After reading this article you will learn about the toxicity of metals in mammals.
Toxicity is defined as capacity of a chemical agent to adversely effect the activity of a living organism, its growth, life span, health and reproductive capacity, Chronic disease, growth, retardation impaired reproduction are common basis for metal toxicity in mammals.
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Toxicity at cellular level causes deranged reproduction, maturation and differentiation in mammals. Some metals affect the permeability of cell membrane and disturb metabolism, others decrease the stability of lysosomal membrane, making disruption of cell functions.
The limits prescribed the Ministry of Health, Government of India, for certain heavy metals in drinking water are given in Table 2.
A normal sewage effluent develops additional mineralisation of 100 to 450 ppm measured as the total dissolved solids in one municipal water-use cycle.
Table 3 gives the recommended maximum concentrations of trace elements in irrigation water recommended by EPA assuming a water application of 3 acre feet/acre/year which can be used.
N.B. L-Less than
+ The result is being reinvestigated.
to calculate the rate of trace 36 elements added in irrigation water.
Analysis of waste water indicates that toxic materials, heavy metals and other minerals can be suitably controlled within a sewage system.
The results shown in Table 3 give the analytical data of the trace metals in raw sewage and treated effluent and the average is taken for the total number samples being investigated by Ghosh from Ganguli Bagan Housing Estate, Calcutta.
The precision, accuracy and confidence limit of the methods used are as mentioned in Standard Methods and the results reported are reproducible and reliable.
Table 4 gives a comparative analytical data obtained from calorimetry and atomic absorption spectroscopy by Ghosh in his analysis of some methods.
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It is, therefore, evident that spectrophootometric method of estimation tallies fairly well with the atomic absorption data.
Analysis of tap water of Meerut (Tej Garhi) and Delhi is given in Tables 6 and 7. In 1965 Goldberg identified the elements as normally occurring in sea water. He eliminated the elements 0, H, CI, Na, Mg, 5, Ca, K, Br, c, sr, B, si and f which are in concentration higher than one part per million.
He also eliminated He, Ne, A, Kr, Xe and Rn because they are biologically inactive. In the Table 8 the heavy elements (H), alkaline earth (A), tracemetals (T), exceptional toxicity (X), concentrated (C) by marine organism in sea water are given in (Table 8).
