The first evidence of microplastic presence in the River Nile in Khartoum, Sudan: Using Nile Tilapia fish as a bio-indicator

Integrated analysis of microplastics origins and impact on prominent aquaculture ecosystems in Bangladesh

Microplastics (MPs) have become a pressing environmental challenge in aquaculture-farmed ponds, particularly in Bangladesh, where research on their prevalence and impact is sparse. This research systematically investigates the distribution, abundance, and features of MPs in water and fish from aquaculture ponds in the western region of Bangladesh. The study reveals that MPs were widespread in water samples, with quantities ranging from 0.095 to 0.36 items/L, predominantly fibers accounted for 60.86 % of the total, followed by 26.08 % fragments, 11.30 % lines, and 1.76 % pellets. Fish samples demonstrated an average MP concentration of 1.19 items/g (23.37 items/individual), in fish gill ranging from 1.05 to 5.04 items/g and in GIT 0.40 to 2.26 items/g across eleven species, predominantly fibers with a 100 % detection rate, showing variability in MP concentration based on tissue type, species, and feeding habits. Fourier transform infrared spectroscopy (FT-IR) was employed to analyze the polymer composition, revealing significant proportions of SSP (W-43.17 %, F-35.22 %), PE (W-5.06 %, F-23.14 %), PP (W-5.57 %, F-8.19 %), nylon (W-15.76 %, F-14.84 %), PVC (W-7.16 %, F-3.58 %), and acrylic (W-5.57 %, F-4.93 %). Strong correlations were found between fish size and MP abundance, indicating that pond environmental contamination is a significant factor in MP ingestion. Pollution risk assessment revealed high contamination MP levels in both water and fish. Among the probable sources, MPs contributions are from agricultural runoff, tires of vehicles (each 14.11 %), fishing nets, fish feed, household wastage, plastic-made feeding equipment, laundry wastage (each 11.76 %), and so on. The research underscores the need for further research on MP exposure to human health and sustainable aquaculture production practices.

Occurrence and characteristics of microplastics in South African beverages

This study presents the first comprehensive assessment of microplastics (MPs) in alcoholic (AB) and non-alcohol (NAB) beverages in South Africa. Beverages in various packaging materials, specifically glass, aluminium, and polyethylene terephthalate (PET) were tested for MP content. The samples were filtered and digested, then stained with Rose Bengal dye to facilitate particle identification, followed by physical and chemical characterisation using stereomicroscopy and micro-Raman spectroscopy, respectively. Fibers were the prevalent shape observed in AB packaged in glass, as well as in NAB (PET), and NAB (Aluminium). The Aluminium samples also exhibited a high abundance of fragments. Multivariate principal component analysis and Pearson correlation coefficient matrix revealed positive correlations between fibers of size ranges 0.02-0.1 mm and 0.1-0.5 mm in NAB samples. While in AB samples, the ranges were observed to be 1-2 mm and 2-3 mm. Six polymers were identified, namely: polypropylene (PP), polyethylene (PE), polyurethane (PU), polyamide (PA), PET, and polybutylene terephthalate (PBT). This study offers a holistic appraisal of MPs in commercially sold beverages in South Africa. It establishes a framework for assessing the socioeconomic impacts of MPs, including their commercial, environmental, social, and sustainability implications.

A review of the ecotoxicological status of microplastic pollution in African freshwater systems

Microplastics (MPs) have found extensive application globally due to their low cost, flexibility and light weight. Microplastic pollution is a growing environmental concern that poses significant threats to aquatic ecosystems worldwide, including African freshwater systems. Nevertheless, although Africa houses some of the deepest and largest freshwater rivers and lakes in the world such as Lake Tanganyika and Victoria, River Congo and the Nile, there is limited information available regarding the presence of MPs in these inland waters. Selected published data on MPs in African freshwater systems, including sediments, biota, rivers, and lakes, were incorporated in this review. The study discovered that the sampling technique employed has a major impact on the morphological characteristics and abundance of MPs in African freshwater systems. Fibers and fragments were the most common shapes; black, white, and transparent were the most prevalent colors; and polyethene terephthalate, polystyrene, and polypropylene were the frequently dominant polymers. As the distance between the sampling sites increased geographically, the polymer similarities declined. MPs have been found to translocate into body cells and tissues where they are capable of causing genetic mutations, cytotoxicity, oxidative stress and neurotoxicity. In Africa, MPs are poorly managed and monitored, and there has been insufficient research done on the possibility that they could be present in drinking water. Considering the fact that humans in the continent are exposed to freshwater and aquatic organisms, the risk assessment routes are currently unvalidated, therefore it was recommended that African nations should strengthen their capacity for plastic management and environmental monitoring. This review provides up to date information on the occurrence, prevalence, ecotoxicity and management of MPs across African freshwater systems.

Detection and characterisation of microplastics in tap water from Gauteng, South Africa

This study reports the presence, concentration, and characteristics of microplastics (MPs) in tap water in three suburbs in Gauteng Province in South Africa. Physical characterisation was conducted using stereomicroscopy and scanning electron microscopy following staining of MPs with the Rose Bengal dye. The concentrations of MPs in all samples ranged from 4.7 to 31 particles/L, with a mean of 14 ± 5.6 particles/L. Small-sized (<1 mm) and fibrous-shaped MPs were most abundant in all samples. Fibers accounted for 83.1% of MPs in samples from all the three areas, followed by fragments (12.4%), pellets/beads (3.1%), and films (1.5%), with a minor variation in the distribution of shapes and sizes in samples from each area. Raman microspectroscopy was used for chemical analysis, and five polymers were identified, namely: high-density polyethylene, polyurethane, polyethylene terephthalate, poly(hexamethylene terephtalamide), and poly(acrylamide-co-acrylic acid). C.I Pigment Red 1, C.I. Solvent Yellow 4, Potassium indigotetrasulphonate, and C.I Pigment Black 7 were the colourants detected. These colourants are carcinogenic and mutagenic and are potentially toxic to humans. The prevalence of MPs in tap water implies their inadequate removal during water treatment. For instance, the presence of poly(AM-co-AA) suggests that drinking water treatment plants may be a potential source of MPs in tap water. Other polymers, e.g., high-density polyethylene may be released from pipes during the transportation of drinking water. The estimated daily consumption of MPs from tap water was 1.2, 0.71, and 0.50 particles/kg.day for children, men, and women, respectively. The findings of this study provide evidence of the presence of MPs in drinking water in South Africa, thus giving some insights into the performance of treatment plants in removing these contaminants and a benchmark for the formulation of standard limits for the amount of MPs in drinking water.

Microplastic Abundance and Sources in Surface Water Samples of the Vaal River, South Africa

Microplastics (MPs) have emerged as a global environmental concern due to their persistent nature. In South Africa, microplastic research has primarily focused on marine systems. However, recent years have seen a shift in focus to studying MPs in South African freshwaters. In this study, MPs with a minimum size of 0.055 mm in surface water of the Vaal River, South Africa, were reported. MPs were 100% prevalent, with a mean numerical abundance of 0.68 ± 0.64 particles/m3. Small-sized MPs of < 1 mm accounted for the largest proportion. MPs were chemically identified as high-density polyethylene, low-density polyethylene, and polypropylene according to their Raman spectra. The prevalence of fragments (41.6%) and fibers (38.5%) over pellets (8.1%) indicates that microplastics are from secondary sources. The prevalence of polyethylene and polypropylene is consistent with microplastics being from secondary sources. These polymers are commonly used in single-use plastics, packing bags, textiles, and containers. These characteristics are of great concern due to their implications on the bioavailability and toxicological impacts of MPs. Consequently, these properties may pose more hazards to aquatic biota inhabiting the Vaal River.