Trace Metal Concentrations in Commercially Important Fishes from some Coastal and Inland Waters in Ghana

An assessment was conducted on the concentrations of zinc, copper, manganese, iron, lead and cadmium in 10 different fish species caught from some coastal and inland waters in Ghana, as part of a project on monitoring of pollution in water bodies in Ghana. Shellfish species (Egeria paradoxa galanata and Atya gabonensis) caught from inland waters had higher elemental concentrations than those caught from coastal waters. Mean concentrations of Fe and Mn were higher in E. paradoxa galanata, A. gabonensis and Trachiurus trachiurus, while Panulirus regius and Sardinella eba had higher mean concentrations of Cu. T. trachiurus, Dentex congoensis and T. ovatus had higher mean concentrations of Pb, while T. trachiurus and S. eba had higher mean concentrations of Zn. Mean Cd concentrations in the fish species were relatively low, with mean concentrations of Cynoglossus cadenati, D. congoensis and T. ovatus below detection limits. The mean concentrations of Zn, Cu, Pb and Cd for shell fishes were comparable to those obtained from previous studies in Ghana. However, they were lower than those reported in other areas of the sub-region. The mean concentrations of Zn, Cu, Pb and Cd in fin fishes were higher than those obtained from previous studies in Ghana. However, these values were comparable to those obtained from other areas in the sub-region. Compared to WHO limits, the levels of Zn, Pb, Cu and Cd in the fish species were lower, and, therefore, safe for human consumption. The study also showed that all the fish species except S. eba, Solar crumophthalmus and P. regius are safe for human consumption with respect to Zn, Cu and Fe.West African Journal of Applied Ecology Vol. 13 2008: pp. 27-3

Water quality characteristics at the estuary of Korle Lagoon in Ghana

The Korle lagoon is a major run-off water receptacle and outlet from the city of Accra into the Gulf of Guinea. Uncontrolled discharges of domestic wastes and industrial effluents as well as raw sewage (which are washed into the lagoon during high tides), have led to its environment being seriously degraded. Physico-chemical and bacteriological studies were conducted to measure the concentration of pollutants at the entrance of the Korle lagoon, from the offshore of the lagoon and from the raw sewage discharged onto the beach at neap and spring tides. Physicalcharacteristics of the lagoon waters, such as pH and temperature, for the two tides did not show any large variations and were fairly comparable. Salinity, suspended solids and conductivity, however, varied significantly with tidal changes. Dissolved oxygen was extremely low at low tide as a result of large quantities of waste materials from domestic and industrial activities which reach the lagoon. This was also evidenced in high biochemical oxygen demand (BOD) as well as high faecal coliforms during neap tide. Changes in the concentrations of nutrients occurred withchanges in tide; these being high, especially at high tide when sewage is back-washed into the lagoon. The study indicated that the entrance of the Korle lagoon to the sea and the adjacent sewage outfall area were polluted and not suitable for primary or secondary contact due to the occurrence of large numbers of coliform bacterial. However, the offshore area showed good water quality

Preliminary survey of the state of pollution of the coastal environment of Ghana

The physico-chemical state of estuaries, lagoons - open and closed - and beaches along the coast of Ghana was studied to provide base-line data for the monitoring of pollution. The main sources of pollution were identified as sewage of both industrial and domestic origin and oil in the form of tarballs. Of the 16 lagoons investigated, 12 were found polluted, 2 grossly polluted. The latter, the Korle and Chemu, serve as receptacles of industrial and domestic wastes. The estuaries were generally slightly polluted or "clean". Sewage pollution of beaches was usually associated with high population areas

Trace Metal Levels in Water and Sediment from the Sakumo II and Muni Lagoons, Ghana

Trace metal (Cu, Zn, Pb, Mn, Fe and Cd) levels were determined in water and sediment from the Sakumo II and Muni lagoons and the Mamahuma and Gbagbla Ankonu feeder streams, which feed the Sakumo II lagoon over a 1-year period, and their occurrences compared. Some physical parameters (temperature, pH and electrical conductivity) were also investigated. The aim of the study was to establish the pollution status of the two lagoons, as well as investigate whether the feeder streams of the Sakumo II lagoon have any influence (in terms of trace metal pollution) on the Sakumo II lagoon. Results showed that upper mean values in water and sediment were Zn ( 0.160 ± 0.01 mg/l, 48.7 ± 0.93 mg/kg), Pb (0.057 ± 0.03 mg/l, 29.2 ± 3.2 mg/kg), Mn (0.798 ± 0.07 mg/l, 668.2 ± 6.3 mg/kg), Cu (0.158 ± 0.01 mg/l), Fe (1.32 ± 0.73 mg/l, 3075 ± 14.7 mg/kg), respectively, for Sakumo II lagoon. Cd levels in water and sediment ranged from 0.004 ± 0.001 to 0.009 ± 0.001 mg/l and < 0.002 to 0.88 ± 0.05 mg/kg respectively, in the Sakumo II lagoon. Compared to the maximum contaminant level (MCL) of 0.005 mg/l, the Cd levels in water from the Sakumo II lagoon may be detrimental to the ‘health’ of the aquatic ecosystem and, consequently, consumers of fish products from the Sakumo II lagoon. Water and sediment in the Muni lagoon had trace metal concentrations with upper mean values as Cd (< 0.002 mg/l, 0.325 ± 0.01 mg/kg), Pb (0.033 ± 0.01 mg/l, 1.46 ± 0.18 mg/kg), Mn (0.434 ± 0.02 mg/l, 63.8 ± 1.50 mg/kg), Zn (0.077 ± 0.001 mg/l, 13.7 ± 0.18 mg/kg), Cu (0.013 ± 0.001 mg/l) and Fe (1.085 ± 0.26 mg/l, 3198.4 ± 3.51 mg/kg), respectively. Generally, trace metal levels detected in sediment from the Mamahuma ( Zn: 10.4 ± 4.10 mg/kg, Pb: 10.6 ± 1.84 mg/kg, Mn: 63.7 ± 4.5 mg/kg, Fe: 7487 ± 23.5 mg/kg, Cd: < 0.002), and from the Gbagbla Ankonu ( Zn: 155 ± 13.9 mg/kg, Pb: 37.4 ± 3.07 mg/kg, Mn: 298.2 ± 2.5 mg/kg, Fe: 3209 ± 50.5 mg/kg, Cd: 0.70 ± 0.05 mg/kg) feeder streams were relatively higher than those in the Sakumo II lagoon. Sediment from the feeder streams, therefore, provided a deeper insight into the long- term pollution state of the feeder streams and, consequently, the Sakumo II lagoon. The streams could, thus, be described as potential sources of trace metal pollution to the Sakumo II lagoon. Trace metal levels were also found to be more concentrated in sediment from the mid-section of the Muni lagoon than those from the northern and southern sections, while the northern section had more trace metal concentrations in water than those from the mid- and southern sections. The study also showed that trace metal levels detected in both water and sediment from the Sakumo II lagoon were higher relative to those from the Muni lagoon. The Sakumo II lagoon could be described as relatively more polluted with trace metal load

Impact of human activities on nutrient and trophic status of some selected Lagoons in Ghana

The nutrient and trophic status were used to assess the impact of human activities on lagoon by determining the trophic status of the lagoons and then using nutrient parameters and transparency in a form of model to predict the trophic status index (TSI) of the lagoon waters. The trophic index of Benya, Nakwa, Amisa and Nyanya ranges between 35.0–39.0 and falls within Carlson’s TSI range scale of 30–40, which implies that their waters are oligotrophic. The Oyibi lagoon is mildly eutrophic (Carlson’s TSI scale of 56) in the riverine portion. However, at the seaward end it has TSI of 42, which is moderately clear. Similarly, Muni lagoon is moderately clear with TSI range of 35.8–43.1. The Sakumo IIlagoon is hypereutrophic at the riverine end (Carlson’s TSI of 87.8). The seaward end is oligotrophic. The high phosphorus (231.9 kg/day) and nitrogen (927.9 kg/day) recorded at Nyanya lagoon are as a result of domestic activities mainly from the wastes generated from humans at the lagoon and its surroundings. The use of nutrients and transparency, in predicting the trophic status of lagoons and coastal waters is a new and emerging scientific way of looking at lagoon trophic status. The nutrient inputs into lagoons, as well as transparency, are direct impacts of humanactivities. The model has proved to be useful in explaining the impact of human activities on the trophic status of lagoons in Ghana. The model was assessed by predicting the observed versus predicted, and this showed a performance index (R2) of 95.1%. This shows that the model is able to use various nutrient and transparency values to predict the trophic status of lagoons. The model is able to predict lower or oligotrophic TSI values better than higher or hypereutrophic values. The model has then been used successfully to predict various TSI values from the lagoons

Impact of mining operations on the ecology of river Offin in Ghana

No Abstract

Total petroleum content and polycyclic aromatic hydrocarbon levels in soil and groundwater at the site of a fuel service station in Accra.

Analysis of Total Petroleum Content (TPC) and Polycyclic Aromatic Hydrocarbon (PAH) in soil and ground-water at the site of a Fuel Service Station indicated leakage of petroleum products from the underground storage tanks buried 3.6 km below the surface. The leakage resulted in contamination of areas within a 60 m radius. In the TPC profiles, distinct peak corresponding to diesel oil occurred between 5 and 17 min; while a hump charac-teristic of mineral oil occurred between 17 and 25 min. In the PAH profiles, 18 compounds were identified and quantified by means of gas chromatography. The TPC levels ranged between 0.918 - 21.9 &#956;g/L for groundwater and 44.1 - 894 mg/kg for soil. The levels of PAHs were low and HM-PAHs were not detected. The total PAH levels varied between 20.93 - 51.85 &#956;g/L for groundwater and 2.07 - 6.5 ng/kg ww for soil. The levels of LM-PAHs were above the International standard of 200 ng/L, while BaP levels were 710 ng/L (indicative of carcino-genic effects). Naphthalene was found to be abundant in the groundwater. Journal of Applied Science and Technology Vol. 13 (1 & 2) 2008: pp. 64-7

Evaluation of urinary arsenic as an indicator of exposure to residents of Tarkwa, Ghana

In Ghana, mining plays a significant role in the economic recovery programme. However, the gains are achieved at the cost of environmentaland human health. For many years, the extraction of gold involved roasting which released airborne particles and large quantities of arsenic(As). Sampling for this study was conducted in March 2004 to assess the contamination status of trace elements, especially As, in water andmine workers in Tarkwa, which has nearly a century of gold mining history. Water and human urine samples were collected from Tarkwa, inaddition to control samples taken from Accra, the capital of Ghana. Arsenic excretion was assessed in the first morning void urine. Concentrations of As and Mn in some water samples from Tarkwa were above the WHO drinking water guidelines. A potential health risk of As and Mn is a concern for the people consuming the contaminated water in this area. Levels of trace elements in water from control site were low compared to levels from Tarkwa. The mean urinary As concentration of 260 ìgl-1 from the study area was comparable to those in Asendemic areas of the world. This indicates relatively high degree of human exposure to As in Tarkwa, Ghana. Relatively low levels of As in water and no significant difference of As concentrations in urine between Tarkwa and Accra may suggest the presence of other sources of As contamination in Ghana, possibly food. This is the first study reporting 23 trace elements in human urine samples from a mining town in Ghana