| Mercury is a global pollutant. The earth surface is an important source ofmercury in atmosphere. There is little research on the direct determination release ofmercury on the intertidal area in the field. Mercury fluxes between sediments–air inJiaozhou Bay tidal zone were determined with fux chamber method and cold vaporatomic fluorescence spectrum in four seasons. At the same time mercuryconcentrations in sediment and atmosphere, mercury species in sediment, and theenvironmental factors were also determined in order to study the changing law ofmercury flux and its influencing factors. The results indicate that:Due to the sediment deposition, mercury content in sediment was changing overtime. The content was at the range of0.188-0.469mg/kg, which was elevated over theprimary standard of the Sediment Quality (GB18668-2002). Atmospheric mercurylevel was higher than the global background value, which indicated that it had been acertain degree of mercury pollution in the northeast intertidal of Jiaozhou Bay.Sediment mercury speciation analysis showed that: it was hosted largely by theoxidizable and residual fractions, while was lower by the exchangeable fraction. Itshowed a decreasing trend in all speciation except the exchangeable fraction wenexposed in light, but the increasing for the exchangeable fraction was tiny comparedwith the other speciations. There is transformation among different mercuryspeciation.There appeared a seasonal variation of mercury concentration in the atmosphere,which was lowest in summer at the level of2.96±0.70ng/m~3（n=15）in June and2.10±0.34ng/m~3（n=15） in July, was and highest in winter at the average of5.41±2.04ng/m~3（n=15）.The mercury flux between sediment-air performed a diurnal variation in intertidal, itreached a maximum value before and after noon and took on a bimodal variation witha whole daylight abservation. It showed release-dominated from the sediment to the atmosphere in spring and summer, while in autumn and winter it showedrelease-dominated before and after noon and settlement-dominated in the sunset, bothcharacteristics were obvious.There was apparent seasonal variation for mercury flux between sediment-air inJiaozhou Bay interdidal. The maximum in spring was2.79ng/(m~2h),while theminimum value was-0.13ng/(m~2h), with an average of0.93±0.79(n=18) ng/(m~2h). The maximum value in summer was2.87ng/(m~2h), the minimum was0.50ng/(m~2h), with an average of1.05±0.54(n=14) ng/(m~2h). In autumn,themaximum was2.47ng/(m~2h),the minimum value was-1.42ng/(m~2h), with anaverage0.22±1.33(n=9) ng/(m~2h). The maximum value in winter was2.75ng/(m~2h),while minimum for-2.47ng/(m~2h), and had an average of0.19±1.56(n=9) ng/(m~2h).They showed a law of summer> spring> autumn> winter. Thevariation tendency was similar in winter campared with the Shilaoren Beach intertidal,while the flux value was smaller in Jiaozhou Bay intertidal. Jiaozhou Bay intertidalMercury flux between sediment-air was low compared with Shilaoren intertidal andForest Walker Branch Watershed and far less than the determination results of thesimulation experiment in Yellow River Estuary, Haibohe Estuary and interdidal inXiamen.The mercury flux was closely related to light intensity, mercury condent insediments and atmosphere, temperature of sediment and air, atmospheric relativehumidity. It was positively related with the light intensity, mercury condent ofsediments, temperature of sediment and air, while was negatively related with themercury condent of atmosphere and atmospheric relative humidity. |
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