Chlorinated Hydrocarbons in Marine Female Fishes of Lagos Lagoon

Three female fish species of Snapper (Lutjanus goreensis), Herring (Sardinella maderensis) and Oarfish (Regalecus glesne) were sampled from Lagos Lagoon during the dry and wet seasons of 2008 and 2009 and subjected to cold extraction and clean-up procedure. Their muscle tissues were analysed for chlorinated hydrocarbons because they can concen trate pesticide residues from sediments and water. The identification and quantitation of the chlorinated hydrocarbon residues were performed using a gas chromatograph with a 63 Ni electron capture detector. The fishes had condition factor of more than 1 except Regalecus glesne. A higher concentration of the residues was observed during the dry season. The residue distribution pattern in muscle tissues of the fishes were: Regalecus glesne > Sardinella maderensis > Lutjanus goreensis. Regalecus glesne recorded the highest chlorinated hydrocarbon content: 6181.16 ng/g. Except for endrin and heptachlor, the estimated daily intakes of the organochlorines were within the acceptable daily intakes while the levels of residues in the fishes were within the permissible residue limits

Assessment of Regulated Disinfection By-products in Ahmadu Bello University Community Drinking Water Supply

Ahmadu Bello University (ABU) water treatment plant was assessed for its quality in terms of its regulated disinfection by-products (DBPs) content between 2008 and 2010. There were highly significant differences in mean concentration levels of these DBPs in the stages of treatment and distribution of the drinking water (F=4.86** - THMs, F=4.93** - HAAs). The pattern of variation of the Trihalomethanes was varied among the regulated trihalomethanes (THMs) while that of the haloacetic acids was consistent, decreasing from after chlorination stage to house level. Only THMs are regulated under the Nigerian drinking water standard with a maximum contaminant level of 0.001 mg/l as against international limits of 0.080 mg/l (USEPA) and 0.10 mg/l (WHO, EU). Mean concentration levels at booster station storage tanks were 0.0013 mg/l (THMs) and 0.5934 mg/l HAAs while at house level mean levels were 0.0107 mg/l (THMs) and 0.4863 mg/l (HAAs). These values show that drinking water produced by the ABU water treatment plant is non-compliant with national standard, but is readily compliant with international standards - USEPA, WHO and EU. However in terms of haloacetic acids (HAAs) the treated water had higher than the maximum permissible limits for HAAs under any of the standards. This calls for more concerted effort in monitoring for these DBPs and reducing their levels in the treated water

Pesticide Contamination in Muscle Tissues of Croaker Fishes from Lagos Lagoon, Nigeria

Two croaker fish species, Pseudotolithus senegalensis and Pseudotolithus typuswere sampled seasonally from Lagos Lagoon between December 2008 and September 2009 and analysed for pesticide residues. The muscle tissues of the fishes were subjected to cold extraction and subsequently clean-up. The detection and determination of the organochlorine residues were performed using gas chromatography.A higher concentration of the pesticide residues was observed during the dry season. There was no particular pattern in the accumulated organochlorine pesticides in the muscle tissues of the fishes. The residue distribution was more in the muscle tissues of Pseudotolithus senegalensis than in Pseudotolithus typus.The levels of OCP were all within permissible limits.The dietary surveys showed a mean fish consumption value of 40 g/day. Except for endrin and heptachlor, the estimated daily intakes of the pesticides were within the acceptable daily intakes

Mesosphere

The earth is surrounded by an atmosphere which is the blanket of gases that has no definite outer edge. Over 80 percent of the gases in the atmosphere are held by gravity within 12.4 mi. (20 km.) of the earth’s surface. The physical and chemical structure of the atmosphere and the interactions occurring there make the atmosphere an integral part of the earth system. It is held near the surface of the planet by the earth’s gravitational attraction. Without the atmosphere there would not be life on earth. The atmosphere contains the air people breathe, protects life from harmful radiation from the Sun and helps keep the planet’s heat from the Sun from escaping back into space. The atmosphere is made up of a mixture of gases, especially nitrogen, oxygen, argon and carbon dioxide. It reaches over 310 mi. (500 km.) above the surface of the planet. There is no exact boundary between the atmosphere and 640 Mesosphere outer space. Atmospheric gases, however, become thinner the higher up the spac

Residue Analysis of Organochlorine Pesticides in Water and Sediments from Agboyi Creek, Lagos.

Microlayer water, mixed layer water, epipellic and benthic sediments were collected from Agboyi Creek, Lagos to analyse organochlorine pesticide residues. Sampling was conducted between December 2008 and September 2009 during the dry and wet seasons to study effects of seasonal variation on the samples. Water samples were subjected to liquid-liquid extraction using dichloromethane, while sediments were subjected to cold extraction with petroleum ether/acetone (1:1 v/v) mixture and clean-up on silica gel adsorbents. The samples were analyzed for aldrin, dieldrin, endrin, DDT, heptachlor, HCH, endosulfan, chlordane and methoxychlor. The detection and determination of the pesticide residues were performed by injecting 1 μL of purified extract into the injection port of a gas chromatograph with a 63Ni electron capture detector (GC-μECD Agilent 7890A) equipped with ChemStation software. Pesticide residues in the epipellic and benthic sediments were higher than the residues in the water. The mixed layer water showed enhanced levels of residues when compared with the microlayer water. The residue levels were higher during the dry season than the wet season. The levels of residues in the water and sediments were below the maximum permissive residue limits

Seawater, Composition of

Seawater is a solution of salts of nearly constant composition, dissolved in variable amounts of water. It is denser than fresh water. It is risky to drink seawater because of its high salt content. More water is required to eliminate the salt through excretion than the amount of water that is gained from drinking the seawater. Seawater can be turned into potable water by desalination processes or by diluting it with freshwater. The origin of sea salt is traced to Sir Edmond Halley, who in 1715 proposed that salt and other minerals were carried into the sea by rivers, having been leached out of the ground by rainfall runoff. On reaching the ocean, these salts would be retained and concentrated as the process of evaporation removed the water. There are more than 70 elements dissolved in seawater as ions, but only six make up more than 99 percent of all the dissolved salts; namely, chloride (55.04 weight percent [wt%]), sodium (30.61 wt%), sulphate (7.68 wt%), magnesium (3.69 wt%), calcium (1.16 wt%), and potassium (1.10 wt%). Trace elements in seawater include manganese, lead, gold, and iodine. Biologically important elements such as oxygen, nitrogen, and iron occur in variable concentrations depending on utilization by organisms. Most of the elements occur in parts per million or parts per billion concentrations and are important to some positive and negative biochemical reactions. Properties such as salinity, density, and pH could be used to highlight the composition of seawater

Oceanography

The ocean is arguably the largest habitat on the planet, and it houses an astounding array of life, from microbes to whales. Oceanography is the branch of Earth science that studies the Earth’s oceans. It is the systematic scientific study of the oceans and deep sea with the goal of understanding their processes and phenomena. The relationship of oceans with other aspects of the Earth’s environment is also highlighted in oceanographic studies. Biology, chemistry, geology and physics together make oceanography a richly interdisciplinary science. Although they contain most of the Earth’s water and carbon and surface heat, and much of its biomass, the oceans do not operate alone. Together with the atmosphere, continents and ice-cover, they form a working platform, driven mostly by energy from the Sun. Earth science has four main components: hydrosphere, solid earth, atmosphere and biosphere. Water at the Earth’s surface or near it, is termed the hydrosphere. It includes oceans, water vapor, ground water, lakes, rivers, and polar icecaps. The water distribution in the hydrosphere is as follows: oceans—97.54 percent, icecaps—1.81 percent, groundwater—0.63 percent, others—0.02 percent. It is obvious that we live on a water planet. Oceanography is studied in order to understand how oceans operate and how they interact with other aspects of the Earth system. Again, oceans are a vast source of food for the world’s population. The oceans hold an enormous reservoir of minerals and they also hold reservoirs of fossil fuels or the potential for harnessing forces for energy development. The study of oceanography may be divided into four branches: biological oceanography, chemical oceanography, geological oceanography and physical oceanograph

Distribution of heavy metals in sediments of Igbede, Ojo and Ojora rivers of Lagos, Nigeria

The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed weekly variations in all the rivers assessed. Statistical analyses also showed different mean levels of trace metals in the aquatic environments, the distribution of which followed the sequence Fe > Zn > Mn > Pb > Cu > Cr > Cd, Fe > Zn > Cu > Mn > Pb > Cr > Cd and Fe > Zn > Mn > Cu > Cr > Pb > Cd in Igbede, Ojo and Ojora rivers respectively. Fe recorded the highest concentration levels (1,582.95 ± 96.57 μg/g–1,910.34 ± 723.19 μg/g) in all the sediments investigated while the Cd levels (0.06 ± 0.10 μg/g–0.47 ± 0.36 μg/g) were the lowest. Expectedly, trace metal concentrations in fine grain muddy sediments of the Igbede and Ojo coastline were much higher than those of Ojora which consist of coarse and sandy deposits covering the near shore area. Generally, the results obtained fell within toler-able limits stipulated by World Health Organization (WHO)