Polycyclic Aromatic Hydrocarbons (PAHs) Levels in Two Commercially Important Fish Species from the Coastal Waters of Ghana and their Carcinogenic Health Risks

Polycyclic aromatic hydrocarbons (PAHs) concentrations were measured by gas chromatography with flame ionization detector (GC/FID) in two fish species, Sardinella maderensis (Flat sardinella) and Galeoides decadactylus (Lesser African threadfin or Shine-nose or Common threadfin) from Ghanaian coastal waters and the carcinogenic health risks, associated with the consumption of these fishes, estimated. The averageconcentrations of PAHs ranged from below detection limit of 0.01 ìg/kg wet wt to 34.04 ± 0.56 ìg/kg wet wt in S. maderensis, and from below detection limit (0.01 ìg/kg wet wt) to 54.13 ± 5.22 ìg/kg wet wt in G. decadactylus.Pyrene had the highest mean concentration of 54.13 ± 5.22 ìg/kg wet wt in G. decadactylus from Tema. Both fish species from Tema and Chorkor showed similar PAH assemblages although the concentrations were different, suggesting common source of PAHs in these coastal environments. G. decadactylus accumulated significantly higher (P < 0.05) concentrations of total PAHs at all the sites, except at Chorkor. High molecular weight PAHs (HMW-PAHs) were generally predominant compared to low molecular weight PAHs (LMW-PAHs). The LMWPAH/HMW-PAH ratios were < 1 for both species, indicating anthropogenic, mainly pyrogenic, origin of PAHs in the Ghanaian coastal environment. With the exception of G. decadactylus from Ada-Foah, benzo(a)pyrene concentrations in the fish samples analysed exceeded the EU recommended limit of 2 ìg/kg wet wt for fish considered safe for human consumption. The estimated carcinogenic potency equivalent concentrations exceeded the screening value for both species from all the study areas, indicating significant carcinogenic health risks associated with the consumption of these fishes. A further study of PAHs and other contaminants in seafood, landed on the coast of Ghana, is recommended in the light of recent discovery and drilling of oil in commercial quantities in Ghanaian coastal waters

Water Quality Status Within The Anchorage Space of Tema Harbour, Ghana

Marine pollution is attributable to anthropogenic introductions of contaminants above their natural background levels and being dispersed by ocean forcing. Assemblages of vessels within offshore platforms and seaport terminals could also be potential sources for marine water contamination. As such, nearshore perimeters of the Tema Port were assessed to review the vessel register and the seawater quality through Automatic Identification System (AIS), in-situ and laboratory analysis. The results of analysed satellite data suggested ~1,600 commercial vessels of over 50 flag states including Ghana were present in the West Africa territorial waters between 2016 and 2020. Bacterial load shows the following order: total heterotrophic bacterial [THB] (364-468 cfu/mL) > total coliform [TC] (26-73 cfu/100 mL) > faecal coliform [FC] (1-13 cfu/100 mL). Phytoplankton species abundances were in order Ceratium spp. (31.8%) >Protoperidinium spp. (30.1%) > Dinophysis spp. (9.3%) > Coscinodiscus sp. (7.3%) > Lingulodinium polyedra (6.9%) = Nitzschia sp. (6.9%). Water temperature ranged between 23.9 and 27.5 oC (surface to 25.4 m depth), salinity 36.03 ± 0.51‰, dissolved oxygen 6.54 ± 0.94 mg/L and pH 8.18 ± 0. 06. Phosphate, ammonia, Cd, As, and Pb levels were low (0.01 to 0.153 mg/L). Nitrate, silicate and Mg were relatively high (0.7 - 2.18 mg/L). Pearson correlation coefficient displayed 0.05 and 0.01 significant levels between total dissolved solids (TDS) and electrical conductivity and salinity, and dissolved oxygen and temperature and arsenic levels. Normalization physicochemical data suggested thermal stratification at 15 m depth. Nutrient and biological results indicated normal water quality conditions, however, relatively high levels of phytoplankton including harmful and toxic species suggested excess nutrient contamination in the study area. Further assessment is recommended to ascertain the link between phytoplankton and nutrient load at the anchorage space.&nbsp

Impact of gold-mining activity on trace elements enrichment in the West African estuaries: The case of Pra and Ankobra rivers with the Volta estuary (Ghana) as the reference

This study aimed at assessing trace element concentrations in two representative estuaries of Ghana (Pra and Ankobra) affected by gold-mining, relative to the levels of the unaffected Volta estuary. Surficial sediments (n = 16–17) were sampled at each estuary and analysed by ICP-MS for 25 elements after pseudo-total digestion. The enrichment and geoaccumulation indexes revealed a moderate to significant contamination of As, Ag and Cu in the Pra and Ankobra estuaries. Spatial maps of concentrations revealed non-localized sources. High As concentrations were attributable to runoff transport and sedimentation of gold mining-tailing particles, as suggested by results from granulometric distributions, correlation and PCA analysis. The probabilities of surpassing the probable effects level (PEL) were 77% for As, 50% for Cr and 27% for Ni in Ankobra; these values were of 13%, 23% and 10% for the Pra. Results reveal potential future implications on ecosystems and human health in these both estuaries as result of the gold-mining activity.International Atomic Energy Agency Research Project RAF7009Ministerio de Economía y Competitividad AGl2014-57835-C2-1-

Radioecological assessment and radiometric dating of sediment cores from dynamic sedimentary systems of Pra and Volta estuaries (Ghana) along the Equatorial Atlantic

The Volta and Pra estuaries (Ghana, West Africa) are dynamical sedimentary systems whose natural equilibrium is being affected by anthropogenic activities. This paper reports depth-distributions of 210Pb, 226Ra, 234Th, 40K, 228Ra and 137Cs for two sediment cores from these estuaries. Bulk densities were not steady-state and well correlated with 40K (p < 0.00005). Unsupported 210Pb profiles were incomplete, non-monotonic and showed large fluctuations. The assumptions involved in the common 210Pb-based dating models were not meet in these dynamical scenarios, and the use of 137Cs as a time-marker is difficult in Equatorial and South-Hemisphere countries due to its low fallout rates. Chronologies have been solved with the new 210Pb-based TERESA model, which operates with varying but statistically correlated fluxes and sediment accumulation rates (SAR). The core from the Volta reflects the conditions prevailing after the construction of the Akosombo Dam, with a mean SAR of 1.05 ± 0.03 g cm−2·y−1, while a higher value of 2.73 ± 0.06 g cm−2·y−1 was found in the Pra, affected by intense gold mining activities along its course. Radiological and radioecological assessments have been conducted by applying the UNSCEAR protocols and the ERICA model, respectively. The measured radionuclide concentrations do not pose any significant risk for the environment and human health.International Atomic Energy Agency (IAEA) Research Project RAF700

Experimental study on the use of granulometric speciation for the radiometric dating of recent sediments

Theoretical and experimental studies have shown that activity concentrations of fallout radionuclides (such as 137Cs and excess 210Pb) decrease with particles size in aqueous suspensions. This paper is aimed at reviewing the theoretical fundamentals for granulometric speciation of radionuclides, and at exploring its practical use in the analytical context of gamma spectrometry for the radiometric dating of recent sediments, with view to: i) improving the detection of 137Cs (since its use as independent chronostratigraphic mark is challenging in the southern hemisphere because its low fallout rate), ii) supporting refined CIC models and normalization techniques in 210Pb-based radiogeochronologies. The work uses surface sediments sampled from the Tinto Estuary (SW Spain), affected by mining and phosphate-fertilizer industries, and from the Ankobra Estuary (Ghana), affected by intensive artisanal gold-mining. Granulometric classes have been separated by a sieving column with decreasing mesh sizes and the obtained cumulative percentage of mass mathematically described by a Rosin-Rammler particle-size distribution. The target radionuclides for gamma spectrometry were 210Pb, 226Ra and137Cs, complemented with 40K, 234Th and 228Ra. Results revealed that, far from ideal experiments, under actual environmental conditions the increase in activity concentrations with decreasing particle sizes is too moderate, and in general they are affected by larger counting uncertainties due to the small available amount of mass. Indeed, there was no correlation between grain-size and 137Cs concentrations (p = 0.25), and similarly for excess 210Pb (p = 0.53). No effect of the organic matter content was observed in 137Cs (p = 0.58) and excess 210Pb (p = 0.85) concentrations. Present results pose some concerns to the general use of granulometric speciation in the context of gamma spectrometry for supporting the radiometric dating of recent sediments. A detailed discussion on the use of normalization methods is also presented.The authors would like to extend gratitude to the International Atomic Energy Agency (IAEA) for supporting the Regional Project RAF7009 and the fellowship GHA -16025.Peer reviewe

Environmental radioactivity and trace metals in surficial sediments from estuarine systems in Ghana (Equatorial Africa), impacted by artisanal gold-mining

This paper reports concentrations of γ-emitter radionuclides (40K, 137Cs, 210Pb, 226Ra, 228Ra, 228Th and 234Th) and some metals (Al, Cr, Fe, Co, Ni, Cu, Zn, As, Sr, Cd, Sb, Cs, Pb, Th and U) in surficial sediments from the Ankobra, Pra and Volta estuaries, in Ghana. Artisanal gold-mining in the Ankobra and Pra basins promoted moderate enrichments of As, Sb, Cu, Cs and Cr in their estuarine sediments, with respect to the reference background of the Volta Estuary. Radionuclide concentrations were in the range found in the Earth's crust. Present data do not support any conclusion on their potential enrichments due to gold-mining activities. Radionuclide isotopic ratios revealed a transfer of 228Ra from sediments to the water column. Pearson correlation coefficient matrices showed different patterns, which were reasonably understood after novel approaches: i) inter-estuaries comparison of slopes in the linear regressions of element-concentrations vs Al, Fe and Cs; ii) study of Al-normalized concentrations of elements; iii) excess 210Pb informing on local sedimentary conditions. The metal enrichments observed in the Ankobra and Pra estuaries are associated with the Fe-rich compounds in sulphide ores (such as FeAsS) transported along the river course and deposited in the estuary.The authors extend gratitude to the International Atomic Energy Agency (IAEA) for supporting the Regional Project RAF7009 and the fellowship GHA-16025.Peer reviewe

Easily accessible language technologies for Slovene, Croatian and Serbian

In this paper we present the pipeline of recently developed language technology tools for Slovene, Croatian and Serbian. They currently cover text segmentation, text normalisation, part-of-speech tagging, lemmatisation and inflectional lexicon lookup. Most rely on machine learning approaches, such as statistical machine translation and conditional random fields, capable of producing high-quality models for the phenomenon covered. Special emphasis is put on easy accessibility of these tools by offering them and the trained models for all three languages as (1) open source via public git repositories and (2) online in the form of web applications and web services