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<p>The effects of three traditional smoking methods on the concentrations of polynuclear aromatic hydrocarbons (PAHs) in smoked fishes were studied. Samples of five different species of fish highly traded for immediate consumption were purchased from fishermen and processed using saw dust smoke, firewood smoke and charcoal smoke respectively. Some of the fresh fishes were also sun-dried and analyzed as control. The PAHs content were extracted with standard dichloromethane using solid-liquid extraction, and analyzed using Gas chromatography – Mass spectrophotometer (GC-MS) method. The results showed that fish samples processed with saw dust smoke recorded the highest concentrations of total PAHs, ranging from 815.75 µg/kg to 1550.28 µg/kg, followed by firewood smoked samples with total PAHs content varying between 738.14 µg/kg to 994.09 µg/kg while charcoal smoked samples recorded the least total PAHs levels of 135.02 µg/kg to 614.42 µg/kg. Benzo(a)pyrene concentrations of 5.68 µg/kg and 5.44 µg/kg respectively were detected in the samples of <em>Arius heude loti </em>and Mud minnow processed using saw dust smoke. The Benzo(a)pyrene levels exceeded the EC regulatory limit of 5 µg/kg. Because benzo(a)pyrene has been associated with intense carcinogenicity in humans, its levels recorded in the smoked <em>Arius heude loti </em>and Mud minnow may have implication for the quality and safety of these fish products. Therefore, it is imperative that regulatory bodies conduct awareness campaigns to educate both the smoked fish processors, traders and consumers on the need to discourage the use of saw dust in smoking fish and adopt safer and improved methods of smoking fishes.</p>

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The amount of cyanide in fresh and cooked tuber parenchyma (pulp) of three cultivars of sweet cassava from two local government areas (LGA) of Benue state was studied. Cassava tubers were collected and carefully peeled to obtain the pulp. The fresh and boiled samples were adequately processed and treated with ninhydrin, Na2CO3 and NaOH and the absorbance of the reaction product measured using UV-Visible spectrometer after construction of a calibration graph using standard cyanide solutions. The amount of cyanide in the fresh pulp varied with differences in cultivars ranging from White Dan-Warri Cultivar: (19.87 to 28.81) mg/kg; Obasanjo cultivar: (17.23 to 28.81) mg/kg and Red Dan-Warri Cultivar (8.23 to 19.31) mg/kg. Also, the cyanide content of cultivars from Oju LGA was generally higher than that of the cultivars from Gwer-east LGA. Cyanide content varied with the period of the day harvested in the order: Afternoon > Evening > Morning for all cultivars. Furthermore, cooking greatly reduced the cyanide content of all the sweet cassava cultivars but boiling was more effective than roasting with the cyanide removal increasing with increase in cooking time. The cyanide content of the tuber parenchyma of the sweet cassava cultivars was very low (<30 mg/kg) which is in agreement with reported values for sweet cassava. However, cooking at a reasonable time interval will further reduce their cyanide levels to further safe limits.

The occurrence and distribution of organochlorine pesticides (OCPs) in aquatic systems is a matter of global concern and poses significant toxicological threats to both organisms and human health. Despite the extensive use of OCPs for pest and disease control in southern Africa, relatively few studies have examined the occurrence and toxicological risks of OCP residues in the region. This study investigates the composition, distribution, and potential sources of OCP contamination in sediments from Richards Bay, a rapidly developing industrial port on the northeast coast of South Africa. Surface sediments collected from Richards Bay Harbour and surrounding areas indicate that OCP contamination in the region is widespread. Total concentrations (∑OCP) in surface samples ranged from 135 to 1020 ng g−1, with hexachlorocyclohexanes (∑HCH; 35–230 ng g−1) and dichlorodiphenyltrichloroethanes (∑DDT; 12–350 ng g−1) the dominant contaminant groups detected. Metabolite isomeric compositions indicate that the presence of aldrin and endosulfan likely result from historical agricultural usage, while recent input of γ-HCH, heptachlor, and endrin may be linked to the illegal use of old pesticide stockpiles. Total DDT concentrations were dominated by p,p′-DDT (80 ± 64 ng g−1), which was attributed to its ongoing use in malaria vector control in the region. A 210Pb-dated sediment core revealed that OCP input to the local environment increased dramatically from relatively low concentrations in the mid-1940s (∑OCP, 355 ng g−1) to peak levels (∑OCP, 781 ng g−1) in the 1980s/1990s. An overall decrease in ∑OCP concentration from the mid-2000s is likely related to restrictions on use following the Stockholm Convention in 2004. Despite current restrictions on use, OCP concentrations exceeded sediment quality guidelines in the vast majority of cases, raising concerns for protected estuarine and mangrove habitats in the area, as well as for local fishing and farming communities.

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