Persian Gulf

Marine Environmental Research 159 (2020) 104961

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An assessment of microplastics threat to the marine environment: A short review in context of the Arabian/Persian Gulf S.M. Al-Salem *, Saif Uddin, F. Al-Yamani Environment & Life Sciences Research Centre, Kuwait Institute for Scientific Research (KISR), P.O. Box 24885, Safat, 13109, Kuwait

A R T I C L E I N F O

A B S T R A C T

Keywords: Microplastics Arabian/Persian Gulf Plastic waste Neuston net Pollution

Microplastics are recognised as a (persistent) pollutant and are believed to be ubiquitous in the marine envi­ ronment. The importance of this issue is evident from the large number of technical publications and research efforts within the past decade. However, the Arabian (Persian) Gulf region has few reported datasets in spite of being an area with excessive plastic use and a hefty generation rate of plastic solid waste. This communication aims at stimulating a discussion on this topic focusing on the available regional and international datasets, along with the environmental conditions that are likely to contribute to the disintegration and transport of the plastic debris rendering it as microplastic. This work also highlights some of the constraints in sampling techniques, identification methods, and the reported units of microplastics. Most studies employ neuston nets of variable dimensions that samples different thicknesses of surface water, which also posses a major constraint in stand­ ardising field sample collection. Extrapolation of a trawl to units such as particles.km 2 without considering the fact that neuston nets collect three-dimensional samples, is also another aspect discussed in this communication. This study also intends to initiate a discussion on standardising the practices across the region to enable an intercomparison of the reported data. In addition, it calls for a comprehensive assessment using the standardized methodology for putting a mitigation plan for microplastics as a potential threat detected in environmental sinks.

1. Introductory remarks The dependency on plastics is noted to be increasing in various sectors. The main application, and by association representing the major demand sector of plastics resin, is packaging (Parker, 2018). This can easily be attributed to improvements of plastic packaging in reducing food wastage and bacterial contamination. Fig. 1 shows the global de­ mand on plastic materials by sector where packaging, building/con­ struction and institutional products represents the major share of the market by 45%, 19% and 12%, respectively. Some 274 million tonnes of plastic solid waste (PSW) is generated annually around the globe (Geyer et al., 2017); with an estimated total mass of 4.8–12.7 million tonnes of plastic debris entering the world’s oceans and water bodies (Jambeck et al., 2015). This fraction of plastic waste is directly associated with mismanaged plastic products, lack of waste management (WM) infra­ structure and social behaviour in developing and developed countries alike. Plastics also posses’ high durability, anti-corrosive nature, me­ chanical integrity and strength, flexibility, insulation properties and can also act as a barrier against gas permeation (Al-Salem and Khan, 2014;

Zhou et al., 2014; Al-Salem et al., 2015; Zdanowicz and Johansson, 2016). This explains the ever increase in the global production capacity of plastics where back in 1950 a mere 1.5 million tonnes were estimated to be the total world’s production of plastics (Plastics Europe, 2008). This estimate has exponentially grown to almost 350 million tonnes in the year 2017 (Plastics Europe, 2018). Since the first reports of plastic debris in the pelagic Sargassum (Carpenter and Smith Jr., 1972), the matter has been noticed elsewhere from remote areas such as Antarctica, mountain-tops and deep-sea oceans (Oliveira and Almeida, 2019). Recent research and concern emanating from marine litter has become a topic of extreme interest among scientists globally. Microplatics fragments in the marine envi­ ronment with their microscopic size, render them easily available for consumption as prey by marine organisms, with potential impacts on their health, especially when microplastics absorb various harmful hy­ drophobic pollutants, consequently, transferring these contaminants in the marine food chain leading to man (Chatterjee and Sharma, 2019). Microplastics pose a concern has been attracting scientific interest due to their longevity, the potential to adsorb and desorb chemicals,

* Corresponding author. E-mail address: [email protected] (S.M. Al-Salem). https://doi.org/10.1016/j.marenvres.2020.104961 Received 2 February 2020; Received in revised form 18 March 2020; Accepted 19 March 2020 Available online 23 March 2020 0141-1136/© 2020 Elsevier Ltd. All rights reserved.

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Marine Environmental Research 159 (2020) 104961

wastewater treatment plants, landfill sites, recycling plants, and openair disposal sites. Past efforts in relation to microplastics assessment and quantification in the marine environment have been focused on North American and West European coastlines with some studies reporting results from Japan and Far-East, Antarctica, South America and Oceania (Barboza and Gimenez, 2015; Reed et al., 2018; Barletta et al., 2019; Cordova et al., 2019). On the other hand, West Asia and in particular the Arabian (Persian) Gulf (also known as the Inner Sea of the Regional Organization for Protection of the Marine Environment -ROPME-sea) (Hamza and Munawer, 2009), is one of the least researched areas in terms of microplastics presence (Fig. 2). In this communication, where the name is stated in context of this sea body, Arabian/Persian Gulf will be used, else we refer to this sea body as the Gulf. This area, in particular, is noted to be the leading oil producer in the world, with high estimates of solid waste (SW) generation, and specifically PSW generation in context of plastics from petrochemicals industry, population and high overall gross domestic product (GDP) as shown in Table 1 (Al-Salem, 2009a, 2009b; GCPA, 2012; Al-Salem, 2019b). More details on the status and marine health of the Gulf can be found elsewhere (Al-Yamani et al., 2004; Al-Ghadban et al., 2008; Al Busaidi et al., 2008; Al-Ghadban and Al-Samak, 2005). A thorough search was conducted on microplastics in the Arabian/ Persian Gulf region using ‘Sciencedirect®‘, ‘Google Scholar®‘, ‘EBSCO Environment Complete®’ and ‘Scopus®’ databases. Only a handful of studies exist in literature with relation to microplastic assessment in the region as of August 2019 after searching the combination of the following keywords: Microplastic, Arabian Gulf and the Persian Gulf. The search results yielded a shy number ranging between 4 (EBSCO) to 433 (Google Scholar) with a high number of repeated works between the databases, highlighting that the data from this particular region of the world, in terms of assessment of microplastics and plastic debris in the marine environment, is quite scant. Few studies have addressed micro­ plastic assessment or identification in the Gulf, including the Iranian coast (Abbasi et al., 2018; Akhbarizadeh et al., 2017; Dobaradaran et al., 2018; Esmaili and Naji, 2018; Naji et al., 2017a, 2017b; Sarafraz et al., 2016), Oman (Aliabad et al., 2019; Lyons et al., 2020), Qatar (Abayomi et al., 2017; Castillo et al., 2016), Kuwait (Saeed et al., 2018). There are no published data available for Saudi Arabia, Bahrain, and the United Arab Emirates. In contrast to microplastics, literature is rich in assess­ ments of metals, organic pollutants and radionuclides (Al-Sarawi et al., 2018; Lyons et al., 2015a, 2015b; Sheppard et al., 2010; Unddin et al., 2015, 2017; Uddin and Behbehani, 2018). To provide a coherent sum­ mary to the reader of baseline environmental status, readers are referred to Table S1 for main baseline research findings of the Arabian/Persian Gulf. This communication aims to highlight the need for undertaking microplastics assessment in the Arabian/Persian Gulf region and initiate a discussion based on limited studies, if it should be considered as a relevant vector for pollution transport and to develop an assessment of likely fate via degradation.

Fig. 1. Plastic resin global demand by sector. Adapted from Geyer et al. (2017).

xenobiotic nature, and their own chemical toxicity (Andrady, 2011; NOAA-MDP, 2014; Oliveira and Almeida, 2019; STAP, 2011; Wagner et al., 2014). To date, there exists only a few studies conducted in the region of the Arabian/Persian Gulf (Abayomi et al., 2017; Abbasi et al., 2018; Akhbarizadeh et al., 2017, 2018; 2019). 1.1. Plastics in the marine environment About 9% of all plastics ever made has been recycled and some 275 million tonnes of PSW is generated on an annual basis (Parker, 2018; Townsend, 2015). Plastics in the marine environment could be present both in macro- and micro-forms with respect to their size. The former is a direct result of mismanaged PSW that is primarily accumulating due to the effluents from waste and industrial outlets. Readers are referred to Jambeck et al. (2015) for a collection of developed and developing countries mismanaged amounts of plastics and marine debris entering the world’s oceans. Florescent techniques of microscopy are typically used to isolate microplastics from other types (Andrady, 2011). Micro­ plastics have been correlated in various studies to the deterioration of the marine environment and biota (Bonann and Orlando-Bonaca, 2018) and ingestion by various marine species (Terepocki et al., 2017; Clukey et al., 2017; Provencher et al., 2018). Plastics are typically comprised of synthetic polymers and chemical additives used to enhance their properties and tailor their application (Lettieri and Al-Salem, 2010). These additives include plasticisers (di-octyl-phthalate, di-isononyl-phthalate), colorants (titanium dioxide) and blowing agents (cyclopentane, liquid CO2) (Al-Salem, 2019a). Plastics can also contain metal or metal ion salts in the form of iron, manganese and cobalt (Brennecke et al., 2016). The presence of such metals has been recently linked with disturbing cellular processes in living organisms and posing a threat to marine environments (Kedzierski et al., 2018). Recent reports generated from beach and shorelines monitoring to identify anthropogenic waste sources indicate that microplastics are generated in a rate between 0.1 and 5500 kg per day (Carbery et al., 2020). Some countries have started taking proactive steps. The Netherlands has become the first nation to ban plastic microbeads in cosmetic products (Alimba and Faggio, 2019), marking a notable milestone in the history of plastics evolution over time (see Fig. S1 in Supplementary Materials File).

2. Microplastics and surrounding environment Microplastics have been defined as plastic particles of size range below 5 mm in size (Arthur et al., 2009). However, the term was initially used back in 2004 when it was used to describe microscopic plastic litter in marine environments (Thompson et al., 2004). These particle should not be confused with microlitter which has been defined previously by Gregory and Andrady (2003) as waste/debris particles that can pass through a 500 μm sieve and retained by a 67 μm sieve (0.06–0.5 mm in diameter). Our attempt to summarize plastic debris according to size and suggested the most appropriate sampling methods, along with the likely sources in the Gulf is presented in Fig. 3, which we believe sets a harmonised standard that encompasses majority of given cases at hand. It should also be mentioned that to date, sampling methodology is not standardised and what is reported as floating microplastics excludes sizes <330 μm (Law et al., 2010; Hidalgo-Ruz et al., 2012; Andrady,

1.2. Rationale and motivation of current work Addressing the microplastics issue is quite challenging from sam­ pling to sorting and determination. The nature of the plastic materials (e. g. chemical structure, size, and potential of contaminants sorption) en­ hances its ability to act as vector for pollution transport in marine and terrestrial environments. The sources of microplastics can be from 2

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Marine Environmental Research 159 (2020) 104961

Fig. 2. Geographical map showing sea and terrestrial bodies surrounding the Arabian Gulf. Note to reader: 1. Kuwait bay, 2. Musa estuary, 3. Hara Mangrove, 4. Strait of Hormouz, 5. Gulf of Oman, 6. Arabian Sea, 7. Chabahar Bay. Original GIS Map was sourced from KISR GIS Group.

sampling techniques. These are stated as per the following classes: � 100 μm; 100 � 350 μm and from 350 μm to �5 mm, as this will allow comparative assessment between results in a more comprehensive manner. In a detailed study, Hartman et al. (2019) highlighted the problems that originate from the lack of standardised terminology governing size class and set a president where common terminology is proposed in their work, whilst defining a framework for areas of un­ certainty in microplastic research. This framework is based on a com­ mon criterion that includes physicochemical properties (e.g. composition, solid state, solubility) as a main criteria and size, shape, colour, and origin. In a follow up communication to the aforementioned, Starck (2019) stated that the criteria require to have the element of biodegradable plastics, which is something that we in this work have added to the discussion element namely due to the overgrowing demand of this class of polymers (see next section). Biodegradables also encompass various metals that are part of pro-degradants that trigger fragmentation of plastics which might result in dispersing heavy metals to terrestrial and marine environments alike. Arabian Gulf Council Countries (GCC) collectively produce 8.0, 7.1, 4.3 and 1.7 million tonnes per annum of polypropylene (PP), high density polyethylene (HDPE), linear low density polyethylene (LLDPE) and low density polyethylene (LDPE), respectively (GCPA, 2012). Other polymer grades used in plastics production include basic chemicals, fertilisers, and polyaromatics are also produced in this region of the world. These polymeric resins are the main constituting elements of day to day commodity commercial grade plastics that contribute to the conversion industry and plastic articles accumulation in the solid waste stream. It should be kept in mind, that the world’s total polymer pro­ duction capacity declared as of 2017 is 348 million tonnes per annum (Plastics Europe, 2018). The investment in this segment of the chemical market is also growing strong in the region, where on an individual basis the State of Kuwait has doubled its investment through EQUATE Petrochemical Company (a joint venture with DOW chemicals) with an amount of 2 billion USD investment focusing on basic chemicals and polyethylene (PE). Ethylene capacity is also growing strong to cover the Asian and world markets through Saudi, Kuwait and UAE industries (Sharma, 2012). Polyolefin (PO) polymers and polyesters are the main converted resin in to cover the basic demand of consumers (Al-Salem,

Table 1 Main characteristics of Arabian/Persian Gulf bordering countries including estimated plastic waste generation. Country

Population (million residents)a

GDP (M $)b

Waste Generation (mtpa)c

Plastic waste Generation (mtpa)

Kuwait Bahrain Saudi Arabia Qatar Iran Oman U.A.E. Iraq

4.13 1.49 32.94

120.12 35.43 686.73

1.75 0.95 16.12

0.31d N/A 1.92e

2.63 81.16 4.63 9.40 38.27

166.92 454.01 70.78 382.57 192.06

1.00 17.88 1.73 5.41 13.14

0.13f 1.96g 0.20h 1.29i N/A

a Total population of nationals and expatriates as of 2017 in accordance with World Bank statistics. b Based on the year 2017 forecast of the World Bank (World Bank, 2018). c Generation of municipal solid waste (MSW) extracted from World Bank report based on million tonnes per annum (mtpa) (Kaza et al., 2018). d Based on assessment of Al-Jarallah and Aleisa (2014) and Al-Salem et al. (2018) taken as 18%. e Taken as 12% of total MSW based on Alhumoud (2015). f Taken as 13% of total MSW based on Hahladakis and Aljabri (2019). g Based on PSW composition (11%) declared by the World Bank report (Hoornweg and Bhada-Tata, 2012). h Taken as 12% of total MSW based on Zafar (2019). i Taken as 24% of total MSW based on City of Dubai Statistics published by Saifaie (2013).

2017). Andrady (2011) has also set a lower limit for microplastic to be 333 μm when neuston nets are used. Gago et al. (2016) stated in their work that to date, no lower boundary limit exists as to the particle size of microplastics. This causes major controversy when results are compared between studies and it also should be noted that the limit of detection is dependent on the sampling technique and its sensitivity with respect to filter or mesh size. Frias and Nash (2019) stressed on the need to have a standardised definition of microplastics and recommended lower limits based on three distinct categories that would complement recent tech­ nological advances in this area of research pertaining available data and 3

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Fig. 3. Sampling and identification methods of microplastics encompassing classification of plastic material and major effect on marine environment. Adapted from Auta et al. (2017) and Oliveira and Almedia (2019).

2009a). On the other hand, Iran’s petrochemical capacity includes basic chemicals along with PO, polyaromatics, polyvinyl chloride (PCV) and other resins; which have increased between the years 1978–2014 by 20 times reaching sixty million tonnes per annum (NPC, 2014). Collec­ tively, the Gulf region covers to a large extent the demand of Asia. A 20 million tonnes increase in PO consumption alone was recorded in Asia between the years 2005–2015 (Al-Salem et al., 2019a). Given these es­ timates, PSW generated rates coupled with lack of waste management (WM) infrastructure and treatment previously depicted in Table 2 can be viewed in an environmentally cautious manner. Concerns of chemical leaching and other associated problems of PSW accumulation in the region is a matter of growing concern to public and private authorities in the Gulf. Health concerns have also been linked with mismanaged PSW exposure and plastic related pollution. One of the most common addi­ tives in plastics is the chemical di-(2-ethylhexyl) phthalate (DEHP). It is typically used as a common plasticizer in PVC manufacturing which has been recently correlated to waist circumference increase and insulin resistance (North and Halden, 2013). Early sexual maturity along with the decrease in male fertility and aggressive behaviour have also been linked to bisphenol-A (BPA), which is used in epoxy plastics and bottles (Singh and Li, 2012). With that in mind, likely PSW contamination sources in and around the Gulf region cause a concern of marine contamination via industrial and waste effluents to the sea and land­ filling near seawater infrastructure. Cole et al. (2011) attributed the occurrence of microplastics to two sources, primary and secondary ones. Primary sources are the ones contributing to microplastics presence by plastic production of the aforementioned size considered as micro­ plastics (e.g. of microscopic size) such as industrial abrasives, exfoliants and engineered pellets. While secondary sources are fragmentation of larger macro (encompassing mesoplastics) debris by photodegradation in a combined effect with wave action and abrasion. In the case of the Gulf, primary sources to date are not quantified as to their actual contribution. The actual marine litter accumulated which is presumed to end its life cycle on the shores of the Gulf, are not quantified to date. On the other hand, secondary sources are presumed by the authors of this article to be of a more pertinent source considering industrial activities and wide spread use of plastic and PSW generated and mismanaged in the region. This is due to the fragmentation of macro sized plastic waste articles that can cause microplastic pollution in and around the Gulf region. However, some studies have suggested that factors like UV ra­ diation, temperature, etc. lead to increased plastics deterioration in terrestrial environment but not so effective when it comes to marine environment (Andrady, 2009). Other studies also attribute microplastics

as a vector for pollutant transport, example of persistent organic pol­ lutants (POPs) adherence has been made (Andrady, 2011). 3. Microplastics in context of Gulf As mentioned earlier in the manuscript, there are limited studies conducted in the region to establish baseline information on micro­ plastics abundance and types. Abbasi et al. (2018) surveyed five sites along Iran’s coastline for the detection of microplastics and identifying their most abundant locations/presence. A total number of 828 micro­ plastic particles that consisted mainly of fibrous fragments with a carbon and oxygen chains, in addition to metal elements. This is also consist with recent trends in the area popularizing polyolefins and biodegrad­ able plastic use ending as a waste component (Al-Salem et al., 2019a, 2019b). Microplastics are known to enter the fish digestive system through two main routes, either through the food web or direct exposure (Jabeen et al., 2017). Furthermore, Akhbarizadeh et al. (2018) studied four types of fish along the South-Western coast of Iran to identify the presence and risk associated with their presence. Microplastics were present in pellet, fibre and fragment shape in the studied specimens. The results indicated that microplastics were present in the range of 5.66 � 1.69 to 18.50 � 4.55 item/10 g fish muscle. The microplastics were present in the fish muscle at a higher rate. Aliabad et al. (2019) evalu­ ated surface seawater for the presence of microplastics in Chabahar Bay (Iran) after analysing 21 neuston net water samples. The materials were mostly of fibre type and were namely made of polyethylene (PE), polypropylene (PP) and polystyrene (PS). A total of 1609 particle were collected and counted as microplastics in this study. One major issue in reporting the presence of microplastics within recent studies is the reported values unit which varies from number of particles to particle per studied area or unit volume. The recent study from Qatar conducted by Abayomi et al. (2017) took a 5-min trawl (1.5 knots) at four stations using a 0.5 � 1.0 m 300 μm neuston net for assessing microplastics in seawater. In addition, triplicate samples were taken at 8 beach locations using quadrat (0.5 � 0.5 m and 0.02 m thick). There is no discrete disclosure of the number of microplastic particles collected and identified. However, the study indicates that thirteen (13) particles from sediments and five (5) from seawater were analysed. The authors also report existence of 4.38–146 x104 particles km 2. This presents a high value when compared to densities from other waters, i.e. North Sea (25–38), Belgian Coast (0.7), Ligurian Sea (1.5–25), Medi­ terranean (10.9–52), British Colombia (1.48) or Southern Ocean (0.032–6.0) (Bergmann et al., 2015). However, past works in the 4

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Marine Environmental Research 159 (2020) 104961

Table 2 Summary of available peer reviewed literature on the Arabian/Persian Gulf with respect to microplastics abundance. Reference

Country

Study Area

Studied Samples/Specimens

Main Results/Findings

Abayomi et al. (2017)

Qatar

Sediment and seawater samples

Fibres (1–5 mm) were the most dominant type found with an abundance of 4.38x104 to 1.46x106 particles.km 2 mainly 10 km offshore.

Abbasi et al. (2018)

Iran

Fish and prawn by trawl nets.

Akhbarizadeh et al. (2018) Aliabad et al. (2019)

Iran

Eighty beaches and four surface stations on the Eastern coast Five distinct sites along coastline South-Western coast

Iran

Chabahar Bay (see Fig. 2)

Seawater samples

Dobaradaran et al. (2018) Khordagui and Abu-Hilal (1994) Saeed et al. (2020)

Iran

Shoreline of Iran (nine Sediment samples stations) 15 sampling locations covering 27000 m2 (each 30 m wide transects) of beach-line between Arabian Gulf and Gulf of Oman Shoreline (Gulf Coast) Sediment, seawater and 87 fish/ mussel gastrointestinal content 8 different types of commercial important fish to the consumers of the Gulf region Bandar Abbas (five locations) Sediment samples Strait of Hormuz (see Fig. 2) Sediment samples Five littoral mollusc species Khor-e-Khoran shore (five Sediment samples locations)

A total number of 828 microplastic particles that consisted mainly of fibrous fragments Microplastics were present in the range of 5.66 � 1.69 to 18.50 � 4.55 item/10 g fish muscle 1609 particle were collected and counted as microplastics consisting mainly of PP, PE and PS. 82,612 particles were counted in the samples

Al-Salem et al. (2020) Naji et al. (2017a) Naji et al. (2017b) Naji et al. (2018) Naji et al. (2019)

UAE Kuwait Kuwait Iran Iran Iran

Four fish types

Mediterranean Sea indicate that microplastics might also be in higher abundance along the Israeli shorelines (1,518,340 particles km 2, van der Hal et al., 2017) and Central-Western Mediterranean including the Corsica shoreline (1.25 � 1.62 particles m 2, Suaria et al., 2016). Another study conducted in Qatar used 120 μm plankton net of 0.5 m diameter and 2.0 m length has reported 0–3 particles m 3 with an average of 0.7 particle m 3. The sampling protocol used involved a submerged neuston net. Considering the fact that there are microplastics with densities more than seawater (e.g. commercial polyesters), sam­ pling within the neustonic layer is very likely to underestimate the abundance. Dobaradaran et al. (2018) studied sediment samples along the shorelines of Iran to report the abundance of microplastics and their metal content. The samples collected and studied originated from nine stations collected in the summer of 2015. A total of 82,612 microplastic particles were counted in the studied samples. The results indicate that the particle size of 2–5 mm and �0.25 mm with 45 and 33% and white and colorless plastics with 62 and 33% were in abundance per m2 of studied areas with metals presence. Recently, Saeed et al. (2018) con­ ducted a study to determine the abundance of microplastics in Kuwait’s waters. Samples of beach sediments, 40 trawls of the coastal areas and examining stomach contents of local marine biota (4 types of fish and two types of clams), were collected. A total of 44 intertidal locations (from Kuwait/Saudi Arabia border to the far end of Northern Kuwait) were sampled. Microplastics were catagorised using micro Raman spectroscopy and identified as PE, PP and PS, which were in 12 locations in the Kuwait Bay and at only 3 locations in the south. The results showed that Kuwait’s coasts were mostly littered with PSW but not microplastics. Naji et al. (2017a) studied the abundance and morphological struc­ ture of microplastics around Bandr Abbas (Iran) in littoral surface sediment samples. Precautions were taken to avoid airborne contami­ nation with the samples which were collected at low tide around the five locations of the study area. The results showed that 80% of the samples contained microplastics, and that fibre materials were most prominent shape found (88%), and majority of plastics were of nylon, PE and polyethylene terephthalate (PET). In a follow up study, Naji et al. (2017b) showed the likely sources of the microplastics along the Iran coastline towards Strait of Hormuz were beach debris, discarded fishing gear, and urban and industrial outflows that contain fibers from clothes. Table 2 summarises the available studies concerning microplastics abundance in the Gulf region. In summary and given the scant literature

22771 items collected of which plastic fragment constituted 27.1% 37 particles in sediments and 3 particles in gut content of Orangespotted grouper 1 particle in three different type of fish species namely Acanthopagrus latus, Acanthopagrus latus and Lutjanus quinquelineatus A total of 307 particles were identified 81 particles analysed from five study locations Microplastics ranged between 0.2 and 21 particles per g tissue Spatial distribution of particles (<1 mm) in mangrove surface showed that over 70% (10–300 μm) particles were predominant and main source was sewage outlets.

on the subject matter, results point towards higher abundance of microplastics on the Eastern and North-Eastern parts along the Iranian coastline. Majority of reported cases show that the most abundant polymer type was PE and PP found in sediment or water samples. This shows a quite logical finding given that majority of consumer oriented articles of plastics in towards both PE and PP. This leads to an accu­ mulated use of such commodities with an increasing reliance by con­ sumer leading to accumulation in municipal outlets and potential sources of microplastics in the Arabian/Persian Gulf. 4. Research efforts and main findings to date Plastics will typically contain chemicals that will either stabilise their performance or aid in their degradation when exposed to the environ­ ment. These will typically contain a list of chemicals such diiso­ heptylphthalate, benzyl butyl phthalate, bis (2-ethylhexyl) phthalate, di-(2-ethylhexyl) adipate (DEHA), di-octyladipate, diethyl phthalates (DEP), butylated hydroxytoluene (BHT), 2- and 3-t-butyl-4 hydrox­ yanisole (BHA) and arsenic compounds (Hahladakis et al., 2018). POPs are naturally present in marine environments. It has been proven that POPs are sorbed by microplastics in seawater (Engler et al., 2012). POPs are known to have an adverse effect on human and ecosystems alike containing chemicals such as dioxin and 2,3,7,8 tetrachlorodibenzo-pdioxin (TCDD, agent orange) (Verma et al., 2016). On the other hand, Andrady (2017) stated that equilibrium coefficient (K) for common POPs in plastic/water system ranges from 103 to 105 in favour of plastics. This makes it likely to have POPs enter the food system of marine organisms and species likely due to the sorbed POPs. Rochman et al. (2013) stated that 78% of the chemicals listed under priority pollutants by the US EPA due to their persistent nature have been associated with plastic debris in marine environments. Alvaerz et al. (2018) used European shags (Phalacrocorax aristotelis) as bioindicators after conducting a detailed field study collecting 41 regurgitated pellets. The plastics occurrence was estimated as 63% and due to the size of the pellets and microplastics, FTIR allowed recording absorbance signals. The Gulf is the home for various seabirds such as the well known Socotra cormorant with colonies stretching throughout the region (Saudi hosting three on its own) (Symens and Werner, 1991). Field studies that can cover birds of the sea and coastal birds of prey can be of extreme interest in identifying the true threat and by association having the creatures act as indicators for the Gulf. In their study, Beer et al. (2018) stated that there were no changes in the fish species of the 5

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Atlantic herring (Clupea harengus) and European sprat (Sprattus sprattus), in the Baltic Sea over three decades (1987–2015). Using similar case histories to have a databank of information will also aid in assessing the situation in the Gulf region since some reports such the ones from Kuwait show no abundance and threat of microplastics in North Arabian Gulf (Saeed et al., 2018). The investigation of the adsorption behaviour and kinetics of major heavy metals reported in the Arabian/Persian Gulf on microplastics has been noted as a gap in published research. The unique characteristics of the region with salinity and water temperature having elevated esti­ mates (see the previous section) makes the adsorption behaviour of previously measured metal contaminates, a matter that requires to be investigated (Uddin et al., 2010, 2012). Some metals reported in pre­ vious studies and detected in Gulf include copper and zinc (Moor et al., 2015). Fragments of PE, PP, PS, and PVC have all been neglected to be aged in the marine environment of the Gulf and adsorption behaviour investigated. The aforementioned represents a major research gap with respect to the Arabian/Persian Gulf region to determine the exact impact of pollutants and transfer of metals from plastic fragments to the actual seawater body. Furthermore, we deduce from this literally exercise that a continuous monitoring survey on major commercial fish stock from outlets are to be sampled and studied for fragments presents in their gut content. This will also determine the sources of microplastics pollution within the Gulf region and pin point it to a higher accuracy. This will also determine the uptake likelihood of major consumed fish products in the region concerning plastic fragments. Legislations that can enforce such actions are also to be developed by concerned regional and local governmental bodies. Another knowledge gap that is currently present in the region is the impact of the arid climatic conditions on the fragmentation of plastics that can easily increase microplastic count in the region. The region is characterised with harsh climatic conditions with elevated UV radiation and ambient temperatures which can easily render macro plastics to be fragmented, and after which accumulated and dispersed as microplastics in the Gulf. Plastics are known to be susceptible to photo-degradation which is induced to a great extent in regions such as the Gulf. The re­ gion exhibits ambient temperatures that exceed 50 � C in summer sea­ sons (maximum surface temperature between 35 and 36 � C) which can render exposed plastics on the surface of the Gulf more susceptible to fragmentation and degradation when compared to other locations around the globe. The exposure to environmental conditions including abrasion and other contact in the sea, will result in change of morphology, inherited properties among other mechanical and physical properties. Readers are referred to Table S2 which shows common ex­ amples of change in crystallinity of plastics with various environmental influencers that are reported in literature. The main reason that crys­ tallinity has targeted attention in research efforts nowadays is its connection to the density of microplastics. Denser polymers will be rendered negatively buoyant leading to corresponding position in den­ sity columns, which on the other hand can determine which type of organism it might attract and end up harming as a potential polluter to its surrounding (Andrady, 2017). Therefore, microplastics can sink down and accumulate in sediments due to having a higher density than sea water (Alomar et al., 2016). This presents an obvious interest in context to the Arabian/Persian Gulf region where estimated timeline of natural and controlled laboratory weathering tests have shown a rapid increase as of late for PO polymers (Al-Salem, 2009b, 2019b; Al-Salem et al., 2016). Comparative assessment of results established in Kuwait between the years 2009 and 2019, show that 1 h is equivalent to 1 day in open (terrestrial) environment for PO materials which makes the weather in North Arabian/Persian Gulf considered the harshest amongst other research findings in literature. These considerations present a valid case for considering the environment of the region to be quite unique and requires more research efforts to understand the impact of exposure on plastics in the Arabian/Persian Gulf. The typical crystal­ linity of semi-crystalline PO polymer such as PE and PP is between 40

and 60%. Table S2 shows a clear change in their crystalline behaviour with exposure to weathering among other environmental influential parameters. The environmental conditions of the Gulf can also increase the mineralisation rate (in biodegradation) of the plastics which transforms it into carbon dioxide (CO2), water (H2O) and biomass. Such plastics are being popularised recently in the Gulf due to their oxo-biodegradable environmentally friendly claims (Al-Salem et al., 2019c). Common ex­ amples of polymers that could face the fate of mineralisation and degradation are nylon and PE in marine environments. A major research gap is the mineralisation kinetics and the deterioration reactions rate where no data in literature exists to date. The biodegradation in marine environments is now governed by a standard for testing within controlled laboratory conditions for plastic materials referred to as ASTM 6691 ‘Test method for determining aerobic biodegradation of plastic materials in the marine environment by a defined microbial consortium or natural sea water inoculum’. This test method, when applied for locally produced biodegradable polymers in Arabian/Persian Gulf region, can also present a very promising insight into the fate on the marine environment. The carbon conversion under simulated marine environments is also measured using respirometry a described previ­ ously by various authors (Shah et al., 2008; Eubeler et al., 2009; Andrady, 2011). 5. Conclusions and future recommendations Plastic solid waste (PSW) generation and accumulation in the envi­ ronment has the potential to fragment into finer particles. These fine fractions are more challenging to sample, identify and manage. They have been suggested to have a negative effect on the marine ecosystem functioning by acting as vectors for contaminant transport into marine food chains. This communication covered the distribution of marine microplastics in the Gulf, with the emphasis to highlight the limitations and data gap necessary to understand the role of microplastic as a vector for contaminant transport in the marine environment. The chemical characteristics of the plastic material and its long degradation time has led to microplastic being characterized as a persistent pollutant. The review of the published information highlighted the scarcity of the published data from the Gulf region. Besides, there are ambiguities in describing the cut-off size, extrapolation of the microplastic counts and abundance without considering the hydrodynamics, sampling tech­ niques, sampling gears. Often the methodology used for identification, and characterization has its own limitations in terms of sample mass requirement. There exists significant concerns in terms of data reporting some indicate particles m 3 and other particles km 2. The studies reviewed in this work have used and subsequently reported, different sampling gears which implies that different depths were sampled. Since different gears were used (e.g. plankton nets are circular, neuston nets are rectangular and varying in dimensions from 0.2 to 0.5 m) and considering that microplastics have different densities varying from 0.910 to 0.925 g cc 1 for typical polyolefinic commercial grade plastics (e.g. polyethylene) to 2.10–2.30 for polytetra-fluoroethylene, restricting the sampling to the neustonic layer is likely to underestimate the particle count in the water column; and how this number can be used for assessing the transfer into the food chain as only pelagic marine feeders are susceptible to microplastic pollution. At this stage, it should be noted that the salinity of Arabian/Persian Gulf, which is considered higher than other regions in the world, could be a major factor in the abun­ dance and separation of plastic debris and particles. Typically, sediment samples are slurried in saline water to allow microplastic’s flotation to the surface. This exercise is rendered to be questionable when Arabian/ Persian Gulf water is used. Identification and separation of plastics types have been a major point raised in various published reports. The main type of separation technique used to date for collected microplastics is conducted via density separation. The density of the collected particles is based on their buoyancy in the sea which will determine what type of 6

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organisms it might attract. Fouling is a major issue that has been dis­ cussed recently in literature where plastic particles will encrust a foulant that will lead to their inevitable fate of sinking to the bottom bed of the sea body. Infrared techniques (IR) are still the most dominant in iden­ tifying plastic types categorized as microplastics. However, their exist various research findings that confuse debris with microplastics where the use of conventional IR is not possible due to particle size. It is rec­ ommended to have a micro-Raman or micro-IR identification in such cases to have a more conclusive dataset for further analysis. Environ­ mental stressors including temperature, radiation and humidity; are common deteriorating factors on polymeric chains that constitute plastic articles. These are typically determined using standardised weathering tests on plastic specimens as per internationally recognised standards. The exposure to environmental conditions including abrasion and other contact in the sea, will result in change of morphology, inherited properties among other mechanical and physical properties. The presence of microplastic in the gut of marine organism seeks attention to understand their turnaround into the environment. The chemical degradability of these microplastic particles and the likelihood of contaminants leaching and desorbing from them is a topic that has not been addressed in details. Based on the studies published in the region, it is felt that there is a need to standardize the methodology for sample collection and reporting units. The use of plankton nets and collection of surface water (0.25–1 m depth) instead of the neustonic layer (first few centimetres of surface) should also be looked at since most of the lighter microplastic particles in the denser saline Gulf water is expected to be at the surface until biofouling takes place. The regional assessment of microplastics is an eminent requirement to assess their efficacy as pollutant transfer vector and risk of marine food chain transfer, impacting marine health as well as human health.

Akhbarizadeh, R., Moore, F., Keshavarzi, B., 2018. Investigating a probable relationship between microplastics and potentially toxic elements in fish muscles from northeast of Persian Gulf. Environ. Pollut. 232, 154–163. Akhbarizadeh, R., Moore, F., Keshavarzi, B., 2019. Polycyclic aromatic hydrocarbons and potentially toxic elements in seafood from the Persian Gulf: presence, trophic transfer, and chronic intake risk assessment. Environ Geochem Hlth 41, 2803–2820. https://doi.org/10.1007/s10653-019-00343-12. Al Busaidi, S.S., Al Rashdi, K.M., Al Gheilani, H.M., Amer, S., 2008. Hydrographical observations during a red tide with fish mortalities at masirah island, Oman. Agric. Mar. Sci. 13, 64–72. Al-Ghadban, A.N., El-Sammak, A., 2005. Sources, distribution and composition of the suspended sediments, Kuwait bay, northern arabian Gulf. J. Arid Environ. 60, 647–661. https://doi.org/10.1016/j.jaridenv.2004.07.017. Al-Ghadban, A.N., Uddin, S., Beg, M.U., Al Dousari, A.M., Gevao, B., 2008. Ecological Consequences of River Manipulation and Drainage of Mesopotamian Marshes on the Arabian Gulf Ecosystem: Investigations on Changes in Sedimentology and Environment Quality with Special Reference to Kuwait Bay. Kuwait Institute for Scientific Research Kuwait. Al-Jarallah, Aleisa, 2014. A baseline study for municipal solid waste characterization for the state of Kuwait. Waste Manag. 34, 952–960. Al-Salem, S.M., 2009a. Establishing an integrated databank for plastic manufacturers and converters in Kuwait. Waste Manag. 29, 479–484. https://doi.org/10.1016/j. wasman.2008.02.030. Al-Salem, S.M., 2009b. Influence of natural and accelerated weathering on various formulations of linear low density polyethylene (LLDPE) films. Mater. Des. 30 (5), 1729–1736. https://doi.org/10.1016/j.matdes.2008.07.049. Al-Salem, S.M., 2019a. Introduction. In: Al-Salem, S.M. (Ed.), Chapter 1 in Plastics to Energy: Fuel, Chemicals & Sustainable Implications. Elsevier, ISBN 978-0-12813140-4. https://doi.org/10.1016/B978-0-12-813140-4.00001-7. Al-Salem, S.M., 2019b. Influential parameters on natural weathering under harsh climatic conditions of mechanically recycled plastic film specimens. J. Environ. Manag. 230, 355–365. https://doi.org/10.1016/j.jenvman.2018.09.044. Al-Salem, S.M., Khan, A.R., 2014. On the degradation kinetics of poly(ethylene terephtalate) (PET)/poly(methyl methacrylate) (PMMA) blends in dynamic thermogravimetry. Polym. Degrad. Stabil. 104, 28–32. https://doi.org/10.1016/j. polymdegradstab.2014.03.024. Al-Salem, S.M., Abraham, G., Al-Qabandi, O.A., Dashti, A.M., 2015. Investigating the effect of accelerated weathering on the mechanical and physical properties of high content plastic solid waste (PSW) blends with virgin linear low density polyethylene (LLDPE). Polym. Test. 46, 116–121. https://doi.org/10.1016/j. polymertesting.2015.07.008. Al-Salem, S.M., Al-Nasser, A., Al-Dhafeeri, A.T., 2018. Multi-variable regression analysis for the solid waste generation in the State of Kuwait, 119. Process Safety & Environmental Protection, pp. 172–180. Al-Salem, S.M., Behbehani, M.H., Karam, H.J., Al-Rowaih, S.F., Asiri, F.M., 2019a. On the kinetics of degradation reaction determined post accelerated weathering of polyolefin plastic waste blends. Int. J. Environ. Res. Publ. Health 16 (3), 395. Al-Salem, S.M., Al-Nasser, A.Y., Behbehani, M.H., Sultan, H.H., Karam, H.J., Al-Wadi, M. H., Al-Dhafeeri, A.T., Rasheed, Z., Al-Foudaree, M., 2019b. Thermal response and degressive reaction study of oxo-biodegradable plastic products exposed to various degradation media. Int. J. Polym. Sci. https://doi.org/10.1155/2019/9612813. Article ID: 9612813. Al-Salem, S.M., Al-Hazza’a, A., Karam, H.J., Al-Wadi, M.H., Al-Dhafeeri, A.T., AlRowaih, A.A., 2019c. Insights into the evaluation of the abiotic and biotic degradation rate of commercial pro-oxidant filled polyethylene (PE) thin films. J Environ Mange 250, 109475. Al-Salem, S.M., Uddin, Saif, Lyons, Brett, 2020. Evidence of microplastics (MP) in gut content of major consumed marine fish species in the State of Kuwait (of the Arabian/Persian Gulf). Mar. Pollut. Bull. 154, 111052. Al-Sarawi, H.A., Jha, A.N., Baker-Austin, C., Al-Sarawi, M.A., Lyons, B.P., 2018. Baseline screening for the presence of antimicrobial resistance in E. coli isolated from Kuwait’s marine environment. Mar. Pollut. Bull. 129, 893–898. https://doi.org/ 10.1016/j.marpolbul.2017.10.044. Al-Yamani, F.Y., Bishop, J., Ramadhan, E., Al-Husaini, M., Al-Ghadban, A.N., 2004. Oceanographic Atlas of Kuwait’s Waters. Kuwait Institute for Scientific Research, Kuwait, p. 203. Alhumoud, J.M., 2015. Municipal solid waste recycling in the Gulf Co-operation Council states, Resources. Conserv. Recycl. 45 (2), 142–158. https://doi.org/10.1016/j. resconrec.2005.01.010. Aliabad, M.K., Nassiri, M., Ko, K., 2019. Microplastics in the surface seawaters of chabahar bay, Gulf of Oman (makran coasts). Mar. Pollut. Bull. 143, 125–133. https://doi.org/10.1016/j.marpolbul.2019.04.037. Alimba, C.G., Faggio, C., 2019. Microplastics in the marine environment: current trends in environmental pollution and mechanisms of toxicological profile. Environ. Toxicol. Pharmacol. 68, 61–74. https://doi.org/10.1016/j.etap.2019.03.001. � Alvarez, G., Barros, A., Velando, A., 2018. The use of European shag pellets as indicators of microplastic fibers in the marine environment. Mar. Pollut. Bull. 137, 444–448. https://doi.org/10.1016/j.marpolbul.2018.10.050. Andrady, A.L., 2009. Fate of plastics debris in the marine environment. In: Proceedings of the International Research Workshop on the Occurrence, Effects, and Fate of Microplastic Marine Debris, September 9-11, 2008. Technical Memorandum NOSOR&R-30, p. 78. January 2009. Andrady, A.L., 2011. Microplastics in the marine environment. Mar. Pollut. Bull. 62, 1596–1605. https://doi.org/10.1016/j.marpolbul.2011.05.030. Andrady, A.L., 2017. The plastic in microplastics: a review. Mar. Pollut. Bull. 119, 12–22. https://doi.org/10.1016/j.marpolbul.2017.01.082.

Author contribution statement Sultan Majed Al-Salem: Conceptualisation, Original Draft Prepara­ tion and Analysis; Saif Uddin: Conceptualisation and Review; Faiza AlYamani: Review and Editing. Declaration of competing interest The authors of this communication declare that they have no known competing interests or personal relationships that could influence the work in any shape or form. Acknowledgment The authors are grateful to the Kuwait Institute for Scientific Research (KISR) for their support. We also would like to thank the blind reviewers for their feedback and comments which enriched this article immensely. Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi. org/10.1016/j.marenvres.2020.104961. References Abayomi, O.A., Range, P., Al-Ghouti, M.A., Obbard, J.P., Almeer, S.H., Ben-Hamadou, R., 2017. Microplastics in coastal environments of the arabian Gulf. Mar. Pollut. Bull. 124, 181–188. https://doi.org/10.1016/j.marpolbul.2017.07.011. Abbasi, S., Soltani, N., Keshavarzi, B., Moore, F., Turner, A., Hassanaghaei, M., 2018. Microplastics in different tissues of fish and prawn from the Musa Estuary, Persian Gulf. Chemosphere 205, 80–87. https://doi.org/10.1016/j. chemosphere.2018.04.076. Akhbarizadeh, R., Moore, F., Keshavarzi, B., Moeinpour, A., 2017. Microplastics and potentially toxic elements in coastal sediments of Iran’s main oil terminal (Khark Island). Environ. Pollut. 220, 720–731. https://doi.org/10.1016/j. envpol.2016.10.038.

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S.M. Al-Salem et al.

Marine Environmental Research 159 (2020) 104961

Arthur, C., Baker, J., Bamford, H., Barnea, N., Lohmann, R., McElwee, K., Morishige, C., Thompson, R., 2009. Summary of the international research workshop on the occurrence, effects, and fate of microplastic marine debris (executive summary). In: Proceedings of the International Research Workshop on the Occurrence, Effects, and Fate of Microplastic Marine Debris, September 9-11, 2008. Technical Memorandum NOS-OR&R-30, p. 7. January 2009. Auta, H.S., Emenike, C.U., Fauziah, S.H., 2017. Distribution and importance of microplastics in themarine environment: a review of the sources, fate, effects, and potential solutions. Environ. Int. 102, 165–176. https://doi.org/10.1016/j. envint.2017.02.013. STAP, 2011. Marine Debris as a Global Environmental Problem : Introducing a solutions based framework focused on plastic. A Scientific and Technical Advisory Panel Information Document. Global Environment Facility, Washington, DC., p. 40. http:// www.stapgef.org/sites/default/files/stap/wp-content/uploads/2013/05/Marine-D ebris.pdf Barboza, L.G.A., Gimenez, B.C.G., 2015. Microplastics in the marine environment: current trends and future perspectives. Mar. Pollut. Bull. 97, 5–12. https://doi.org/ 10.1016/j.marpolbul.2015.06.008. Barletta, M., Lima, A.R.A., Costa, M.F., 2019. Distribution, sources and consequences of nutrients, persistent organic pollutants, metals and microplastics in South American estuaries. Sci. Total Environ. 651, 1199–1218. https://doi.org/10.1016/j. scitotenv.2018.09.276. Bergmann, M., Gutow, L., Klages, M., 2015. Marine anthropogenic litter. https://doi.org/ 10.1007/978-3-319-16510-3. Bonanno, G., Orlando-Bonaca, M., 2018. Perspectives on using marine species as bioindicators of plastic pollution. Mar. Pollut. Bull. 137, 209–221. https://doi.org/ 10.1016/j.marpolbul.2018.10.018. Brennecke, D., Duarte, B., Paiva, F., Caçador, I., Canning-Clode, J., 2016. Microplastics as vector for heavy metal contamination from the marine environment. Estuar. Coast Shelf Sci. 178, 189–195. https://doi.org/10.1016/j.ecss.2015.12.003. Carbery, M., MacFarlane, G.R., O’Connor, W., Afrose, S., Taylor, H., Palanisamia, T., 2020. Baseline analysis of metal(loid)s on microplastics collected from the Australian shoreline using citizen science. Mar. Pollut. Bull. 152, 110914 https:// doi.org/10.1016/j.marpolbul.2020.110914. Carpenter, E.J., Smith Jr., K.L., 1972. Plastics on the sargasso sea surface. Science 175, 1240–1241. https://doi.org/10.1126/science.175.4027.1240. Castillo, A.B., Al-Maslamani, I., Obbard, J.P., 2016. Prevalence of microplastics in the marine waters of Qatar. Mar. Pollut. Bull. 111, 260–267. https://doi.org/10.1016/j. marpolbul.2016.06.108. Chatterjee, S., Sharma, S., 2019. Microplastics in our oceans and marine health. Field Actions Sci. Rep. , Special Issue 19, 54–61. Clukey, K.E., Lepczyk, C.A., Balazs, G.H., Work, T.M., Lynch, J.M., 2017. Investigation of plastic debris ingestion by four species of sea turtles collected as bycatch in pelagic Pacific longline fisheries. Mar. Pollut. Bull. 120 (1–2), 117–125. https://doi.org/ 10.1016/j.marpolbul.2017.04.064. Cole, M., Lindeque, P., Halsband, C., Galloway, T.S., 2011. Microplastics as contaminants in the marine environment: a review. Mar. Pollut. Bull. 62 (12), 2588–2597. https:// doi.org/10.1016/j.marpolbul.2011.09.025. Cordova, M.R., Purwiyanto, A.I.S., Suteja, Y., 2019. Abundance and characteristics of microplastics in the northern coastal waters of Surabaya, Indonesia. Mar. Pollut. Bull. 142, 183–188. https://doi.org/10.1016/j.marpolbul.2019.03.040. Dobaradaran, S., Schmidt, T.C., Nabipour, I., Khajeahmadi, N., Tajbakhsh, S., Saeedi, R., Mohammadi, M.J., Keshtkar, M., Khorsand, M., Ghasemi, F.F., 2018. Characterization of plastic debris and association of metals with microplastics in coastline sediment along the Persian Gulf. Waste Manag. 78, 649–658. https://doi. org/10.1016/j.wasman.2018.06.037. Engler, R.E., 2012. The complex interaction between marine debris and toxic chemicals in the ocean. Environ. Sci. Technol. 46 (22), 12302–12315. Esmaili, Z., Naji, A., 2018. Comparison of the frequency, type and shape of microplastics in the low and high tidal of the coastline of Bandar Abbas. J. Oceanogr. 8, 53–61. Frias, J.P.G.L., Nash, R., 2019. Microplastics: finding a consensus on the definition. Mar. Pollut. Bull. 138, 145–147. Gago, J., Galgani, F., Maes, T., Thompson, R.C., 2016. Microplastics in seawater: recommendations from the marine strategy framework directive implementation process. Front. Mar. Sci. 3, 219. https://doi.org/10.3389/fmars.2016.00219. GCPA, 2012. GCC petrochemicals & chemicals industry: facts & Figures 2012. Available at: https://www.gpca.org.ae/adminpanel/pdf/ff12e.pdf. Geyer, R., Jambeck, J.R., Law, K.L., 2017. Production, use, and fate of all plastics ever made. Sci. Adv. 3 (7), e1700782 https://doi.org/10.1126/sciadv.1700782. Gregory, M.R., Andrady, A.L., 2003. Plastics in the marine environment. In: Andrady, AnthonyL. (Ed.), Plastics and the Environment. John Wiley and Sons, ISBN 0-471-09520-6. Hahladakis, J.N., Aljabri, H.M.S.J., 2019. Delineating the plastic waste status in the State of Qatar: potentialopportunities, recovery and recycling routes. Sci. Total Environ. 653, 294–299. https://doi.org/10.1016/j.scitotenv.2018.10.390. Hahladakis, J.N., Velis, C.A., Weber, R., Iacovidou, E., Purnell, P., 2018. An overview of chemical additives present in plastics: migration, release, fate and environmental impact during their use, disposal and recycling. J. Hazard Mater. 344, 179–199. https://doi.org/10.1016/j.jhazmat.2017.10.014. Hamza, W., Munawar, M., 2009. Protecting and managing the arabian Gulf: past, present and future. Aquat. Ecosys. Health Manag. 12 (4), 429–439. https://doi.org/10.1080/ 14634980903361580. Hartmann, N.B., Hüffer, T., Thompson, R.C., Hassell€ ov, M., Verschoor, A., Daugaard, A. E., Rist, S., Karlsson, T., Brennholt, N., Cole, M., Herrling, M.P., 2019. Are we speaking the same language? Recommendations for a definition and categorization

framework for plastic debris. Environ. Sci. Technol. 53 (3), 1039–1047. https://doi. org/10.1021/acs.est.8b05297. Hidalgo-Ruz, V., Gutow, L., Thompson, R.C., Thiel, M., 2012. Microplastics in the marine environment: a review of the methods used for identification and quantification. Environ. Sci. Technol. 46 (6), 3060–3075. https://doi.org/10.1021/es2031505. Hoornweg, D., Bhada-Tata, P., 2012. What a Waste: A Global Review of Solid Waste Management. World Bank’s Urban Development Series Knowledge Papers no.15 March. Jabeen, K., Su, L., Li, J., Yang, D., Tong, C., Mu, J., Shi, H., 2017. Microplastics and mesoplastics in fish from coastal and fresh waters of China. Environ. Pollut. 221, 141–149. Jambeck, J.R., Geyer, R., Wilcox, C., Siegler, T.R., Perryman, M., Andrady, A., Narayan, R., Law, K.L., 2015. Plastic waste inputs from land into the ocean. Science 347 (6223), 768–771. https://doi.org/10.1126/science.1260352. Kaza, S., Yao, L., Bhada-Tata, P., Van Woerden, F., 2018. What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050. Urban Development Series, Washington, DC. https://doi.org/10.1596/978-1-4648-1329-0. World Bank. Kedzierski, M., D’Almeida, M., Magueresse, A., Le Grand, A., Duval, H., C� esar, G., Sire, O., Bruzaud, S., Le Tilly, V., 2018. Threat of plastic ageing in marine environment. Adsorption/desorption of micropollutants. Mar. Pollut. Bull. 127, 684–694. https://doi.org/10.1016/j.marpolbul.2017.12.059. Khordagui, H.K., Abu-Hilal, A.H., 1994. Man-made litter on the shores of the United Arab Emirates on the arabian Gulf and the Gulf of Oman, water. Air Soil Pollut. 76, 343–352. Law, K.L., Mor� et-Ferguson, S., Maximenko, N.A., Proskurowski, G., Peacock, E.E., Hafner, J., 2010. Plastic accumulation in the North Atlantic subtropical gyre. Science 329 (5996), 1185–1188. https://doi.org/10.1126/science.1192321. Lettieri, P., Al-Salem, S.M., 2011. In: Letcher, Trevor, Vallero, Daniel (Eds.), ThermoChemical Treatment of Plastic Solid Waste, Chapter 17 in ‘Handbook of Waste Management and Recycling’. Elsevier, ISBN 978-0-12381-475-3. https://doi.org/ 10.1016/B978-0-12-381475-3.10017-8. Lyons, B.P., Barber, J.L., Rumney, H.S., Bolam, T.P.C., Bersuder, P., Law, R.J., Mason, C., Smith, A.J., Morris, S., Devlin, M.J., Al-Enezi, M., Massoud, M.S., Al-Zaidan, A.S., AlSarawi, H.A., 2015a. Baseline survey of marine sediments collected from the State of Kuwait: PAHs, PCBs, brominated flame retardants and metal contamination. Mar. Pollut. Bull. 100, 629–636. Lyons, B.P., Devlin, M.J., Abdul Hamid, S.A., Al-Otiabi, A.F., Al-Enezi, M., Massoud, M. S., Al-Zaidan, A.S., Smith, A.J., Morris, S., Bersuder, P., Barber, J.L., Papachlimitzou, A., Al-Sarawi, H.A., 2015b. Microbial water quality and sedimentary faecal sterols as markers of sewage contamination in Kuwait. Mar. Pollut. Bull. 100, 689–698. Lyons, B.P., Cowie, W.J., Maes, T., Le Quesne, W.J.F., 2020. Marine plastic litter in the ROPME Sea Area: current knowledge and recommendations. Ecotoxicol. Environ. Saf. 187, 109839. https://doi.org/10.1016/j.ecoenv.2019.109839. Moore, A.B.M., Bolam, T., Lyons, B.P., Ellis, J.R., 2015. Concentrations of trace elements in a rare and threatened coastal shark from the Arabian Gulf (smoothtooth blacktip Carcharhinus leiodon). Mar. Pollut. Bull. 100, 646–650. https://doi.org/10.1016/j. marpolbul.2015.06.005. Naji, A., Esmaili, Z., Khan, F.R., 2017a. Plastic debris and microplastics along the beaches of the Strait of Hormuz, Persian Gulf. Mar. Pollut. Bull. 114, 1057–1062. https://doi. org/10.1016/j.marpolbul.2016.11.032. Naji, A., Esmaili, Z., Mason, S.A., Vethaak, A.D., 2017b. The occurrence of microplastic contamination in littoral sediments of the Persian Gulf, Iran. Environ. Sci. Pollut. Res. 24, 20459–20468. https://doi.org/10.1007/s11356-017-9587-z. Naji, A., Nuri, M., Vethaak, A.D., 2018. Microplastics contamination in molluscs from the northern part of the Persian Gulf. Environmental Pollution 235, 113–120. https:// doi.org/10.1016/j.envpol.2017.12.046. April 2018. Naji, A., Nuri, M., Amiri, P., Niyogi, S., 2019. Small microplastic particles (S-MPPs) in sediments of mangrove ecosystem on the northern coast of the Persian Gulf. Mar. Pollut. Bull. 146, 305–311. NOAA-MDP, 2014. Report on the Entanglement of Marine Species in Marine Debris with an Emphasis on Species in the United States. National Oceanic and Atmospheric Administration Marine Debris Program, Silver Spring, MD, p. 28. North, E.J., Halden, R.U., 2013. Plastics and environmental health: the road ahead. Rev. Environ. Health 28, 1–8. NPC, 2014. Iran’s Petrochemical Industry Report, Annual Report. International Affairs Department, National Petrochemical Company (NPC). Oliveira, M., Almeida, M., 2019. The why and how of micro(nano)plastic research. Trends Anal. Chem. 114, 196–201. https://doi.org/10.1016/j.trac.2019.02.023. Parker, L., 2018. Fast facts about plastic pollution. Natl. Geogr. News. Available at: http s://news.nationalgeographic.com/2018/05/plastics-facts-infographics-ocean-p ollution/. Plastics Europe, 2008. Plastics - the Facts, an Analysis of European Plastics Production, Demand and Waste Data. Association of Plastics Manufactures. Plastics Europe, 2018. Plastics - the Facts, an Analysis of European Plastics Production, Demand and Waste Data. Association of Plastics Manufactures. Provencher, J.F., Vermaire, J.C., Avery-Gomm, S., Braune, B.M., Mallory, M.L., 2018. Garbage in guano? Microplastic debris found in faecal precursors of seabirds known to ingest plastics. Sci. Total Environ. 644, 1477–1484. https://doi.org/10.1016/j. scitotenv.2018.07.101. Reed, S., Clark, M., Thompson, R., Hughes, K.A., 2018. Microplastics in marine sediments near rothera research station, Antarctica. Mar. Pollut. Bull. 133, 460–463. https:// doi.org/10.1016/j.marpolbul.2018.05.068. Rochman, C.M., Browne, M.A., Halpern, B.S., Hentschel, B.T., Hoh, E., Karapanagioti, H., et al., 2013. Classify plastic waste as hazardous. Nature 494, 169–171.

8

S.M. Al-Salem et al.

Marine Environmental Research 159 (2020) 104961 Townsend, T., 2015. Eight million tonnes of plastic are going into the ocean each year. Plastic Waste Washed up on a Beach in Haiti. The Conversation. http://theconversati on.com/eight-million-tonnes-of-plastic-are-going-into-the-ocean-each-year-37521. Uddin, S., Al-Ghadban, A.N., Al Khabbaz, A., 2010. Localized hyper saline waters in arabian Gulf from desalination activity - an example from South Kuwait. Environ. Monit. Assess. 181, 587–594. Uddin, S., Gevao, B., Al-Ghadban, A.N., Nithyandan, M., Al-Shamroukh, D., 2012. Acidification in arabian Gulf – insights from pH and temperature measurements. J. Environ. Monit. 14 (5), 1479–1482. https://doi.org/10.1039/C2EM10867D. Uddin, S., Aba, A., Fowler, S.W., Behbehani, M., Ismaeel, A., Al-Shammari, H., Alboloushi, A., Mietelski, J.W., Al-Ghadban, A., Al-Ghunaim, A., Khabbaz, A., Alboloushi, O., 2015. Radioactivity in the Kuwait marine environment–Baseline measurements and review. Mar. Pollut. Bull. 100, 651–661. Uddin, S., Behbehani, M., Aba, A., Al Ghadban, A.N., 2017. Naturally occurring radioactive material (NORM) in seawater of the northern arabian Gulf – baseline measurements. Mar. Pollut. Bull. 123, 365–372. Uddin, S., Behbehani, M., Al-Ghadban, A., Sajid, S., Al-Zekri, W., Ali, M., Al-Jutaili, S., Al-Musallam, L., Vinod, V., Al-Murad, M., Alam, F., 2018. 210Po concentration in selected calanoid copepods in the northern Arabian Gulf. Mar. Pollut. Bull. 133, 861–864. van der Hal, N., Ariel, A., Angel, D.L., 2017. Exceptionally high abundances of microplastics in the oligotrophic Israeli Mediterranean coastal waters. Mar. Pollut. Bull. 116 (1–2), 151–155. Verma, R., Vinoda, K.S., Papireddy, M., Gowda, A.N.S., 2016. Toxic pollutants from plastic waste- A review. Procedia Environ. Sci 35, 701–708. https://doi.org/ 10.1016/j.proenv.2016.07.069. Wagner, M., Scherer, C., Alvarez-Munor, D., Brennholt, N., Bourrain, X., Buchinger, S., Fries, E., Grosbois, C., Klasmeier, J., Marti, T., Rodriguez-Mozaz, S., Urbatzka, R., Vethaak, A.D., Winther Nielsen, M., Reifferscheid, G., 2014. Microplastics in freshwater ecosystems: what we now and what we need to know. Environ. Sci. Eur. 26, 12–20. World Bank, 2018. World bank national accounts data and OECD national accounts data files. Available at: https://data.worldbank.org/indicator/NY.GDP.MKTP.CD?locat ions¼ZQ. Zafar, S., 2019. Waste management scenario in Oman. Available at: https://www.bio energyconsult.com/waste-oman/. Zdanowicz, M., Johansson, C., 2016. Mechanical and barrier properties of starch-based films plasticized with two- or three component deep eutectic solvents. Carbohydr. Polym. 151, 103–112. https://doi.org/10.1016/j.carbpol.2016.05.061. Zhou, J., Haldeman, A.T., Wagener, E.H., Husson, S.M., 2014. CO2 plasticization and physical aging of perfluorocyclobutyl polymer selective layers. J. Membr. Sci. 454, 398–406. https://doi.org/10.1016/j.memsci.2013.12.044.

Saeed, T., Jandal, N., Al-Mutairi, A., Taqi, H., Zafar, J., 2018. Assessment of the Microplastic Pollution of Kuwait’s Marine Environment, EM076C, Final Report. Kuwait Institute for Scientific Research. Saeed, T., Jandal, N., Mutairi, A., Taqi, H., 2020. Microplastics in Kuwait marine environment: results of first survey. Mar. Pollut. Bull. 152, 110880. Saifaie, A.A., 2013. Waste management in Dubai, envirocities eMagazine. Available at: http://en.envirocitiesmag.com/articles/pdf/waste_management_eng_art1.pdf. Sarafraz, J., Rajabizadeh, M., Kamrani, E., 2016. The preliminary assessment of abundance and composition of marine beach debris in the northern Persian Gulf, Bandar Abbas City, Iran. J. Mar. Biol. Assoc. U. K. 96, 131–135. https://doi.org/ 10.1017/S0025315415002076. Sharma, S., 2012. Global petrochemical industry overview. Proceedings. Indian Petrochem, Mumbai, India. Sheppard, C., Al-Husiani, M., Al-Jamali, F., Al-Yamani, F., Baldwin, R., Bishop, J., Benzoni, F., Dutrieux, E., Dulvy, N.K., Durvasula, S.R.V., Jones, D.A., Loughland, R., Medio, D., Nithyanandan, M., Pilling, G.M., Polikarpov, I., Price, A.R.G., Purkis, S., Riegl, B., Saburova, M., Namin, K.S., Taylor, O., Wilson, S., Zainal, K., 2010. The Gulf: a young sea in decline. Mar. Pollut. Bull. 60, 13–38. https://doi.org/10.1016/j. marpolbul.2009.10.017. Singh, S., Li, S.S., 2012. Bisphenol A and phthalates exhibit similar toxicogenomics and health effects. Gene 494, 85–91. Starck, 2019. Letter to the editor regarding “are we speaking the same language? Recommendations for a definition and categorization framework for plastic debris” environmental science & technology, 53. https://doi.org/10.1021/acs.est.9b01360, 4677 4677. Suaria, G., Avio, C.G., Mineo, A., Lattin, G.L., Magaldi, M.G., Belmonte, G., Moore, C.J., Regoli, F., Aliani, S., 2016. The Mediterranean Plastic Soup: synthetic polymers in Mediterranean surface waters. Sci. Rep. 6, 37551. Symens, P., Werner, M., 1991. Status of the Socotra cormorant in the Arabian Gulf after the 1991 Gulf War oil spill, with an outline of a standardised census technique. In: Krupp, F., Abuzinada, A.H., Nader, I.A. (Eds.), A Marine Wildlife Sanctuary for the Arabian Gulf. Environmental Research and Conservation Following the 1991 Gulf War Oil Spill. NCWCD, Riyadh and Senckenberg Research Institute. Frankfurt a.M. Available at: http://www.jubail-wildlife-sanctuary.info/abstracts/abstracts.html. Terepocki, A.K., Brush, A.T., Kleine, L.U., Shugart, G.W., Hodum, P., 2017. Size and dynamics of microplastic in gastrointestinal tracts of northern fulmars (fulmarus glacialis) and sooty shearwaters (ardenna grisea). Mar. Pollut. Bull. 116, 143–150. Thompson, R.C., Olsen, Y., Mitchell, R.P., Davis, A., Rowland, S.J., John, A.W.G., McGonigle, D., Russel, A.E., 2004. Lost at sea: where is all the plastic? Science 304 (5672), 838. https://doi.org/10.1126/science.1094559.

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