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B. Yan et al.
of plastic formed through the processing of physical, chemical, biological, and nonbiological decomposition, etc., from the large pieces of plastics entering the environment [13]. For example, many industrial raw materials, household articles, plastic
garbage, packaging materials, and other products produced by human activities
contain plastic components. All these could serve as possible sources of microplastic
through fragmentation or degradation.
Microplastics in the marine environment mainly comes from surface runoff from
terrestrial rivers. The plastic garbage discarded along the coast enters into the marine
environment through the runoff and ocean currents. Garbage stacking and wastewater
treatment near the shoreline would contribute to the marine microplastic accumulation. In addition, near-marine aquaculture plastic products are also an important
source of marine microplastics.
The public has come to realize that the large amount of microplastics in the ocean
is a global concern. As the main pollution area, microplastics could be found in
various marine environments, from coastal to deep-sea environments. At the very
beginning, most researches focused on microplastic distribution in surface water.
Later, researchers found that in spite of the property of buoyancy, microplastics
could be still transported into sediments after being ingested by a marine organism
or colonized by microorganisms [10, 14].
More and more studies have shown that the level of microplastic in different sediment environments (such as coastal, nearshore, offshore, deep sea, etc.) is relatively
high. It is now widely accepted that marine sediments are considered to be long-term
microplastic deposits [15], therefore, the effects of microplastics on sedimentary
communities and geochemical cycles are worth studying.
2 Environmental Fate and Transport of Microplastics
2.1 The Transport of Microplastics in the Marine
Environment
In order to understand the fate of microplastics, it is important to know their behaviors
of transport. It is well known that air, water, and living things are the transmission
factors of microplastics, among which the water environment transports the most
microplastics. In aquatic environments, abiotic factors such as water flow, currents,
depth, wind, surface area, and density of suspended particles would all affect the
transport of microplastics. Microplastics generally float on the overlying water due
to their lower density and higher buoyancy and exist in the ocean surface. As a carrier
of microplastics, surface water can concentrate microplastics more easily than the
bottom water [16]. Generally, the smaller the size of microplastics, the greater the
buoyant force of microplastics, and more easily rising to the surface of the sea. Landbased microplastics enter the ocean through rivers and it is often called advection
transport [16].
B. Yan et al.
of plastic formed through the processing of physical, chemical, biological, and nonbiological decomposition, etc., from the large pieces of plastics entering the environment [13]. For example, many industrial raw materials, household articles, plastic
garbage, packaging materials, and other products produced by human activities
contain plastic components. All these could serve as possible sources of microplastic
through fragmentation or degradation.
Microplastics in the marine environment mainly comes from surface runoff from
terrestrial rivers. The plastic garbage discarded along the coast enters into the marine
environment through the runoff and ocean currents. Garbage stacking and wastewater
treatment near the shoreline would contribute to the marine microplastic accumulation. In addition, near-marine aquaculture plastic products are also an important
source of marine microplastics.
The public has come to realize that the large amount of microplastics in the ocean
is a global concern. As the main pollution area, microplastics could be found in
various marine environments, from coastal to deep-sea environments. At the very
beginning, most researches focused on microplastic distribution in surface water.
Later, researchers found that in spite of the property of buoyancy, microplastics
could be still transported into sediments after being ingested by a marine organism
or colonized by microorganisms [10, 14].
More and more studies have shown that the level of microplastic in different sediment environments (such as coastal, nearshore, offshore, deep sea, etc.) is relatively
high. It is now widely accepted that marine sediments are considered to be long-term
microplastic deposits [15], therefore, the effects of microplastics on sedimentary
communities and geochemical cycles are worth studying.
2 Environmental Fate and Transport of Microplastics
2.1 The Transport of Microplastics in the Marine
Environment
In order to understand the fate of microplastics, it is important to know their behaviors
of transport. It is well known that air, water, and living things are the transmission
factors of microplastics, among which the water environment transports the most
microplastics. In aquatic environments, abiotic factors such as water flow, currents,
depth, wind, surface area, and density of suspended particles would all affect the
transport of microplastics. Microplastics generally float on the overlying water due
to their lower density and higher buoyancy and exist in the ocean surface. As a carrier
of microplastics, surface water can concentrate microplastics more easily than the
bottom water [16]. Generally, the smaller the size of microplastics, the greater the
buoyant force of microplastics, and more easily rising to the surface of the sea. Landbased microplastics enter the ocean through rivers and it is often called advection
transport [16].