**3.1 Definition**

Microplastic specifications can be found in two broad categories, primary and secondary [24]. Primary microplastics are manufactured particles that are characterized as microbeads, nurdles, and fibers in size dimensions of 5 mm or smaller. Any interception technology must be equipped with appropriately sized filters to remove the particles from contaminated environmental media. Secondary microplastics are formed from larger plastics or macroplastics through the effects of weathering and physical deterioration in the environment. Weathering by photochemical oxidation, UV rays, and wind and wave action leads to the fragmentation of macroplastics to form microplastics. Aquatic plastic debris can be organized by size as mega (>1 m)-, macro (<1 m)-, meso (<2.5 cm)-, micro (<5 mm)-, and nano (<1 μm)-dimensions [25]. A recently proposed size schema separates microplastics in marine environments into the following categories: nano (1–1000 nm)-, micro (1–1000 μm)-, meso (1–10 mm)-, and macroplastics (≥1 cm). Size schemes are proposed to address the sampling problems encountered in the field, but these schemes are lacking since it is difficult to provide a microplastic sample that is spatially representative of a specific environmental space [26–29].

### **3.2 Composition**

Chemical composition and environmental impacts of microplastic samples differ broadly (**Table 2**). Microplastic composition reflects the use and disposal of the most popular macroplastics such as the polyolefins [polypropylene (PP) and polyethylene (PE)], polyvinyl chloride (PVC), polyurethane (PU), polyethylene terephthalate (PET), polystyrene (PS), and polycarbonate (PC). The composition of this list represents a large fraction of plastic use and global plastic production [2]. The high molecular weight of most plastic polymers renders them biochemically inert initially and hence have an inherent low toxicity due to lack of water solubility [30]. Many polymer compositions can contain small concentrations of unpolymerized monomer [31]. Monomers can be toxic and carcinogenic as in the case of styrene or vinyl chloride [32]. Problematic plastics such as PVC, PU, PS, and PC can contain toxic monomers or additives. Additives can include fillers, plasticizers, coloring agents, antimicrobials, flame retardants, and other material property modifiers [33]. These materials represent a source of health risks for humans and other species [34].

### **3.3 Origin**

Microplastics can be produced directly for use as raw materials in the fabrication of larger items. Environmental processes are known to form microplastic particles through mechanical destruction of macroplastic materials such as automobile tires disintegrating during wear and use [35]. As ingredients of abrasive, cleaning, and cosmetic products, microplastics have been manufactured as articles of commerce [36]. Microplastics were found to form during material wear of macroplastics by industrial processes and via physical breakdown of macroplastics [35, 36]. Their abundance and in situ effects of the environment have not been well quantified due in part to the random composition of particles of non-uniform shapes which are difficult to assess by representative samples [37]. The abundance of micro-, meso-, and macroplastics floating in the marine environment has been estimated from aggregated data derived from a host of surveys [38]. An estimate of global plastic pollution identifies at least 5.25 trillion plastic pieces of plastics, and most of its composition is microplastics [39]. Plastic marine debris (PMD) surveys suggested estimates of the total burden could be at least an order of magnitude lower than what has been observed in the environment [40]. A concern for a missing debris component has been interpreted as losses to deep sea and sediment sinks as prominent components to marine plastic fate [41].

### **3.4 Analytical protocols**

An understanding of microplastic pollution requires the use of proper and clear terminology for use in the design of data collection and supporting analytical protocols, enhanced coordination of strategic design for research directions, and most importantly a consensus development of mitigation management practices tailored to the global problem solution [42]. Composition, dimensions, and shape of plastic debris can be defined explicitly to properly design sampling protocols and conduct the requisite analytical determinations (biological, chemical, and physical) using a wide array of techniques ranging from microscopy to different forms of spectroscopy [43]. Physicochemical properties (polymer composition, solid state, solubility) are employed as standards accompanying size, shape, color, and origin for categorical identification [44].

Standardized quantification and analysis procedures designed to analyze microplastics are critical to the design and data collection for comparative research studies [45]. Microplastics have high surface area solids and should be described in consensus terms [46]. The surface area of environmentally sampled microplastics was found to be a very important descriptor along with an accurate parameter to

**307**

*The Importance of Biofilms to the Fate and Effects of Microplastics*

chemical, biological, and physical characterization of samples [50].

field results acceptable to the general research community?

Without the proper knowledge of the environmental behavior of microplastics, we are incapable of solving the growing problem of microplastic management as applied to reducing the problem dimensions and human health risk. The necessary knowledge rests on properly designed research efforts and the use of harmonized and consensus analytical tools employed in the data gathering. What parameters for quantifying microplastics are available at a status that permits the comparison of

A consortium of microorganisms composed of cells adhering to a surface is called a biofilm [51, 52]. The physical setting for cells to adhere to a surface occurs through the intermediacy of extracellular polymeric substances (EPS) which forms a slimy extracellular matrix **Figure 1** [53]. Microbial cells in the biofilm produce the EPS which are composites of extracellular polysaccharides, proteins, lipids, and DNA [54, 55]. The cellular agglomeration of biofilms forms a three-dimensional structure as a community that offers significant protection against the forces levied

Microbial cells composing a biofilm are distinct from the planktonic cells of the same organism, which are single-cell organisms that are free to float or swim in an aquatic medium [57]. Biofilm structures are formed in response to a variety of different factors enabling biofilm development [58, 59]. Surface recognition is important to specific or nonspecific attachment sites, toxic materials, or antibiotics, and nutritional stress may complicate biofilm growth **Figure 2** [60]. A cell that switches to the biofilm mode of growth undergoes a shift of observable behavior of the bacteria resulting from the interaction of its genotype with the environment that is required of a microbial cell in the transition from planktonic to sessile growth in the regulation genes of the biofilm. A biofilm can mimic a hydrogel, a three-dimensional (3D) network of hydrophilic polymers complex containing a

describe plastic size coupled with a description of plastic quantity per spatial area. As widespread contaminants, microplastics can be found in virtually all environmental partitions [47]. Features such as spatial information, contamination sources, fate, and environmental concentration are difficult to assemble and the variety of analytical procedures currently in use hinders a timely and proficient gathering of information [48]. Methods currently used to sample and detect microplastics are under review which is aimed to identify flaws in design and suggest alternatives [49]. Analytical protocols must be designed to include bulk sample collection, particle separation, digestion, identification and quantification, and mitigation of cross-contamination in the form of transportable and consensus tools. This enhanced ability to sample and analyze microplastics enables the use of more representative samples and helps enhance the determination of the sample features mentioned previously. Incorporation of these features provides an enhanced ability to sample and analyze microplastics leading to the utilization of more representative samples attuned to the sample features required for the formulation of standard methods. The inclusion of new and novel analytical methodology can assist the

*DOI: http://dx.doi.org/10.5772/intechopen.92816*

**3.5 Concerns**

**4. Biofilms**

**4.1 Structure**

by the environment [56].

### *The Importance of Biofilms to the Fate and Effects of Microplastics DOI: http://dx.doi.org/10.5772/intechopen.92816*

describe plastic size coupled with a description of plastic quantity per spatial area. As widespread contaminants, microplastics can be found in virtually all environmental partitions [47]. Features such as spatial information, contamination sources, fate, and environmental concentration are difficult to assemble and the variety of analytical procedures currently in use hinders a timely and proficient gathering of information [48]. Methods currently used to sample and detect microplastics are under review which is aimed to identify flaws in design and suggest alternatives [49]. Analytical protocols must be designed to include bulk sample collection, particle separation, digestion, identification and quantification, and mitigation of cross-contamination in the form of transportable and consensus tools. This enhanced ability to sample and analyze microplastics enables the use of more representative samples and helps enhance the determination of the sample features mentioned previously. Incorporation of these features provides an enhanced ability to sample and analyze microplastics leading to the utilization of more representative samples attuned to the sample features required for the formulation of standard methods. The inclusion of new and novel analytical methodology can assist the chemical, biological, and physical characterization of samples [50].

### **3.5 Concerns**

*Bacterial Biofilms*

other species [34].

nent components to marine plastic fate [41].

**3.4 Analytical protocols**

for categorical identification [44].

**3.3 Origin**

the most popular macroplastics such as the polyolefins [polypropylene (PP) and polyethylene (PE)], polyvinyl chloride (PVC), polyurethane (PU), polyethylene terephthalate (PET), polystyrene (PS), and polycarbonate (PC). The composition of this list represents a large fraction of plastic use and global plastic production [2]. The high molecular weight of most plastic polymers renders them biochemically inert initially and hence have an inherent low toxicity due to lack of water solubility [30]. Many polymer compositions can contain small concentrations of unpolymerized monomer [31]. Monomers can be toxic and carcinogenic as in the case of styrene or vinyl chloride [32]. Problematic plastics such as PVC, PU, PS, and PC can contain toxic monomers or additives. Additives can include fillers, plasticizers, coloring agents, antimicrobials, flame retardants, and other material property modifiers [33]. These materials represent a source of health risks for humans and

Microplastics can be produced directly for use as raw materials in the fabrication of larger items. Environmental processes are known to form microplastic particles through mechanical destruction of macroplastic materials such as automobile tires disintegrating during wear and use [35]. As ingredients of abrasive, cleaning, and cosmetic products, microplastics have been manufactured as articles of commerce [36]. Microplastics were found to form during material wear of macroplastics by industrial processes and via physical breakdown of macroplastics [35, 36]. Their abundance and in situ effects of the environment have not been well quantified due in part to the random composition of particles of non-uniform shapes which are difficult to assess by representative samples [37]. The abundance of micro-, meso-, and macroplastics floating in the marine environment has been estimated from aggregated data derived from a host of surveys [38]. An estimate of global plastic pollution identifies at least 5.25 trillion plastic pieces of plastics, and most of its composition is microplastics [39]. Plastic marine debris (PMD) surveys suggested estimates of the total burden could be at least an order of magnitude lower than what has been observed in the environment [40]. A concern for a missing debris component has been interpreted as losses to deep sea and sediment sinks as promi-

An understanding of microplastic pollution requires the use of proper and clear terminology for use in the design of data collection and supporting analytical protocols, enhanced coordination of strategic design for research directions, and most importantly a consensus development of mitigation management practices tailored to the global problem solution [42]. Composition, dimensions, and shape of plastic debris can be defined explicitly to properly design sampling protocols and conduct the requisite analytical determinations (biological, chemical, and physical) using a wide array of techniques ranging from microscopy to different forms of spectroscopy [43]. Physicochemical properties (polymer composition, solid state, solubility) are employed as standards accompanying size, shape, color, and origin

Standardized quantification and analysis procedures designed to analyze microplastics are critical to the design and data collection for comparative research studies [45]. Microplastics have high surface area solids and should be described in consensus terms [46]. The surface area of environmentally sampled microplastics was found to be a very important descriptor along with an accurate parameter to

**306**

Without the proper knowledge of the environmental behavior of microplastics, we are incapable of solving the growing problem of microplastic management as applied to reducing the problem dimensions and human health risk. The necessary knowledge rests on properly designed research efforts and the use of harmonized and consensus analytical tools employed in the data gathering. What parameters for quantifying microplastics are available at a status that permits the comparison of field results acceptable to the general research community?
