Hi Supriti,

By "hazard index", do you mean the ratio of exposure concentration to effects threshold? If so, then a value of 200 is possible and simply means that the exposure concentration is very high relative to the effects threshold.

Wayne

Yes, in very heavy polluted soils especially near oil wells. 

The hazard quotient (HQ) or hazard index (HI) is a ratio of estimated exposure dose (ADD) and reference dose (RfD), It indicates the health risk owing to adverse effects out of exposure to toxicants

HQ = ADD/RfD

HI = ΣHQ

where RfD represents a toxicity index of a daily exposure to the population in comparison to a safe level of exposure orally over a lifetime. Thus, an index value < 1 is assumed to be safe over a lifetime.

Supriti, in your case HI is too high which has negative implication fro human health perspective

Please refer :

H.A. Elwell, M.A.Stocking 1976, Vegetal cover to estimate soil erosion hazard in Rhodesia, Geoderma, vol 15, issue, 1  (  cross references also ).

Yes, i can possible in highly polluted soils.......