The presence of pharmaceutical residues in discharges that end up in rivers is a growing concern for the disruption of aquatic ecosystems and human health. The risk of exposure to these medical wastes becomes greater because they are not biodegradable even after sewage treatment. This study aimed to remove trimethoprim (antibiotic), paracetamol (painkiller), and nevirapine (anti-retroviral) from wastewater using activated carbon made from rice husks, an agricultural waste that was investigated as a potential adsorbent. The instrument used for analysis was a liquid chromatography-tandem mass spectrometer (LC-MS/MS). The powdered carbon of rice husks was carbonated at a temperature of 500oC and then activated by phosphoric acid to increase its porosity. After activation, it was successfully characterized by the use of Scanning electron microscopy which showed irregular cavities with open fine pores. Fourier transform infrared showed different functional groups which determined adsorbent- adsorbate interactions while X-ray diffraction revealed amorphous particle arrangement. The effects of the adsorbent dose, contact time, pH, and initial drug concentration were studied. Freundlich and Langmuir's isotherms were used in the evaluation of adsorption phenomena. Thus, obtained results showed that rice husks activated carbon is an effective adsorbent.

Open dumpsites are one of the main sources of heavy metals and as a result, lots of research has been undertaken on the pseudo-total content of heavy metals in dumpsite soils, but little research on the forms in which they exist. The current research was carried out to determine levels of chromium, lead and cadmium in the various fractions of Dandora dumpsite soil and how they are fractionated in the topsoil and subsoil horizons. Samples were obtained from eight sites with depths of (0-30 cm) and (30-60 cm) for topsoil and bottom soils respectively. The modified Community Bureau of Reference (BCR) sequential extraction procedure was used and metal analysis performed using flame atomic absorption spectrophotometry. The metals (lead, chromium and cadmium) total concentration (µg/g) in the upper soil profile ranged from 42.22 to 1096.21, 38.26 to 180.60 and 11.23 to 44.22 while the lower soil profiles were 54.19 to 239.28, 30.56 to 76.48 and 9.47 to 22.56, respectively. The concentration of lead in various fractions of the upper soil profile followed the order; reducible > oxidisable > residual > exchangeable, while that of chromium was residual > oxidisable > reducible > exchangeable. Cadmium followed the order exchangeable > residual > reducible > oxidisable. The percentage of the metals in non-residual fraction were Pb (78%), Cr (58.7%) and Cd (70%). Their mobility factors were (Pb) 39.7 (Cr) 7.75 and (Cd) 5.02 in the upper soil profiles. Thus, the results suggest that Dandora dumpsite is highly polluted with the selected heavy metals.

Environmental pollution by heavy metals is presently a serious threat to public health. Despite the toxic contaminants contained in municipal waste, most of the dumpsites remain unregulated and uncontrolled. The objective of this study was to determine the levels of Pb, Cr and Cd in the leaves of tobacco tree plants growing around the dumpsite so as to assess their impact on the environment. The pseudo-total concentration of the metals in the soil was done so as to calculate the transfer factors.pH and total organic carbon (TOC) of the soil was also determined. Soil and plant samples were collected thrice from thirty two sampling sites along the off-loading path from the centre of Dandora dumpsite up to a distance of 700 m away from the centre at depth of 0-30cm (top soil).  Metal analysis was done using flame atomic absorption spectroscopy (FAAS). Pb levels ranged from 7.58±0.34 to 16.57±0.79 µg/g in the washed leaves and 9.22±0.36 to 19.27±0.40 µg/g in the unwashed leaves. Cr levels ranged from 5.11±0.40 to 14.4±0.91 µg/g in the washed leaves and 5.01±0.45 to 15.50±0.40 µg/g in the unwashed leaves. While Cd levels ranged from 0.24±0.01 to 3.62 ±0.17 µg/g in the washed leaves and 0.37±0.02 to 3.68±0.25 µg/g in the unwashed leaves. All these levels were above World Health Organization recommended limits in plants of Pb (0.3 µg/g), Cr (3 µg/g) and Cd (0.2 µg/g). Pearson correlation of the levels in the plants with their concentrations in the soils gave significantly positive values. This suggest that high metal concentration in the soil leads to increased mobility and hence bioavailability. Results obtained therefore suggest that Dandora dumpsite is highly polluted and people should be discouraged from using waste from the dumpsite as manure.