RESUMEN
The information on pharmaceutical compounds' distribution and their possible risks in marine ecosystems along the Kenya coast is limited especially in the peri-urban creeks. Hence, this study aimed to determine pharmaceutical residue levels and distribution in selected peri-urban creeks in Mombasa and Gazi bay. The target compounds were analgesic (acetaminophen), antibiotics (trimethoprim and sulfamethoxazole), antiepileptic (carbamazepine), and antiretroviral (nevirapine). Pharmaceutical residues in grab surface seawater in wet and dry seasons ranged from below detection limit (BDL)-1065.6 µg L-1 and BDL-71.3 µg L-1, respectively. The concentration of the pharmaceutical residues was high in Tudor creek in the dry and wet seasons with a mean concentration of 63.3 µg L-1 and 233.1 µg L-1 respectively compared to Makupa creek (dry season, 54.2 µg L-1; wet season 16.2 µg L), and Mtwapa creek (dry season, 43.1 µg L-1; wet season, 15.0 µg L-1). Gazi Bay being used as a control site had a mean concentration of 21.3 µg L-1 and 3.1 µg L-1 during the dry season and wet season respectively. Acetaminophen and nevirapine were the most ubiquitous compounds in seawater since they were found in all seawater samples collected. Risk quotients (RQ) for invertebrates and algae based on the mean concentrations of the analytes were estimated to provide a preliminary environmental risk assessment. The results suggest that the studied acetaminophen, trimethoprim, sulfamethoxazole, and carbamazepine in seawater pose low (0.01 ≤ RQ < 0.1) to medium (0.1 ≤ RQ < 1) ecological risk whereas nevirapine poses medium to high (RQ ≥ 1) ecological risk to the ecosystems of Mombasa periurban creeks and Gazi bay. Further research, however, is encouraged on the distribution of pharmaceuticals in the marine environment and the long-term synergistic effects of mixtures of these compounds on marine biota.
RESUMEN
210Po in marine sediment from three peri-urban creeks in Mombasa was analyzed by alpha spectrometry in order to determine its baseline contamination levels. The mean 210Po activity in marine sediment from Mtwapa, Tudor and Makupa creeks were 18.67 ± 1.8, 21.17 ± 2.2 and 13.09 ± 1.6 Bq Kg-1 dw, for surface sediment and 37.56 ± 2.14, 28.64 ± 2.86 and 30.42 ± 2.1 Bq Kg-1 dw respectively, for sediment cores. Comparison of 210Po activity in surface sediment indicated that 210Po in the creeks could be originating from the same source. However, comparison of activities in the entire cores from the three creeks indicated that 210Po sources could have been different in the past. 210Po activities in this study were relatively elevated compared to marine environments under similar anthropogenic influence and there is need to understand its source and fate.