Analysis and prediction of the dynamics of Polycyclic aromatic hydrocarbons in the coastal environment polluted by heavy oil.

在事故发生7年后，在纳霍德卡石油泄漏严重污染现场的海岸砂和其他介质中，发现多环芳烃（PAHs）的浓度与事故发生后的背景浓度一样低。油渣只在岩石的空洞中被发现，两年后，这些残留物中的多环芳烃含量下降到原来的三分之一，但此后，多环芳烃含量保持在原来的水平，这表明多环芳烃将与油渣一样长期存在。对河流水体、SS和沉积物中多环芳烃的监测表明，沉积物中多环芳烃的主要吸附剂是有机物。有机质分配系数Koc与辛醇-水分配系数具有较好的相关性，可以用线性自由能假设来描述。表层沉积物和河水之间多环芳烃的交换速度足够快，因此我们认为沉积物和河水之间的分配大致处于平衡状态。在实验室实验中，我们考察了溶解有机物（DOM）对沉积物与水体之间PAHs分配的影响，发现随着芳香环数量的增加，DOM的作用也随之增加，同时也发现为了准确描述这一现象，我们必须考虑DOM对沉积物颗粒的吸附。如上所述，在沿海环境中，水和沿海颗粒介质之间的交换速度足够快，可以在几年内将污染物从污染地点清除，而在河口，这一速度如此之快，以至于我们可以假设近似平衡。多环芳烃对颗粒物的吸附主要是对有机物的吸附，分配系数随着芳烃环数的增加而增大，可以用线性自由能假设粗略估计。

The concentration of polycyclic aromatic hydrocarbons (PAHs) in the coastal sands and other media of a heavily polluted site of the Nakhodka oil spill were found to be as low as the background after the 7 years of the accident. Oil residues were found only in the hollows and cavities of the rocks, and PAH contents in those residues decreased to one thirds of the original value in two years, but after that, PAHs contents remained at the same level, suggesting that PAHs will remain long as oil residues.Two years of monitoring of PAHs in the river water, SS and sediments revealed that the main sorbent of the PAHs in the sediments was organic matter. Organic matter based partition coefficient Koc was found to be well correlated to octanol-water partition coeffient, and can be described by using liner free-energy assumption.The exchange of PAHs between surface sediments and river water was sufficiently fast for allowing us to consider that the partition between the sediments and water is approximately in equilibrium.In the laboratory experiments, we investigated the effect of dissolved organic matter (DOM) on the partition of PAHs between sediments and water, and found that as the number of aromatic rings increases, the effect of DOM increases, and also found that for the precise description of the phenomena, we have to take into account the adsorption of DOM to the sediment particles.As described above, in the coastal environment, exchange between water and coastal particulate media is sufficiently fast to remove the pollutants from the polluted sites in several years, and at the mouth of the river, that is so fast that we can assume an approximate equilibrium. Sorption of PAHs to particulate matter is mainly to organic matter, and the partition coefficient is larger as the number of aromatic rings increases, and can be roughly estimated by using linear free energy assumptions.