RESULTS AND DISCUSSION

Results obtained arc presented in Table No. 3 and Figure No. 2. It was observed that at all the spots the lead content of N. Indicant leaves was highest in the month of November as compared with that of October and December, 1982. The values of the lead content of leaves in the month of November were in the range of 46 to 156 ppm while it was 10 to 40 ppm and 38 to 103 ppm in the month of October and December respectively. The highest value, 156 ppm, was recorded in November at Spot No. 4, near (i) Mulchand, which is one of the highly-dense traffic intersections in South Delhi and is also near to the (i) Jawaharlal Nehru Stadium, (where the major events of the Games such as Opening Ceremony, Foot Ball, Athletics and the Closing Ceremony; were held) and (ii) the Games Village where arrangements for, the accommodation of the players and officials were made and the events of Weightlifting were also held. This intersection had traffic How for almost 20 hours a day during the Games. Spot Nos. 1,6 and 7 which arc in the close vicinity of the various stadia where the Games were held recorded the lead values in N. indicum leaves between 75 to 100 ppm in November while at the Spot No. 5, Ashram, it was a 120 ppm though there was no sports activity but the higher value might be due to the increased traffic from Haryana, U.P., Rajasthan States, other parts of the South Delhi, etc. which intersect the Ring Road at spot No. 5 near Ashram. At all the spots the lead content of N. indicum leaves was less in December as compared with that of November but it was more than that of October, which may be due to the fact that the Games were over only on 4th December and there was perhaps prolonged additional playing of vehicles until the mid-December or so unlike October.

Table 3 : Lead content (expressed as ppm) of NERIUM INDICUM (N) and FUCAI.YPTUS ROSTRA'I A (E) leaves collected from different traffic intersections on the Ring Road, in the city of Delhi in October, November and December, 1982

Sr. No.	Name of the traffic intersection	October		November		December
		N	E	N	E	N	E
1.	AZADPUR	18	33	100	58	51	56
2.	PUNJABI BAGH	10	21	84	79	58	69
3.	DHAULA KUAN	36	34	46	66	38	51
4.	MULCHAND	35	39	156	100	70	73
5.	ASHRAM	38	36	120	84	103	70
6.	INDRAPRASTHA	34	24	75	54	42	41
7.	KHYBER PASS (MALL ROAD)	40	22	83	57	42	42

In case of E. restrain leaves it was observed (hat at all the spots the lead content of the leaves was highest in the month of November, followed by Desember and October. The values of lead content in the month of November were in the range of 54 to 100 ppm while it was 41 to 73 ppm and 21 to 39 ppm in the months of December and October respectively. The highest value recorded, was 100 ppm, in November it spot No.4 Mulchand, which was similar to that of the values obtunded in case of the N.Indicum leaves Spot Nos 1 6 and'7 which were close to the Stadium recorded the lead content values in. is. rostrata leaves between 54 to 58 ppm in November, while it was 84 ppm at Spot No. 5, Ashram. Similar higher value was obtained at Spot No. 5 in case of N. indicum leaves also.

It was observed that the lead content of the N. indicum leaves was higher than that of E rostrata leaves in most of the samples analysed throughout the study period. This could be due to the fact that N. indicum plants were growing on the road-divider channel and thus receiving the direct effect of autoexhaust : whereas, the E. rostrata plants were growing on the road boundary and thus receiving less quantities of the exhust gases from the automobiles.

The differences encountered in the values of lead content of the leaves of both the plant species studied at different places were due to the presence of different levels of lead in the ambient air which is the function of the traffic density. Since there was no other source of any kind of the atmospheric lead pollution except the autoexhaust, the accumulation of the lead by the plant leaves could be attributed to the absorption from aerial lead. All the seven spots studied were more or less isoccological with respect to edaphic, microclimatic and management conditions as far as the cultivation of the plants were concerned.

It is seen from the results obtained that the was an increase in the lead content of the leaves both the plants species studied in the month of November as compared with that of October and the same again declined in the month of December, but it was more than values observed in the month of October. I Uglier values of lead content of leaves were observed at the sites which were closer to the spoils complexes, and hence had increased automobile traffic. The elevated values al Spot No. 5, though quite away from am sports complex, could be attributed to the increased, traffic density at this intersection during the (James because of increased number of incoming automobile.' from neighbouring states regions

CONCLUSIONS

There was considerable increase in the lead content of the leaves of N. indicum and E. rostrata plants in the month of November, 1952 as compared with that of October, 1932. The increase was more in the leaf samples collected from the sites closer to the different complexes of the Games where the traffic density was obviously expected to be higher than the other sites.

There was decline in the lead content of leaves of both the plant species studied in the month of Dec. as compared with that of November.

The higher values of lead content of leaves at Spot No. 5, Ashram, were perhaps due to the high density of traffic at the intersection where the vehicles hail to wait for the clearance of traffic signal for quite-some time and thereby burning more fuel. It is suggested that an appropriate multidirectional fly-over may be built at this intersection which could ensure the smooth flow of traffic, thus, help reducing the ambient lead pollution from automobiles.

The scope of the study has been limited due to the want of the data on traffic density and actual ambient air quality monitoring for lead at different traffic intersections which could not be done for several reasons. A detailed transplantation study covering these aspects has been planned and is being undertaken.

ACKNOWLEDGEMENTS

Authors arc thankful to Drs. N. Chaudhury, Chairman; G. D. Agrawal, Member Secretary and B. Sen Gupta, Scientist, of the Central Board for help and encouragement.

REFERENCES

• D. Bryce-Smith. Lead pollution-a growing hazard to public health. Chem. Br., 7 : 54-56 (1971).
• A.C. Chamberlain. Fallout of lead and uptake by crops. Atmos, Environ., 17(4) : 693-706 (1983).
• H.V. Warren and R.E. Delavault. Trans Roy Soc. Canada. 54 : 11 (1960).
• H. L. Cannon and J. M. Bowles. Contamination of vegetation by tetra ethyl lead. Science, 137(3535) : 765-766 (1962).
• R. L. Mitchell and J. W. S. Keith. The lead content of pasture herbage. J. Sci I'd. Agric, 17 : 437-4-fi) (1966)
• G. T. Goodman, and T. M. Roberts. Plants and soils as indicators of metal in air. Nature, 231 : 287-292 (1971).
• A. Burkitt, P. Lester and G. Nickles. Distribution of heavy metals in the vicinity of an industrial complex. Nature, 238 : 377-378 (1972).
• C. Williams. The accumulation of lead in soil and herbage at Rothamsted Experimental station. J. Agric. Sci. Camb., 82 : 189-192 (1974).
• J. C. Tyell, M. F. Hovmand and II. Mossbaek, Atmosphericlead pollution of grass grown in a background area of Denmark. Nature, 280 : 425-426 (1979)
• A. L. Page, T. J. Ganje and M. S. Joshi. Lead quantities in plants, soil and air near some major highways in Southern California. Hilgardia, 41 (1) : 1-31 (1971).
• C.B. Pandey, T.S. Patcl, D.J. Parikh, S.K. Chatter-jce and N. L. Ramanathan. Environmental lead exposure as a health problem in India (an over view). J. Environ. Bio., 4(3) : 127-148 (1983).