Assessment Of Polycyclic Aromatic Hydrocarbons In Locally Smoked Fish Sold In Lagos Markets

Polycyclic aromatic hydrocarbons (PAHs) are known widespread contaminants which represent an important group of carcinogens. This study reports the concentrations of PAHs in smoked fishes locally sold in two markets in Lagos state, Nigeria. The amounts of PAHs present in the samples were quantified using gas chromatography coupled with flame ionization detector (GC-FID). The total concentration of PAHs detected in each sample are 127.5, 86.06, 58.39 and 101.58 μg/kg dry weight for the following fish species respectively; Scomberomorus tritor, Tilapia guinensis, Ilisha africana and Clarias gariepinnus. Benzo[a]pyrene was present in all the samples and the concentration exceeds the permissible limit of 5.0 μg/kg except in one of the fish species. The abundance of high molecular weight PAHs in three of the fish species suggests that pyrolysis was the method used in the smoking process. From the maximum limit set by the European Commission for the sum of PAH, only S. tritor exceeded the 30 μg/kg limit with 54.68 μg/kg present

Isotope sourcing of prehistoric willow and tule textiles recovered from western Great Basin rock shelters and caves e proof of concept

Isotope and trace-metal analyses were used to determine the origin of plants used to manufacture prehistoric textiles (basketry and matting) from archaeological sites in the western Great Basin. Research focused on strontium (87Sr/86Sr) and oxygen (18O/16O) isotope ratios of willow (Salix sp.) and tule (Schoenoplectus sp.), the dominant raw materials in Great Basin textiles. The oxygen-isotope data indicated that the willow and tule used to produce the textiles were harvested from the banks of rivers or in marshes characterized by flowing water and not from lakes or sinks. The strontium-isotope data were useful in showing which plants came from the Humboldt River and which came from rivers headed in the Sierra Nevada

Trace and major elements distribution in coastal sediment cores from Lagos Lagoon,Nigeria

Heavymetalscontaminationinaquaticecosystemshasbeena majorconcern,however,noinformationisavailableaboutthe concentrations, depthdistributionsandecologicalrisksofheavy metals insedimentscoresfrommicrotidallagoonalecosystemin Lagos, Nigeria.Foursedimentcoreswerecollectedusinga 50 cm × 3.5 cmWildco®handcorer.Elementaldeterminations werecarriedoutusingtheMicrowavePlasmaAtomicEmission Spectrometry (4200MP-AES)afterextraction.Theconcentrations of heavymetalsinthesedimentcoresindicatedenhanceddegree of contaminationinfluenced byanthropogenicdischargesespe- cially industrialeffluents. Verticaldepthdistributionsindicated varieddepositionalperiodslargelycontrolledbyincreasing anthropogenicland-basedactivities.Theremarkablemetalpollu- tion ofcoresedimentsraisestheconcernpotentialsourcesof metals tothelagoonalecosystemandecologicalriskstothebiota, humans, andtheenvironment.Theresultsofelementalcon- centrations shouldbeconsideredasbaselinedataforheavymetals in sedimentsintheregion

Management of the palatally displaced canine

The maxillary permanent canine is a common tooth to deviate from its normal path of eruption and become displaced, usually into the roof of the mouth or palate. This article outlines the assessment, diagnosis and potential early management options for a palatally displaced permanent canine tooth (PDC). Some adverse consequences of a PDC are discussed

Polycyclic aromatic hydrocarbons in imported Sardinops sagax: Levels and health risk assessments through dietary exposure in Nigeria

Polycyclic aromatic hydrocarbons (PAHs) occurrence and assessment of dietary exposure from imported canned sardines (Sardinops sagax) commercially marketed in local stores and supermarkets in Nigeria were evaluated for the first time. PAHs determinations were performed using high performance liquid chromatography (HPLC) (Agilent 1290 model) equipped with UV-VIS diodes array detector (DAD) at l = 210 nm and 214 nm. The percentage recoveries were higher than 96%. The degree of contamination expressed as total concentration of PAH congeners ranged between 2.53 and 35.55 mg kg�1 dry weight (d. w.) at l = 210 nm, and 1.30 and 27.93 mg kg�1 (d.w.) at l = 214 nm. The carcinogenic (TEQBaP) and mutagenic toxicities (MEQBaP) of eight priority PAHs were evaluated. Benzo[a]pyrene, benzo[b] fluoranthene, benzo[k]fluoranthene and indeno[1,2,3-c,d] pyrene contributed significantly to the total carcinogenic equivalents of PAHs. The mutagenic equivalents were largely dominated by chrysene, benzo [b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene and indeno[1,2,3-c,d]pyrene equivalence factors. The estimated lifetime average daily dose (LADD), average annual excess risk (AR), excess cancer rate (ECR), and hazard quotient risk (HQ) were evaluated for adults, children and preteens exposure related risks. The LADD, ECR, AR and HQ of PAHs for carcinogenic and non-carcinogenic risks are relatively higher in preteens than children and adults

Development and Evaluation of New Indices for Sediment-associated Contaminants.

New indices (modified hazard quotient, mHQ and ecological contamination index, ECI) are developed for evaluating sediment-associated heavy metals contamination. In evaluating the proposed indices, the concentration and chemical fractionation of five heavy metals (Cd, Cr, Cu, Ni and Pb) determined in benthic sediments from five tropical ecosystems off the Bight of Bonny were used to assess the degree of contamination and estimate the extent of anthropogenic inputs from industrial activities into these ecosystems. The analysis shows that the mean concentrations (mg/kg, dw) of Cd, Cr, Cu, Ni and Pb vary from 4.33 – 5.67, 11.12 – 28.52, 30.26 – 43.72, 2.02 – 2.60 and 162.0 – 190.37, respectively. An important observation is that the mean metal levels during the wet and dry seasons did not show significant variability at all sites. The spatial distribution and severity of sediment-associated contamination by heavy metals based on the developed indices (mHQ and ECI) are in the descending sequence: Cd>Pb>Cu>Cr>Ni. Hence, the observed trend is in good agreement with existing pollution indices. Contamination severity index, mean hazard quotients and modified risk assessment code are also used to identify the pollution hotspots, which reflect medium risk contamination ecological systems. Aquatic pollution indicators (potential contamination index, ECI, hazard quotients, and mHQ) reveal significant anthropogenic contamination of Cd and Pb in the sediments, while Cr, Cu and Ni show relatively low degree of contamination. PCI generally follows the sequence Cd>Pb>Cu>Cr>Ni. Principal component analysis (PCA) and factor analysis indicate that heavy metals in the benthic sediments originate mostly from anthropogenic sources

Toxic metals in cigarettes and human health risk assessment associated with inhalation exposure

This study evaluated the concentrations of cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), lead (Pb), and zinc (Zn) in 10 branded cigarettes commonly consumed in Nigeria. Chemical sequential extraction method and pseudo-total metal digestion procedure were used for extraction of metals from filler tobacco and filter samples. Samples were analyzed using flame atomic absorption spectrometry (FAAS). The filler tobacco of cigarettes had Cd, Cu, Fe, Mn, Pb, and Zn concentrations in the ranges of 5.90–7.94, 18.26–34.94, 192.61–3494.05, 44.67–297.69, 17.21–74.78, and 47.02–167.31 μg/cigarette, respectively. The minimum and maximum concentrations in the filter samples were 8.67–12.34 μg/g of Cd, 1.77–36.48 μg/g of Cu, 1.83–15.27 μg/g of Fe, 3.82–7.44 μg/g of Mn, 4.09–13.78 μg/g of Pb, and 30.07–46.70 μg/g of Zn. The results of this study showed that the concentrations of heavy metals in the filler tobacco samples were consistently higher than those obtained for the cigarette filters except for Cd. Toxic metals were largely found in the most labile chemical fractions. Moderate to very high risks are found associated with potential exposure to Cd and Pb. The carcinogenic risks posed by Cd and Pb ranged between 1.87E-02 and 2.52E-02, 1.05E-03 and 4.76E-03, respectively, while the non-carcinogenic risk estimates for Cd and Pb were greater than 1.0 (HI > 1). Toxic metals in cigarette may have significant carcinogenic and non-carcinogenic health effects associated with inhalation exposure. Continuous monitoring and regulations of the ingredients of imported and locally produced tobacco products are advocated