Acute toxicity testing of fresh water mussel Lamellidens consobrinus to HgCl2, CdCl2 and ZnSO4 was carried out. The median lethal concentration (LC50) of HgCl2, CdCl2 and ZnSO4 for 24, 48, 72 and 96 hrs were 1.9616, 1.8602, 1.6983 and 1.4066; 1.9050, 1.8631, 1.7542 and 1.6195; 1.9952, 1.9664, 1.9529 and 1.6756 ppm respectively. Analysis of results indicates that L. consobrinus is highly sensitive to HgCl2 than CdCl2 and ZnSO4. The toxicants can be arranged in order of their toxicities as Hg>Cd>Zn.DOI: 10.3126/on.v8i1.4326

Lead poisoning is a phenomenon which with growing globalization is being a subject of worry.ALA i.e Amino levulinic acid is a precursor of hemoglobin, which is synthesized in mitochondria by two main components succinyl Co-A and glycine in presence of ALA-S i.e. amino levulinic acid-synthase. Urinary ALA (ALA-U) has been a recommended biomarker for lead exposure. Inhibition of Amino levulinic acid-dehydratase (ALA-D) results into activation of ALA-S which further synthesizes ALA, excess of ALA is accumulated in the blood, plasma, urine. Present manuscript is focused on the estimation of levels of ALA in the urine of gasoline and pertol pump workers, by acidifying the urine to extract out ALA and reading it colorimetrically as they are exposed to fumes released by gasoline, petrol, and petroleum products which contains lead. Awareness and safety measures such as protective masks and gears should be provided by the respective organisations to the workers.