海洋生态与环境科学重点实验室知识库

微塑料（Microplastic）通常是指粒径<5 mm的塑料微粒，作为一种新兴污染物，其在海洋水体和沉积物中广泛存在，且易被误食从而进入生物体内，进而对海洋生物的生长、发育和行为等产生影响。科学认识微塑料在海洋环境及生物体内的污染现状是剖析其对海洋生态系统危害、评估其生态风险的基础。

象山湾位于浙江省东北部沿海，是众多渔业生物的产卵场、育幼场和重要的海水养殖区。受长期的渔业生产和其他人类活动影响，该海域的微塑料污染问题比较明显。本研究以典型的半封闭海湾—象山湾为研究对象，以2019年5月份象山湾生物资源与环境调查研究为基础，围绕微塑料在象山湾多介质（表层海水、表层沉积物和生物体）中的分布特征和组成结构，以及微塑料在不同营养级生物体内的传递累积效应等科学问题展开研究。主要研究内容和结果如下：

1. 微塑料在表层海水中的分布特征和组成结构。表层海水中微塑料的丰度范围为0.03-0.70个/立方米，平均丰度为0.17±0.18个/立方米。共检出六种形状的微塑料，分别为泡沫状（64.4%）、碎片状（11.7%）、颗粒状（8.0%）、线状（6.9 %）、薄膜状（5.0%）和纤维状（4.0%）；傅里叶显微变换红外光谱仪（μ-FTIR）共鉴定出聚苯乙烯（PS，66.9%）、聚乙烯（PE，22.8%）、聚丙烯（PP，8.2%）、人造丝（RY，1.7%）和聚氯乙烯（PVC，0.4%）五种成分组成的微塑料；检出的微塑料粒径范围在206-4940 μm间，平均粒径为1554±1103 μm。受养殖设施和径流输入等因素影响，湾底区域微塑料丰度显著高于其他采样区域。

2. 微塑料在表层沉积物中的分布特征和组成结构。象山湾表层沉积物中微塑料的丰度范围为（40±16-240±86）个/千克（干重），平均丰度为139±87个/千克（干重），湾内微塑料分布较为均匀，未发现显著的区域性差异。共检出六种形状类型的微塑料，分别为纤维状（65.4%）、碎片状（13.8%）、颗粒状（10.0%）薄膜状（5.9%）、线状（3.0%）和泡沫状（1.9%）；共鉴定出RY（63.1%）、PP（23.6%）、PE（5.5%）、聚对苯二甲酸乙二醇酯（PET，3.3%）、聚酰胺（PA，2.2%）、PS（1.9%）和聚乙烯醇（PVA，0.4%）七种成分组成的微塑料；沉积物微塑料粒径在165-4789 μm间，平均粒径为1157±883 μm。受塑料类型和密度等影响，象山湾表层沉积物中微塑料可能主要来源于沿岸生活污水排放，相较于表层海水，象山湾表层沉积物微塑料分布较为均匀。

3. 微塑料在常见海洋生物体内的分布特征、组成结构及其生物累积效应。在23种常见海洋生物体内的微塑料平均丰度为1.0±1.3个/个体。其中，斑鰶（Konosirus punctatus， 2.8±1.5个）丰度最高，短棘银鲈（Gerres lucidus，0.2±0.4个）最低。共检出纤维状（88.7%）、碎片状（10.1%）和颗粒状（1.2%）3种形状微塑料，成分则包括RY（67.6%）、PET（15.8%）、PP（7.5%）、PVA（2.5%）和PE（2.1%）等12种；检出的微塑料粒径范围为105-4759 μm，平均粒径1276±1019 μm。表明象山湾海洋生物体内微塑料污染具有普遍性，组成特征与该海域环境中的微塑料分布和组成有一定相关性。基于氮稳定同位素技术的研究结果表明，以鹰爪虾（Trachypenaeus curvirostris，营养级为2.0；δ¹⁵N为8.8±0.3‰）为基准物种，象山湾海域23个物种的δ¹⁵N比值为7.7-14.5‰，营养级范围为1.7-3.7。但是，生物体内的微塑料丰度随营养级升高呈现减少趋势，在海洋食物网中营养级放大系数（TMF）较低（0.17），表明微塑料在象山湾海洋食物网中累积放大效应不明显。

Microplastics generally refer to plastic particles with particle size less than 5 mm. As an emerging pollutant, it is widely present in marine environment, and can be ingested into living organisms, affecting the physiological activities of marine organisms. Understanding the pollution status of microplastics in the marine environment and organisms is fundmental for assessment of its ecological risks on orgamisms and threat to marine ecosystems .

Xiangshan Bay is located on the coast of Zhejiang Province in southeastern China. It is a spawning ground, a nursery ground for many fisheries and an important marine aquaculture area. Affected by long-term fishery production and other human activities, the problem of microplastic pollution in Xiangshan Bay was serious. In the present study, the pollution status of microplastics in the surface water, sediments and organisms collected in Xiangshan Bay during the surveys of fishery resources in spring 2019 was investigated and evaluated. Moreover, the transfer and biomagnification of microplastics in the food web were analyzed using trophodynamics methods. The research results were as follows:

1. Microplastic pollution in the surface seawater of Xiangshan Bay. The average abundance of microplastics in the surface seawater was 0.17±0.18 items/m³, varying from 0.03-0.70 items/m³. A total of six shape types were identified, including foam (64.4%), fragment (11.7%), granule (8.0%), column (6.9%), film (5.0%) and fibers (4.0%) were detected, and five chemical component including polystyrene (PS, 66.9%), polyethylene (PE, 22.8%), polypropylene (PP, 8.2%), rayon (RY, 1.7%) and polyvinyl chloride (PVC, 0.4%). The particle size of the microplastics ranged from 206 to 4940 μm and averaged 1554±1103 μm. The results showed that the microplastics abundance in the basin (southwest part) of the bay is apparently higher than in other part of the water. The plastics coming from concentrated aquaculture facilities and abundant river influx around the west part of the bay might make large contributions to the high microplastics abundance in the water of the basin of the bay.

2. Microplastic pollution in the surface sediments of Xiangshan Bay. The average abundance of microplastics in the surface sediments was 139±87 items/kg (dry weight), ranging from 40±16 items/kg to 240±86 items/kg. The microplastics in the surface sediments were spatially evenly distributed in the bay. A total of six shape types of mrcroplastcs were identified, including fibers (65.4%), fragment (13.8%), granule (10.0%), film (5.9%), column (3.0%) and foam (1.9%). In terms of chemical composition, seven microplastics were detected: RY (63.1%), PP (23.6%), PE (5.5%), polyethylene terephthalate (PET, 3.3%), polyamide (PA, 2.2%), PS (1.9%) and polyvinyl alcohol (PVA, 0.4%). The particle size of the microplastics ranged from 165 to 4789 μm, with an average of 1157±883 μm. The microplastics in the surface sediments of the bay might mainly originate from coastal domestic sewage discharge around the bay. Compared to the microplastics in the surface seawater, the microplastics in the surface sediments of bay was more spatially evenly distributed.

3. Microplastic pollution in common marine organisms and the transfer and bioaccumulation of microplastics in the marine food webs of Xiangshan Bay. The average abundance of microplastics in 23 marine organisms was 1.0±1.3 items/individual, with the higest level in Konosirus punctatus (2.8±1.5 items/individual) and the lowest level in Gerres lucidus (0.2±0.4 items/individual). Three shape types of microplastics were observed: fibers (88.7%), fragment (10.1%) and granule (1.2%). In terms of chemical composition, twelve microplastics were detected. Of them, the most common microplastics were RY (67.6%) and PET (15.8%), followed by PP(7.5%), PVA (2.5%) and PE (2.1%). The particle size of the microplastics was between 105-4759 μm, with an average particle of 1276±1019 μm. The presence of microplastics in the marine organisms of bay is universal, which is to some extent correlated with the microplastics pollution in the environment. But plastics from aquaculture facilities might make less contributions to the microplastics in the organisms. The trophic relations of the 23 organisms were constructed using nitrogen stable isotope ratio (δ¹⁵N), with the secondary consumer shrimp (Trachypenaeus curvirostris) as the baseline species (trophic level, TL=2.0; δ¹⁵N=8.8±0.3‰). The δ¹⁵N ratios of these organisms ranged from 7.7‰ to 14.5‰ and the TL ranged from 1.7 to 3.7. However, the abundance of the microplastics in the organisms tended to decrease with increasing TL with a low trophic magnification (TMF = 0.17). This finding suggested that microplastics could be diluted in the marine food web of Xiangshan Bay.

第1章 引言……………………………………………………….…………….….1

1.1 海洋微塑料概述…………………………………………………….…………1

1.2 海洋微塑料在不同环境介质中的分布………………………………….……2

1.2.1 表层海水中的微塑料………………………………………………..……2

1.2.2 沉积物中的微塑料…………………………………………..……………3

1.2.3 海洋生物体内的微塑料………………………………………..…………4

1.3 海洋微塑料的环境效应………………………………………………….……5

1.4 研究区域、意义与内容………………………………………………….……6

1.4.1 研究区域与研究意义……………………………………………..………6

1.4.2 研究内容…………………………………………………………..………6

1.4.3 研究技术路线……………………………………………………..………7

第2章 微塑料在表层海水中的分布特征和组成结构……………………9

2.1 材料与方法………………………………………………………….…………9

2.1.1 样品采集……………………………………………………..……………9

2.1.2 微塑料的分离与鉴定……………………………………………………10

2.1.3 质量控制…………………………………………………………………11

2.1.4 数据分析…………………………………………………………………11

2.2 结果……………………………………………………………………...……11

2.2.1 象山湾主要养殖渔具塑料类型…………………………………………11

2.2.2 表层海水中微塑料的丰度和分布特征…………………………………12

2.2.3 表层海水中微塑料的形状类型、粒径分布和成分组成………………12

2.3 讨论………………………………………………………………...…………17

2.3.1微塑料在表层海水中的丰度及其影响因素……………………….……17

2.3.2 微塑料在表层海水中的组成特征………………………………………18

2.3.3 微塑料在表层海水中分布的空间差异…………………………………20

第3章 微塑料在表层沉积物中的分布特征和组成结构……………… 23

3.1 材料与方法…………………………………………………………...………23

3.1.1 样品采集…………………………………………………………………23

3.1.2 微塑料的分离与鉴定……………………………………………………23

3.1.3 质量控制…………………………………...…………………….………24

3.1.4 数据分析…………………………………………………………………24

3.2 结果……………………………………………………………...……………24

3.2.1 微塑料的丰度与分布特征………………………………………………24

3.2.2 微塑料的形状类型、粒径分布和成分组成……………………………25

3.3 讨论……………………………………………………………...……………27

3.3.1 微塑料在表层沉积物中的丰度及与表层海水的相关性………………27

3.3.2 微塑料在表层沉积物中的组成特征……………………………………29

3.3.3 微塑料在表层沉积物中分布的空间差异………………………………31

3.3.4 养殖设施对表层沉积物中微塑料丰度的影响…………………………31

第4章 微塑料在生物体内的分布、组成结构及其生物累积效应……33

4.1 材料与方法…………………………………………………………...………33

4.1.1 样品采集…………………………………………………………………33

4.1.2 实验室分析………………………………………………………………33

4.1.3 质量控制…………………………………………………………………39

4.1.4 数据分析…………………………………………………………………39

4.2 结果………………………………………………………………...…………39

4.2.1 象山湾食物网常见海洋生物的δ¹⁵N及营养级……………..….………39

4.2.2 生物组织内微塑料的丰度………………………………………………39

4.2.3 微塑料的形状类型、粒径分布和成分组成……………………………42

4.3 讨论……………………………………………………………………...……45

4.3.1 海洋生物对微塑料的摄取及其影响因素………………………………45

4.3.2 微塑料在鱼类不同组织内的累积分布特征……………………………47

4.3.3 生物体内微塑料组成特征………………………………………………48

4.3.4 养殖设施对象山湾生物体微塑料的影响………………………………49

4.3.5 微塑料在食物网上的生物累积效应评估………………………………50

第5章 结论与展望……………………………………………………..………51

5.1 主要结论…………………………………………………………...…………51

5.2 创新点……………………………………………………………...…………52

5.3 不足与展望……………………………………………………...……………52

5.3.1 不足………………………………………………….…………...………52

5.3.2 展望………………………………………………….…………...………52

参考文献…………………………………………………………………...………55

致 谢………………………………………………………………….….…………67

作者简历及攻读学位期间发表的学术论文与研究成果…………..……69