Silt sampling and disposal on the Birmingham Canal Network
Background
With evidence indicating contamination of canal silt we wanted to know how the present British Waterways set up dealt with historically contaminated silts and what was done with them. Of particular importance was the Birmingham Canal Network including the route taken by the Alfred Matty boats between Trinity Street and Rattlechain.
We also wanted to know what information they held concerning testing for waste contaminated with white phosphorus, which fairly obviously would have been significant from what we know about the historic transport of the waste from Trinity Street to Rattlechain.
1. We Asked : Does British Waterways test silt samples to detect contamination?
They replied : British Waterways test silt samples when it carries out dredging works and also when it carried out the national survey in 1992.
They also supplied a very helpful British Waterways paper that gives a historical perspective on the issue of silt being classed as controlled waste since 1988. To read this document, THE INFLUENCE OF REGULATIONS ON THE MANAGEMENT OF DREDGING AND DREDGING DISPOSAL ON INLAND WATERWAYS IN THE UK, Beckwith, P. R., Hanbury, R.G. and Smith N. A (Beckwith et al 1995) click here.
2. We Asked : Who carries out this testing?
They replied : The 1992 details are given in paper Beckwith et al 1995. For dredging projects it will depend upon who is carrying out the dredging as to who is sampling – it is often the contractor or their agent although British Waterways may have taken some preliminary samples.
3. We Asked : How does British Waterways dispose of silt on the Birmingham Canal Network?
They replied : It depends on the quality of the silt and the availability of land. Various papers give various options (off site to merchant landfill, use of our own landfills in the past, processing by mobile plant [see Environmental Dredging on the Birmingham Canals: Water Quality and Sediment Treatment, Bromhead, J.C. and Beckwith, P.R. (1994), Journal of Institution of Water and Environmental Management, 8, pp 350 -359] and deposit as activity exempt from licensing in certain areas where material is suitable.
4. We Asked : What chemicals are tested?
They replied : Details are given in paper Beckwith et al 1995 of the parameters that samples were analysed for in 1992. This has reduced to :
pH; Arsenic; Barium; Cadmium; Chromium (total) Copper; Lead; Mercury; Nickel; Selenium; Zinc; Sulphide; Total Cyanide; Molybdenum; Boron; speciated PAH; TPH. Additional parameters added based on local circumstances – recent pollutions, adjacent site history, etc.
PAH = Polycyclic Aromatic Hydrocarbons
TPH = Total Petroleum Hydrocarbons
5. We Asked : Who carries this out?
They replied :In 1992 details are given in paper Beckwith et al 1995. For dredging projects it will depend upon who is carrying out the dredging as to who is sampling, it is often the contractor or their agent although British Waterways may have taken some preliminary samples.
6. We Asked : Has evidence of phosphatic muds/elemental phosphorus ever been detected as a consequence of historic transport?
They replied : British Waterways has no records of phosphatic muds/elemental phosphorus detected as a consequence of historic transport
7. We Asked : Do we have information on fires linked to historic transport on the BCN?
They replied : No – British Waterways does not hold the information.
They then refer to the Waterways Trust who can consult the historic archives held by them. They also supplied three helpful PDF’s which can be read below.
1. Dredging Inland Waterways; The environmental and financial consequences of implementing EU Directives into UK Law by N. A. Smith and P.R. Beckwith which gives an insight into the problems created for organisations like British Waterways by new (and often poorly thought out) legislation.
2. Defining Times discusses the implication of the 2005 regulation change that redefined fairly innocuous soil like material as “hazardous waste”. Without detailed testing, soil is now generally classified using a “worst case scenario” principle, and has to be handled accordingly. This means that relatively innocuous silt from the canal network is now hazardous waste – so just what does that make the muck in Rattlechain?
3. Article from Wastes Management April 1999, As Clear As Mud is more of the same.
WHAT DOES THIS MEAN?
The paper Environmental Dredging on the Birmingham Canals: Water Quality and Sediment Treatment, Bromhead, J.C. and Beckwith, P.R. (1994), Journal of Institution of Water and Environmental Management, 8, pp 350 -359, was presented at a meeting of IWEM’s West Midlands Branch, held in Birmingham on 24 November 1993, and at IWEM’s symposium on Contaminated Land: From Liability to Asset, held in Birmingham on 8 February 1994.
The abstract states –
Sediments in sections of the central Birmingham canals are heavily contaminated with heavy metals and mineral oils. The sediments promote high levels of metals within the water column, which suppress the establishment of aquatic vegetation and fisheries. Sediment disturbance by boat traffic results in the release of mineral oils which cause unsightly surface oil sheens.
Studies into a variety of treatment methods indicated that removal and ex-situ treatment of the contaminated sediments would significantly improve water quality and result in environmental benefits.
Funding from Birmingham City Council and British Waterways enabled the award of a contract with a value of approximately £800,000 and commencement in February 1993 for the removal and processing of about 24,000 m3 of sediments by soil washing prior to off-site disposal. The nature of the sediments and water are reviewed, and the results of the soils washings are discussed. The impact of the dredging operations on water quality was monitored during the works and generally observed to be localized. An environmental management plan is now being implemented and the objectives for this are discussed.
The document THE INFLUENCE OF REGULATIONS ON THE MANAGEMENT OF DREDGING AND DREDGING DISPOSAL ON INLAND WATERWAYS IN THE UK by Beckwith, P. R., Hanbury, R.G. and Smith N. A of British Waterways states that silt samples were taken every 2Km, analysed, and used to classify the network of canals and disposal options for the silt in that section.
It will be interesting to see the classification for the canals in the Rattlechain area.