Huanghe estuary implied a low probability of toxic effect, despite a sharp contamination trend pertaining to Hg and Pb since 1980s.

The geochemical characteristics of eight heavy metals (Cd, Co, Cr, Cu, Ni, Pb, V and Zn) in two sediment cores from Bohai Bay, North China, were studied. Sediment samples were collected from 27 stations in spring 2008. A sequential extractions, procedure was used to gain their fractionation information. Five operationally defined fractions were obtained by this protocol, i. e. exchangeable (L1), bound to carbonates (L2), bound to Fe/Mn-oxides (L3), bound to organic matter and sulphides (LA), and residual fraction (R5). Combined with ecological risk in total contents and fraction, a series of results and viewpoints with regard to distribution characteristics of heavy metals were presented, as well as ecological risk and controlling factors. Heavy metals in sediments were mainly concentrated in the middle region with fine particle. The distributions of V, Ni, Cu, Pb, Co, Cd were mainly controlled by nature source, while Zn and Cr can be easily impacted by environment or human input. Coming from atmospheric deposition and riverine, Pb was different with other heavy metals. Sequential extractions suggested that V, Zn, Cr were mainly composed with residual fractions, while Co, Ni, Cu were dominated by labile fractions. The percentage of labile Co increased from inner to outside, labile Ni reached maximum at station A3, labile Cu and Pb concentrated in the middle of Bohai Bay, while Cu achieved maximum at station D1 near Yellow River. Labile heavy metals were enriched near the estuary of Haihe River. The order of enrichment factors (EF) of heavy metals was Pb > Cd > Zn > Cr > V > Co > Cu > Ni. And the EF of Pb, Cd and Zn were above 1, suggesting that they could be polluted by exterior input, while the sediment quality was relatively good in general. The ratios of labile and residual fraction showed that V and Cr were clean, Zn was partly in slightly polluted, Co was mostly slightly polluted, Cu was from clean to moderately polluted, Ni was polluted from slightly to heavy, and Pb was polluted heaviest in all heavy metal. In conclusion, V, Cr and Co were clean, Cu and Zn may be polluted, while Pb was polluted heaviest.

The effects of typical organic pollutants (ethanol, acetone, ON, OP) on pH and marine carbon dioxide system were investigated in laboratory simulated experiments. The results indicated that the growth of biological carbon fixed system was promoted by ethanol and acetone of low concentration (< 0.5 mmol x L(-1)) (t = 7 d). So pH increased while DIC, HCO3(-) and p(CO2) significantly decreased compared to the controls (p <0.01). The concentrations of ethanol and acetone which resulted in the maximum decrease of carbon dioxide parameters were 0.25 mmol x L(-1) and 0.1 mmol x L(-1), respectively. When the infusion of organic pollutants were higher than the "critical concentration", the carbon dioxide parameters increased and pH decreased compared to the controls with the decrease of carbon fixation strength of alga. As for ON and OP groups, when they were in the range of experimental concentration, decreasing trends of inorganic carbon in sea water were always found. The concentration changes of DIC (DeltaDIC) under the press of the four typical organic pollutants were significantly negatively correlated with the changes of dry weight of alga (p < 0.01 or p < 0.05) and the coefficient parameters were -0.902, -0.945, -0.898 and -0.918, respectively (t = 7 d). The main controlling factor to the variation of carbon dioxided system was the adaption of biological carbon fixed system to different concentration and kind of organic pollutants.

The geochemical characteristics of nitrogen forms in different grain size sediments of Jiaozhou Bay were investigated employing the sequential extraction technique. Results showed that the transferable nitrogen in Jiaozhou Bay sediments can be divided into four forms, ion exchangeable form (IEF-N), weak acid extractable form (WAEF-N), strong alkaline extractable form (SAEF-N) and strong oxidant extractable form (SOEF-N). The percentages of nitrogen forms for transferable nitrogen in different grain size sediments were different. Generally, for all grain size sediments, the SOEF-N was the primary form accounted for 35.38%, 44.38% and 58.69% of transferable nitrogen for fine, medium and coarse sediments. And for medium and coarse grain size sediment, SAEF-N was the dominant inorganic nitrogen accounted for 26.31% and 25.85%, respectively. And for fine-grained sediments, IEF-N was the primary inorganic nitrogen accounted for 27.67% of transferable nitrogen. The correlation analysis showed that generally, nitrogen was positive correlated with fine and medium grain size but negative correlated with coarse sediments. In addition, nitrogen in different grain size sediments had also positive correlations with phytoplankton abundance, chlorophyll-a and NO3- concentrations of overlying water. The results showed that sediments had great influences on element concentrations of overlying water, and on the other side, it also illustrated that sedimentary nitrogen was an excellent indicator of hypereutrophication and had essential environmental significance.

The geochemical characteristics of phosphorus forms in different grain size sediments, the influencing factors as well as the bioavailability of phosphorus in Jiaozhou Bay were investigated employing the sequential extraction method. The results showed that inorganic phosphorus was the dominant form of total phosphorus and organic phosphorus was only the minor part. The detrital carbonate-bound phosphorus was the largest part of total phosphorus. The grain size, organic carbon, temperature, pH and etc. are the main controlling factors of phosphorus in sediments. Except for Ca-P, most of other phosphorus forms contents increased as the grain size decreased. The bioavailability research showed that the bioavailable phosphorus was mainly the exchangeable phosphorus, phosphorus bound to Al and Fe and organic phosphorus. Moreover, the potential bioavailable phosphorus proportion in total phosphorus increased as the grain size decreased. The bioavailable phosphorus in different grain size sediments has positive correlationship with phytoplankton abundance and phosphate in overlying water.

Phosphorus is a key biogenic element and plays an essential role in global biogeochemical cycles. The geochemical characteristics of phosphorus as well as the controlling factors and the environmental marker function in Jiaozhou Bay sediments were presented. The different forms of sedimentary phosphorus were studied in three sediment cores, which are forms of inorganic phosphorus, exchangeable phosphorus, phosphorus bound to Al-Fe, and calcium, occluded phosphorus as well as total phosphorus and organic phosphorus, respectively. The vertical profiles of various forms of phosphorus in response to 210Pb chronological studies of sediment cores were investigated in order to reveal sedimentary environment changes. The results showed that inorganic phosphorus was the dominant form of total phosphorus and organic phosphorus was only the minor part. The detrital carbonate-bound phosphorus was the largest part of total phosphorus. The concentrations and burial fluxes of phosphorus were controlled by source and environmental factors including pH, salinity, temperature and grain size of sediments etc. Moreover, the analysis of OC/OP ratios suggested that the terrestrial inputs were the dominant source of Jiaozhou Bay sediments. The sedimentation fluxes of phosphorus increased in the past two decades, as a result, the pollution was still serious from the 1980 to 2000. But the state has greatly improved since 2000. The Fe-P, Al-P and Oc-P have close relationships with the degree of pollution and may act as good indicators for environment pollution in Jiaozhou Bay.