In this study, an attempt was made to examine the effects of dumpsite leachate on soil biological
sentinels by collecting leachate samples from Ikhueniro and Otofure dumpsites in Benin City Nigeria, and analyzed using
standard methods. The parameters include pH, chemical oxygen demand, biochemical oxygen demand, phosphate, sulphate,
chloride, nitrate, chromium, cadmium and lead. The mean results showed pH (8.30 ±0.14), BOD (566 mg/l), COD (1713
mg/l), Phosphate (7.73 ± 0.14 mg/l), Sulphate (22.40 ± 0.75 mg/l), Chloride (187.5 ± 1.12 mg/l), Nitrate (1.47 V 0.06 mg/l),
Chromium (0.06 ± 0.1 mg/l), Cadmium (0.20 ± 0.1 mg/l), Lead (1.03 ± 0.04) for Ikhueniro and pH (8.0 ± 0.1), BOD (315
mg/l), COD (1095 mg/l), Phosphate (5.85 ± 0.19 mg/l), Sulphate (31.70 ± 0.73 mg/l), Chloride (135.25 ± 1.59 mg/l), Nitrate
(0.93 ± 0.09 mg/l), Chromium (0.06 ± 0.1mg/l), Cadmium (0.109 ± 0.1mg/l), Lead (0.015 ± 0.005 mg/l)for Otofure
respectively. Different concentrations of leachate ranging between 25% and 100% was used and the growth of
Nitrosomonas
sp reduced from 6.4×10
4(cfu/ml) – 2.9×10
4(cfu/ml), when compared to the control which increased from
6.4×10
4(cfu/ml) – 1.0×10
5(cfu/ml). The percentage survival of
Lumbricus terrestris
was 2.19%, 1.14%, 3.42%, 6.69%, with
varying concentrations of 25%, 50%, 75%, and 100% respectively. The method implored for analysis shows the leachate
sample was toxic to both test organisms.
Nitrosomonas sp and
Lumbricus terrestris may be used as indicator organisms for
leachate toxicity in the soil.
