Seasonal Variation Of Microplastics Research Articles

Seasonal variation of microplastics in tropical mangrove waters of South-western India

The current study investigates the seasonal variations in microplastic (MP) contamination, specifically those ranging in size from 0.1 mm to 5 mm, within the tropical mangroves of Kota, South-western India. Mean concentrations ( ± standard deviation) of 1.42 ± 0.92 MPs/L (post-monsoon), 0.62 ± 0.38 MPs/L (pre-monsoon), and 0.19 ± 0.08 MPs/L (monsoon) were observed. Fibers emerged as the most abundant category across all samples, with a dominant size fraction of less than 1 mm. Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) analyses identified various polymer types, including polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polystyrene (PS), and polyvinyl chloride (PVC). Potential sources of microplastic contamination in the region could be ascribed to tourism, marine product-related industries, prawn farming, and residents. The findings of this study offer crucial insights into the seasonal fluctuations of microplastic contamination in the Kota mangrove ecosystem.

Abundance, characteristics and seasonal variation of microplastics in a domestic sewage treatment plant in Nanjing, China

Sewage treatment plants are a potential route of microplastics (MPs) into the environment, hence it's urgent to investigate MPs in wastewater and sludge through lengthy sampling campaigns. In this study, a sewage treatment plant in Nanjing, China was chosen, seasonal variation of MPs in influent was analyzed by collecting samples during a 12-month sampling campaign (at monthly intervals over a one-year period). Abundance and characteristic of MPs from different treatment stages were also investigated. The results showed that there was a seasonal variation in the amount of MPs in influent and the abundance of MPs was significantly greater in summer than other seasons. The average MPs abundance was 41.0 items/L and 3.0 items/L in influent and effluent, with a total 92.6 % removal rate. Overall, 125–355 μm were the main size in each treatment section, with fibers dominant shape and transparent main color. Additionally, the primary polymer compositions of MPs were polyethylene (PE) and polypropylene (PP) using micro-Roman spectroscopy. The daily MPs emission from effluent and sludge was estimated to be 300 million and 1274 million items/d, demonstrating that the sewage treatment plant is an important source of MPs into the environment despite the high removal rate of MPs.

Characteristics and seasonal variation of microplastics in the wastewater treatment plant: The case of Bursa deep sea discharge

Microplastics (MPs) are an emerging pollutant that can be detected in all ecosystems, especially aquatic ecosystems. Wastewater treatment plants (WWTPs) are important point sources of MP release into the sea. In this study, the characteristics of MPs in wastewater and sludge samples taken from different units of WWTP in Bursa-Gemlik district for 12 months were investigated. Wastewater and sludge samples collected from 7 different points were classified as size, shape, color, and counted. The amount of MP in the influent and effluent of the WWTP, respectively; 107.1 ± 40.2 MP/L and 4.1 ± 1.1 MP/L. Although the MP removal efficiency of the WWTP is 96.17 %, approximately 74,825,000 MP is discharged into the Marmara Sea every day. The amount of MP in the sludge is 14.3 ± 7.1 MP/g. The amount of MP accumulated in 22tons of waste sludge formed daily in WWTP was calculated as 314,600,000 MP, and the annual accumulated amount was calculated as approximately 1.15 × 1011 MP. The MPs in the WWTP were mainly 1–0.5 mm in size. Fibers were the dominant MP shape in both the wastewater and sludge samples. Black and transparent were the dominant MP colors. Seven different polymer types of MPs were detected, which were mainly types of polyethylene, polypropylene, and polyethylene terephthalate. Despite the high removal efficiency in the investigated WWTP, it has been shown that it acts as an important source of MPs to the sea ecosystem due to the high discharge rates.

Effect of monsoon on microplastic bioavailability and ingestion by zooplankton in tropical coastal waters of Sabah

Plankton seasonality in tropical coastal waters is becoming more apparent as a result of monsoon-driven changes in environmental conditions, but research on the monsoonal variation of microplastics (MP) is still limited. We examined the monsoonal variation of MP in the water column and their ingestion by zooplankton in Sepanggar Bay, Sabah, Malaysia. MP concentrations were significantly higher during the Southwest monsoon whereas MP ingestions showed no monsoonal difference across major zooplankton taxa. Canonical Correspondence Analysis (CCA) and Generalized Additive Models (GAM) indicate that MP concentrations were driven by changes in rainfall and salinity while MP bioavailability to zooplankton was consistent regardless of monsoon. MP ingestion increased progressively up the planktonic food chain, and bioavailability of fibers and small-sized MP of high-density polymers to zooplankton was proportionately higher. Distinct changes in the MP concentration relative to the monsoons provide new insights into the seasonal variation of MP in tropical coastal ecosystems.

Spatial, seasonal and ecological risk assessment of microplastics in sediment and surface water along the Thoothukudi, south Tamil Nadu, south east India.

Microplastics are a widespread environmental contaminant that raises serious concern for aquatic organisms. Hence, the present study was conducted to investigate the spatial and seasonal variation of microplastics, their characteristics, polymer types and the risk assessment caused by the microplastics in six sampling sites along the Thoothukudi region. The average microplastic abundance ranged from 32 ± 26 to 232 ± 229 items/kg and 54 ± 41 to 619 ± 377 items/l in sediment and surface water, respectively, and they exhibited a significant spatial difference among the sampling sites. The microplastic abundance also showed a significant difference among the seasons with the monsoon significantly recording the highest mean microplastic abundance in sediment (160 ± 130 items/kg) and surface water (454 ± 374 items/l). In sediment and surface water, fragment (sediment: 52.72%, surface water: 40.89%), 0.5-1mm (sediment: 43.96%, surface water: 31.11%) and blue-coloured (sediment: 52.33%, surface water: 41.85%) microplastics were dominant with no significant difference both spatially and seasonally. Polyethylene, the dominant polymer, was observed in both the sediment and surface water, accounting for about 47.58% and 49.83%, respectively, and it showed no significant difference among the selected sites. This signifies that they are homogenously distributed along the coast and further suggests that these particles persisted in the sediment and surface water for a longer period of time. The results of the polymer hazard index show that the sediment (PHI = 1181.63) and surface water (PHI = 1018.66) were severely contaminated (hazard level V) with microplastic polymers such as PE, PP, PS, PET and PA. It was also found that the degree of the microplastic contamination in sediment (PLI = 3.57) and surface water (PLI = 3.84) was lower (hazard level I). The overall risk index (RI) for sediment (253.48) and surface water (444.74) falls under the higher risk category. From the correlation analysis, a significantly positive relationship was observed between microplastics in sediment and surface water based on each classification (abundance, shape, size, colour and polymer). This suggests that microplastics rejoin the water column from the sediment through resuspension, which occurs due to the circulation, tides and sedimentation rate. This might be the reason for the higher microplastic abundance in the surface water than in the sediment. As a result, proper management measures to reduce plastic waste disposal in the marine environment should be implemented to lessen the effects of microplastics on marine biota and on public health.

Seasonal variation in microplastics and zooplankton abundances and characteristics: The ecological vulnerability of an oceanic island system

The ingestion of microplastics (MPs - plastic particles <5 mm) by planktivorous organisms represents a significant threat to marine food webs. To investigate how seasonality might affect plastic intake in oceanic islands' ecosystems, relative abundances and composition of MPs and mesozooplankton samples collected off Madeira Island (NE Atlantic) between February 2019 and January 2020 were analysed. MPs were found in all samples, with fibres accounting for 89 % of the particles. MPs and zooplankton mean abundance was 0.262 items/m3 and 18.137 individuals/m3, respectively. Their monthly variations follow the seasonal fluctuation of environmental parameters, such as currents, chlorophyll-a concentration, sea surface temperature and precipitation intensity. A higher MPs/zooplankton ratio was recorded in the warm season (May-Oct), reaching 0.068 items/individual when considering large-sized particles (1000–5000 μm). This is the first study to assess the seasonal variability of MPs in an oceanic island system providing essential information respecting its ecological impact in pelagic environments.

Urban natural wetland as a sink for microplastics: A case from Lalu Wetland in Tibet, China

Microplastics have been reported in a wide range of aquatic habitats. The wetlands are considered to be important roles in microplastic migration in water bodies. Nevertheless, knowledge about the occurrence and fate of microplastics in urban natural wetland is still limited for us to better understand how they become a sink of microplastics. In this study, the distribution and characteristics of microplastics in surface water, surface sediments, and sediment cores of the Lalu Wetland watershed, China's highest urban wetland, were investigated in August 2020 and January 2021. The abundances of microplastics in the surface water were 0.06–3.05 MPs/L. Microplastic abundance in the surface sediment and sediment core was 0.01–1.10 MPs/g and 0–16.23 MPs/g, respectively. The abundance of microplastics in the water was significantly lower in the wetland than that in the channel in the watershed. Comparing the wetland inlet and outlet water, the microplastic interception rates were 53% in January and 95% in August. The characteristics and seasonal variation of microplastics in the Lalu Wetland implied that urban natural wetlands were good at intercepting microplastics, and vegetation growth might play an important role on the interception of microplastics by the wetland. The increasing of microplastics from bottom to top in the sediment cores of Lalu Wetland also indicated that the ecological risks of microplastics accumulation in sediments of urban natural wetland required further attention.

Occurrence and Seasonal Variation of Microplastics in the Effluent from Wastewater Treatment Plants in Qingdao, China

Wastewater treatment plants (WWTPs) are considered as one of the important sources of microplastics (MPs) in the marine environment. In this paper, the characteristics of MPs in the effluent discharged from five WWTPs in Qingdao, China, in winter and summer were analyzed. The results showed that only fibers and fragments were observed, with fibers as a dominant part. Rayon was the most domain polymer type, followed by Polyethylene terephthalate (PET) and chlorinated polyethylene (CPE). The average sizes of fiber MPs were 1010 ± 924 µm and 610 ± 691 µm in winter and summer, respectively. The contents of rayon were higher in summer than in winter. More small and transparent MPs were observed in summer. Rayon abundances ranged from 4.1 to 19.9 items/L and 33.3 to 116.7 items/L, with 12.3 ± 5.6 items/L and 67.6 ± 30.6 items/L as the average value in winter and in summer, respectively. The abundances of other polymer type MPs were 7.23~19.65 items/L with average value of 12.7 ± 4.7 items/L in winter and 12.0~20.0 items/L with 16.8 ± 4.7 items/L in summer. The daily emissions were estimated as 8.38 × 109~4.25 × 1010 items (9.2~27.8 kg) for rayon and 8.0 × 109~1.2 × 1010 items (7.6~5.3 kg) discharged for the other polymer type MPs from the five WWTPs. The results indicated that the seasonal variation of characteristics and emission of MPs in the effluent from WWTPs was mainly caused by increasing discharge of rayon, which may relate to people’s living habits and tourism activities.

Seasonal Variation in Microplastics and Zooplankton Traits: The Ecological Vulnerability of an Oceanic Island System

Seasonal Variation in Microplastics and Zooplankton Traits: The Ecological Vulnerability of an Oceanic Island System

Spatial and seasonal variation of microplastics and possible sources in the estuarine system from central west coast of India

The versatile use of various synthetic polymers, including plastics, generates a large volume of non-degradable waste, which is eventually responsible for forming microplastics (MPs) in aquatic environments. The present study describes the significant spatial and seasonal variation on the abundance of MPs and their physiochemical nature along the Mandovi-Zuari estuarine system of Goa, west coast of India. During the wet season (September), the average abundance of MPs was found relatively higher in water (0.107 particles/m3) and sediment (7314 particles/kg) than those found in the dry season (April) (0.099 particles/m3 in water and 4873 particles/kg in sediment). During the wet season, heavy rain and excessive riverine freshwater influx carry more terrestrial plastic debris in the estuarine system which causes higher averages MPs density in surface water and sediment. <300 μm sized particles and black colored MPs were predominant equally in water and sediment during both seasons. MPs of different shapes like fragments, fibres, films and beads accounted for most collected samples. The Micro-Fourier Transform Infrared Spectroscopy (μ-FTIR) based compositional analysis identified approximately 33 types of polymers, of which polyacrylamide (PAM), polyacetylene, polyamide (PA), polyvinyl pyrrolidone (PVP), polyvinyl chloride (PVC), and polyimide (PI) were abundant. Fragmentation of larger plastic particles due to mismanaged treated and untreated STPs and washing machine effluents are the primary sources of these MPs in the estuarine system. Moreover, these estuaries also receive a variety of domestic, industrial and other wastes from local cities, ports, and fishing jetties. Thus the present study enlightens the current distribution of MPs and their sources in the Mandovi-Zuari estuarine system and thus provides very useful information to the stakeholder and concerned departments for initiating the mitigation measures.

Distribution and Seasonal Variation of Microplastics in Tallo River, Makassar, Eastern Indonesia.

Attention towards microplastic (MP) pollution in various environments is increasing, but relatively little attention has been given to the freshwater-riverine environment. As the biggest city in the eastern Indonesia region, Makassar can be a potential source of MP pollution to its riverine area. This study aimed to determine the spatial trends, seasonal variation, and characteristics of MPs in the water and sediment of Tallo River, as the main river in Makassar. Water samples were collected using a neuston net and sediment samples were collected using a sediment corer. The samples collected contained MPs with an abundance ranging from 0.74 ± 0.46 to 3.41 ± 0.13 item/m3 and 16.67 ± 20.82 to 150 ± 36.06 item/kg for water and sediment samples, respectively. The microplastic abundance in the Tallo River was higher in the dry season and tended to increase towards the lower river segment. Fragments (47.80–86.03%) and lines (12.50–47.80%) were the predominant shapes, while blue (19.49–46.15%) and transparent (14.29–38.14%) were the most dominant color. Polyethylene and polypropylene were the common MP polymers found in the Tallo river. Actions to prevent MP pollution in the Makassar riverine area are needed before MP pollution becomes more severe in the future.

Effects of seasonal variation and resuspension on microplastics in river sediments

Although microplastics are an emerging pollutant of global concern, little is known about the environmental behavior of microplastic in sediments. This study investigated the occurrence and seasonal variation of microplastics in the sediments of Liangfeng River, China with a fluorescence staining method, and then explored the transfer of microplastics at the water and sediment interfaces during resuspension. The results showed that smaller microplastics were detected in the sediments, which were concentrated in the size range of 50–500 μm. Microplastic abundance in the sediments in the dry season were slightly higher than those from the rainy season, and the rainy season promotes the accumulation of smaller microplastics in the sediment along the river-flow direction but not for the dry season. The shape of microplastics were predominantly fibers, followed by fragments and films. Polyethylene was the most abundant polymer, accounting for more than 50% of the total. Microplastics in the surface sediment move both to the overlying water and deeper sediment during the disturbance process. Disturbance-induced resuspension and vertical transport have significant effects on small-sized microplastics (50–500 μm). Small-sized microplastics can potentially migrate and redistribute via resuspension at different temporal and spatial scales, as some extent of resuspension is occurring in most river systems, especially in urban areas with boat traffic.

The seasonal distribution characteristics of microplastics on bathing beaches along the coast of Qingdao, China

Microplastics pollution in nearshore marine environment has become increasingly prominent and has received widespread attention. As a major leisure and entertainment place in coastal cities, bathing beaches not only provide an environment for microplastics to enter the ocean, but also provide a place for the retention of microplastics. In this paper, the distribution, composition and seasonal variation of microplastics in seawater and sediments of six bathing beaches along the coast of Qingdao were studied. The results showed that the average abundance of microplastics in the sediments of the Qingdao bathing beach was 91.11 ± 26.76 items/m2 (13.77 ± 4.39 items/kg) in the winter and 147.78 ± 34.80 items/m2 (21.98 ± 5.97 items/kg) in the summer. The microplastic abundance in the seawater in the summer (average: 567.50 ± 101.06 items/m3) was significantly higher than that in the winter (average: 326.11 ± 49.03 items/m3, p < 0.05). The abundance of microplastics at the six bathing beaches increased from east to west, consistent with the transport direction of coastal currents. The microplastic abundance in the sediment of non-swimming zone of the bathing beach was significantly higher than that in swimming zone (p < 0.05), and the microplastic abundance in the seawater of the swimming zone was slightly higher than that of the non-swimming zone but with no significant difference (p > 0.05). To an extent, it can reflect the correlation between the abundance of microplastics and human recreational activities. The microplastics detected at the bathing beaches were mainly lines (80.5%) and fragments (7.9%) with a size range of 100 to 1000 μm. Rayon (41.8%) and polyethylene terephthalate (PET, 16.9%) were the main polymer types. The microplastic characteristics showed significant seasonal differences, more diversity in summer than in winter. These results emphasized that the distribution and movement of microplastics in bathing beaches were affected by seasons, human activities and coastal currents.

Seasonal variation and risk assessment of microplastics in surface water of the Manas River Basin, China

The ubiquity of microplastics in the environment has caused great influence to ecosystems and seriously threatened human health. To better understand the variation in microplastics in different seasons in an inland freshwater environment and determine the sources of microplastic pollution and its migration features, this study investigated the characteristics of microplastic pollution during dry (April) and wet (July) seasons in surface water of the Manas River Basin, China. The size, color, shape, area distribution and compound composition of microplastics were studied. Moreover, the risk of microplastic contamination was explored based on risk assessment models. The results demonstrated that the degree of pollution caused by microplastic abundance was minor in this study area. The average abundance of microplastics in April (17 ± 4 items/L) was higher than that in July (14 ± 2 items/L). The range in the abundance of microplastics in April and July were 22 ± 5–14 ± 3 items/L and 19 ± 2–10 ± 1 items/L, respectively. Highly hazardous polymers such as Polyvinyl chloride (PVC) and Polycarbonate (PC) have a significant impact on the results of the evaluation of the presence of microplastics. This study is an important reference for understanding the characteristics of the seasonal variation in microplastics in inland freshwater environments and has practical significance, as it will allow relevant agencies to accurately assess the pollution level of microplastics in different seasons. It is of practical significance to understand the sources and sinks of microplastics in inland freshwater environment.

Abundance, characteristics and seasonal variation of microplastics in Indian white shrimps (Fenneropenaeus indicus) from coastal waters off Cochin, Kerala, India

The microplastic contamination of seafood species is increasingly becoming a global concern due to its potential influence on food safety and human health. This study investigated the presence and seasonal variation of microplastics in a commercially important marine shrimp species, Fenneropenaeus indicus, from the coastal waters of Cochin, India. The soft tissues of 330 shrimps were examined over a period of 12 months, from March 2018 to February 2019. A total of 128 microplastics were detected, of which 83% were fibres. An average (mean ± SD) of 0.39 ± 0.6 microplastics/shrimp (0.04 ± 0.07 microplastics/g wet weight) was obtained from the shrimps sampled. Microplastic contamination was significantly higher in July–August (Monsoon season) compared with other months. This study reports microplastic contamination in F. indicus for the first time. Results also suggest that consumption of peeled but undeveined or whole dried white shrimps can be one of the ways of the human uptake of microplastics, especially during the monsoon season.

Various forms and deposition fluxes of microplastics identified in the coastal urban atmosphere

Pollution by microplastics has become a major global issue affecting the marine environment. However, there has been little research on microplastics in the atmosphere. Here, we study microplastics in precipitation samples collected in Yantai, a coastal city in Shandong Province, East China. This paper is the first report on the different shapes, deposition fluxes and seasonal variation in microplastics in the coastal urban atmospheric environment. The samples collected were pre-filtered using a set of stainless steel sieves with mesh sizes of 5 and 1 mm. Residues, such as insects and plant debris retained on a stainless steel sieve of mesh size 5 mm were discarded or archived. Residues retained on a stainless steel sieve of mesh size 1 mm were air-dried and placed under a stereomicroscope to select and count putative microplastics with different morphologies and different size fractions of 1−2, 2−3 and 3−5 mm. Samples that had passed through a mesh size of 1 mm were filtered again using a 5-μm pore size nitrocellulose filter for further microscopic observation and the selection and enumeration of smaller microplastics. Some of these samples containing organisms were digested with hydrogen peroxide (30%) to avoid interference during the observation and selection of the microplastics. Putative microplastics were identified using Fourier transform infrared spectroscopy. Four shape types of microplastics, namely fibers, fragments, films and foams were found in the atmospheric samples. The majority were fibers of different colors (white, black, red and transparent) that accounted for about 95% of the microplastics. Fragments accounted for about 4% and films and foams accounted for fewer than 1%. The main polymers were polyethylene terephthalate in the case of most of the fibers, polyvinyl chloride in the case of some fibers and films, polyethylene for the fragments, and polystyrene for the foams. Microplastics with sizes below 0.5 mm accounted for more than 50% throughout the year, followed by the size ranges 0.5−1 mm,1−2 mm and then 2−3 mm. Microplastics with size range of 3−5 mm appeared only in the spring samples at low abundance. In general, the amount of microplastics decreased dramatically with increasing particle size. The 100−300 μm size fraction formed the highest proportion of microplastics below 0.5 mm in size, accounting for about 62%, and those below 50 μm showed the lowest abundance. The annual site deposition flux of atmospheric microplastics attained a maximum of 1.46×105 n/(m2 a), that of the fibers up to 1.38×105 n/(m2 a), and those of the fragments, films and foams up to 6.29×103, 7.65×102 and 2.45×102 n/(m2 a), respectively. Deposition fluxes of different shape types ranged from 0.0 to 6.02×102 n/(m2 d), and the fibers were also the commonest of the four shape types. The deposition flux of microplastics showed some seasonal variation, being higher in the spring, summer and winter and lowest in the autumn. Based on the observation site (1.6 km from the coastline), the length of Yantai urban coastline (100 km) and the annual deposition flux in this study, it was estimated that the total number of microplastics deposited in the urban area was about 2.33×1013 particles, equivalent to about 0.9 to 1.4 tonnes. We suggest that atmospheric microplastics, through precipitation to land and sea, be a key source of microplastics in the coastal and oceanic environments. Moreover, a systematic study is urgently required in the future for a better understanding of pollution and precipitation of atmospheric microplastics and their environmental impact.