Many marine bays have been polluted along with the rapid development of industry and population size, and understanding the transporting progresses of pollutants is essential to pollution control. In order to better understanding the transporting progresses of pollutants in marine, this paper carried on a comprehensive research of the theories of transporting processes of Cu in Jiaozhou Bay. Results showed that the transporting processes of Cu in this bay could be summarized into seven key theories including homogeneous theory, environmental dynamic theory, horizontal loss theory, source to waters transporting theory, sedimentation transporting theory, migration trend theory and vertical transporting theory, respectively. These theories helpful to better understand the migration progress of pollutants in marine bay.
This paper quantified the horizontal and vertical transferring processes of As in coastal waters in the southwest and the bay mouth of Jiaozhou Bay using investigation data in July and October 1982. Results showed that the horizontal absolute loss amounts of As contents in surface waters were 0.20-2.44 μg L -1 , and the horizontal relative loss amounts in surface waters were 19.23%-87.14%, respectively. The horizontal absolute loss amounts of As contents in bottom waters were 0.27-2.44 μg L -1 , and the horizontal relative loss amounts in bottom waters were 25.00%-54.46%, respectively. The vertical absolute dilution amounts of As contents were 0.02-0.28 μg L -1 , and the vertical relative dilution amounts were 1.78-16.66%. The vertical absolute accumulation amounts of Pb contents were 0.10-0.86 μg L -1 , and the vertical relative accumulation amounts were 7.35%-35.83%. The vertical absolute dilution amount and vertical relative dilution amount of As’s contents were 0.20-0.76 μg L -1 and 19.23%-27.14%, respectively. The vertical absolute accumulation amount and vertical relative accumulation amount of As’s contents were 0.28-4.12 μg L -1 and 25.00%-91.96%, respectively. The changes of As contents in surface and bottom waters were determined by the source inputs of As and the transferring distance of As from the terrisgenous sources.
In the process of rice cultivation, fertilizer reduction can effectively reduce the concentration of phosphorus (P) in overlying water and leaching water. In this study, the variation characteristics of P in overlying and leaching water under the conditions of fertilizer reduction and straw application and its impact on the environment were studied through a two-season rice field experiment. Four treatments were set, including no fertilizer without straw (CK), conventional fertilization (CF), 20% reduction in nitrogen (N) and P fertilization (RF), and 20% reduction in N and P fertilization with the wheat straw (RFWS). The results showed that RF could effectively reduce the risk of P loss due to its ability to decrease the concentration of P in overlying and leaching water. RFWS increased P concentrations in overlying and leaching water of rice fields. Total dissolved phosphorus (TDP) was the main form of total phosphorus (TP), and soluble reactive phosphorus (SRP) was the main form of TDP. The concentration of TP, TDP, and SRP in the overlying and leaching water peaked on the first day after fertilization, and then gradually decreased. The high-risk period of P loss was 0 to 10 days after fertilization. This study could provide appropriate strategies to reduce the risk of P loss during local rice cultivation and protect local water resources from eutrophication.
In order to quantify the vertical transporting process of substance in marine bay waters, this paper established vertical content difference model, substance sedimentation amount model and substance accumulation amount model, and demonstrated the model performance based on the quantification of the vertical transporting process of Cu in Jiaozhou Bay, Shandong Province, China. Results showed that during 1982-1985 the absolute sedimentation amount and relative sedimentation amount of Cu were 0.29-18.23 μg L−1 and 74.3%-96.2%, respectively, and for absolute accumulation amount and relative accumulation amount were 0.32-3.71 μg L−1 and 76.1%-95.6%, respectively. By means of these models, the horizontal and vertical changes in surface and bottom waters and the change processes could be defined. This approach was straightforward yet was reliable enough to quantify the vertical transporting process of substance in marine bay.
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