Fighting against POLLUTION to Save Environment

Autoexhaust lead pollution of roadside ecosystem in Delhi:

J. Ind. Asso. Environ. Mgmt. 19, 21-27, 1992.

D. B. BORALKAR, S. K. TYAGI and S. B. SINGH
Central Pollution Control Board, 'Parivesh Bhawan' , CBD-Cum-office Complex, East Arjun Nagar,
Shahdara DELHI-110 032

A and C : Geometric mean of 10, once-a-month, observations
B : Geometric mean of 7, once-a-month, observations
D : Geometric mean of 9, once-a-month, observations

The base data (Table 4) were subjected to the analysis of variance. The variation in ambient air lead concentration is significant (F-calculated 8.785 is greater than F-Table 3.49) between timings. The variation due to location (F-calculated 3.269 is equal to F-Table 3.26) is not significant. As expected, lead concentration in ambient air during lean traffic period (between 12 noon and 4 p.m.) was lower than the morning and evening peak periods (9 a.m. to 12 noon and 4 p.m. to 7 p.m.). If any two timings are taken in pair for the analysis of variance, the variation between any pair of timings remains significant. Ambient air quality in regard to lead and other pollutants is required to study the impact of lead in synergism with other environmental constituents on plants specially located in traffic intersections. For such purpose, the 10-hr long measurement between 0900 and 1900 hours was decided to be adopted.

It was felt that a 10-hr continuous air sampling might adversely affect the SPM retention of the glass fibre filter (EPM 2000, Whatman). To examine this aspect, at Delhi Gate Traffic intersection, cumulative deposition of lead and SPM was studied. The results revealed that cumulative values of hourly lead and SPM deposition were in quite conformity with the values corresponding to those of total hours (Table 5). It was, therefore, concluded that a representative air sampling of 10-hour day time traffic hours can be done continuously.

Lead in Soil

The base data (Table 6) show that lead in the soil has increased in May 1985, compared with that in Feb. 1985, in all the pots of 3 plant species and at all locations. The analysis of variance of the data revealed no significant difference in lead content of soil between locations, seasons and plant seasons (F-calculated 6.67 is greater than F-Table 3.80) indicates significant variation.

Table 5 : COMULATIVE DEPOSITION OF LEAD AND SUSPENDED PARTICULATE MATTER*

*At Delhi Gate Traffic Intersection on 04/06/85

Condensed version of Table 6 is given with a view to indicate that winter and summer values of lead at Azadpur intersection, being significantly different from the rest, cause interaction between locations and seasons to be significant.

Table 6 : LEAD IN SOIL FROM POTS WITH DIFFERENT PLANT SPECIES AND DIFFERENT LOCATIONS (ug/gm)

Lead content of plants (ug/g dry wt. of root + shoot + leaf washing) of different locations in February, 1985 and May, 1985 is presented in Table 7. It is seen from the results that, at most of the traffic intersections, the lead content was higher as compared with that at NPL Nursery. The response of all the three species was different to the lead accumulation. Maximum accumulation of lead in samples of both the months, i.e., February (first quarter) and May, 1985 (second quarter) was found in Eugenia (Jamun) followed by Nerium and Alstonia. The accumulation of lead in plant species from five intersections was not found to be related to the traffic density .

Table 7 : LEAD CONTENT OF PLANTS* OF DIFFERENT PLANT SPECIES COLLECTED FROM DIFFERENT LOCATIONS

* (ug/g Dry Wt. of Root + Shoot + Leaf Washing)