02 to 24 ± 3.12 × 104/ml (Figure 2). At 12 h of exposure, the highest viability of cells was recorded: 6 ± 10.03 × 104/ml, which was consistently the same in all concentrations of exposure. However, at 24 h of exposure, the highest

viability (18 ± 2.14 × 104/ml) was recorded at the doses of 0.5 and 1.0 mg/l and the total cell count decreased from 16 ± 2.01 × 104/ml to 14 ± 1.02 × 104/ml at exposure of 2 to 5 mg/l ZnO NPs. This reflects that at high concentration the viability of coelomocytes decreases significantly. Similarly, at 36 h of exposure of up to 1 mg/l, the viability of coelomocytes recorded was 20 ± 2.01 × 104/ml, selleck chemicals and this was gradually decreased (14 ± 2.01 × 104/ml) by increasing the concentration of nanoparticles. At 48 h, the number of coelomocytes was similar to that of control (24 ± 2.12 × 104/ml) at 0.5 mg/l but gradually decreased with the increase in the concentration of nanoparticles. Results indicate that the viability of coelomocytes deceases with the increase in the concentration of NPs (100 nm). Figure 2 Viability of coelomocytes after exposure to ZnO NPs (100 nm) at different intervals. After exposure to 50-nm ZnO at 12 h, the viability recorded was 6 ± 1.0× 104/ml which was dependent on neither the size nor the concentration of NPs. However, at 24 h, the

uptake of NPs triggers cell replication and increases the number of coelomocytes from 10 ± 2.04 × 104/ml to 18 ± 3.12 × 104/ml (Figure 3). However, there was a little trend in the decrease in the number of coelomocytes: 14 ± 1.12 × 104/ml. At 48 h, the highest cell count was recorded at exposure of 0.5 mg/l. There was a gradual Cell Cycle inhibitor decrease in coelomocytes (18 ± 2.08 × 104/ml to 12 ± 1.06 × 104/ml). However, the total viability

ranges were between 6 ± 1.02 × 104/ml and 20 ± 3.12 × 104/ml. Results indicate that exposure up to 1 mg/l increases the replication of coelomocytes (Figure 4). Yang et al. [33] also recorded the uptake of NPs which depends on their size and concentration. Figure 3 Viability of coelomocytes after exposure to ZnO NPs (50 nm) at different intervals. Figure 4 Total viability of coelomocytes after exposure to ZnO NPs: (A) 100 nm and (B) 50 nm. Earthworms in general are tolerant to many chemical contaminants including heavy metals and organic pollutants in MRIP soil and can bioaccumulate them in their tissue [34]. They absorb the dissolved chemicals through their moist body wall due to the interstitial water and also ‘ingest’ by mouth while the soil passes through the gut. They either ‘biotransform’ or ‘biodegrade’ chemical contaminants, rendering them harmless in their bodies. Satchell [35] suggested that earthworms can uptake chemicals from soil pore water through passive ‘absorption’ of the dissolved fraction through their body wall. Coelomic uptake can also occur as soil is ingested and passed through the coelomic cavity.