Field Microplastics Observation And Its Possible Policy Regulation For Typical Marine Fishery Area

As an important basic material,plastic has been widely used in agricultural and industrial production and daily life since the mid-20th century.A lot of waste plastics have been discharged into the sea and gradually decomposed into tiny plastic fragments.Generally,plastics with a diameter less than 5 mm are called microplastics.It has become a new class of environmental pollutants that pose a great threat to ecological safety and may be harmful to marine life and even human health.More than 60%of the world’s population lives in coastal areas,which also have the highest concentration of plastic emissions.As one of the largest mariculture countries in the world,various kinds of plastic fishing gear facilities are widely used in the typical bays and factory mariculture activities along the southeast coast of China.These have become one of main source of microplastics.However,compared with estuaries,tidal flats and other coastal environments,the environmental status and influencing factors of microplastics in coastal fish culture areas are less well known.At the same time,to deal with various environmental and ecological problems that may be caused by marine microplastics,there is still a global lack of a comprehensive and systematic control system for coastal marine plastic garbage.China also lacks policies and corresponding management measures for marine plastic control and microplastic pollution prevention and control in coastal fishery waters.Therefore,it is of great scientific value and practical significance to grasp the occurrence state and influencing factors of microplastics in typical coastal fishery waters and factory farming seawater,and to carry out policy research and analysis on this basis,and propose effective control countermeasures.The fishery waters in the southeast coast of China are the most important aquaculture areas.Zhanjiang Bay is a typical semi-enclosed bay and an important aquaculture base in southern China.It is also one of the main oyster farming areas in China.Longjiao Bay is located on the west coast of the Taiwan Strait,in Fujian province,whose gross Marine product ranks the third in China and its aquatic product export ranks the first in China for six consecutive years.In recent years,urbanization and industrialization have been developing rapidly,and the space for coastal aquaculture has been squeezed.Therefore,factory mariculture has become a typical representative of small and medium-sized Gulf aquaculture models.In this study,combined with the characteristics of fish farming and socio-economic activities in the southeast coast of China,we choose a typical fishing areas(Zhanjiang Bay)in northern South China Sea and the coast of Taiwan strait factory mariculture system(Longjiao Bay),to carry out the seawater pollution characteristics of the microplastic,spatial distribution,seasonal change and influence factors of research.These will provide important basic data and scientific basis for the monitoring of environmental microplastics pollution in coastal fishery waters in China.This study was conducted in September 2017,January 2018 and May 2018 to study the abundance composition,spatial distribution and seasonal variation(highwater period,level-water period and dry season)of microplastics in Zhanjiang Bay.The results showed that:1)the detection range of microplastics in surface seawater of Zhanjiang Bay was n.d.-2.65 n/m3(mean value 0.37±0.57 n/m3),and the microplastic abundance was relatively high in the high-water and level-water periods(the range was 0.03-1.52 n/m3 in high-water period,and the mean value was 0.40 n/m3 in September;the range was 0.05-2.65 n/m3 in level-water period,and the mean value was 0.50 n/m3 in May),while the abundance was lower during the dry season(n.d.-1.21 n/m3,mean 0.28 n/m3).2)Microplastics smaller than 3 mm predominated(81%),with the major forms being fragments(47.0%),films(37.0%),and foams(10.6%).3)Polyethylene(PE)(20%),rubber(20%),and polypropylene(PP)(15%)were the most abundant(n.d.-1.21 n/m3,the mean value was 0.28 n/m3 in January).Foam and fragment were the most important forms of microplastics in abundant and dry water period,respectively.3)Polyethylene(PE)(20%),rubber(20%)and polypropylene(PP)(15%)were the main components of microplastics in Zhanjiang Bay,of which PE(34%)and PP(31%)were the most important forms of microplastics in abundant and dry water period,respectively,and PE(34%)and PP(31%)were the most important forms of microplastics in abundant and dry water period,respectively.4)The seasonal differences in spatial distribution were obvious:during the high-water period,the high abundance of microplastics appeared at the top of the bay(1.14 n/m3)and showed a decreasing trend toward the mouth of bay(0.03 n/m3).The distribution of microplastics during the dry period was opposite to that during the high-water period,with the microplastic abundance gradually increasing from the top of the bay(n.d.)to the mouth of the bay(1.12 n/m3).During the level-water period,the microplastic abundance showed a high distribution pattern in the bay top and bay mouth,and a low distribution pattern in the central of bay.5)Source analysis showed that mariculture activities were the main source of microplastics in Zhanjiang Bay.The cluster analysis showed that,the non-point source pollution caused by farming activities,different from the point source pollution caused by industrial activities,and the seasonal changes of microplastics at the bay mouth site might be related to the coastal currents near the west of Guangdong.In a word,different seasons and differences in farming types can have a significantly influence on the source,morphology,composition,abundance anddistribution of microplastics.In this study,we carried out a study on the temporal changes of microplastic abundance and other characteristics in Longjiao Bay from April to December 2018.The results showed that:1)The factory mariculture in Longjiao Bay was mainly in the flowing water aquaculture model,and microplastics could be detected in the water.The abundance range was 250-5 150 n/m3,with an average of 1594.2±1352.2 n/m3.The temporal variation of microplastic abundance was roughly consistent with the aquaculture cycle(100-120 days).2)Unlike the open system,there was a higher abundance of microplastics in the Longjiao Bay.The size of microplastics in factoryfarmed water was mainly large(0.3-5 mm:92.03%),consisting mainly of granular(41.36%)and fibrous(34.93%),with white(45.42%),yellow(32.13%)and black(19.55%)colors,PE(34.40%)and with polyethylene terephthalate(PET,30.18%)as the main components.Based on the morphology,color,size and component characteristics of microplastics,it can be inferred that microplastics mainly originated from the local fish farming activities,i.e.,aging of their own equipment and feeding activities.3)The correlation analysis showed that the tiny plastic in the aquaculture water abundance was positively correlated with the local seafood production relations.This indicated that high abundance of microplastics would increase the risk of intake of farmed organisms and might cause health problems to farmed organisms.So it was necessary to study the toxicology of microplastics in organisms in the factory mariculture model.Black seabream(Acanthopagrus schlegelii)is widely distributed in the coastal areas of China and is a typical cultured economic fish.In this study,we selected black seabream juvenile fish from aquaculture plants and focused on the comparative toxicological experiments of water-soluble microplastics and traditional microplastics on the growth of black seabream.The results showed that:1)microplastics had a significant effect on the growth rate(body weight growth rate)of black seabream,protease activity and feed conversion ratio.Microplastics might be ingested by farmed organisms,which not only affected the growth and development quality of farmed organisms,but also caused significant potential harm to fishery food safety and human health.2)The influences of PE and polyvinyl alcohol(PVA)were different.After 8 weeks,the weight gain rate and feed efficiency of the experimental group fed 30 pieces of microplastics a day were significantly lower than those of the control group.n the microplastics recovered from digestive tract,feces and water,it was found that the amount of debris recovered from PE group was significantly higher than that from PVA group.3)Pepsin activity increased with the amount of microplastics fed,but trypsin activity in the intestine was opposite.The effect of PE group on black seabream was found to be significantly higher than that of PVA group.4)There was a positive correlation between trypsin activity and weight gain rate.It was assumed that microplastics would decrease trypsin after ingestion into the intestinal tract of fish,thus affecting the growth of the microplastics.5)The effect of water-soluble PVA on the growth of black seabream was significantly lower than that of water-insoluble PE,indicating that PVA plastic was more environmentally friendly and had a certain application and promotion prospect in mariculture,which could alleviate the current microplastic pollution problem in mariculture to a certain extent.Based on the widespread detection of microplastics in open fishery waters and indoor aquaculture environment,this study further carried out research on the policies,regulations and management measures for microplastics pollution control in marine fishery waters and mariculture.Specifically,we analyzes the current status of global marine microplastic pollution control,systematically combs international and national(regional)policies,regulations and management measures related to microplastics,and compares and analyzes relevant policies in different dimensions from the perspectives of secondary and primary sources.It is found that:1)China’s existing marine microplastics control policies and measures were not comprehensive enough;2)China’s fisheries-related microplastics policies,regulations and management had not received much attention;3)There was still a lack of long-term incentive governance mechanism for plastic prevention and control policies and management measures;4)It was suggested that China should take the lead in proposing corresponding policies or action plans on the basis of existing laws and regulations,and strive to play a leading role in the world.Based on the above comparative studies,we carried out a combing and analysis of the challenges,policy recommendations and prevention measures for microplastics control in China’s coastal fishery waters.The details were as follows:1)Sorted out the problems and challenges of microplastics control in China’s coastal fishery production:complicated formation mechanism of microplastics hazards,multiple control scenarios,wide migration paths,unclear authority and responsibility of governance entities,international environmental pressure,and how to balance rapid economic development and ecological environment carrying capacity,and.2)Put forward policy recommendations for microplastics control in coastal fishery waters,mainly including:establishing a fishery waters Plastic garbage classification and recycling system,the establishment of fishery waters extended producer responsibility system,the establishment of "integrated land and sea" comprehensive management mode,improving public awareness of environmental protection,improving water treatment technology,and the establishment of the whole life cycle of the control system.3)In view of the hazards of microplastics in marine aquaculture,put forward the microplastics in marine aquaculture prevention and control policy and Management recommendations,including improving fishing gear management policies,establishing a risk assessment system for marine aquaculture microplastics,incorporating microplastics into marine aquaculture water quality monitoring indicators,suggesting that microplastics seriously pollute sea areas to limit or prohibit marine aquaculture,suggesting that microplastic characteristics of indicators into seafood food safety control system,and establishing a marine aquaculture pollution enterprise responsibility system and market control mechanism.