On the Morrocan Atlantic coast, the estuary of the Bouregreg was submitted to many anthropic effects. After the dam Sidi Mohammed ben Abdellah was built in 1974, the flow became almost null. The waters of the estuary ...On the Morrocan Atlantic coast, the estuary of the Bouregreg was submitted to many anthropic effects. After the dam Sidi Mohammed ben Abdellah was built in 1974, the flow became almost null. The waters of the estuary are meant for recreational activities, fishing, but at the same time they receive water collecting domestic and industrial wastewater. The waste in old landfills was not treated and leaked into the river water. The matter gets worse with the action of tides which make it difficult to escape the pollution load （physicochemical, bacteriological, heavy metals, etc.）. The concentrations of heavy metals （Pb, Fe, Cu and Cr） recorded in the sediments are higher than those found in the two molluscs. However, we have found out that Mytilus has accumulated more heavy metals （Cr, Pb and Zn） than Solen marginatus. The Zn makes an exception： It presents a greater concentration in the molluscs （63.015 mg/kg dry weight for Mytilus and 232.736 mg/kg dry weigh for Solen） than in the sediments （57.639 mg/kg）. The amount of these metals exceeds the standard values. The impact of the marine pollution on human health derives from the consumption by humans of heavy-metal polluted molluscs. The detected concentrations of these pollutants are superior to the permissible maximum amounts.展开更多
Zhangjiakou is a northern Chinese city that hosted the Beijing 2022 Winter Olympic Games. As an important ice and snow tourist destination, it is essential to investigate Zhangjiakou’s rate of landscape pattern chang...Zhangjiakou is a northern Chinese city that hosted the Beijing 2022 Winter Olympic Games. As an important ice and snow tourist destination, it is essential to investigate Zhangjiakou’s rate of landscape pattern change,the landscape ecological security level, and ecosystem service value, particularly the tourism ecological service value during its construction. With land use data from 2000 to 2020, this study comprehensively analyzed the dynamic changes in Zhangjiakou, including land use dynamics, the land use transfer matrix, landscape vulnerability,landscape disturbance, ecosystem service value, tourism ecological service value, and other aspects. The results show that the landscape pattern in Zhangjiakou was greatly disturbed from 2015 to 2018, and the landscape ecological security was threatened in the process of landscape pattern adjustment. By 2020, after the landscape pattern was adjusted and stabilized, the landscape ecological security was restored, and the ecosystem service value was significantly improved, especially the tourism ecological service value. The results of this study will play an important role in promoting the optimization of Zhangjiakou’s ice and snow landscape pattern and the improvement of tourism ecological value. In addition, it provides important lessons for the development of other ice and snow tourist destinations.展开更多
文摘On the Morrocan Atlantic coast, the estuary of the Bouregreg was submitted to many anthropic effects. After the dam Sidi Mohammed ben Abdellah was built in 1974, the flow became almost null. The waters of the estuary are meant for recreational activities, fishing, but at the same time they receive water collecting domestic and industrial wastewater. The waste in old landfills was not treated and leaked into the river water. The matter gets worse with the action of tides which make it difficult to escape the pollution load （physicochemical, bacteriological, heavy metals, etc.）. The concentrations of heavy metals （Pb, Fe, Cu and Cr） recorded in the sediments are higher than those found in the two molluscs. However, we have found out that Mytilus has accumulated more heavy metals （Cr, Pb and Zn） than Solen marginatus. The Zn makes an exception： It presents a greater concentration in the molluscs （63.015 mg/kg dry weight for Mytilus and 232.736 mg/kg dry weigh for Solen） than in the sediments （57.639 mg/kg）. The amount of these metals exceeds the standard values. The impact of the marine pollution on human health derives from the consumption by humans of heavy-metal polluted molluscs. The detected concentrations of these pollutants are superior to the permissible maximum amounts.
文摘Zhangjiakou is a northern Chinese city that hosted the Beijing 2022 Winter Olympic Games. As an important ice and snow tourist destination, it is essential to investigate Zhangjiakou’s rate of landscape pattern change,the landscape ecological security level, and ecosystem service value, particularly the tourism ecological service value during its construction. With land use data from 2000 to 2020, this study comprehensively analyzed the dynamic changes in Zhangjiakou, including land use dynamics, the land use transfer matrix, landscape vulnerability,landscape disturbance, ecosystem service value, tourism ecological service value, and other aspects. The results show that the landscape pattern in Zhangjiakou was greatly disturbed from 2015 to 2018, and the landscape ecological security was threatened in the process of landscape pattern adjustment. By 2020, after the landscape pattern was adjusted and stabilized, the landscape ecological security was restored, and the ecosystem service value was significantly improved, especially the tourism ecological service value. The results of this study will play an important role in promoting the optimization of Zhangjiakou’s ice and snow landscape pattern and the improvement of tourism ecological value. In addition, it provides important lessons for the development of other ice and snow tourist destinations.
