Occurrence of PAHs in water samples of the Diep River, South Africa

Occurrence of polycyclic aromatic hydrocarbons (PAHs) in freshwater may aggravate the water crisis currently being experienced in the Western Cape Province of South Africa. However, there is dearth of data on the levels of PAHs, which is necessary for effective assessment of water quality as well as remediation strategies. This study therefore assessed levels of PAHs in the Diep River freshwater system of Western Cape Province, South Africa. A liquid-liquid extraction solid-phase extraction gas chromatography flame ionisation detection (LLE-SPEGC-FID) method was developed to simultaneously determine the 16 United States Environmental Protection Agency (USEPA) listed priority PAHs in water samples. The SPE-GC-FID method allowed an acceptable linearity (R2 > 0.999) within the calibration range of 1 to 50 μg/mL. Instrument detection limits ranged between 0.02 and 0.04 μg/mL and instrument quantification limits between 0.06 and 0.13 μg/mL. Recovery study results were also acceptable (83.69–96.44%) except for naphthalene, which had recovery of 60.05% in spiked water matrix. The seasonal averages of individual PAH detected at the studied sites ranged between not detected (nd) and 72.38 ± 9.58 μg/L in water samples.Keywords: PAHs, Diep River, GC-FID, freshwate

Spatio-temporal variation of organotin compounds in seawater and sediments from Cape Town harbour, South Africa using gas chromatography with flame photometric detector (GC-FPD)

AbstractThe spatio-temporal variation of two organotin compounds (OTCs) of tributyltin and triphenyltin in the seawater and sediment of Cape Town harbour was investigated. The organotin compounds were determined by GC-FPD following prior extraction with 0.02% tropolone. The concentration of OTCs varies for locations in Cape Town harbour. The concentration of OTCs in seawater ranges from 0.067±0.01 to 111.290±32.20×10−3μg/l for TBT while that of TPT ranges between between ND±SD and 23008.0±0.03×10−3μg/l respectively between locations. Relatively higher concentrations were measured for TBT and TPT during summer than in winter and spring seasons (p⩽0.05). Apparently, the observed high or low values recorded for TBT in Cape Town harbour could be the result of an increase or decrease in the traffic of ships and boats. TBT was detected in all the sediment samples analysed except for location 9 (entrance to harbour), the two control sites (which are located far away from the inner harbour where boating activities are taking place), and location 12 (Robinson dry dock 2) where the samples were not at all found. For the control sites, antifouling compounds TBT and TPT were not detected throughout except for TBT that was found in control A during summer. The seasonal variation of OTC abundance in sediment was also investigated. The results indicated that TBT is present throughout the seasons but is predominantly present in this order summer>winter>spring

Occurrence of PAHs in water samples of the Diep River, South Africa

Occurrence of polycyclic aromatic hydrocarbons (PAHs) in freshwater may aggravate the water crisis currently being experienced in the Western Cape Province of South Africa. However, there is dearth of data on the levels of PAHs, which is necessary for effective assessment of water quality as well as remediation strategies. This study therefore assessed levels of PAHs in the Diep River freshwater system of Western Cape Province, South Africa. A liquid-liquid extraction solid-phase extraction gas chromatography flame ionisation detection (LLE-SPE-GC-FID) method was developed to simultaneously determine the 16 United States Environmental Protection Agency (USEPA) listed priority PAHs in water samples. The SPE-GC-FID method allowed an acceptable linearity (R2 > 0.999) within the calibration range of 1 to 50 µg/mL. Instrument detection limits ranged between 0.02 and 0.04 µg/mL and instrument quantification limits between 0.06 and 0.13 µg/mL. Recovery study results were also acceptable (83.69–96.44%) except for naphthalene, which had recovery of 60.05% in spiked water matrix. The seasonal averages of individual PAH detected at the studied sites ranged between not detected (nd) and 72.38 ± 9.58 µg/L in water samples

Distribution and seasonal variations of selected heavy metals in seawater from Cape Town harbour of Western Cape Province, Republic of South Africa

This study was carried out to determine the distributions and effects of seasonal variations in concentrations of some selected heavy metals namely; Cr, Mn, Co and Ni in sea water collected from twelve locations from Cape Town harbour, Western Cape Province, Republic of South Africa. The water samples were analysed for the heavy metals by inductively coupled plasma- mass spectrometry (ICP-MS) with an Agilent 7700 ICP-MS. A significant correlation was measured for Mn and Ni during winter. For Cr and Co high concentrations were recorded in summer than in winter. Metal concentrations in the harbour ranged from (8.050 ± 0.590 μg/L ) to (44.580 ± 40.300 μg/L) for Cr, from (5.710 ± 1.870 μg/L) to (1054.420 ± 2556.320 μg/L) for Mn, from (0.330 ±0.090 microgram/L) to (30.700 ± 33.160 microgram/L) for Co and from (4.220 ± 4.210 μg/L) to (19.630 ± 12.180 μg/L) for Ni respectively. These results are indicative of the contribution of heavy metal pollution from the inflow of rain water, storm water drains, streams which carry runoff from industrial, urban and residential sources. High values of trace metals could be traced to anthropogenic and natural sources. Apparently, Ship repair activities are also suspected to be responsible for elevated concentrations in the upper reaches of the harbour