Conclusions

A long-term programme of measurements of trace and major elements, in air particulate and rainwater at ground level at three rural locations in England, has been maintained over the period 1996-1998. Concentrations of 35 elements in air and 25 elements in rainwater (plus nitrate and sulphate) have been measured on a quarterly basis during this three-year period.

These measurements have also been compared with earlier data from the 1990s along with corresponding historical data, compiled since the early 1970s, to investigate any long-term changes in relation to changes in methods of energy production, energy consumption and emissions control policy.

The main conclusions are:

Air (ng m-3)

As (0.3 - 0.9); ~3 at Styrrup.

Cd (0.1 - 0.4).

Cr (0.4 - 0.9); ~5 at Styrrup.

Cu (2 - 4); ~8 at Styrrup.

Ni (0.8 - 2); ~4 at Styrrup.

Pb (4 - 20); ~40 at Styrrup.

Zn (16 - 32);~60 at Styrrup.

Rainwater (m g l-1)

As (0.1 - 0.3); ~0.5 at Styrrup.

Cd (0.1 - 0.2); ~0.3 at Styrrup.

Cr (0.1 - 0.5).

Cu (1 - 2); 6 - 9 at Chilton, Styrrup and Wraymires.

Ni (0.4 - 1); ~2 at Styrrup.

Pb (2 - 5).

Zn (10 - 21);~40 at Styrrup.
 
 

Recommendations

The following recommendations are:

The Rural Trace Elements network is the longest running network, for the measurement of metals, in the UK. Since the early 1970s this monitoring network has produced a unique time-series dataset for concentrations of 35 elements in air particulate and some 25 elements in rainwater. The continued operation of this small network is recommended to allow further data to be collected. This would allow any further changes in concentrations of airborne trace and major elements at rural UK locations to be quantified. Therefore, any such changes may then be examined and related to changes in methods of energy production, energy consumption and industrial emissions which may be brought about by future changes in relevant UK Government or EC policy and legislation, e.g. the future EC daughter Directives that will set limit values for As, Cd, Hg and Ni concentrations in air.

In view of the future EC daughter Directive on Hg concentrations in air, consideration should be given to more detailed measurements of airborne mercury. Information is only available on particulate-bound mercury from the current network. AEA Technology made measurements of both particulate and total gaseous mercury (TGM) at Chilton over a period of a year in 1995/1996. This work could be re-started, either at Chilton or at another appropriate location(s), so that improved data on airborne Hg levels at UK rural locations can be obtained.

The dataset could be subjected to a more thorough and rigorous statistical examination. This may allow a more detailed investigation of the long-term trends, or a more accurate identification of the source or sources of potentially toxic heavy metals at rural locations in the UK.

An archive of samples, including both air filters and rainwater, has been assembled over the years. Retrospective analysis of those that have produced anomalous results is possible for confirmation. Also many historical measurements, particularly Cd in air particulate and other heavy metals, e.g. As in rainwater, were below the prevailing analytical limits of detection. Appropriate samples could be re-analysed using more appropriate and improved analytical techniques to further improve the quality of the dataset.

Expansion of the current suite of analytes to include the measurement of other metals should be considered. For example, concentrations of platinum, palladium and rhodium could be measured in both current and historical samples, to assess the impact of the introduction of catalytic converters to vehicle exhausts on levels of these metals on the UK rural environment.
 
 
 
 

References

Baker, S J (1997). Trace and major elements in the atmosphere at rural locations: summary of data obtained for the period 1992-1996. AEA Technology Report AEAT-2397/20174003.

Campbell, G, Vincent, K, Downing, C, Hasler, S, Donovan, B, Smith, M, Sansom, L and Page, H (1998). Acid Deposition Monitoring in the UK: 1986 to 1997. AEA Technology Report AEAT-3716/20017301.

Cawse, P A (1974). A survey of atmospheric trace elements in the UK (1972-73). AERE Harwell Report R-7669, HMSO, London.

Cawse, P A (1975). Anomalous high concentrations of particulate bromine in the atmosphere of the UK. Chemosphere, 2, 107-112.

Cawse, P A (1987). Trace and major elements in the atmosphere at rural locations in Great Britain, 1972-1981. In Pollutant Transport and Fate in Terrestrial Ecosystems. Special Publication Number 6 of the British Ecological Society (edited by P J Coughtry, M H Martin and M H Unsworth). Blackwell, Oxford.

Cawse, P A, Baker, S J and Law, D V (1995). A survey of trace elements in Great Britain, 1972-1991. AEA Technology Report AEA/CS/18358008/REMA-039.

Campbell, G W (1992). Lead in United Kingdom precipitation. Report LR 907 (AP), Warren Spring Laboratory, Stevenage, Herts.

Chamberlain, A C (1960). Aspects of the deposition of radioactive and other gases and particles. Int. J. Air Pollut., 3, 63-68.

DETR (1998). Expert Panel on Air Quality Standards: Lead. DETR Report. The Stationary Office, London.

DETR (1999). National Air Quality Information Archive at DETRís Web Site (at http://www.environment.detr.gov.uk/airq/aqnfo.htm).

EC (1982). EC Council Directive (82/884/EEC) on a limit value for lead in air. Official Journal of the European Communities, 25, No. L 378, 1982.

Gee, D R (1998). Non-automatic monitoring of lead and multi-element surveys: data summary 1997. GMSS Ltd Report to DETR.

Harrison, R M and Sturges, W T (1983). The measurement and interpretation of Br/Pb ratios in airborne particles. Atmospheric Environment, 17, 311-328.

Lee, D S, Garland, J A and Fox, A A (1994). Atmospheric concentrations of trace elements in urban areas of the United Kingdom. Atmospheric Environment, 28, No. 16, 2691-2713.

Lee, D S, Espenhahn, S E and Baker, S J (1995). Base cation concentrations in air and precipitation in the United Kingdom. Department of the Environment Report No. DoE/HMIP/RR/95/012.

Lee, D S, Dollard, G J and Pepler, S (1996). Gas- and particle-phase mercury in the atmosphere of the United Kingdom. AEA Technology Report to the Environment Agency.

Pattenden, N J and Wiffen, R D (1976). The particle size dependence of the collection efficiency of an environmental aerosol sampler. AERE Harwell Report R-8607, HMSO, London.

Playford, K and Baker, S J (1998). Atmospheric inputs to the North Sea: results for 1996 and 1997. AEA Technology Report AEAT-3324/20174202.

Playford, K and Baker, S J (1999). Atmospheric inputs to the North Sea: results for 1996 to 1998. AEA Technology Report AEAT-5697/20174202.

Salway, A G, Eggleston, H S, Goodwin, J W L and Murrells, T P (1996). UK emissions of air pollutants 1970-1994. A report of the National Atmospheric Emissions Inventory. AEA Technology Report AEAT/RAMP/20090001/R/003.

Salway, A G (1999). Private communication. Data are to be published in the DETR Report , Digest of Environmental Statistics No 21, 1999.

Stevenson, K J (1994). Airborne lead concentrations in the United Kingdom, 1985-1992. Report LR 1006, Warren Spring Laboratory, Stevenage, Herts.

Suess, H E and Urey, H C (1956). Abundances of the elements. Rev. Mod. Phys., 28, 53-74.

Vincent, K J (1999). Private communication.

Vincent, K J, Campbell, G W, Downing, C E H, Hasler, S E, Davies, M, Stedman, J R, Sansom, L E, Briscombe, C and Page, H M. Acid deposition monitoring in the United Kingdom: The first ten years. AEA Technology Report AEAT/20017001/REMA-304.

WHO (1987). World Health Organisation. Air Quality Guidelines for Europe. WHO Regional Publications, European Series No. 23, Copenhagen, WHO Regional Office for Europe, 1987.