Fish is the cheapest source of protein, minerals, and vitamins for most households in sub–Saharan Africa. Of late, microplastic and metal pollution have raised concerns about food safety, especially in informal markets where fish is commonly sold and consumed. Informal roadside fish markets are, however, almost absent from this literature, and the extent to which post harvest handling adds to the contaminant load of the tissue that is actually eaten is unknown. This study assessed microplastic and element contamination in ready to eat braaied (open fire grilled) fish sold by roadside vendors in Thohoyandou, Limpopo Province, South Africa. Fish samples (n = 4 per stall) were collected from nine stalls, and microplastics extracted from the dorsolateral white muscle were characterised by morphology, colour and polymer type using stereomicroscopy and micro–Fourier transform infrared (µ–FTIR) spectroscopy, while element concentrations in the same tissue were determined by inductively coupled plasma mass spectrometry (ICP–MS) following microwave assisted acid digestion. The study indicates high microplastic burdens, dominated by fibres, films, and fragments. Total microplastic abundances differed significantly among sites, with mean values ranging from 105 particles kg− 1 at site 9 to 470 particles kg− 1 at site 1. Transparent microplastics dominated, and colours such as black, blue, red, yellow, green and other occurred at much lower concentrations. Polymer identification by µ–FTIR showed that polyethylene (40.5
Glyphosate in southern South America is considered a pseudopersistent contaminant. Given Roundup®’s multiple effects on health, reproduction, and overall species well-being worldwide, it is imperative to evaluate its effects on exposed biota. We evaluated the effects of two concentrations of Roundup Control Max® (0.7 mg/L and 7 mg/L; the former being environmentally relevant) over 14 days of exposure on aerobic metabolism, oxidative stress, and fatty acid profiles in the economically relevant fish species Piaractus mesopotamicus, and compared them with a control experiment. The results showed no significant variation in basal or post-exercise metabolism but revealed significant differences in the delta between these parameters. Oxidative stress was elevated in the brains of exposed individuals but not in the liver. Lipid profiles did not vary significantly among individuals exposed to the herbicide. Our findings highlight this formulation’s influence on a key metabolic parameter and oxidative stress. It also advances the biological and nutritional characterization of P. mesopotamicus. Further studies should continue to evaluate the effects of chronic herbicide exposure on the aerobic metabolism of this and other species.
The rapid population growth across Africa has increased the demand for food production, resulting in increased pesticide use. South Africa is among the top four pesticide importers in Sub-Saharan Africa, raising significant concerns regarding the contamination of freshwater ecosystems. Organochlorine pesticides (OCPs), historically used for agriculture and vector control, persist in the environment due to their high lipophilicity and long half-lives. Despite bans on many OCPs, residues remain in aquatic systems, potentially affecting non-target organisms such as fish. Similarly, neonicotinoids, introduced as safer alternatives, are now linked to adverse effects on aquatic biota, yet little is known about their bioaccumulation in wild fish species in southern Africa. This study investigated 13 neonicotinoids and 19 OCPs in fish muscle tissue from the Inkomati and Letaba catchments. Only two OCPs, p,p’-DDE and p,p’-DDD, were detected, likely due to ongoing DDT use in malaria control. Concentrations were generally low and varied between sites, with higher values found in the Letaba catchment. Neonicotinoids were detected at low concentrations, with acetamiprid and imidacloprid being the most prevalent, although the concentrations were lower than those reported globally. Muscle tissue, representing long-term exposure, may underestimate total pesticide burdens due to lower lipid content than other tissue types. Findings suggest that the detected residues reflect the persistent legacy of historical DDT use, potential ongoing localised DDT use for malaria vector control, as well as ongoing neonicotinoid use in agricultural systems. Although concentrations were below levels of concern for vertebrates, this study highlights the need for continued monitoring and expanded tissue analysis to better understand bioaccumulation and ecological risks in southern African freshwater systems.
Naturally occurring radionuclides in marine food webs are an important radiation exposure pathway for coastal populations, especially in high-background natural radiation areas (HBNRAs). This study investigated the accumulation, spatial distribution, ecological controls, and radiological implications of 238U, 232Th, 210Po, and 210Pb in 15 commercially and ecologically important gastropod species collected along the heavy mineral-rich Kollam coast of southwest India. The activity concentrations ranged from BDL(≤ 0.5)–1.8 Bq kg−1 for 238U, 0.62–4.1 Bq kg−1 for 232Th, 14.7–76.4 Bq kg−1 for 210Po, and 3.2–56.4 Bq kg−1 for 210Pb, with overall accumulation following 210Po ≫ 210Pb ≫ 232Th > 238U. Significant differences were observed among species, taxonomy, feeding guilds, and stations for 210Po and 210Pb (Kruskal–Wallis, p < 0.01), whereas 238U and 232Th showed limited biological variability. Strong positive correlations between 210Po and 210Pb (r > 0.80, p < 0.001) and elevated 210Po/210Pb ratios (1.09–4.59) indicated preferential enrichment and retention of 210Po. The annual committed effective dose (ACED) was estimated to vary between 62.5 and 229.5 µSv y−1, with an average value of 178 µSv y−1. Although the carcinogenic risk to the general public was minimal, the results highlight the importance of thorough tailored species-specific ecological monitoring, guidelines for human consumption, and strategies for sustainable management.
This study investigated the presence of microplastics (MP) in drainage channels that carry stormwater and greywater runoffs from areas surrounding the industrial sites on Viti Levu, Fiji’s main island. Water samples were collected, digested with hydrogen peroxide, separated by density separation and filtered through an aluminum oxide Anodisc membrane filter (0.2 μm pore size) for particle recovery. The filter membranes were observed under a microscope for the presence, size and morphology of MP. 93.4
