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Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr, and Zn) were determined in soil and Digitaria eriantha plants within the vicinity of three coal power plants (Matla, Lethabo, and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05 ± 0.02 to 1836 ± 70 μg g(-1), 0.08 ± 0.05 to 1744 ± 29 μg g(-1), and 0.07 ± 0.04 to 1735 ± 91 μg g(-1) in Matla, Lethabo, and Rooiwal, respectively. Total metal concentration in the plant (D. eriantha) ranged from 0.005 ± 0.003 to 535 ± 43 μg g(-1) in Matla, 0.002 ± 0.001 to 400 ± 269 μg g(-1) in Lethabo, and 0.002 ± 0.001 to 4277 ± 201 μg g(-1) in Rooiwal. Accumulation factors (A) of less than 1 (i.e., 0.003 to 0.37) at all power plants indicate a low transfer of metal from soil to plant (excluder). Enrichment factor values obtained (2.4-5.0) indicate that the soils are moderately enriched with the exception of Pb that had significant enrichment of 20. Geo-accumulation index (I-geo) values of metals indicate that the soils are moderately polluted (0.005-0.65), except for Pb that showed moderate to strong pollution (1.74-2.53).

The distribution and potential sources of 15 polycyclic aromatic hydrocarbons (PAHs) in soils in the vicinity of three South African coal-fired power plants were determined by gas chromatography-mass spectrometry. PAH compound ratios such as phenanthrene/phenanthrene + anthracene (Phen/Phen + Anth) were used to provide reliable estimation of emission sources. The total PAH concentration in the soils around three power plants ranged from 9.73 to 61.24 μg g(-1), a range above the Agency for Toxic Substances and Disease Registry levels of 1.0 μg g(-1) for significantly contaminated site. Calculated values of Phen/Phen + Anth ratio were 0.48 ± 0.08, 0.44 ± 0.05, and 0.38 + 0.04 for Matla, Lethabo, and Rooiwal, respectively. Flouranthene/fluoranthene + pyrene (Flan/Flan + Pyr) were found to be 0.49 ± 0.03 for Matla, 0.44 ± 0.05 for Lethabo, and 0.53 ± 0.08 for Rooiwal. Such values indicate a pyrolytic source of PAHs. Higher molecular weight PAHs (five to six rings) were predominant, suggesting coal combustion sources. A good correlation existed between most of the PAHs implying that these compounds were emitted from similar sources. The carcinogenic potency B[a]P equivalent concentration (B[a] Peq) at the three power plants ranged from 3.61 to 25.25 indicating a high carcinogenic burden. The highest (B[a] Peq) was found in samples collected around Matla power station. It can therefore be concluded that the soils were contaminated with PAHs originating from coal-fired power stations.

This article investigates the impact of anthropogenic activities on an important surface water from physico-chemical, chemical and microbial perspectives. The surface water, referred to as Blesbokspruit is in the West Rand District of South Africa. Potential impactors include wastewater treatment plant, mines, farmlands and informal settlements. Water samples were collected from nine purposively selected sampling points and analysed in 2014. The mean values of analysed variables across sampling sites and periods ranged from pH: 7.4-8.4; EC: 93.0 - 146.6 mS/m; TSS: 11.3 – 39.0 mg/L; TDS: 590.3 - 1020.3 mg/L; COD: 15.6- 34.8 mg/L. Those for anions varied from NO3-: 0.2- 2.1 (mg/L) N; PO43- : 0.4-0.9 mg/L and SO42-: 118.6 - 379.5 mg/L. The metallic variables ranged from As: 0.01-0.06 mg/L; Cd: 0.02-0.06 mg/L; Fe: 0.04-0.73 mg/L; Cu: 0.02 – 0.05 mg/L and Zn: 0.05 – 0.15 mg/L. The Faecal coliform varied from 15.9-16878.5 cfu/100 ml; Total coliform: 92.9-430294 cfu/100 ml and HPC from 4322.5-39776 cfu/1ml. Detection of toxic metals and pathogenic organisms above target safety limits indicate unsuitability of the water for domestic use with impact on the health of aquatic ecosystem. The study generally revealed the impact of anthropogenic activities on the surface water quality.

This article reports on the level of toxic trace metals (Cd, Pb, Mn, Zn, Cu and Ni) in surface water and sediment along the Blaauwbankspruit in the West Rand District of South Africa. This spruit serves as receiving channel of wastewaters from sewage treatment plant and a gold mine. Some physical and chemical influences of released wastewater on the quality of the surface water, which is utilized for agricultural purposes was studied. Total trace metals in water and sediment samples were digested using mineral acid and then analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometry. The mean concentrations of analyzed trace metals in water samples ranged from trace – 0.05, trace –0.11, 4.35 – 942.2, 0.10 – 0.41, 0.08 – 0.88 and 0.15 – 0.42 mg/l for Cd, Pb, Mn, Zn, Ni and Cu, respectively. The mean levels of trace metals in sediment samples also ranged between trace – 0.12,trace – 0.38, 12.3 – 2957.2, 0.13 – 2.57, 0.39 – 1.96 and 0.18 – 2.84 mg/g, respectively, in the above metallic order. Higher metallic load in sediments, compared to those in water samples were obtained. Safety limits, specified by the Department of Water Affairs and Forestry for the use of water for domestic and irrigational purposes were exceeded in many samples. This further highlights the serious concern regarding the use of contaminated surface water. In addition, higher values of determinants obtained from sampling points close to the wastewater treatment plant and the mine exit channels strongly revealed their influence on the general quality of the stream. Detection of metals such as cadmium and lead above acceptable limits has dire consequences across the food chain.

Groundwater (well water) from a residential area within the vicinity of an industrial estate in Lagos, Nigeria were sampled and analysed by Flame Atomic Absorption Spectroscopy for their heavy metals content. This was with a view of assessing the quality of the water, which was being used for domestic activities, especially, drinking usually without treatment. Total trace metal determination by mineral acid digestion of water samples was applied. This method proved to be better than an extractive concentration technique in the quality assurance protocols with the recovery range being 90.7 ± 0.006–97.6 ± 0.003%. Mean concentration of trace metals in water samples ranged from Fe: 0.05–0.47 mg l−1; Al: 0.1–1.54 mg l−1; Cu: 0.14–1.39 mg l−1; Zn: 0.04–0.43 mg l−1; Cd: trace–0.02 mg l−1; Pb: trace–0.03 mg l−1, Mn: 0.01–0.18 mg l−1 and Ni: 0.02–0.11 mg l−1. Physical parameters of water samples examined were within the drinking water safety limits except for conductivity. Results generally indicate the presence of heavy metal constituents in groundwater samples. Detection of metals such as cadmium and lead which have serious health implications above WHO and USEPA limits in drinking water gives cause for concern.

Persistent organochlorine pesticides (OCPs) such as DDT and its metabolites (DDDs and DDEs), chlordane, hexachlorobenzene (HCB), heptachlor and endosulfan were determined in drinking-, ground-, surface- and marine waters from the Eastern Cape Province of South Africa. Percentage recoveries of the OCPs from spiked river water ranged from 71.03 ± 8.15% (dieldrin) to 101.25 ± 2.17% (α-BHC). The levels of OCPs ranged from 5.5 ng/L (2,4-DDD) to 160 ng/L (HCB) in the water samples. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulfan and chlordane were detected.

This study reports the level of total petroleum hydrocarbons (TPHs) and trace metals in dusts from some petroleum handling facilities (gasoline stations), selected high traffic density roads and residential areas within the Tshwane Metropolitan area in South Africa. Total petroleum hydrocarbons in dust samples were extracted using soxhlet extraction and isolated gravimetrically after column cleanup, while total trace metals in dust samples were digested using mineral acid digestion and analyzed using atomic absorption spectrometry (AAS). The mean TPH level from the residential sites ranged from 206 +/- 20.3-300 +/- 36.4 microg g(-1) while those from gasoline stations and high traffic density roads varied between 562 +/- 43.9-340 +/- 62.6 microg g(-1) and 404 +/- 32.7-852 +/- 55.4 microg g(-1) respectively. Mean concentrations of analyzed trace metals at residential areas ranged from 0.04 +/- 0.02-0.07 +/- 0.03 microg g(-1); ND; 0.21 +/- 0.01-0.34 +/- 0.02 microg g(-1); 0.66 +/- 0.06-2.11 +/- 0.82 microg g(-1); 18.7 +/- 0.86-33.4 +/- 0.83 microg g(-1) and 0.07 +/- 0.04-0.23 +/- 0.01 microg g(-1) for Cd, Pb, Cu, Zn, Mn and Cr respectively. Mean levels from gasoline stations ranged between 0.05 +/- 0.02-0.17 +/- 0.07; 0.08 +/- 0.02-0.12 +/- 0.04; 0.21 +/- 0.04-4.34 +/- 0.60; 7.44 +/- 0.40-13.0 +/- 0.56; 23.36 +/- 4.37-131 +/- 10.5 and 0.05 +/- 0.02-0.17 +/- 0.05 microg g(-1) while those from high traffic density roads ranged from 0.07 +/- 0.04-0.10 +/- 0.04; ND-0.30 +/- 0.05; 0.67 +/- 0.05-3.80 +/- 0.82; 2.40 +/- 0.25-10.6 +/- 0.96; 19.8 +/- 1.03-108 +/- 4.44 and 0.06 +/- 0.02-0.12 +/- 0.04 microg g(-1) also in the above metal order. Contamination by TPH and trace metals both at gasoline stations and high traffic density roads is revealed by their significantly higher values compared to those of residential areas.

This paper presents an assessment of the level of vanadium in foods (Plantain, Musa spp; Yam, Discorea rotundata; and Maize, Zea mays) from ten popular market places in Lagos metropolis, Nigeria. Total acid leaching digestion method was employed and determination was by Flame Atomic Absorption Spectrophotometry. The concentration of the metal obtained ranged from 0.01 ± 0.001 (M 3 ) - 0.62 ± 0.002 (M 2 ) for Musa spp; 0.02 ± 0.001 (M 3 , M 5 , M 9 ) - 0.41 ± 0.002 (M 3 ) for Discorea rotundata; and 0.01 ± 0.001 (M 1 ) - 0.35 ± 0.001 (M 6 ) for Zea mays. The overall mean concentrations of the metal were 0.19, 0.13 and 0.09mg g -1 in the same food order. The quality assurance of the analytical protocol was in the range of 91.5 - 98.1 % with C.V. of between 1.5 – 3.4%, which was adjudged acceptable for the analytical protocol. Vanadium was detected in all analysed foods with some elevated concentrations. Key Words: Vanadium, foods, AAS, coal, city, terminals African Journal of Science and Technology Vol.5(1) 2004: 15-21

Levels of Cd, Hg and Zn in some surface waters from the Eastern Cape Province, South Africa, Water SA, 29 (4) 2003, p.377

Persistent organochlorines such as SDDT, chlordane, hexachlorobenzene (HCB), heptachlor and endosulfan were determined in water and sediment samples of freshwater systems in the Eastern Cape Province of South Africa that receive runoff from agricultural lands and effluents from industries. The organochlorine pesticides (OCPs) in water and sediments were determined by liquid/liquid extraction and Soxhlet extraction methods, respectively. Percentage recoveries ranged from 71.03 + 8.15 % (dieldrin) to 101.25 + 2.17 % (a-BHC) in water and from 88.22 + 7.85 % (endrin) to 109.63 + 5.10 (b-BHC) in sediment. The OCP levels ranged from trace (2,4'-DDD) to 450 + 0.0002 ng/ℓ (b-BHC) in water samples and from trace (aldrin and 2,4'-DDD) to 184 x 103 + 0.7 ng/kg (b-BHC) in sediments for triplicate analyses. Some endocrinedisrupting OCPs such as 2,4'-DDT, 4,4'-DDT, 2,4'-DDE, heptachlor, endosulfan and the chlordanes were detected. Water SA Vol.29(3) 2003: 323-330

Different extraction methods were evaluated for the determination of fifteen organochlorine pesticides (OCPs) in water and sediments. Liquid-liquid extraction (LLE) was evaluated for the pesticides analyses in water while Soxhlet extraction (SE) and microwave assisted extraction (MAE) methods were compared in sediment. Of all the extracting solvents used, dichloromethane gave the best results. Percentage recoveries ranged from 71.03 +/- 8.15 (dieldrin) to 101.25 +/- 2.17% [a-benzenehexachloride (alpha-BHC)] in water with LLE. In sediments the percentage recoveries with Soxhlet extraction method varied between 88.22 +/- 7.85 (endrin) and 109.63 +/- 5.10% (beta-BHC) and ranged from 74.11 +/- 9.82 (2,4 DDT) to 97.50 +/- 4.56% (alpha-BHC) with MAE. The limits of detection for the OCPs ranged from 5.5 to 20.6 ng/l and between 0.6 and 2.1 ng/g. respectively. The LLE and the SE methods were applied to water and sediments samples, respectively, from marine and freshwater sources in the Eastern Cape Province of South Africa that receive runoffs from agricultural lands and effluents from industries. The levels of OCPs ranged from 5.5 (2,4-DDD) to 450 +/- 0.10 ng/l (beta-BHC) in water samples and from 0.6 (aldrin and 2,4-DDD) to 184 +/- 0.12 ng/g (beta-BHC) in sediments for triplicate analyses. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulphan and the chlordanes were detected.

Trace levels of Cd were determined in Umtata River which may affect human health. The levels of Zn were also determined since Zn can provide partial protection against the toxic effect of Cd in humans. The levels of Cd varied between trace and 0.007 mg/ℓ while that of Zn ranged from trace to 0.019 mg/ℓ. Generally the levels of Cd and Zn found in the river were below the South African water quality guidelines for Cd and Zn, respectively. The hazard quotients for Cd in the river were calculated in order to show the potential health risks of cadmium to local primary users of water from river and the values were within acceptable limits. Keywords: Cadmium, River water, Health risk WaterSA Vol.30(4) 2004: 507-513