Microplastics in Ghanaian coastal lagoon sediments: Their occurrence and spatial distribution

This is the author accepted manuscript.Each year millions of tonnes of plastic are produced worldwide and around 8 million tons are deposited into our marine environment. Rivers comprise the major conduit for plastic transport with their deltas, estuaries and coastal lagoons being the key interface between lotic aquatic and the oceanic environment. However, we have very little knowledge of the role of coastal lagoons in the plastic pollution pathways. We present the spatial and temporal distribution and abundance of microplastics in sediments from two coastal lagoons in Ghana, West Africa. Sediment cores were taken from Mukwei Lagoon, Kpeshie Lagoon and from the mangroves at Kpeshie Lagoon; areas approximately 5-15km East from the centre of Accra. Microplastics were detected in all samples with a decreasing trend recorded from West to East. All three sites recorded a similar depth profile for plastics: after an initial increase from the surface samples, there was a significant decrease in microplastic concentrations with depth.Academy of Medical Science

Microplastic ingestion by pelagic and demersal fish species from the Eastern Central Atlantic Ocean, off the Coast of Ghana

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordWe present data on the occurrence of microplastics in fish from the Guinea current region off Ghana's Coast. Frequency of occurrence of microplastics in the fish species followed the order: Sardinella maderensis (41%) > Dentex angolensis > (33%) > Sardinella aurita (26%). Mean numbers of microplastics ingested were 40.0 ± 3.8, 32.0 ± 2.7 and 25.7 ± 1.6 for S. maderensis, D. angolensis and S. aurita respectively. Industrially produced pellets were the most dominant (31%) microplastic type followed by microbeads (29%), burnt film plastics (22%) and unidentified fragments (9%). Microfibers (2%), threads (2%) and foams (1 and below 1 for S. maderensis. The findings of the study show the common occurrence of microplastics in fish stocks and pave the way for future studies on microplastics in this Region.Academy of Medical Science

Human health risk and food safety implications of microplastic consumption by fish from coastal waters of the eastern equatorial Atlantic Ocean

Data availability: Data will be made available on request.We examined the gastro-intestinal tracts (guts) of 160 fish species obtained from Nigerian coastal waters for microplastics and estimated annual microplastic intake by adult human population in the region from the fish species. A total of 5744 microplastics were recovered from the fish species analyzed with an average of 39.65 ± 5.67 items/individual. Microbeads (43%) occurred in all guts assessed, followed by fragments (27%), burnt film (14%), thread (9%), fibers (4%), and pellets (3%). Most microplastics recovered were below 1000 μm with the least size being 85 μm. Based on the size classes estimated for this study, we argue based on literature that close to 15% (i.e., >100 μm) of the microplastics in the guts studied have the potential to translocate gut barriers of the fish species into muscles, where they get ingested by humans, and thereon get translocated to other human organ tissues. The estimated annual intake of microplastics from the consumption of whole fish by the adult population followed the trend; M. cephalus (178,220) > I. Africana (131,670) > P. senegalensis (115,710) > P. jubelini (109,060) > S. maderensis (101,080) > G. decadactylus (101,346) > S. melanotheron (65,170). Estimated annual intakes were generally higher for fish species with broad habitat and feeding preferences.Global Challenges Research Fund (GCRF), U

Craving and emotional responses to trauma and cannabis cues in trauma-exposed cannabis users: influence of PTSD symptom severity

Conditioned craving to trauma cues and avoidance learning have both been implicated in the high concurrence of trauma-related distress and substance misuse. Using a cue-exposure paradigm involving personalized trauma, cannabis, and neutral cues, we examined if conditioned craving and/or elevated negative affect to trauma cues are mechanisms linking PTSD and cannabis use disorder. Fifty-one trauma-exposed cannabis users were randomly presented the three cue types. Craving and emotional responses were evaluated after each cue using the Marijuana Craving Questionnaire–Short Form (Heishman et al., 2001) and the Positive and Negative Affect Schedule (Watson et al., 1988). Relief cannabis craving (compulsivity and emotionality) was significantly higher after trauma than cannabis and neutral cues (p's < 0.001) and was also higher among those with more severe PTSD symptoms (p's < 0.05). The relationship between PTSD symptom severity and cannabis craving was stronger after trauma than cannabis cues for the compulsivity component of craving (p < .05). Relief craving was also higher after the cannabis cue than after the neutral cue (expectancy and purposefulness; p < .001). Negative affect was significantly higher: after trauma than cannabis and neutral cues (p's < 0.001); and among those with more severe PTSD symptoms (p <. 005). Positive affect was significantly lower after trauma than cannabis cues (p < .05). Trauma cue exposure might promote cannabis misuse through conditioned craving as well as the desire to relieve negative affect. Conditioned cannabis craving involving an uncontrollable compulsion to use cannabis in response to trauma reminders appears particularly likely among cannabis users with more severe PTSD symptoms

An avirulent Brachyspira hyodysenteriae strain elicits intestinal IgA and slows down spread of swine dysentery

Abstract Swine dysentery caused by Brachyspira hyodysenteriae, results in substantial economic losses in swine producing countries worldwide. Although a number of different vaccine approaches have been explored with regard to this disease, they show limitations and none of them have reached the market. We here determine the vaccine potential of a weakly haemolytic B. hyodysenteriae strain. The virulence of this strain was assessed in experimental infection trials and its protection against swine dysentery was quantified in a vaccination-challenge experiment using a seeder infection model. Systemic IgG production and local IgA production were monitored in serum and faeces respectively. Across all trials, pigs that were colonized by virulent, strongly haemolytic B. hyodysenteriae strains consistently developed swine dysentery, in contrast to none of the pigs colonized by the weakly haemolytic B. hyodysenteriae vaccine strain. In the seeder vaccination trial nearly all immunised animals developed swine dysentery on subsequent challenge with a virulent strain, but the speed of spread of swine dysentery and faecal score were significantly reduced in animals immunised with the weakly haemolytic strain compared to sham-immunised animals. The IgA response of immunised animals upon challenge with a virulent B. hyodysenteriae strain significantly correlated to a later onset of disease. The correlation between local IgA production and protection induced by a weakly haemolytic B. hyodysenteriae strain provides leads for future vaccine development against swine dysentery

Radioactivity concentrations and their radiological significance in sediments of the Tema Harbour (Greater Accra, Ghana)

Studies on environmental radioactivity in tropical Africa are scarce. Therefore, a baseline study of natural (238U, 210Pb, 226Ra, 232Th, 228Ra, 228Th, 40K) and anthropogenic (137Cs) radionuclides was carried out on Tema Harbour (Greater Accra, Ghana) surface sediments and on their radiological significance. Grab surface sediment samples were collected from 21 stations within the Tema Harbour and their radioactivity concentrations measured by gamma spectrometry. The mean sediment radioactivity concentrations (Bq kg−1 dw) were 34 for 238U, 210 for 210Pb, 14 for 226Ra, 30 for 232Th, 29 for 228Ra, 31 for 228Th, 320 for 40K, and 1.5 for 137Cs. Large 238U/226Ra disequilibria were observed in the harbour sediments and a complex dynamics of several mixed sources of sediments within the Tema Harbour can be inferred from the spatial variations in the radioactivity concentrations. The estimated total absorbed dose rate in air (D), radium equivalent activity (Raeq), external hazard index (Hex), annual gonadal dose equivalent (AGDE) and annual effective dose equivalent (AEDE) indicated no significant radiological risks from the sediment radioactivity concentrations. Application of the Environmental Risk from Ionising Contaminants Assessment and Management tool (ERICA) confirmed that the potential dose rates to biota from the sediment radioactivity concentrations are unlikely to pose appreciable ecological risks. The radioactivity levels are compared with levels reported in sediments from other coastal areas of the world