Abundance and distribution of marine litter on the beaches of Okinawa Island, Japan.

This study evaluated the distribution and abundance of marine litter on 30 beaches around Okinawa Island, Japan. Beach quality indices and multivariate statistical analyses were used to assess the quality of the beaches and their pollution patterns. A total of 11,626 items weighing 513.49 kg with an average density of 0.13 ± 0.10 items/m2 were collected. Litter was dominated by plastics (81.72 %), broken glass (8.38 %), and cigarette butts (7.44 %), and 74.05 % of total litter was from land-based sources. Single-use plastics (SUPs) were present in all surveyed beaches and made up 30.54 % of the total litter. The clean coast index (CCI), plastic abundance index (PAI), and hazardous index (HI) were between 0.1 and 7.6, 0.1-4.0 and 0.01-1.42, respectively, indicating low to moderate levels of pollution of Okinawan beaches. This study should aid in the formation of strategies to deal with marine litter in Okinawa, other areas of Japan and the Asia-Pacific region.

Preliminary characterization and probabilistic risk assessment of microplastics and potentially toxic elements (PTEs) in garri (cassava flake), a common staple food consumed in West Africa.

Garri from cassava is one of the most consumed foods in West Africa, hence this research was conducted to examine microplastics (MPs) and potentially toxic elements (PTEs) in garri from Nigeria (West Africa) and Japan. This is the first investigation on MPs in garri samples that has been reported in the literature. The study analyzed both packaged and unpackaged vended garri samples using microscopic/spectroscopic and X-ray fluorescence techniques for MPs and PTEs respectively. Microplastic particles in the garri samples ranged from (or were between) 2.00±2.00 - 175.00±25.16 particles/50 with > 90 % as fragments and consisted of polyacrylamide, polyethylene terepthalate, polyvinyl alcohol, high density polyethylene, polyvinyl chloride acrylonitrile, polyethylene chlorinated, polypropylene with silicate mix, polychloroprene and polyethylene chlorosulphonated. The mean concentration of PTEs raged from ND to 0.07 mg/g for Cr and Mn, 0.73 to 5.63 mg/g for Fe, ND to 0.57mg/g for Co, 0.23 to 1.21 mg/g for Ni, 0.15 to 1.53 mg/g for Cu, and 0.12 to 0.63 mg/g for Zn. However, their daily intake was low for both adult and children as with the MPs. The sources of MPs and PTEs were mainly from the garri production processes, atmospheric dusts and during packaging. The non-carcinogenic risk for all samples was low for MPs while in openly vended garri, Ni and Cr in all sample poses carcinogenic risks. There is a need to improve indigenous garri processing techniques to minimize contamination. This research emphasizes the critical necessity to understand the consequences of MPs on human health.

Review of microplastics in museum specimens: An under-utilized tool to better understand the Plasticene.

This study summarises the status of microplastic research in marine and freshwater specimens in natural museum collections around the world. Abundances, distributions, and types of microplastics in the archived collections are discussed. Museum collections can fill knowledge gaps on evolution of microplastic pollution before and during the Plasticene era. The specimens in these studies, ranging from plankton to vertebrates, were collected and archived between 1900 and 2019, and are dominated by specimens from marine ecosystems. All the specimens included in this review were preserved by freezing or in ethanol/formaldehyde except for specimens in one study that were preserved via cryomilling. Microfibers were the most common microplastics in the reviewed studies. We recommend more microplastic studies over a wider taxonomic range of species and across a longer span of years utilizing archival specimen collections around the world in order to establish reference points and develop temporal trends for microplastic pollution of the environment.

Impact of polystyrene microplastic exposure on lipid profile and oxidative stress status of male and female Wistar rats.

Microplastics (MPs) are currently global environmental pollutants, and their associated health risks cannot be ignored. However, research on MP toxicity in mammals is limited. We investigated the effects of polystyrene microplastic (PS-MP) particles on the lipid profile and oxidative stress markers of Wistar rats. Two forms of PS-MP-pristine polystyrene and Styrofoam microplastics-particles of diameter <5 mm were used in this study. Each form was separately incorporated into rat feed in varying proportions of 1, 5 and 10%. A total of seventy rats (thirty-five male and thirty-five female rats) were used for this study and were separately distributed into seven groups of five rats each. The rats were then randomly assigned to a control group which received normal rat feed and water and six (6) test groups which were fed varying percentages (1, 5 and 10) of polystyrene microplastics diet for a period of 90 days. The rats were sacrificed under mild diethyl ether anesthesia 12 hr after cessation of treatment and blood was collected for lipid profile and oxidative stress analyses. Results obtained showed that oral exposure to microplastics caused decreased high density lipoprotein cholesterol (HDL-C) and increased low density lipoprotein cholesterol (LDL-C) in the rats. In contrast, there were no significant changes in oxidative stress parameters in the rats following microplastics exposure. Atherogenic indices in the PS-MP exposed rats differed according to gender. These results indicated that PS-MP dietary exposure may lead to dyslipidemia and male rats had higher cardiovascular risk.

Spatiotemporal variations in marine litter along the Gulf of Guinea coastline, Araromi seaside, Nigeria.

This study assessed the seasonal variation in the magnitude of marine litter along the Gulf of Guinea coastline, Araromi seaside, Nigeria with a survey of twenty sampling sites. The total number of litter items collected was 29,029 comprising 7358 and 21,671 items in the dry and rainy season respectively. The average number of items per square meter was higher in the rainy season (1.80 ± 0.35) than in the dry season (0.61 ± 0.19). Plastic materials dominated the litter composition with 86 % and 91.8 % in the dry and rainy season respectively. The beach cleanliness assessed as clean coast index (CCI) depicted the beach as dirty (12.26 ± 3.74) during the dry season and extremely dirty (36.13 ± 6.91) in the rainy season. The hazardous item index (HII) also showed the coastline was littered with hazardous items. These results provide baseline data for marine litter management along the Gulf of Guinea coastlines and other coastlines in Africa.

Chronic toxic effects of polystyrene microplastics on reproductive parameters of male rats.

Microplastics have become a significant environmental concern. However, information on toxicity of microplastics in terrestrial organisms is limited. In this study, the chronic toxic effects of polystyrene microplastics (PS-MPs) on the reproductive system and serum antioxidants of male albino Wistar rats fed for 90 days with standard rat feed containing 1-10% granules of crushed polystyrene disposable plates were evaluated. Significant reductions in volume, motility, epididymal sperm count and serum testosterone level were observed. Histological examination of testicular architecture showed distorted testes with vacuolated seminiferous tubules at the highest percentage, together with increased catalase and decreased superoxide dismutase activities. This study showed that ingestion of PS-MPs caused reproductive dysfunction in male rats and contributes to understanding the potential toxicity of microplastics in terrestrial animals.

Assessment of heavy metal pollution in soils and health risk consequences of human exposure within the vicinity of hot mix asphalt plants in Rivers State, Nigeria.

This study evaluated the level of heavy metal pollution in soils within the vicinity of hot mix asphalt (HMA) plants and the health risk consequences of human exposure to the heavy metals. Soil samples collected from two asphalt plants during dry and rainy seasons were analyzed for Cr, Co, Cu, Ni, Mn, Cd, Pb, and Zn with atomic absorption spectrophotometer (AAS). Health risk indices were assessed as chronic daily intake (CDI), hazard quotient (HQ), hazard index (HI), and carcinogenic risk (CR) while the degree of pollution was assessed with geo-accumulation index (Igeo) and contamination factor (CF). The pollution assessment revealed that the soil samples were moderately to highly polluted with Cd. In both seasons, Zn and Mn, respectively, had the highest CDI values for ingestion, inhalation, and dermal route for both asphalt plants while Cd has the least CDI values for all the routes in both plants. The HQ and HI values for all the metals were less than 1.00E + 00 indicating no non-carcinogenic risk from exposure to any of the metals. Furthermore, the dermal route was found to be the least likely model for health risks associated with human exposure to soil heavy metals within the vicinity of the plants. The CR values for the metals were also within threshold value indicating non-significant cancer risk from exposure to the metals. Though no significant health risks were observed in the study, clean and efficient production of hot mix asphalt should be encouraged to minimize health risks and environmental pollution during production and usage.