Occurrence and Toxicity of Hydrocarbon Residues in Crab (Callinectes sapidus) from Contaminated Site

To elucidate seasonal changes in hydrocarbons including polycyclic aromatic hydrocarbons (PAHs) due to oil spill, tissues of blue crab (Callinectes sapidus) were investigated. Total petroleum hydrocarbons (n-alkanes) concentrations ranged from 0.17-0.32ìg/gdw and 0.28-0.62ìg/gdw during the dry and wet seasons respectively. Thetissues accumulate a complex spectrum dominated by heavier hydrocarbons, alkylsubstituted and PAHs. The impact of biogenic contribution through dietary uptake was related to the elevated levels, particularly of the PAHs. Studies of other site specific, resident organism are recommended in order to be able to establish the extent of toxicity

Seasonal Metal Distribution in Ondo Coastal Sediment, Nigeria

The distribution of heavy metals in streambed sediment from an oil-producing region in Nigeria has been examined between the two distinct seasons (dry and wet). The highest mean concentration duringthe dry season (wet season in brackets) was 2083.3±355.5 (2264.2±347.3)mg/kg Cu and 0.16±0.06 (0.19±0.09)mg/kg Zn respectively. With similar patterns at both seasons, the order of increasing concentration was Z

Seasonal Metal Distribution in Ondo Coastal Sediment, Nigeria

The distribution of heavy metals in streambed sediment from an oil-producing region in Nigeria has been examined between the two distinct seasons (dry and wet). The highest mean concentration duringthe dry season (wet season in brackets) was 2083.3±355.5 (2264.2±347.3)mg/kg Cu and 0.16±0.06 (0.19±0.09)mg/kg Zn respectively. With similar patterns at both seasons, the order of increasing concentration was Z

Occurrence and Toxicity of Hydrocarbon Residues in Crab (Callinectes sapidus) from Contaminated Site

To elucidate seasonal changes in hydrocarbons including polycyclic aromatic hydrocarbons (PAHs) due to oil spill, tissues of blue crab (Callinectes sapidus) were investigated. Total petroleum hydrocarbons (n-alkanes) concentrations ranged from 0.17-0.32ìg/gdw and 0.28-0.62ìg/gdw during the dry and wet seasons respectively. Thetissues accumulate a complex spectrum dominated by heavier hydrocarbons, alkylsubstituted and PAHs. The impact of biogenic contribution through dietary uptake was related to the elevated levels, particularly of the PAHs. Studies of other site specific, resident organism are recommended in order to be able to establish the extent of toxicit

Concentration and bioavailability of cadmium by some plants

A survey was carried out to evaluate the existing level of cadmium in three plant species within and around a refuse site at Ojota, Lagos State, Nigeria. Concentration ranged from background levels to levels well in excess of the maximum tolerable limit in agricultural soils. In the leaves, the least (highest in bracket) of cadmium concentration was 0.24 (4.99)mg/kg while in the roots, it was 0.39 (11.03)mg/kg. The apparent influence of anthropogenic inputs at the refuse site was reflected by the relatively higher concentrations than other sampling locations. The influence of some physicochemical parameters such as pH and Soil organic matter on the relative mobility of cadmium and its redistribution amongst the different plant species was investigated and found to be generally consistent with findings and experimental observations of other workers. An initial evaluation is made of the potential of the species as indicator plants and that vegetables from refuse sites should be avoided and discouraged either as livestock or human feeds

Lead Exposure: A Contributing Cause of the Current Breast Cancer Epidemic in Nigerian Women

Breast cancer incidence in Nigerian women has significantly increased during the past three decades in parallel with the rapid industrialization of that country. This suggested that the associated widespread contamination of the soil and of the water supplies by lead (Pb) and other industrial metals was a major contributing cause. Because of its many domestic, industrial, and automotive uses, Pb is of particular concern as it has been shown to promote the development of mammary tumors in murine mammary tumor virus-infected female C3H mice at levels as low of 0.5 ppm Pb in the drinking water. Lead belongs to the group of selenium-antagonistic elements that interact with selenium (Se), abolishing its anti-carcinogenic effect. Lead on chronic, low-level exposure in addition also accelerates tumor growth rates. Higher levels of Pb were found in blood and head hair samples of newly diagnosed patients with breast cancer, all with infiltrating ductal carcinoma, the most common form of breast cancer in Nigeria, seen at Obafemi Awolowo University, than in cancer-free controls from the same area. Evidence for interactions between Pb and Se was obtained from blood, hair, and tumor biopsy tissue analyses. Furthermore, the Pb levels in hair samples of the patients were directly correlated with the volumes of their tumors, in accord with the tumor growth-promoting effects of Pb. Conversely, Se levels in hair and blood were inversely correlated with the tumor volumes, consistent with the anti-proliferative effects of Se. Several other elements, e.g., Cd, Hg, Cr, Sn, and As, were detected in the scalp hair of the patients and the controls, although at significantly lower levels than those of Pb. However, correlation calculations revealed them also to interact with Se, suggesting that only a fraction of the Se in organs and tissues is actually present in bioactive forms. In metal-exposed subjects, a state of latent Se deficiency may exist, resulting in depressed immune functions and increased cancer susceptibility. Evidence is presented to show that Pb and other metals also interact with iodine, another vitally important essential trace element believed to protect against breast cancer development. Public health programs aiming at lowering the breast cancer risk of Nigerian women thus will have to include effective measures to protect the population from exposures to Pb and other industrial metals that are presently contaminating the environment and the water supplies

Influential factors on the levels of cation exchange capacity in sediment at Langat river.

An exploratory study was carried out at 22 sampling stations along the Langat River, Selangor in order to investigate on the vitality of cation exchange capacity (CEC) in sediment (0–5 cm). Parameters such as pH, Eh, salinity, and electrical conductivity (EC) were determined. The CEC in sediment has been calculated by the determination of Ca2+, Na+, Mg2+, and K+ using the flame atomic absorption spectrophotometer, while the organic matter content in sediment was ascertained using the loss on ignition method. The characteristic of the sediment shows that pH (3.09–7.46), salinity (0.02–10.71 ppt), EC (3.39–517 μS/cm) and Eh (−16.20–253.10 mV) were substantially high in variation. This study also revealed that exchangeable Ca2+ and Mg2+ were controlled by organic matter contents, while exchangeable Na+ and K+ were influenced by salinity. Salinity was observed to play a major part in controlling all the exchangeable cations, as it gives strong significant correlations with Na+, K+, Mg2+, CEC, and organic matter at p < 0.01. The presence of seawater, clay mineralogy, and organic matter proves that it does play an important role in determining the CEC and soon relates to the pollution magnitude in the sediment