Thrushes (Aves: Passeriformes) as indicators of microplastic pollution in terrestrial environments

Widespread microplastic and nanoplastic contamination in the intestines of birds: A case study from Chengdu, China

Widespread pollution of microplastics (MPs) and nanoplastics (NPs) poses significant threats to organisms and human health. However, the extent of MPs and NPs contamination and their ecological risks to wildlife remain underexplored. In this study, we used Laser Direct Infrared (LDIR) spectroscopy to identify and characterize MPs in the intestinal contents of 49 bird species, and Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) to identify NPs in the intestinal contents of five species. LDIR analysis indicated that chlorinated polyethylene (CPE) and polyvinyl chloride (PVC) were the most prevalent plastics among 32 identified types. MP particle sizes below 100 μm were most abundant, and MPs were predominantly in the form of fragments or pellets. We also found that birds with narrower dietary niche breadth had more MPs. Herbivorous and carnivorous birds had higher MP abundance than omnivorous species, which suggests the capacity of MP accumulation across diet categories. The Polymer Hazard Index (PHI) for MPs revealed that most species sampled were classified at hazard levels III or IV. Py-GC/MS identified four types of NPs in bird intestines, including nylon 66 (PA66), PVC, polyethylene (PE), and polypropylene (PP). This study advances our knowledge of plastic pollution ingested by terrestrial organisms and the risks associated with increased plastic pollution in the environment.

Microplastic contamination in threatened wild felids of India: Understanding environmental uptake, feeding implications, and associated risks

While the presence of microplastics (MPs, <5 mm) in various aquatic organisms is well-documented, studies on the accumulation of MPs in terrestrial predators remain limited worldwide, including in India. This study aims to evaluate, for the first time, the occurrence of MPs in the scat of mid-sized felids-fishing cat and jungle cat-from their overlapping habitat in the Gangetic Estuary of India. The risk assessment of MPs and management recommendation for MP mitigation was also discussed in this context. Notably, our study is the first to report the presence of MPs and mesoplastics in fishing cat from India and jungle cat globally. The abundance of MPs was found to be higher in jungle cat (12.6 ± 1.93 MP/g d.w) compared to fishing cat (10.5 ± 2.12 MP/g d.w) in the Gangetic estuary. Furthermore, fiber-shaped (70.37%) and 1-5 mm-sized (47.73%) MPs predominated in both felid species, while fiber bundles were observed only in jungle cat. Red-colored MPs (27.62%) were predominantly found in fishing cat, whereas transparent MPs (33.33%) were more common in jungle cat. Scanning electron microscopy revealed possible environmental and digestive degradation marks on the MPs. A total of seven synthetic and one natural polymer were identified, with Ethylene Vinyl Alcohol (55.56%) being predominant in fishing cat and Polyethylene (33.33%) more common in jungle cat. Polymer risk assessment indicated that the MPs in fishing cat fall into the danger category, Group IV (PHI 100-1000), while jungle cat possess high threat under extreme danger category, Group V (PHI >1000). The observed MPs and mesoplastics in felids probably come from adjacent environmental uptake and/or accumulate through trophic transfer from prey items. The evidence of MPs in felids may pose a threat to the big cat-Royal Bengal tigers in the Sundarbans. Therefore, various landscape-based policy implementations are recommended to mitigate MP pollution.

Microscopic anthropogenic waste ingestion by small terrestrial European passerines: evidence from finch and tit families

Microscopic anthropogenic waste (MAW) has become a major environmental concern worldwide. Our study aimed to assess the accumulation of MAW in the gastrointestinal tracts of nine common European passerine species from finch (Fringillidae) and tit (Paridae) families, and evaluate their suitability for environmental monitoring. We searched for MAW in the birds' stomachs and intestines and identified suspected particles using Raman microspectroscopy. In total, we found 57 MAW particles in 31 out of 149 analyzed individuals, 7 of which were microplastics (polyethylene, polyethylene terephthalate, polystyrene), 1 was identified as carbon nanotube, while 49 were cellulosic-based (cotton, cellulose, rayon, viscose). The generalized linear mixed models identified bird family and time in season as significant predictors of MAW ingestion. Finches ingested more MAW than tits, and higher ingestion rates were observed during the non-breeding period. Other predictors, including bird sex, age, gastrointestinal tract section, and site, showed varying but non-significant effects. As predicted, the studied species exhibited a lower ingestion rate of MAW compared to terrestrial birds studied so far, possibly due to their diet and feeding behavior. Given that these species are prey for many avian and non-avian predators, they may contribute to the transfer of MAW to higher trophic levels.

High microplastic pollution in birds of urban waterbodies revealed by non-invasively collected faecal samples

Plastic waste concentrates in aquatic environments, where wildlife can ingest or absorb it. In birds, plastic particles have been identified in hundreds of aquatic and terrestrial species leading to adverse effects. Most studies investigating microplastic pollution in birds use dead individuals or invasive techniques. However, microplastic ingestion can also be determined by analysing birds' faeces. There is a lack of information regarding microplastic pollution of birds inhabiting urban freshwaters, where very high pollution levels are expected. We analysed body condition of individual birds inhabiting freshwaters in the city of Münster (Germany) and microplastic contamination in their faeces. We found microplastic particles (mainly fibres) in all species (Mallard Anas platyrhynchos, Jack Snipe Lymnocryptes minimus, Black-headed Gull Chroicocephalus ridibundus and Common Moorhen Gallinula chloropus) and most samples (98 %). Microplastic pollution ranged from 0.26 to 72.03 particles per mg faeces. The observed microplastic pollution frequency and pollution levels were much higher compared to other studies of birds in freshwater environments, probably resulting from the high contamination of urban waters. We found no effect of the number of microplastic particles on body condition. As all investigated species are at least partially migratory, a long-distance transport of microplastic particles may increase the probability that migratory birds transport (and excrete) microplastic particles to remote locations that otherwise suffer from little anthropogenic pollution. We demonstrate that non-invasively collected faecal samples collected during bird ringing/banding can be used as indicators of microplastic pollution, and call for more studies investigating the effects of microplastics on birds - with a special focus on urban freshwaters.

Microplastic Contamination of the Turkish Worm Lizard (Blanus strauchi Bedriaga, 1884) in Muğla Province (Türkiye)

Because of their diversity, microplastics (MPs), which are synthetic particles smaller than 5 mm, are highly bioavailable and widely distributed. The prevalence of microplastics in aquatic habitats has been extensively studied but less is known about their presence in terrestrial environments and biota. This study examined MP intake in terrestrial environments utilizing gastrointestinal tracts (GITs), with a particular focus on the Turkish worm lizard (Blanus strauchi). Suspected particles discovered in the GITs were removed, measured, and characterized based on size, shape, color, and polymer type in order to evaluate MP ingestion. Out of 118 samples analyzed, 29 specimens (or 24.57%) had microplastic particlesMP length did not significantly correlate with snout-vent length (SVL) and weight. These correlations were tested to determine whether the size or weight of Blanus strauchi influenced the amount or size of MPs found within the GITs. Also, MP consumption by the worm lizard did not correlate with the year of sampling. All particles identified as fibers through FT-IR spectroscopy analysis. The most common type of microplastic was polyethylene terephthalate (PET). The most often detected color was blue, with mean MP lengths ranging from 133 µm to 2929 µm. It has been demonstrated that worm lizards inhabiting soil or sheltering under stones in bushy areas with sparse vegetation consume MPs. Predation is regarded to be the most likely way through which MPs infiltrate terrestrial food webs.

Tire-Road-Wear Particles and Glass Beads in the Gizzard of the Endangered Terrestrial Bird, Okinawa Rail (Hypotaenidia okinawae)

This study analyzed microplastics and glass beads (GBs; an indicator of traffic-derived particulate contamination) in 42 gizzards of an endangered terrestrial bird, the Okinawa rail (Hypotaenidia okinawae). Black rubber fragments (BRs) were found in 57% of the specimens (1-184 items/individuals), and GBs were found in 48% (1-32 items/ind.). FTIR identified the rubbers as the same materials used in tire tread. A significant positive correlation was found between abundances of BRs and GBs in the gizzards (p < 0.01), suggesting the same source and exposure pathway. Large quantities of BRs, namely tire-road-wear particles (TRWPs), were also found in environmental samples (road dust, roadside soil, and side-ditch sediment) and diet organisms of the Okinawa rail (earthworm, millipede, and snail). The characteristics of these particles (appearance, material type, and size distribution) were consistent between the gizzard contents and the environmental samples. The concentration ratio of GBs and BRs in the Okinawa rail was similar to that in side-ditch sediment and diet organisms, especially earthworms. These results indicate that Okinawa rails are exposed to traffic-derived contaminants including TRWPs via ground-feeding along the roadside. To our knowledge, this is the first evidence of TRWPs exposure in terrestrial bird species.

Species-specific accumulation of microplastics in different bird species from South China: A comprehensive analysis

Microplastics are widespread in many bird species, but the inter-specific variations of microplastic contamination are still unclear. The present study measured microplastics in 24 bird species from South China and investigated the impacts of bird physiological and ecological traits on microplastic contamination. The median abundances of microplastics ranged between 5-167 particles per individual or 0.023-3.58 particles per g body weight. Approximately 60 % of microplastics were within the size range 20-50 µm, with the primary polymer types of polypropylene (PP) and polyethylene terephthalate (PET). There was no significant correlation between microplastic abundances and bird body weights and trophic levels (δ15N) in different bird species. Insectivorous birds had significantly higher abundances of microplastics smaller than 0.1 mm than granivorous, piscivorous, and carnivorous birds (p < 0.01), which was further supported by the meta-analysis of microplastic contamination in birds. On contrary, meta-analysis results indicate that piscivorous birds tend to accumulate larger microplastics (> 1 mm) than other bird species. Microplastic contamination in different bird species was more influenced by diet source rather than trophic level and body weight. Potential ecotoxicological risks were observed for most insectivorous species in the preliminary risk assessment. Particular concern should be paid on insectivorous birds, which have been scarcely studied for microplastics but were at high exposure risks of microplastics among bird species.

Characterization of plastic ingestion in urban gull chicks and its implications for their use as pollution sentinels in coastal cities

The increase of plastic pollution represents a significant ecological threat, particularly in human-impacted environments. However, the effects of plastic ingestion by urban wildlife are less understood. This study investigates the presence of microplastic (MPs; plastic <5 mm in size) and macroplastics (MaPs, plastic >5 mm in size) in yellow-legged gull (Larus michahellis) chicks inhabiting the urban marine ecosystem of Barcelona (northeastern Spain). The stomach contents of 56 gull chicks were analysed, revealing the presence of MPs in 100 % of the individuals and MaPs in 19.64 % of individuals. Additionally, trophic analysis, through stomach content and stable isotope determination, identified links between diet and plastic ingestion, with diet diversity associated with higher MaP abundance. These results highlight the high presence of plastics in the early stages of an urban-dwelling wildlife species and open the potential role of the use of urban gull chicks as sentinels of marine and terrestrial pollution in urban coastal areas. The findings suggest that chicks can serve as bioindicators of plastic pollution, emphasizing the urgent need to address the high levels of plastic contamination in urban environments.

Unscrambling why plastics aren't detectable in chicken eggs

Several food groups have been reported to contain varying concentrations of plastics. This study was designed to quantitatively investigate for the first time in Australia the presence of plastics in store-bought chicken eggs. Three commonly consumed brands of free-range, free-range organic, barn-laid and backyard (home-laid) chicken egg samples were analyzed for seven common polymers (i.e., polypropylene, polyethylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, poly-(methylmethacrylate) and polycarbonate). Samples were extracted by enzyme digestion and pressurized liquid extraction, followed by quantitative analysis through double-shot microfurnace pyrolysis coupled to gas chromatography-mass spectrometry. No plastics were detected at concentrations > limit of detection (LOD) (from 0.04 μg/g for PS to 0.22 μg/g for PVC) in the egg samples analyzed, regardless of brand and category, suggesting limited exposure of Australians to plastics from consuming eggs This study provides valuable baseline data and underscores the importance of continued monitoring to ensure the safety and integrity of food supplies in the face of rising environmental plastic pollution.

Exposure to polystyrene microplastics reduces sociality and brain oxytocin levels through the gut-brain axis in mice

The rising global prevalence of microplastics (MPs) has highlighted their diverse toxicological effects. The oxytocin (OT) system in mammals, deeply intertwined with social behaviors, is recognized to be vulnerable to environmental stressors. We hypothesized that MP exposure might disrupt this system, a topic not extensively studied. We investigated the effects of MPs on behavioral neuroendocrinology via the gut-brain axis by exposing adolescent male C57BL/6 mice to varied sizes (5 μm and 50 μm) and concentrations (100 μg/L and 1000 μg/L) of polystyrene MPs over 10 weeks. The results demonstrated that exposure to 50 μm MPs significantly reduced colonic mucin production and induced substantial alterations in gut microbiota. Notably, the 50 μm-100 μg/L group showed a significant reduction in OT content within the medial prefrontal cortex and associated deficits in sociality, along with damage to the blood-brain barrier. Importantly, blocking the vagal pathway ameliorated these behavioral impairments, emphasizing the pivotal role of the gut-brain axis in mediating neurobehavioral outcomes. Our findings confirm the toxicity of MPs on sociality and the corresponding neuroendocrine systems, shedding light on the potential hazards and adverse effects of environmental MPs exposure on social behavior and neuroendocrine frameworks in social mammals, including humans.

The Presence of Microplastics in the Gastrointestinal Tracts of Song Thrushes (Turdus philomelos) Wintering in Apulia (Southern Italy)-Preliminary Results

The term microplastics (MPs) describes a heterogeneous mixture of particles that can vary in size, color, and shape. Once released into the environment, MPs have various toxicological and physical effects on wildlife. The Song Thrush (Turdus philomelos) is a migratory species, staying in Italy in late autumn and winter. The aim of this study is to assess, quantify, and characterize the presence of microplastics in Song Thrushes hunted in the Apulia region of Italy. The birds (n = 360) were hunted in the Bari countryside and donated for research purposes by hunters. MPs were classified in relation to their shape in fibers, films, fragments, and pellets; then, they were divided according to their color and the length of the particles was measured. Nikon image analysis software was applied to the litter size measurements. Of the total of 360 birds, MPs were detected in the stomachs of 129 birds shot in December and 128 birds shot in January. The majority of ingested MPs were fibers that were observed in all contaminated birds. Film fragments were observed in every contaminated specimen. Among all the MPs found, 31.75% were red, 30.13% were black, and 25.91% were blue, while the other colors were less represented. This study provides the first analysis of MPs bioaccumulation in Song Thrushes wintering in the Apulia region, and the high contamination of thrushes confirmed the ubiquity of MPs in terrestrial ecosystems.

Microfibers in the Diet of a Highly Aerial Bird, the Common Swift Apus apus

Microplastic pollution is a pervasive global issue affecting various ecosystems. Despite the escalating production and well-documented contamination in both aquatic and terrestrial environments, the research focused on airborne microplastics and their interaction with terrestrial birds remains limited. In this study, we collected fecal sacs from Common swifts (Apus apus) to investigate their diet and to evaluate the potential ingestion of microplastics by both adults and nestlings. The diet was mainly composed of Hymenoptera and Coleoptera and did not differ among sexes and age classes. The 33% of nestlings' and 52% of adults' fecal sacs contained anthropogenic items, the totality of which was in the shape form of fibers. The 19.4% of the anthropogenic items were chemically characterized as microplastics, either polyethylene terephthalate (PET; two microfibers) or cellophane (four microfibers). Airborne anthropogenic items, including microplastic, might be passively ingested during the Common swift aerial feeding. In addition, our findings suggest that these ingested microparticles have the potential to be transferred to the offspring through food. While further research is essential to elucidate the pathways of microplastic ingestion, our results reinforce the evidence of the transfer of anthropogenic items from the atmosphere to the biota.

Terrestrial wildlife as indicators of microplastic pollution in western Thailand

Plastic pollution in terrestrial wildlife represents a new conservation challenge, with research in this area, especially within protected areas (PAs), being scant. This study documents the accumulation of microplastics (MPs) in terrestrial wildlife both inside and outside PAs in western Thailand. Carcasses of road-killed vertebrates in good condition, as well as live tadpoles, were collected to examine their exposure to plastic pollution. The digestive tracts of the vertebrate carcasses and the entire bodies of tadpoles were analyzed for MPs, which were identified if they measured over 50 µm. A total of 136 individuals from 48 vertebrate species were examined. The sample comprised snakes (44.12%), birds (11.03%), lizards (5.15%), tadpoles (32.25%), amphibians (5.88%), and mammals (1.47%). In total, 387 MPs were found in 44 species (91.67%), with an average occurrence of 3.25 ± 3.63 MPs per individual or 0.05 ± 0.08 MPs per gram of body weight. The quantities of MPs significantly varied among the animal groups, both in terms of number per individual (p < 0.05) and number per gram of body weight (p < 0.01). Furthermore, a significant difference in MP quantities was observed between specimens collected inside and outside PAs on an individual basis (p < 0.05), but not on a body weight basis (p = 0.07). Most MPs were fibers (77%), followed by fragments (22.22%), with only a minimal presence of film (0.52%) and foam (0.26%). Of all the MPs identified, 36.84% were confirmed as plastics or fibers made from natural materials, and 31.58% were plastics, including Polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), Polyvinylidene chloride (PVDC), and polyester (PES). Additionally, fibers made of cotton, and those containing polyurethane (PU), rayon, PES, and combinations of rayon and PU, were identified. The quantities of MPs were significantly influenced by animal body weight, factors associated with human settlement/activity, and land use types. Our findings highlight the prevalence of plastic pollution in terrestrial vertebrates within Thai PAs. Further toxicological studies are required to establish plastic pollution standards. It is proposed that snakes, obtained from road kills, could serve as a non-invasive method for monitoring plastic pollution, thus acting as an indicator of the pollution threat to species within terrestrial ecosystems. There is an urgent need for the standardization of solid waste management at garbage dump sites in remote areas, especially within PAs. Conservation education focusing on MP occurrence, potential sources, and impacts could enhance awareness, thereby influencing changes in behaviors and attitudes toward plastic waste management at the household level.

Birds as bioindicators of plastic pollution in terrestrial and freshwater environments: A 30-year review

Plastic pollution is a global concern that has grown ever more acute in recent years. Most research has focused on the impact of plastic pollution in marine environments. However, plastic is increasingly being detected in terrestrial and freshwater environments with key inland sources including landfills, where it is accessible to a wide range of organisms. Birds are effective bioindicators of pollutants for many reasons, including their high mobility and high intra- and interspecific variation in trophic levels. Freshwater and terrestrial bird species are under-represented in plastic pollution research compared to marine species. We reviewed 106 studies (spanning from 1994 onwards) that have detected plastics in bird species dwelling in freshwater and/or terrestrial habitats, identifying knowledge gaps. Seventy-two studies focused solely on macroplastics (fragments >5 mm), compared to 22 microplastic (fragments <5 mm) studies. A further 12 studies identified plastics as both microplastics and macroplastics. No study investigated nanoplastic (particles <100 nm) exposure. Research to date has geographical and species' biases while ignoring nanoplastic sequestration in free-living freshwater, terrestrial and marine bird species. Building on the baseline search presented here, we urge researchers to develop and validate standardised field sampling techniques and laboratory analytical protocols such as Raman spectroscopy to allow for the quantification and identification of micro- and nanoplastics in terrestrial and freshwater environments and the species therein. Future studies should consistently report the internalised and background concentrations, types, sizes and forms of plastics. This will enable a better understanding of the sources of plastic pollution and their routes of exposure to birds of terrestrial and freshwater environments, providing a more comprehensive insight into the potential impacts on birds.

White Stork Pellets: Non-Invasive Solution to Monitor Anthropogenic Particle Pollution

The present study applied a non-invasive method to analyse anthropogenic particles and prey items in white stork (Ciconia ciconia) pellets. Pellets (n = 20) were obtained from white stork nests during the 2020 breeding season from two sites in Croatia. In total, 7869 anthropogenic particles were isolated. The majority of particles were fragments, while previous studies on other birds often reported fibres. An ATR-FTIR polymer analysis detected glass and construction and building materials, as well as several compounds associated with plastic masses. Polymer investigation revealed the presence of dotriacontane and octacosane, which are by-products of polyethylene (PE) degradation and transformation. Additionally, the detection of vinylidene chloride (VDC) highlights the historical contribution of polyvinylidene chloride (PVDC) to plastic pollution. Significant variation in particle quantity and size between the sampling sites was detected, with larger particles found at sites associated with the metal mechanical engineering industry and agriculture. Prey assessment revealed chitin remains of large insects such as Orthoptera and Coleoptera. This research confirms the potential of pellet analysis as a valuable tool for assessing the presence of anthropogenic particles in the environment. However, further research is needed to fully understand the extent of particle ingestion, particle sources and potential impact.

Accumulation of microplastics in predatory birds near a densely populated urban area

The pollution due to plastic and other anthropogenic particles has steadily increased over the last few decades, presenting a significant threat to the environment and organisms, including avian species. This research aimed to investigate the occurrence of anthropogenic pollutants in the digestive and respiratory systems of four birds of prey: Common Buzzard (Buteo buteo), Black Kite (Milvus migrans), Eurasian Sparrowhawk (Accipiter nisus), and Northern Goshawk (Accipiter gentilis). The results revealed widespread contamination in all species with microplastics (MPs) and cellulosic anthropogenic fibers (AFs), with an average of 7.9 MPs and 9.2 AFs per specimen. Every digestive system contained at least one MP, while 65 % of specimens exhibited MPs in their respiratory systems. This is the work reporting a high incidence of MPs in the respiratory system of birds, clearly indicating inhalation as a pathway for exposure to plastic pollution. The content of MPs and AFs varied significantly when comparing specimens collected from central Madrid with those recovered from other parts of the region, including rural environments, suburban areas, or less populated cities. This result aligns with the assumption that anthropogenic particles disperse from urban centers to surrounding areas. Additionally, the dominant particle shape consisted of small-sized fibers (> 98 %), primarily composed of polyester, polyethylene, acrylic materials, and cellulose fibers exhibiting indicators of industrial treatment. These findings emphasize the necessity for further research on the impact of plastic and other anthropogenic material contamination in avian species, calling for effective strategies to mitigate plastic pollution.

Biovectoring of plastic by white storks from a landfill to a complex of salt ponds and marshes

Research into plastic pollution has extensively focused on abiotic vectors, overlooking transport by animals. Opportunistic birds, such as white storks (Ciconia ciconia) often forage on landfills, where plastic abounds. We assess plastic loading by ingestion and regurgitation of landfill plastic in Cadiz Bay, a major stopover area for migratory white storks in south-west Spain. On average, we counted 599 storks per day moving between a landfill and a complex of salt ponds and marshes, where they regurgitated pellets that each contained a mean of 0.47 g of plastic debris, dominated by polyethylene. Modelling reliant on GPS tracking estimated that 99 kg and >2 million particles of plastic were biovectored into the wetland during 2022, with seasonal peaks that followed migration patterns. GPS data enabled the correction of field censuses and the identification of plastic deposition hotspots. This study highlights the important role that biovectoring plays in plastic transport into coastal wetlands.

Microplastic Quantification in Aquatic Birds: Biomonitoring the Environmental Health of the Panjkora River Freshwater Ecosystem in Pakistan

Microplastic pollution has become a global concern, with potential negative impacts on various ecosystems and wildlife species. Among these species, ducks (Anas platyrhynchos) are particularly vulnerable due to their feeding habits and proximity to aquatic environments contaminated with microplastics. The current study was designed to monitor microplastic (MP) pollutants in the freshwater ecosystem of the Panjkora River, Lower Dir, Pakistan. A total of twenty (20) duck samples were brought up for four months and 13 days on the banks of the river, with no food intake outside the river. When they reached an average weight of 2.41 ± 0.53 kg, all samples were sacrificed, dissected, and transported in an ice box to the laboratory for further analysis. After sample preparation, such as digestion with 10% potassium hydroxide (KOH), density separation, filtration, and identification, the MP content was counted. A total of 2033 MP particles were recovered from 20 ducks with a mean value of 44.6 ± 15.8 MPs/crop and 57.05 ± 18.7 MPs/gizzard. MPs detected in surface water were 31.2 ± 15.5 MPs/L. The major shape types of MPs recovered were fragments in crop (67%) and gizzard (58%) samples and fibers in surface water (56%). Other types of particles recovered were fibers, sheets, and foams. The majority of these detected MP particles were in the size range of 300-500 µm (63%) in crops, and 50-150 µm (55%) in gizzards, while in water samples the most detected particles were in the range of 150-300 µm (61%). Chemical characterization by FTIR found six types of polymers. Low-density polyethylene (LDPE) had the greatest polymer detection rate (39.2%), followed by polyvinyl chloride (PVC) (28.3%), high-density polyethylene (HDPE) (22.7%), polystyrene (6.6%), co-polymerized polypropylene (2.5%), and polypropylene homopolymer (0.7%). This study investigated the presence of microplastics in the crops and gizzards of ducks, as well as in river surface water. The results revealed the significant and pervasive occurrence of microplastics in both the avian digestive systems and the surrounding water environment. These findings highlight the potential threat of microplastic pollution to wildlife and ecosystems, emphasizing the need for further research and effective mitigation strategies to address this pressing environmental concern.

First Report on Microplastics Quantification in Poultry Chicken and Potential Human Health Risks in Pakistan

Microplastics (MPs) are an emerging environmental health concern due to their widespread occurrence in food sources such as fish, meat, chicken, honey, sugar, salt, tea and drinking water, thereby posing possible risks to human health. This study aimed to observe the existence of MPs in the crop and gizzard of the farm chicken, a significant food source in Pakistan. Twenty-four chicken samples were taken from eight poultry farms across Punjab, Pakistan. A total of 1227 MP particles were found from 24 samples (crop and gizzards) originating from the 8 poultry farms. In all, 429 MP particles were found in 24 chicken crops, with a mean of 17.8 ± 12.1 MPs/crop. In contrast, 798 MP particles were found in 24 chicken gizzards, with a mean of 33.25 ± 17.8 MPs/gizzard. Comparatively larger particles, ranging between 300-500 µm, were more abundant (63%) than other considered sizes (300-150 µm [21%] and 150-50 µm [16%]). Additionally, fragments were the dominant type of shape in both sample types (crop [64%] and gizzard [53%]). The predominant colours of particles extracted from gizzards and crops were yellow (32%) and red (32%), respectively. Chemical characterisation of these particles detected four types of polymers: polyvinyl chloride (PVC) at 51.2%, followed by low-density polyethylene (LDPE) at 30.7%, polystyrene (PS) at 13.6% and polypropylene homopolymer (PPH) at 4.5%. In conclusion, we provide evidence for MPs in the gizzards and crops of farmed chickens which may originate from contaminated poultry feed. Only a few studies have been reported globally to assess MPs ingestion in chickens. The current study is the first report from Pakistan. It could be a valuable addition to support MPs literature to establish a relationship between MPs contamination and intake through the food chain.

Microplastic Pollution: Chemical Characterization and Impact on Wildlife

Microplastics are small pieces of plastic that are less than 5 mm in size and can be found in most environments, including the oceans, rivers, and air. These small plastic particles can have negative impacts on wildlife and the environment. In this review of the literature, we analyze the presence of microplastics in various species of wildlife, including fish, birds, and mammals. We describe a variety of analytical techniques, such as microscopy and spectrometry, which identify and quantify the microplastics in the samples. In addition, techniques of sample preparation are discussed. Summary results show that microplastics are present in all the wildlife species studied, with the highest concentrations often found in fish and birds. The literature suggests that microplastics are widely distributed in the environment and have the potential to affect a wide range of species. Further research is required to fully understand the impacts of microplastics on wildlife and the environment.