What is a Microplastic?
The term microplastic was first used in a report published by the US Air Force Materials Laboratory in 1968. In the report in question, microplastic was used to describe the particles formed as a result of deformation in plastic materials subjected to high stresses.
In 1972, the world became aware of the presence of micro-sized plastic particles in the aquatic environment for the first time, when it was reported for the first time that large numbers of small floating plastic particles were found in the surface water of the Sargasso Sea. In 2004, these small particles were defined as microplastics. Later, plastics smaller than 5 mm were accepted as microplastics by the Steering Committee of the National Oceanic and Atmospheric Administration (NOAA) Marine Debris Program. In the future, plastics of different sizes were standardized.
Accordingly, Macroplastic ≥ 25 mm, Mesoplastic 25 – 5 mm, Microplastic ≤5 – 1 mm, Mini-microplastic <1mm – 1µm and Nanoplastic < 1µm were determined. Although the main source of microplastics in the aquatic environment is microplastics formed as a result of the breakdown of larger plastic parts, microplastics are also produced industrially for different purposes. In order to define those formed as a result of the deterioration of large parts and those produced industrially, the industrial ones were named as primary and the others as secondary microplastics.
Microplastic (MPP) Problems in Water!
Microplastics have become a concern reflected by sites with unusually high concentrations and a threat to the environment with the possibility of even higher concentrations in the future. As a result, the use and subsequent release of microplastics must be drastically reduced as part of a global initiative, even before the availability of research studies outlining these long-term risks.
Microplastic particles (MPPs) have become a global problem as they are added to products used almost every day. MPPs can be found in a number of cosmetic and personal care products, including washes, soaps, face and body scrubs, toothpaste and lotions. One of the primary problems is the disposal of microplastics found in cosmetics and personal products into household drains without any precautionary recycling measures.
Discarded MPPs and other types of plastic debris end up in municipal wastewater treatment plants (WWTPs) due to the durability and frequent use of synthetic polymers. Recently published research reports point to WWTPs as possible sources of microplastics polluting water systems. On the other hand, the researchers could not conclusively confirm the relationship between WWTPs and microplastic pollution found in rivers. There is an ongoing debate as to whether discharged effluents significantly contribute to microplastic accumulation, there is a lack of certainty about how such pollutants operate during the transport processes of wastewater treatment plants.
Both environmental scientists and plant design engineers will benefit from an in-depth understanding of the transport routes of microplastics and their accumulation during wastewater treatment processes. A comprehensive study can help improve and expand existing treatment plant processes to deal with and eliminate this type of pollutant. The exact origin of microplastics is difficult to pinpoint due to their fragmented nature, small size, and variable source. However, the disposal of plastics in the immediate environment must be addressed in a global initiative even before a full environmental risk assessment.
Specifically, the presence of microplastics in the environment, MMPs with extremely high concentrations in certain regions, and the certainty that these concentrations will continue to rise is sufficient to justify a global effort. The main sources of microplastics should be questioned and analyzed with some methodologies to assess their capacity to problematize water resources in urban environments as well as to determine their impact on the environment. The presence of microplastics in the environment, MMPs with extremely high concentrations in certain regions, and the certainty that these concentrations will continue to rise is sufficient to justify a global effort.
The presence of microplastics in the environment, MMPs with extremely high concentrations in certain regions, and the certainty that these concentrations will continue to rise is sufficient to justify a global effort.
Origin and Characterization of Microplastics
According to the National Oceanic and Atmospheric Administration (NOAA) from the U.S. Department of Commerce, plastic is the most common type of marine debris found in the ocean and the Great Lakes (Ocean). Its presence in aquatic environments, including beaches, ocean surface waters, deep-sea sediments, freshwater lakes and tributaries, has been investigated in recent decades. It is a result of the increased production of plastic materials and the many gaps in their proper disposal; has become a global problem.
According to the literature, the amount of plastic entering the ocean has been increasing rapidly over the years. Currently, between 0.48 and 1.27 million tons of plastic waste enters the ocean each year, and this number is expected to double in the next 10 years. These materials are suitable for many industrial applications due to the presence of stable carbon-hydrogen bonds, but also make them resistant to degradation in the environment and therefore tend to accumulate over time.
There is not much consensus among the authors on the definition of microplastics, but in general they can be called synthetic organic polymer particles with a size less than 5 mm. Many published studies refer to microplastics as plastic particles or debris less than 5 mm in length, but there is no consensus on the lower limit. Some researchers adopt a 0.5 or 1 mm boundary between macro or meso plastic and micro plastic.
Most of the published data refer to plastic particles ranging from 1 to 5 mm. Researchers Ballent et al. recognized as three categories of microplastics: fibers, fragments, and spherical deposits. Common plastic polymers include polypropylene (PP), polyethylene (PE), low density polyethylene (LDPE), and polyacrylates. There have been many studies investigating the existence of plastic materials in different aquatic environments. However, some have focused on microbeads, the primary microplastics of spherical shape.
These are mostly used in healthcare and personal care products, and others work on the broader range of materials classified as microplastics, including primary and secondary microplastics. Primary microplastics refer to microparticles produced on the aforementioned scale, and secondary microplastics are products of degradation of larger plastic material by mechanical or photooxidative means. The lack of standardization causes difficulties in comparing results and discussing possible solutions to this environmental problem.
Primary microplastics include particles used in exfoliating personal care products such as facial cleansers and moisturizers, shampoos, cosmetics, and shaving products. Most of the microbeads in these products are composed of polyethylene (PE) and polypropylene (PP) and are used for emulsion stabilization, viscosity regulation and skin care. After use, these products are washed down the sewer and the microplastics are transported via wastewater to municipal wastewater treatment plants, where they can eventually reach the environment. Primary microplastics also include industrial abrasives or “cleaners” used to clean surfaces, plastic powders used in modeling, particles used in drilling fluids for oil and gas exploration, as well as raw materials used for plastics manufacturing in many industrial applications.
Because secondary microplastics are produced to break down larger plastic materials, there are many sources that can contribute to their presence in the environment. According to the study by Duis and Corrs, 75–90% of the plastic found in the aquatic environment comes from land-based sources and 10–25% from ocean-based sources. Regarding land-based sources, they hypothesized that the most important route of secondary microplastics to the environment is loss from improper management of landfills and waste collection. There are also ways related to the actions of natural events (such as hurricanes, tsunamis and strong seas), agricultural activities, the use of synthetic textiles and other different human activities.
In 2014, Desforges and colleagues documented the abundance, composition, and distribution of microplastics off the coast of the northeastern Pacific Ocean and British Columbia. Considering the fibers and their fragments, a concentration range 3 ranging from 8 to 9200 particles per m was observed. Lower concentrations have been observed in offshore Pacific waters, and higher concentrations have been noted near shore with the widespread presence of fiber. According to this research, materials found near urban areas likely come from land-based sources. In certain areas, the material has been found to consist of debris trapped and condensed by natural ocean activity.
A recent study by Ballent and colleagues investigated the presence of microplastics on the Canadian Lake Ontario shoreline and evaluated its abundance and distribution pattern in three accumulation zones: nearshore, flank, and beaches. The impact of microplastic pollution on benthic ecosystems and on the food chain was also analyzed.
Lake Ontario and St. Sampling sites by depositional environment and instrument type where microplastics in sediments in the Lawrence River were analyzed. The watershed borders directly on Lake Ontario and St. It shows the regions flowing into the Lawrence River. In this particular study, the material was counted and divided into three categories: fibers, fragments, and spherical beads. Many factors have been shown to be determinative in the distribution of microplastics. This aquatic environment is associated with highly urbanized and industrialized areas, with the morphology of shorelines, variations in topography, etc. It includes the fact that it is surrounded. In addition, the density and shape of microplastic particles can also affect dispersion patterns in Lake Ontario, according to the researchers.
Although the polymers from which microplastics are made (such as PE and PP) have a lower density than water, the material was found in the sediment and can be attributed to the increase in the net density of microplastic particles by biofouling, adsorption. Natural substances on the surface, inorganic fillers during manufacture and fecal express. Regarding the shape of the material collected from Lake Ontario, it was found that there were more fibers in the sediments and more microbeads in the surface water.