Seasonal and spatial distribution of microplastics in sediments by FTIR imaging throughout a continuum lake - lagoon- beach from the Tunisian coast

Identification and morphological characterization of different types of plastic microparticles

The knowledge of the polymeric composition of microplastics (MPs) is interesting because offers useful information on the resistance, durability, and degradability of these materials, also allowing progress in the control of this contamination. However, there is currently a lack of reliable standardized methods for the identification, and characterization of the plastic microparticles. This work uses different techniques in a complementary manner for the identification, and characterization of MPs that more frequently are found in the environment. A total of 10 types of plastics were collected (polystyrene (PS), polyethylene terephthalate (PETE), polyethylene (PE), high- and low-density polyethylene (HDPE and LDPE, respectively), polyvinyl chloride (PVC), polypropylene (PP), polytetrafluoroethylene (PTFE), Polyamide (PA, Nylon 6,6) and poly-carbonate (PC)) and their chemical identification were analyzed by reflectance-attenuated infrared (FTIR-ATR). Furthermore, the samples were observed using light microscopy, and scan-ning electron microscopy (SEM). Also, staining with 12 different dyes was performed to improve the identification of microplastics. The results of this study revealed that PETE, PE, HDPE and LDPE, whose SEM images exhibited smoothness and flat uniformity of their surface, were not (or less) susceptible to adsorb staining solutions while PP, PA, PVC, and PTFE, were capable of adsorbing the dye solutions.

Microplastics pollution in the Surma River, Bangladesh: A rising hazard to upstream water quality and aquatic life

The ecological health of freshwater rivers is deteriorating globally due to careless human activities, for instance, the emission of plastic garbage into the river. The current research was the first assessment of microplastics (MPs) pollution in water, sediment, and representative organisms (fish, crustacean, and bivalve) from the Surma River. Water, sediment, and organisms were sampled from six river sites (Site 1: Charkhai; Site 2: Golapganj; Site 3: Alampur; Site 4: Kazir Bazar; Site 5: Kanishail and Site 6: Lamakazi), and major water quality parameters were recorded during sampling. Thereafter, MPs in water, sediment, and organism samples were extracted, and then microscopically examined to categorize selected MPs types. The abundance of MPs, as well as size, and color distribution, were estimated. Polymer types were analyzed by ATR-FTIR, the color loss of MPs was recorded, the Pollution Load Index (PLI) was calculated, and the relationship between MPs and water quality parameters was analyzed. Sites 4 and 5 had comparatively poorer water quality than other sites. Microplastic fibers, fragments, and microbeads were consistently observed in water, sediment, and organisms. A substantial range of MPs in water, sediment, and organisms (37.33-686.67 items/L, 0.89-15.12 items/g, and 0.66-48.93 items/g, respectively) was recorded. There was a diverse color range, and MPs of <200 μm were prevalent in sampling areas. Six polymer types were identified by ATR-FTIR, namely Polyethylene (PE), Polyamide (PA), Polypropylene (PP), Cellulose acetate (CA), Polyethylene terephthalate (PET), and Polystyrene (PS), where PE (41%) was recognized as highly abundant. The highest PLI was documented in Site 4 followed by Site 5 both in water and sediment. Likewise, Sites 4 and 5 were substantially different from other study areas according to PCA. Overall, the pervasiveness of MPs was evident in the Surma River, which requires further attention and prompt actions.

Comparison of ATR-FTIR and NIR spectroscopy for identification of microplastics in biosolids

Biosolids are considered a potentially major input of microplastics (MPs) to agricultural soils. Our study aims to identify the polymeric origin of MPs extracted from biosolid samples by comparing their Attenuated Total Reflection (ATR) - Fourier-transform infrared (FTIR) spectra with the corresponding near-infrared (NIR) spectra. The reflectance spectra were preprocessed by Savitzky-Golay (SG), first derivative (FD) and compared with analogous spectra acquired on a set of fifty-two selected commercial plastic (SCP) materials collected from readily available products. According to the results portrayed in radar chart and built from both ATR-FTIR and NIR spectral datasets, the MPs showed high correlations with polymers such as polyethylene (LDPE, HDPE), polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP) and polyamide (PA), determined in SCP samples. Each unknown MP sample had on average three or more links to several types of SCP, according to the correlation coefficients for each polymer ranging from 0.7 up to 1. The comparison analysis classified the majority of MPs as composed mainly by LDPE/HDPE, according to the top correlation coefficients (r > 0.90). PP and PET were better identified with NIR than ATR-FTIR. In contrast to ATR-FTIR analysis, NIR was unable to identify PS. Based on these results, the primary sources of MPs in the biosolids could be identified as discarded consumer packaging (containers, bags, bottles) and fibers from laundry, disposable glove, and cleaning cloth. SYNOPSIS: Microplastics (MPs) are considered contaminants of emerging concern. This study compares two simple and fast spectroscopy techniques to identify microplastics in the biosolid matrix.

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.

Binational survey using Mytilus galloprovincialis as a bioindicator of microplastic pollution: Insights into chemical analysis and potential risk on humans

Microplastic (MP) contamination in edible mussels has raised concerns due to their potential risk to human health. Aiming to provide valuable insights regarding the occurrence, physicochemical characteristics, and human health implications of MP contamination, in the present study, two nationwide surveys of MP contamination in mussels (Mytilus galloprovincialis) were conducted in Morocco and Tunisia. The results indicated that MP frequency ranged from 79 % to 100 % in all the analyzed samples. The highest MP density was detected in mussels from Morocco (gills "GI": 1.88 MPs/g ww^-1; digestive glands "DG": 0.92 MPs/g ww^-1) compared to mussels of Tunisia (GI: 1.47 MPs g^{- 1}; DG: 0.79 MPs g^{- 1}). No significant differences in MP density were found between the two organs (GI and DG) for both countries. MPs were predominantly blue and black fibers, and smaller than 1000 μm. Seven polymeric types were identified, of which PET, PP, and PE were the most abundant, accounting for >87 % of all samples. Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray (EDX) showed that most MPs have noticeable signs of weathering and inorganic components on their surface. The highest MP daily intake was found in children, while the lowest was estimated in women and men. Moreover, the annual dietary exposure of MPs through mussel consumption was estimated to be 1262.17 MPs/year in Morocco and 78.18 MPs/year in Tunisia. The potential risk assessment of MPs in mussels based on the polymer hazard index (PHI) was estimated in the high-risk levels, implying that MPs may pose health risks to humans. Overall, this research suggests that the consumption of mussels represents a considerable MP exposure route for the Moroccan and Tunisian populations.