An investigative study was carried out to determine the proximate composition, heavy metals and ratio of foot weight to shell weight of Tympanotonus fuscatus and Pachymelina aurita in the riparian area of the University of Lagos between March and May, 2017. The shell length, foot weight and shell weight of T. fuscatus ranged from 1.80-6.00 cm, 0.10-2.10 g and 0.30-6.40 g respectively and has means of 3.48±0.98 cm, 0.63±0.41 g and 2.21±1.37 g respectively. Also, the shell length, foot weight and shell weight of P. aurita ranged from 1.70-5.70 cm (3.44±0.85 cm), 0.10-1.70 g (0.62±0.37 g) and 0.30-6.40 g (2.13±1.17 g) respectively. The proximate compositions obtained were: %Protein (T. fuscatus: 47.53±20.79 and P. aurita: 45.83±19.74), %Fat (T. fuscatus: 4.75±4.24 and P. aurita: 2.00±0.00), %Fibre (T. fuscatus: 1.13±0.88 and P. aurita: 2.38±0.18), %Ash (T. fuscatus: 15.25±1.77 and P. aurita: 17.75±17.32) and %Moisture (T. fuscatus: 17.75±17.32 and P. aurita: 19.50±14.14). There was no significant difference in the means of the proximate compositions of the species when compared with a Student t test. % Foot Weight: % Shell Weight of T. fuscatus was 22.16:77.85 and % Foot Weight: % Shell Weight of P. aurita was 22.56:77.45. All the heavy metals analyzed were below the limit recommended by FAO/WHO except chromium in P. aurita and Iron that were above the safe level in both species. It should therefore be noted that T. fuscatus and P. aurita found around the riparian area of the Lagos Lagoon, though being good protein sources of food, may pose risk of chromium and iron induced illnesses.
Keywords: Tympanotonus fuscatus, Pachymelina aurita, Proximate, Heavy metal, lagoon.