Iranian Journal of

Background and Objective: Recently, microplastics (MPs) have been found in the aquatic and terrestrial environments, air, and food. Other pollutants can be transported by MPs and pose a threat to the human, animal, and environment. Measurement and evaluation of microplastics can either increase knowledge about them or boost understanding of their possible harmful effects. However, no standard method has been established to measure microplastics and the measurement of microplastics has been done by various methods in different published studies. The aim of current study was to investigate different methods of measuring microplastics in water and wastewater environment and identifying the strengths and weaknesses of these methods.
Materials and Methods: The present review study was conducted during the winter 2021, by searching the papers cited in PubMed, Google Scholar, Web of Science, and Scopus databases using the keywords "Microplastic", "Water", "Drinking-water", "Wastewater", "Surface", "Bottled-water" and "Marine" and selecting articles published between 2015 and 2021 in reputable journals.
Results: The main stages of MPs measuring in various studies included sampling and sieving, pretreatment and digestion, density separation, counting and Identification of MPs by their chemical composition.
Conclusion: Digestion using H₂O₂, density separation using NaCl, counting by stereomicroscope, and Spectroscopy using FTIR and micro-RAMAN are the most widely used methods in the studies related to detecting MPs in water and wastewater environment. However, different methods of measuring and identifying microplastics have made comparing the results of studies difficult and it seems that efforts should be made to standardize these methods.

Background and Objective: Microplastic pollution due to its small size can be used by a wide range of marine organisms and accumulate mainly in their digestive system, as they have been found in the tissues of aquatic animals, including fish. Due to the nutritional importance of fish for humans, it is very important to check their contamination. The main purpose of this research is to investigate the presence of microplastics in skipjack tuna (Katsuwonus pelamis) in the Oman Sea.
Materials and Methods: 17 pieces of skipjack tuna were used. After the biometry, dissection and isolation of the digestive system of the fish, the digestion and extraction of microplastics were done using KOH solution. Identification and counting were also done by a stereomicroscope equipped with a digital camera. FTIR spectrophotometric analyses were performed to investigate the polymers.
Results: The total frequency and average frequency of microplastics are 331 particles and 19.4±7.3 particles per individual, respectively. String (64.35%) and pieces (28.7%) were the dominant forms in the samples. The highest color spectrum was assigned to red (28.7%) and the lowest to violet (1.51%). The largest number of identified microplastics had a size of 0.5-1 mm (53%). Analysis of particles by ATR-FTIR method showed that nylon polymer and polycarbonate were the dominant polymer particles.
Conclusion: Microplastics are present in all samples. The abundance of microplastics in water, sediments and contaminated bait makes them easily available and swallowed by fish, which is most likely the main reason for the presence of microplastics in fish.
 

Background and Objective: Given the concern about the presence of microplastics in the air and settled dust, and the lack of a standard approach for their detection, it is necessary to investigate the methods and techniques used to study this type of pollution in Iran. Therefore, this study aimed to systematically review the methods and techniques used for sampling, quantification, and characterization of microplastics in the air and settled dust in indoor and outdoor environments in Iran.
Materials and Methods: In this systematic review, the keywords Microplastic*, Air*, Atmosphere*, Dust, Indoor, Outdoor, Iran, and their corresponding Persian equivalents were searched until Dec 1, 2023, in Scopus, PubMed, Web of Science, Google Scholar, Magiran, and SID databases. Obtained articles from the databases were analyzed in order to find the eligible ones.
Results: Overall, 175 articles were found in the initial search, and after removing the duplicates and nonrelevant, 13 eligible articles were included in the study. In most of the studies, the samples were digested with H₂O₂, and the microplastics were mainly analyzed using a variety of microscopes and µRaman spectroscopy. The abundance of microplastics in the indoor environment was much higher than in the outdoor environment.
Conclusion: The results of this study showed that there is the required equipment for the sampling and analysis of microplastics in air and settled dust in Iran, and these pollutants have been detected in both indoor and outdoor environments.