.Armosphur &nrrronmenr Yol 16. No. 3. pp. 615.620. 1982

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Pergamon Press Ltd.

URBAN LEAD-A STUDY OF ENVIRONMENTAL LEAD AND ITS SIGNIFICANCE TO SCHOOL CHILDREN IN THE

VICINITY OF A MAJOR TRUNK ROAD

I. B. MILLAR

District Community Physician for Greenwich, Greenwich and Bexley Area Health Authority

and

P. A. COONEY*

Department of Consumer Protection and Environmental Health, London Borough of Greenwich. Peggy Middleton House, 50 Woolwich New Road, Woolwich SE 18 6HQ

(firsr receked 1 I December 1980 and infinalform 5 .Llap 1981)

Abstract-iMeasurements of children’s blood lead levels were ascertained in relation to lead in air and lead in dust attributed to an Inner Londonarterial highwaycarryingabout 35,OOOvehicles per day. Thecontribution of lead from deteriorating paintwork was also examined.

INTRODUCTION Table 1

In 1978, following extensive publicity of the lead and health issue, especially the vexed question of lead in petrol, a small group of children living on or near the Rochester Way (AZ) or attending Deansfield Schools adjoining the road were given blood lead tests, and the mean of their results was 17pg (lOOmI)-’ (Millar, 1979a).

However, since then the lead debate has if anything grown and as a result parents of children and the governing body at Deansfield Schools requested a further, more extensive survey. A report on an en- vironmental survey carried out by the G.L.C. in 1979 indicated low levels of air and dust lead around Deansfield School, airborne lead being below the G.L.C. guideline.

Although there was no evidence to suggest that there were any new factors since the previous small survey in 1978 the Area Health Authority recognised that the petition represented a certain amount of parental anxiety and agreed to a modest survey.

Width of carriageway Width of street* Height of flanking buildings Length of building frbntaget Road direction Gradient Traffic lanes

Vehicles per day Peak hourly flow “/, Diesel

Restrictions to flow

Driving pattern

* Between frontage of buildings.

On the basis of this evidence of parental anxiety and representation by the Greenwich London Borough Council the Area Health Authority agreed that a modest blood-lead survey of the children attending Deansfield School should be undertaken, in agreement with the teaching staff and Parents Association, and that this survey should run concurrently with the measurement of airborne lead, in dust and soil, noise and carbon monoxide, which would be carried out by staff of the Council’s Environmental Health Department.

t Length of building frontage unbroken by side turnings at Rochester Way between Westmount Road and Glennesk Road.

BLOOD LEAD SURVEY

Topography and rrafFc

The characteristics of the part of the study area where Deansfield School is situated are given in Table 1.

* Author to whom correspondence should be addressed.

In consultation with the Divisional Education Office and Deansfield Parents Association it was decided that the tests would cover 257; of the children attending Deansfield Junior, Infants and Nursery Schools, the children to be drawn from every class in the same ratio and oniy from those who had attended the school all their school lives. To obtain a sample of children exposed only to vehicle pollution from Rochester Way whilst attending the school it was agreed to exclude children living on Rochester Way from the 25% sample. At the same time the survey would be extended to include children living on the Rochester Way who had attended the school all their school lives, and to children living on Rochester Way who attended other schools. The samples were drawn as shown in Table 2.

8m 24m

2 storey 2lOm

E-W I :30 upwards 10 E

Two-Way : Single Lane

35.COO ‘700

30”” (High pro- portion Hea\? Goods) Single sel of traffic lights touards west

end of section. Slow monng. station- ary for Iona periods with exteniive tail- back from traffic

lights.

615

616 I. B. MILLAR and P. A. COONEV

Table 2. Sample distribution

Deansfield schools Infants Juniors Total

Number of children on roll 25” NuAber actually tested (Non-Rochester Way residents) Additional children living on Rochester Way who were tested:

Total number tested male female Other schools:

Children associated with Rochester Way who were tested:

233 321 554 58.25 80.25 138.5

61 76 137

15 20 35

76 96 172 38*(7) 52*(12) 90(191 38* (8) 44*(g) 82(16)

26*(14) 23*(1Ol 49(24)

l Inclusive of ( ) children living on Rochester Way.

In order to incorporate the effect, if any, of Roches- ter Way residence on the Deanstield schoolchildren 257,, of the 15 infants and 20 juniors living on Rochester Way would need to be added.

Accordingly, separate results were prepared for 65 infants and 81 juniors, in each case showing the effect of including the 4 or 5 children living on Rochester Way with the highest blood lead levels and the 4 or 5 children with the lowest levels (see Table 3). Selection of the children was as equal as possible by age and sex. The response proved to be successful in these respects as indicated by the fact that the number of children

from the first of two Deansfield Schools selection lists, i.e. the more preferred list, was 827, for infants and 84 7, for juniors.

The survey was carried out over the period between 19 and 28 March 1980. The arrangements for blood sampling were similar to those in the previous surveys (Millar, 1978and 1979). Venepuncture was the method used and the blood lead analyses were carried out at the Department of Chemical Pathology and Human Metabolism in the University of Southampton using the Delves’ cup method with atomic absorption spec- trophotometry (Delves, 1970).

Table 3. Blood lead level means

School

Results in gg (100mll- ’ Number of Standard

children Mean deviation Range

Deanstield infants Children not living on Rochester Wav Children living onRochester Way All males All females Infants + 4 highest levels of

children living on Rochester Way Infants +4 lowest levels of

children living on Rochester Way Deansfield juniors Children not living on Rochester Way Children living on-Rochester Way All males All females Juniors + 5 highest levels of children living on Rochester Way Juniors + 5 lowest levels of children living on Rochester Way Total other schools

(three schools) Henwick School Kidbrooke School Gordon School Infants only Juniors only Infants living on Rochester Way Juniors living on Rochester Way Al1 males All females

61 15

38 38

65

65

76 20

52 42

81

81

49 iF 20 16

26 23 14 10 25 24

14.02 3.36 6-23 12.15 2.19 8-17 14.11 3.15 6-23 13.18 2.65 8-23

14.08 3.3 6-23

13.76 3.44 6-23

12.18 2.83 6-21 11.28 1.42 8-12 12.06 2.42 b-19 11.9 2.86 8-2 I

12.19 2.74 E-21

12.01 2.82 6-21

12.46 2.97 8-25 11.78 4.58 8-17 12.63 4.22 8-25 12.81 1.73 10-15 12.9 3.17 8-25 11.97 2.72 8-17 13.46 3.79 8-25 12.22 1.8 8-14 12.26 2.53 8-17 12.68 3.42 8-25

A study of environmental lead and its significance 617

Results

The total number of blood samples taken was 221, with no failures. The overall mean blood lead level was

12.67 pg (100 ml)- I. Details of the various groups are given in Table 3.

The overall mean for this survey was lower than the overall mean for the group of 34 children tested in 1978 (Millar, 1979a). It has to be taken into account, however, that the mean age for this survey was older than in 1978. A comparison can be made of the results of children tested in both years. There were 12 such children, of whom 8 were pre-school and 4 were attending Deansfield Nursery School in 1978 and 9 were attending Deansfield Nursery and Infants School and 3 were attending the other schools in 1980. The means for these children were 16.74 and 13.97pg (1OOml)-1 in the years 1978 and 1980 respectively. This reduction is significant (P c 0.01). The mean age of these children at the time of the survey was 44.5 months in 1978 and 62.5 months in 1980. In the 1980 survey there was a rising blood level over the four 5- month age bands for all the children from age 45-50 mths to 60-65 mths, i.e. 12.08, 13.81, 14.23 and 14.39pg (lOOmI)-‘. Even if the age effect found in other surveys (Millar 1978 and 1979b) is applied the significance between the two surveys still remains (at least P < 0.05).

The difference between the means for Deansfield Infants and Deansfield Junior Schools was significant, with or without children living on Rochester Way (P < 0.01). The difference in the mean for children at Deansfield Infants School not residing on Rochester Way (14.02 pg (100 ml)- i) from the mean for children attending this school and living on Rochester Way (12.15pg (lOOml)-l) was significant (P < 0.05). The small difference in the means between the sexes for infants at Deansfield School, whether resident or not on Rochester Way, was not significant. In general the means for the classes in Deansfield Infants and Junior Schools represented an age sequential effect, the main trend downwards occurring about the level ofclass 1 C, or 6-7 years of age.

Twenty-five of the twenty-seven highest blood lead levels found in the survey occurred amongst children not living on Rochester Way and 14 of these 25 children (11 of them male) attended Deansfield Infants School.

The percentage of relatively high blood lead levels amongst Deansfield infant males was over twice that in any other group. Comparison within the Infants groups is given in Table 4.

The difference between the mean for Deansfield male infants and the mean for all other groups was significant (P < 0.01) as was the difference between the mean for Deansfield male infants and ail other males (P < 0.02).

The difference mentioned above in the means be- tween children attending Deansfield Infants School who resided or did not reside on Rochester Way was not parallelled by the findings in children at the other schools. It was possible to match accurately 1-I pairs of children and 5 other pairs fairly closely for age and sex in relation to residence on or away from Rochester Way. The difference in the means for these groups was opposite to that for Deansfield School but it was SO small (1.2~~ (lOOml)-i) that it did not exceed the difference between twins in the survey, of whom there were several pairs. Even this small difference was due entirely to the only relatively high result in the survey.

ENVIRONMENTAL MOSlTORISC

Assessment of trafic pollution

Measurements ofairborne lead, lead in dust and soil, were made along a two-hundred metre stretch of the Rochester Way between Deansfield School (Glenesk Road) and traffic lights at the junction of Westmount Road, where the A2 reduces to single carriageways and traffic congestion occurs.

Airborne lead levels were recorded at four sites namely Deansfield School playground approximately 2 m from the kerb and approximately 5 m from the kerb in the front gardens of numbers 664,601 and 572 Rochester Way. Dust samples were taken at 16 sites, the pavements outside the above addresses plus 549 and 626 Rochester Way (6 sites), the thresholds or bay windows of these properties (6 sites), and Deansfield School playground at increasing distances from the road (4 sites). Soil samples were taken from the front gardens of 549,572,601,626 and 664 Rochester Way.

Monitoring of lead in air was undertaken for a period of 13 weeks from 4 February, 1980 to 4 May, 1980 inclusive using Millipore 0.8 membrane filters, changed weekly. Dust and soil samples were collected on 14th April, 1980.

Reference lecels

The G.L.C. Air Quality Guideline for the maximum acceptable level of lead in air in the urban environment is3pgm-’ (averaged over 3 months); the EEC suggest an annual limit of 2 pg m- 3 in places where people are exposed continually for long periods. At present there

Table 4. Analyses of results from the 67 children under 6 y 3 mths

Mean age in Mean blood lead level Number months (pg(lM) ml)- t)

Deansfield male infants 21 62.2 15.58 All other groups 46 61.9 13.23 All other males 13 63.5 12.26

618 LB. M~LLAR and P. A. COOKEY

is no reference level for the concentration of Iead in environmental dust. Comparison can be made, however, with levels ascertained at other sites through- out London ranging from 300 to 3OtXppm., with levels of 2000 ppm. being quite common in samples taken throughout the Borough. The Poisonous Waste Unit of the G.L.C. puts the maximum lead level of uncontaminated soil at SOOppm although levels in excess of 1000 ppm are commonly found at sites where there is no known incidence of contamination.

Collection and analysis of all the samples, and interpretation of the results were undertaken by Ofhcers of the Pollution Control Section, Department

of Consumer Protection and Environmental Health, using facilities made available by the Department of Chemistry, Thames Polytechnic. Results and Com- parison of Measured Values with Reference Levels are given in Tables 5 and 6.

At none of the sites did the monthly airborne lead levels exceed the G.L.C. guideline of 3 pg m - 3 (3 months average). The mean concentration at Deans- field School over the whole sampling period was 1.35pgme3 , and at no time did the weekly level exceed 2ggme3. The general trend was for the lead con- centration to increase towards the traffic lights, in- dicative of increased exhaust emission attributable to

Table 5. Airborne lead concentrations

Monthly mean

Deansfield schooi

(Site c1)

Lead concentration (pug m- ‘)

664 R. Way 601 R. Way (Site H) (Site M)

572 R. Way (Site L)

4/2/80-l l/2:80 1 l/2/80-18/2/80 1 ai2/80-2s~2JaO 25/2/a+ 3/3!80 February 3/3/8~~0/3/80

10/3/8&l 7/3/80 17/3/80-2413180 24/3/8(r31/3/80 March 3 l/3/80- a/4,80 8/4/a@-14i4/80

~4~4~8U2~~4~80 2~~4~8~28j4~80 28/4/80- 4/S/80 April Overall mean (Three months average)

1.24 1.85 1.97 2.67 1.56 1.42 1.89 2.18 1.66 2.03 1.53 1.93 1.18 1.49 1.16 1.54 0.95 2.50 1.20 1.86 1.36 1.59 1.30 1.28 1.39 1.37 1.35 1.44 0.70 1.17 1.22 1.37

1.35 1.72

1.50 2.29 1.66 3.28 2.18 1.92 2.26 I.47 1.11 1.69 2.56 1.72 2.40 2.83 1.85 2.27

2.06

2.45 2.53 3.06 2.46 2.62 2.50 1.32 2.14 1.90 1.96 1.40 2.31 1.51 1.45 1.01 1.55

2.01

Table 6. Lead in dust and soil

Nature of sample

Dust 1. ,I

*, 9, I. . . ., 3, ” 3.

1% 11 ,. ,, 90

Soil 1. ,. 7, ,*

Position of sample Lead content ppm*

1 m from kerb outside school 2320 (1310) 2 * ” ” No. 601 m R. Way 2060 (1330) 2m * ‘I *’ No. 549 ” 2400 (1390) 2 ” ” ” No. 572 m *, 1910 (1340) 2 ” ” ” No. 626 m ” 1940 ( 1220) 2 ” ” ” No. 664 m ” 2220 (1400) Front door of No. 601 R. Way 1850 (1410) Bay window of No. 549 v 2800 (1690) Front door of No. 572 ” 3420 (1750) Bay window of No. 626 ” 2470 (1750) Bay window & front door of 664 R. Way 2550 (1610) Window ledges of No. 664 R. Way 660 - Deansfield playground 3 from kerb m 250 (90)

*. . . 37 ” m ” 390 (80) (I. ., 48 ” m ” 1180 (340) I. . . 87 ” m ” 220

Front garden of No. 601 R. Way 430 t :::; . . ., . . No. 549 ‘* 550 (410) .t ” 1. No. 572 ” 1580 (7601 . . *, ** No. 626 ” 1110 (800) ,. ,. 1. No. 664 ” 910 (630)

l Figures in brackets show corresponding soluble lead.

.A study of environmental lead and its significance

impeded traffic flow. Despite being a major trunk road the lead in air figures recorded were within the range commonly reported at urban sites near roads (DHSS, 1980). An explanation for this could be the high percentage of diesel fueled heavy goods vehicles (8 a.m.-4p.m., average of 30 T,,).

Discussion

The mean concentration of lead in pavement dust was 2 140 ppm and house frontage dust 2620 ppm. both of which were within the range commonly found in London.

Soil lead levels were ambiguous in that they ap- peared to relate more closely to the degree of care expended upon the front garden than anything else. Therefore, no conclusions could be drawn from this aspect of the work.

Lead in dust levels in Deansfield School playground were low, possibly as a result of constant sweeping operations. The analytical results showed a marked increase in level at a distance of 48m from the kerb. This sample site was situated within an open-fronted shelter where children could sit and eat sandwiches, or gain protection from inclement weather. Whilst sam- pling it was observed that paint on the ceiling had badly deteriorated, the floor of the shelter being covered in several places with large flakes of paint. Paint on the walls also showed distinct signs of having been picked, although generally it was in good decorative condition.

The urban environmental lead levels found at Rochester Way are similar to those reported at sites near busy roads. There were no children in the survey with blood lead levels exceeding 3Opg (lOOmI)- ’ and only 2.12 “/; had levels exceeding 20 pg( 100 ml) - i. There is one aspect, however, which calls for further comment. The mean blood lead level of males younger than 6 y 3 mths at Deansfield Infants School was above the survey mean. This elevation, though small, was nevertheless significant. When linked with the single dust lead sample from Deansfield playground, which was so much higher than the other playground samples, one must consider the possibility that there may have been a slight contribution to lead uptake in these children from paint.

Paint samples were collected and sent to the Public Analyst for analysis, the results of which, given in Table 7, showed that the paint had a lead content greatly in excess of the “less than 1 YO” standard set by the G.L.C. for use in dwellings or in schools, thus constituting a serious health hazard to children par- ticularly those with pica. The distribution of small particles of paint into playground dust was directly responsible for the elevated lead level.

When informed of the findings regarding this paint ILEA immediately began stripping and repainting the two playground shelters. Further sampling was carried out and although the ceiling and walls were no longer a problem there remained sufficient paint within the playground dust to present a health hazard. Once again the ILEA responded quickly to advice from the Borough Consumer Services and Environmental Health Officer and vacumn cleaned and washed the shelters and surrounding playground.

In general, airborne lead is not the major contrib- utor to blood lead: for the population at large dietary sources are usually more important. Increasing petrol consumption in Denmark between 1962 and 1976 was associated with a decrease in the lead content of spring and winter wheat. barley and total diet (Solgaard er al., 1979) leading these workers to conclude that the direct uptake of lead from air is generally small and that lead in the edible parts of crops comes mainly from the soil. This is not to detract from the contribution to blood lead from airborne lead which has been the subject of so much detailed study. The present survey does not indicate that the finer variations of uptake between the Rochester Way and non-Rochester Way environments can be easily distinguished. This is not unlike a recent extensive study of the effects of automobile traffic on blood lead levels in Dallas, Texas, (Johnson er al., 1978) which included over 120 children aged up to 8 y whose mean blood lead level was calculated to be 15~g(lOOml)- ‘. The air lead levels matched traffic density and at the highest counting site of 25,000 cars/day the mean air lead value was 1.9pgme3. However, there was no detectable relationship between blood lead levels and traffic density. The only associ- ation was between the higher blood lead levels and smoking in adults which was highly significant for females.

Further sampling was undertaken after a period of approximately 3 months when wind blown material had accumulated sufficiently to enable verification of the cleaning programme.

The findings of this survey are reassuring with regard to Deansfield School and again suggest that lead from vehicles on Rochester Way is not contribu-

619

Table 7. Lead in paint

Location

Playground shelter roof (top layer) Playground shelter roof (all layers) Playground shelter wall

Total lead (ppm)

3500

360,000 (36 7;)

25.000 (2.5 7;)

Soluble lead (ppm)

1600

120,000 (12%)

3cHm

620 I. B. MILLER and P. A. COONEY

ting measurably to the blood lead levels of children living or being educated there. These levels are towards the lower end of the EEC reference range and there is some evidence that they may be lower than they were eighteen months earlier.

The most significant feature of this survey was the discovery of leaded paint within the playground shelter. This presented a greater and more immediate threat to the health of the children attending Deans- field School than airborne lead from the Rochester Way.

Acknowledgements-The authors thank all those who helped to carry out this survey, and in particular Dr. H. T. Delves, Department of Chemical Pathology and Human Metabolism, University of Southampton for undertaking the blood lead analyses, Dr. A. C. Turner, Warren Spring Laboratory, for arranging the use of monitoring equipment, Thames Polytechnic for the use of analytical facilities, Mr. P. Blake, Technical Officer, London Borough of Greenwich, for his invaluable work on the analysis of samples obtained

during the environmental study and the nurses, technicians and administrators whose etliciency gave the survey an assured and uncomplicated character.

REFERESCES

Delves H. T. (1970) A micro-sampling method for the rapid determination of lead in blood by atomic absorption spectrophotometry. Analyst 95, 431-435.

Department of Health and Social Security (1980): Report of a Working Party on Lead in the Environment.

Johnson D. E.. Prevost R. J., Tillery J. B.. Kimball K. T. and Hosenfeld J. M. (1978) Epidemiologic study of the Effects of Automobile Traffic on Blood Lead Levels. Sponsored by U.S. Environmental Protection Agency.

Millar I. B. (1978) Monitoring of lead in the environment. J. Epidemiol. Community Hlth 32, 1 I l-l 16.

Millar I. B. (1979a. b) Blood lead level survey-Rochester Way. London, S.E.9, Archs Dis. Child/l. 54. 729.

Millar I. B. (1979) Report on EEC Survey at Greenwich:‘Bexley (unpublished).

Solgaard P.. Aarkrog A., Fenger J., Flyger H. and Graabaek A. M. (1979) Lead in Danish Food-stutTs. Dan Med. Bull. 26, 179-182.