Flame ionization gas chromatographic determination of phthalate esters in water, surface sediments and fish species in the Ogun river catchments, Ketu, Lagos, Nigeria.

The detection and quantification of four phthalate esters-dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and diethylhexyl phthalate (DEHP)-in water, sediment, and some fish species were carried out using flame ionization gas chromatography. The samples were collected from the Ogun river catchments, Ketu, Lagos. The DMP was not detected in the water and fish samples but was detected in sediments collected from four of the six sampling sites. The concentration of DEP, DBP, and DEHP in the fish species ranged from 320.0-810.0, 380.0-1,080.0, and 40.0-150.0 µg/kg in Tilapia sp.; 310.0-860.0, 400.0-1,170.0, and 40.0-110.0 µg/kg in Chrysichthys sp.; and 320.0-810.0, 400.0-3,970.0, and 30.0-300.0 µg/kg (DEHP) in Synodontis sp., respectively. The differences in fish phthalate levels are not statistically significant at p < 0.05, an indication that phthalate esters accumulation is not fish species dependent. The DEP, DBP, and DEHP values recorded are considerably higher than the maximum allowed concentrations for drinking water prescribed by the US Environmental Protection Agency. The phthalate pollution index and biosediment accumulation factor values were also calculated.

Total petroleum hydrocarbons and trace heavy metals in roadside soils along the Lagos-Badagry expressway, Nigeria.

This study reports the level of total petroleum hydrocarbons (TPH) and trace heavy metals (lead, copper, and cadmium) in soil samples collected randomly from Iyana-Iba garage, Lagos State University bus stop, Adeniran Ogunsanya College of Education bus stop, and a control site off Lusada-Atan road, near Crawford University, Igbesa, Ogun state. TPH was estimated gravimetrically after Soxhlet extraction and column clean up, while soil metals were determined by atomic absorption spectrometry using mineral acid digestion. For TPH, the sites have mean values of 19.43+/-1.27, 16.11+/-1.85, and 11.43+/-4.33 mg/g with a control mean value of 0.33+/-0.16 mg/g. For trace heavy metals, cadmium was not detected. However, the mean levels of lead are 4.24+/-3.10, 3.72+/-0.60, and 3.70+/-1.32 microg/g, respectively, whereas mean copper concentrations are 20.63+/-9.02, 19.35+/-3.61, and 16.76+/-3.02 microg/g in all sites, respectively, compared to the control mean of 0.25+/-0.13 and 5.99+/-1.23 microg/g for lead and copper, respectively. Sites studied have higher levels of TPH and metals compared to the control soil samples. This is indicated by a statistically significant difference found between the concentration of analyzed elements in soils collected along Lagos-Badagry expressway and the control site.