Microplastic contamination in surface waters of the Küçükçekmece Lagoon, Marmara Sea (Turkey): Sources and areal distribution

The estuarine plastics menace: Insights into prevalence, characterization and polymeric risk assessment of microplastics in the Mahi River Estuary, Gujarat, India

Microplastic contamination (MP) has created havoc in all eco-systems especially the estuarine environment. The current investigation focused on assessing MP contamination along the Mahi River Estuary in Gujarat. Thirty sampling sites were selected along the estuary, spanning from Khambhat to Kamboi. Sediment samples were collected, processed, and analyzed for MPs. A total of 1371 MP particles were found, with an average abundance of 0.76 ± 0.25 MPs/g dry weight. The MP abundance was recorded at its highest and lowest at Chokari and Umraya, respectively. The MP abundance varied significantly between study sites. Fibers were reported dominantly, followed by fragments, films, and foam. Size-wise, 1-2 mm and <1 mm-sized MPs were prevalent. Various colours of MPs were also recorded. Polyethylene tetraphene, polyethylene, and polypropylene are the most abundant. Tourism, fishing activities, and a lack of waste management practices can be the possible reasons for MPs input in to estuarine habitats.

A review of plastic debris in the South American Atlantic Ocean coast - Distribution, characteristics, policies and legal aspects

The presence of plastics in the oceans has already become a pervasive phenomenon. Marine pollution by plastics surpasses the status of an emerging threat to become a well-established environmental problem, boosting research on this topic. However, despite many studies on the main seas and oceans, it is necessary to compile information on the South American Atlantic Ocean Coast to identify the lack of research and expand knowledge on marine plastic pollution in this region. Accordingly, this paper conducted an in-depth review of monitoring methods, sampling, and identification of macroplastics and microplastics (MPs) in water, sediments, and biota, including information on legal requirements from different countries as well as non-governmental initiatives. Brazil was the country with the highest number of published papers, followed by Argentina. MPs accounted for 75 % of the papers selected, with blue microfibers being the most common morphology, whereas PE and PP were the most abundant polymers. Also, a lack of standardization in the methodologies used was identified; however, the sites with the highest concentrations of MPs were the Bahía Blanca Estuary (Argentina), Guanabara Bay (Brazil), and Todos os Santos Bay (Brazil), regardless of the method applied. Regarding legislation, Uruguay and Argentina have the most advanced policies in the region against marine plastic pollution due to their emphasis on the life cycle and the national ban on certain single-use plastics. Therefore, considering its content, this expert review can be useful to assist researchers dealing with plastic pollution along the South American Atlantic Ocean Coast.

A characterization and an exposure risk assessment of microplastics in settled house floor dust in Istanbul, Turkey

The presence of microplastics in the indoor environment presents growing environmental and human health risks because of their physicochemical and toxic characteristics. Therefore, we aimed to isolate, identify, and characterize plastic debris in settled house floor dusts. This study is a rare study which assess the risks of plastic debris in settled house dust through multiple approaches including the estimated daily intake, pollution loading index, and polymer hazard index. The results indicated that polyethylene and polypropylene were the predominate polymer type of plastic debris in settled house dust with various shapes and colors. The risk assessment results also indicated the serious impact of microplastics in terms of extremely dangerous contamination as well as the fact that they present a polymer hazard. Results indicated that humans have a higher risk of exposure to microplastics via ingestion rather than inhalation. In addition, infants had a higher risk of potential intake compared to other age groups.

The new era hypothesis of coastal degradation: G(s) elements-gallium, gadolinium, and germanium

Mining of precious metals contributes to environmental pollution, especially in coastal areas, and conventional treatment methods are not always effective in removing metal contaminants. Some of these metals, such as gadolinium, germanium and gallium, have caused increasing concern worldwide, as little is known about their current concentrations in the aquatic environment and their biological significance. Therefore, the aim of this study was to determine for the first time the variation of average G(s) concentrations (gallium, gadolinium and germanium) by month/season/site differences along the coast of Istanbul. The ecological risk index was calculated to assess the contamination of seawater and to serve as a diagnostic tool for the mitigation of water pollution. The average distribution G(s) in seawater was in the following order: Ga > Gd > Ge. In addition, the potential ecological risk in the sampling areas ranged from 68 to 1049. Of the three metals, Gd poses the highest ecological risk (grade III). In the spatial distribution of ecological risks, Gd mainly originated from discharges from wastewater treatment plants. Therefore, the sources of the anthropogenic Gd anomaly in wastewater should be identified, as this indicates the possibility of human exposure to potentially harmful anthropogenic compounds.

Seasonal variation in plastic litter pollution in mangroves from two remote tropical estuaries of the Colombian Pacific

Mangroves in estuaries are highly vulnerable to the impacts of plastic litter pollution, because their location at river mouths and the high capacity of mangrove trees to trap plastic items. Here, we present new results on the abundance and characteristics of plastic litter during high and low rainfall seasons in mangrove waters and sediments of the Saija and Timbiqui River estuaries in the Colombian Pacific. In both estuaries, microplastics were the most common size (50-100 %), followed by mesoplastics (13-42 %) and macroplastics (0-8 %). Total abundances of plastic litter were higher during the high rainfall season (0.17-0.53 items/m-3 in surface waters and 764-832 items/m-2 in sediments), with a moderately positive relationship between plastic abundances recorded in both environmental matrices. The most common microplastics were foams and fragments. Continuous research and monitoring are required for a better understanding and management of these ecosystems and their threats.

Kıyı Lagün Sedimentlerinde Mikroplastiklerin Oluşumları ve Mekansal Dağılımları: Küçükçekmece Lagünü Örneği

Nehir, haliç ve lagünler, karasal ve deniz ekosistemleri arasında bağlantıyı sağlarken, tıpkı diğer kirleticilerde olduğu gibi sediment yapılarında da mikroplastik kirliliği hakkında kapsamlı bir profil ortaya koymaktadır. Bu çalışmada, Küçükçekmece Lagünü’nün üç farklı sucul alanından (deniz, kanal ve göl) alınan sediment örneklerinde mikroplastik bolluğu ve karakterizasyonunun belirlenmesi amaçlanmıştır. Bu kapsamda, lagünde belirlenen 5 istasyondan 12 aylık (Mart 2019 – Şubat 2020) sediment örnekleri alınmıştır. Mikroplastik ön işlemlerine tabi tutulan sediment örneklerinde, stereomikroskop ile mikroplastik bolluğu sayımı ve kategorizasyonu (boyut, tip ve renk) yapılmıştır. Ortalama mikroplastik bolluğu 2922,32±517,35 MP/kg olarak belirlenmiş olup, tespit edilen ortalama mikroplastik bolluğu değeri, ülkemizde daha önce yapılmış benzer çalışmalara kıyasla 2,4 kat daha yüksek bulunmuştur. Liflerin (%59) baskın mikroplastik tipi olduğu, baskın mikroplastik renginin siyah (%42) olduğu ve MP boyutlarının %50’sinin 1-100 μm arasında olduğu belirlenmiştir. Mevsimsel mikroplastik dağılımı irdelendiğinde ise, en yüksek bolluk değerlerinin yağışlı sezon olan kış aylarında olduğu tespit edilmiştir. Çalışma alanında en yüksek ortalama mikroplastik bolluğuna sahip L1 istasyonu, Küçükçekmece Lagünü Bağlantı Alanı temsil etmekte olup, lagündeki tüm antropojenik baskıların hissedildiği istasyon olarak ortaya çıkmaktadır. Bu çalışma, dünyanın diğer bölgelerindeki benzer sediment alanları için mikroplastik bolluğu ve dağılımı hakkında temsili veriler sağlamayı amaçlamaktadır.

Dynamic characteristics of microplastics under tidal influence and potential indirect monitoring methods

Rivers are an important channel for the transport of microplastics from inland areas to the ocean. It is of great significance to explore the dynamic changes in microplastic pollution characteristics under tidal fluctuations to understand the exchange of microplastics between rivers and oceans. In this study, the occurrence of microplastics in typical tidal channels in the lower reaches of the Dong River was investigated during the wet and dry weather seasons, and high frequency continuous dynamic monitoring of microplastics was carried out in a typical tidal cross section during a tidal cycle. The abundances of microplastics during wet and dry weather seasons were 3.97-102.87 ± 28.63 item/m³ and 5.43-56.43 ± 14.32 item/m³, respectively. The microplastics generally exhibited a fluctuating growth pattern, with low contents in the upstream area and high contents in the downstream area, and the abundance of microplastics differed greatly in the different functional zones. The dynamic monitoring results showed that the abundance of microplastics was clearly affected by the tides, in that it increased during the flood tide and decreased during the ebb tide, with abundances ranging from 11.15 to 95.26 item/m³. In addition, there was a significant linear relationship between the abundance of microplastics and flow in the typical tidal cross section. The relationship between the response of microplastic pollution characteristics and tides combined with local hydrometeorological factors may be a potentially effective real-time monitoring method for assessing microplastic pollution indirectly.

Microplastics in water systems: A review of their impacts on the environment and their potential hazards

Microplastics, the microscopic plastics, are fragments of any type of plastic that are being produced today as plastic waste originating from anthropogenic activities. Such microplastics are discharged into the environment, and they enter back into the human body through different means. The microplastics spread in the environment due to environmental factors and the inherent properties of microplastics, such as density, hydrophobicity, and recalcitrance, and then eventually enter the water environment. In this study, to better understand the behavior of microplastics in the water environment, an extensive literature review was conducted on the occurrence of microplastics in aquatic environments categorized by seawater, wastewater, and freshwater. We summarized the abundance and distribution of microplastics in the water environment and studied the environmental factors affecting them in detail. In addition, focusing on the sampling and pretreatment processes that can limit the analysis results of microplastics, we discussed in depth the sampling methods, density separation, and organic matter digestion methods for each water environment. Finally, the potential hazards posed by the behavior of aging microplastics, such as adsorption of pollutants or ingestion by aquatic organisms, due to exposure to the environment were also investigated.

Plastic waste in sandy beaches and surface water in Thanh Hoa, Vietnam: abundance, characterization, and sources

The occurrence and characterization of marine debris on beaches bring opportunities to track back the anthropogenic activities around shorelines as well as aid in waste management and control. In this study, the three largest beaches in Thanh Hoa (Vietnam) were examined for plastic waste, including macroplastics (≥ 5 mm) on sandy beaches and microplastics (MPs) (< 5 mm) in surface water. Among 3803 items collected on the beaches, plastic waste accounted for more than 98%. The majority of the plastic wastes found on these beaches were derived from fishing boats and food preservation foam packaging. The FT-IR data indicated that the macroplastics comprised 77% polystyrene, 17% polypropylene, and 6% high-density polyethylene, while MPs discovered in surface water included other forms of plastics such as polyethylene- acrylate, styrene/butadiene rubber gasket, ethylene/propylene copolymer, and zein purified. FT-IR data demonstrated that MPs might also be originated from automobile tire wear, the air, and skincare products, besides being degraded from macroplastics. The highest abundance of MPs was 44.1 items/m³ at Hai Tien beach, while the lowest was 15.5 items/m³ at Sam Son beach. The results showed that fragment form was the most frequent MP shape, accounting for 61.4 ± 14.3% of total MPs. MPs with a diameter smaller than 500 μm accounted for 70.2 ± 7.6% of all MPs. According to our research, MPs were transformed, transported, and accumulated due to anthropogenic activities and environmental processes. This study provided a comprehensive knowledge of plastic waste, essential in devising long-term development strategies in these locations.

Evaluation of Istanbul from the environmental components' perspective: what has changed during the pandemic?

This study aims to determine the 1-year change over the pandemic period in Istanbul, the megacity with the highest population in Turkey, based on environmental components. Among the environmental topics, water consumption habits, changes in air quality, changes due to noise elements, and most importantly, the changes in usage habits of disposable plastic materials that directly affect health have been revealed. The results obtained showed that, in Istanbul, 8.1 × 10⁸ gloves should be considered waste, and considering the population living in districts along coastal areas, the number of waste masks that are likely to end up in the sea was 325.648 pieces/day. The results of the air quality and noise measurements during the pandemic showed that reductions in parallel with human activities were recorded with the lockdown effect. The average noise values of the districts along both sides of the Bosporus, where urbanization is concentrated, were between 50 and 59 dB. The precautions taken during the pandemic have had an effective role in reducing air pollution in Istanbul. In the measurements, the parameters with effective reductions were PM₁₀ (7-47%), PM_2.5 (13-48%), NO₂ (13-38%), and SO₂ (10-56%). As a result, Istanbul's year of changes during the pandemic period, in terms of water, air, noise, and solid plastic wastes, which are the most important components of the environment, is presented.

Occurrence, sources and environmental risk assessment of pharmaceuticals in the Sea of Marmara, Turkey

In the present study, the occurrence and spatial distribution of selected eleven pharmaceuticals were investigated in the Sea of Marmara, Turkey. Samples were collected from different depths of the nine stations in April and October 2019. Pharmaceuticals were analyzed using liquid-liquid and solid-phase extraction (SPE) methods followed by high-performance liquid chromatography (HPLC). All target pharmaceutical compounds were detected at least once in the study area. Gemfibrozil, which belongs to the lipid regulatory group, was the most frequently detected in seawater at high concentrations (<0.016-9.71 μg/L). Ibuprofen (<0.015-2.13 μg/L) and 17α-ethynylestradiol (<0.010-3.55 μg/L) were identified as the other frequently detected pharmaceuticals. In addition, the presence of these selected compounds in April was higher than in October. According to the risk assessment results, naproxen, diclofenac, clofibric acid, gemfibrozil, 17β-estradiol, and 17α-ethynylestradiol represent a high risk to aquatic organisms in the Sea of Marmara. These findings underline the importance of continued monitoring of these compounds as relevant organic contaminants in the study area to take appropriate measures to protect the ecosystem and, ultimately, human health.

A review of plastic pollution in aquatic ecosystems of Turkey

Turkey is one of the major plastic pollution sources in the Mediterranean and the Black Sea. This review summarizes present information, data, and legislation on plastic pollution in Turkish aquatic ecosystems. According to results derived from reviewed studies, both macro- and microplastic pollutions were documented in Turkish aquatic ecosystems. Most of the studies on plastic pollution in Turkish waters were performed in the marine environment while only four were conducted in freshwater environments. Spatially, the majority of these studies, which were on levels in the marine environment, were conducted on the northeastern Mediterranean coasts of Turkey, especially Iskenderun and Mersin Bays. Additional studies were carried out on either the ingestion/presence/impact of microplastics by/to aquatic organisms or the entanglement of marine organisms in plastics. There were also studies assessing the microplastic content of commercial salt, and another has reported microplastic presence in traditional stuffed mussels sold in Turkish streets. Some studies were conducted on microplastic presence and/or their removal in wastewater treatment plants in Mersin, Adana, Mugla, and Istanbul cities. Macro- and microliter loading from a few Turkish rivers to the sea was also estimated. All these investigations indicate that Turkish aquatic environments have significant plastic pollution problems, which were also underlined by the legislative studies. The need for further studies in this field still exists, especially in freshwater environments.

Current status of microplastics pollution in the aquatic environment, interaction with other pollutants, and effects on aquatic organisms

Microplastics, as emerging pollutants, have received great attention in the past few decades due to its adverse effects on the environment. Microplastics are ubiquitous in the atmosphere, soil, and water bodies, and mostly reported in aqueous environment. This paper summarizes the abundance and types of microplastics in different aqueous environments and discusses the interactions of microplastics with other contaminants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), antibiotics, and heavy metals. The toxicity of microplastics to aquatic organisms and microorganisms is addressed. Particularly, the combined toxic effects of microplastics and other pollutants are discussed, demonstrating either synergetic or antagonistic effects. Future prospectives should be focused on the characterization of different types and shapes of microplastics, the standardization of microplastic units, exploring the interaction and toxicity of microplastics with other pollutants, and the degradation of microplastics, for a better understanding of the ecological risks of microplastics.

Temporal changes in water quality index of polluted lagoon ecosystems: a case study on the Küçükçekmece Lagoon

For lagoon ecosystems, it is crucial to conduct long-term monitoring of the water quality parameters and predict their potential effects. This study aimed to analyse the changes in the water quality index (WQI) profile of the Küçükçekmece Lagoon in Istanbul, Turkey, which has been facing ecological problems, and determine the increased stress in aquatic biota due to different pollutants. To begin, the sampling data were obtained from the Küçükçekmece Lagoon throughout a 13-month period in 2018-2019. The estimated WQI values were compared to studies conducted in the same study area within the last 20 years. Then, the relationship between the acute toxicity of surface waters, which is the recommended parameter for analyses in this field, and the WQI was determined. Although the water class has generally been defined as 'good quality' (WQI = 86), the study found it to be 'very poor quality' (WQI = 112 and 97, respectively) with bloom events and toxicity effects in spring and autumn. When compared with the WQIs calculated from the last 20 years, a significant improvement in water quality at station L1 (decreased from WQI = 288 to WQI = 161) and a deterioration at station L2 (increased from WQI = 71 to WQI = 100) were observed. The acute toxicity and water quality classes were highly positively correlated (r = 0.773; p < 0.01). The method, used for the first time in this area, was able to interpret the acute toxicity of lagoon surface waters and WQI data. Furthermore, the use of this method was recommended for rapid analysis of the increased stress in aquatic biota.

Evaluation of microplastics removal efficiency at a wastewater treatment plant discharging to the Sea of Marmara

Levels, composition and fate of microplastics (MPs) were investigated along different compartments of a secondary wastewater treatment plant (WWTP) with nutrient removal on the northern Sea of Marmara coast (Istanbul, Turkey). When all samples were combined, fibers were found to be the most dominant particles, followed by hard fragments. 500-1000 μm and 1000-2000 μm were the most common size ranges for wastewater and sludge, respectively. Rate of removal differed for sizes and shapes of the particles combined. Hard fragments of <500 μm and fibers of size ranges 250-500 μm and 1000-2000 μm were more successfully removed within the WWTP. Size averages increased throughout the WWTP units. 84.6-93.0% removal was achieved for grab and 3-hr composite samples. Despite the high removal rates of the WWTP, 2,934 × 10⁶ microplastic particles/d were released in the effluent to the Sea of Marmara. Our results show that the Ambarlı WWTP considerably contributes to microplastics contamination in the Sea of Marmara since the plant has a high operating capacity.

Distribution and characteristics of microplastics in the basin of Chishui River in Renhuai, China

As an emerging pollutant, microplastics widely exist in rivers all over the world. Due to the differences of economic development, economic structure and population in different regions, the abundance of microplastics in rivers is different. In those areas where agriculture is developed, the content of film microplastics is more, while in densely populated areas, the content of fibrous microplastics is more. Taking Renhuai Basin of Chishui River as the research object, the pollution characteristics and current situation of microplastics in the basin were analyzed, and the contamination risk of microplastics was evaluated. The abundance of microplastics in Renhuai basin of Chishui River ranges from 1.77 to 14.33 items/L. The main forms of microplastics were fibrous (59.4%), white (including transparent) (41.3%) and polychromatic (44.1%). The particle size of microplastics was mainly 500- 1000 μm (63.9%). According to the assessment, the risk of microplastics in the basin is 111.79, which is a secondary risk area. This study can provide a further reference for understanding the pollution characteristics of microplastics in rivers.