ﺑﺮرﺳﯽ آﻟﻮدﮔﯽ ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏ در رﺳﻮﺑﺎت ﺑﺴﺘﺮ ﻧﺎﺣﯿﻪ ﺳﺎﺣﻠﯽ ﺟﻨﻮب درﯾﺎي ﺧﺰر

Investigation of microplastic pollution in the Southern Caspian Sea coastal sediments

وﺟﻮد ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏ ﻫﺎ )ذرات ﭘﻼﺳﺘﯿﮏ ﮐﻮﭼﮑﺘﺮ از 5 ﻣﯿﻠﯽ ﻣﺘﺮ( در ﻣﺤﯿﻂﻫﺎي درﯾﺎﯾﯽ ﺑﻪ دﻟﯿﻞ وزن ﭘﺎﯾﯿﻦ، ﻣﺎﻧﺪﮔﺎري ﺑﺎﻻ و ﺧﻄﺮآﻓﺮﯾﻨﯽ ﺑﺮاي ﺟﻮاﻣﻊ درﯾﺎﯾﯽ ﻣﺮﺗﺒﻂ، ﺑﺎﻋﺚ ﻧﮕﺮاﻧﯽ رو ﺑﻪ رﺷﺪ ﺟﻬﺎﻧﯽ ﺷﺪه اﺳﺖ. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻃﺒﯿﻌﺖ و ﺧﻄﺮات ذرات ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏ ﺑﺮاي ﺟﻮاﻣﻊ ﮐﻔﺰي و ﮔﻮﻧﻪﻫﺎي اﻗﺘﺼﺎدي درﯾﺎي ﺧﺰر اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺎ ﻫﺪف ﺑﺮرﺳﯽ ﭘﺮاﮐﻨﺪﮔﯽ ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏ ﻫﺎ در رﺳﻮﺑﺎت ﺑﺴﺘﺮ ﻣﻨﻄﻘﻪ ﺳﺎﺣﻠﯽ ﺣﺎﺷﯿﻪ ﺟﻨﻮﺑﯽ درﯾﺎي ﺧﺰر اﻧﺠﺎم ﺷﺪ. ﻧﻤﻮﻧﻪﻫﺎي رﺳﻮب ﺑﺎ اﺳﺘﻔﺎده از ﺑﻨﺘﻮز ﮔﯿﺮ ون وﯾﻦ از ﺷﺶ اﯾﺴﺘﮕﺎه آﺳﺘﺎرا، ﺑﻨﺪراﻧﺰﻟﯽ، ﮐﯿﺎﺷﻬﺮ، رودﺳﺮ، ﺳﺎري و ﺑﻨﺪر ﺗﺮﮐﻤﻦ در زﻣﺴﺘﺎن 1397 ﺑﺮداﺷﺘﻪ ﺷﺪﻧﺪ. اﯾﺴﺘﮕﺎه ﺳﺎري ﺑﺎ ﻣﯿﺎﻧﮕﯿﻦ 340±20 ﻗﻄﻌﻪ در ﯾﮏ ﮐﯿﻠﻮﮔﺮم از رﺳﻮﺑﺎت ﺧﺸﮏ ﺑﯿﺸﺘﺮﯾﻦ و اﯾﺴﺘﮕﺎه ﺑﻨﺪر ﺗﺮﮐﻤﻦ ﺑﺎ 156/66±75/71 ﻗﻄﻌﻪ در ﮐﯿﻠﻮﮔﺮم داراي ﮐﻤﺘﺮﯾﻦ ﻓﺮاواﻧﯽ ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏ ﺑﻮدﻧﺪ. اﻧﺪازه ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏ ﻫﺎ 9/7- 0/2 ﻣﯿﻠﯽﻣﺘﺮ ﻣﺘﻐﯿﺮ ﺑﻮد و ﺑﯿﺸﺘﺮ ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏﻫﺎي ﯾﺎﻓﺖ ﺷﺪه )35/54 %( اﻧﺪازه 1-2 ﻣﯿﻠﯽﻣﺘﺮ داﺷﺘﻨﺪ. ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏ ﻫﺎي اﺳﺘﺨﺮاج ﺷﺪه ﻋﻤﺪﺗﺎً رﺷﺘﻪاي ﺑﻮدﻧﺪ و ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏﻫﺎي ﻗﻄﻌﻪاي و ﻓﯿﻠﻢ ﻫﻢ ﻣﺸﺎﻫﺪه ﺷﺪﻧﺪ. در ﻧﻤﻮﻧﻪﻫﺎي ﺑﺮرﺳﯽ ﺷﺪه ﺗﻨﻮع رﻧﮕﯽ ﺑﺎﻻﯾﯽ ﻣﺸﺎﻫﺪه ﺷﺪ ﮐﻪ رﻧﮓﻫﺎي آﺑﯽ )63/85 %( و ﻗﻬﻮهاي )20/31 %(، داراي ﺑﯿﺸﺘﺮﯾﻦ ﻓﺮاواﻧﯽ ﺑﻮدﻧﺪ. ﺑﺎ اﺳﺘﻔﺎده از آﻧﺎﻟﯿﺰ ATR-FTIR 4 ﻧﻮع ﭘﻠﯿﻤﺮ ﺳﻠﻮﻓﻮن، ﭘﻠﯽاﺗﯿﻠﻦ، ﭘﻠﯽﭘﺮوﭘﯿﻠﻦ و ﭘﻠﯽوﯾﻨﯿﻞ اﺳﺘﺎت ﺷﻨﺎﺳﺎﯾﯽ ﺷﺪﻧﺪ. ﻓﺮاوانﺗﺮﯾﻦ ﻣﯿﮑﺮوﭘﻼﺳﺘﯿﮏ ﺷﻨﺎﺳﺎﯾﯽ ﺷﺪه ﺳﻠﻮﻓﻮن ﺑﻮد. در ﭘﺎﯾﺎن ﯾﮏ ﻧﺘﯿﺠﻪ ﮔﯿﺮي ﻣﺸﺨﺺ اراﺋﻪ ﺷﻮد و از ﮐﻠﯽ ﮔﻮﯾﯽ ﺧﻮدداري ﮔﺮدد.

The presence of microplastics (less than 5 mm in size) in marine environments, owing to their persistence and risks they impose to marine communities has become a growing global concern. Considering the hazardous nature of microplastic particles to benthic communities and commercial species of the Caspian Sea, the study was conducted to investigate the distribution of microplastics in sediments of the southern shores of the Caspian Sea. Sediment samples were taken by a Van Veen grab at sampling sites located in Astara, Bandar Anzali, Kiashahr, Rudsar, Sari and Turkmen port in winter 2018. The highest frequency of microplastics was observed at Sari station (mean 340±20 items/kg dry sediment) and the lowest at Turkmen port station with (mean 156.66±75.71 items/kg dry sediment). The size of the microplastics varied from 0.2-9.2 mm and most of the microplastics found (35.54%) were 1-2 mm in size. The extracted microplastics were mainly filamentous, although microplastic fragments and films were also observed. In the examined samples, high color diversity was observed and blue (63.85%) and brown (20.31%) were most frequent colors. Using ATR-FTIR analysis, 4 types of polymers including cellophane, polyethylene, polypropylene and polyvinyl acetate were identified. The most abundant microplastics identified were cellophane. This study is among very few studies on microplastic contamination in the sediments of the southern Caspian Sea and the obtained results are vital for further studies in future.