Between 1965-70 Brofiscin quarry was used as a disposal site for industrial and chemical waste.
The wastes included toxic substances such as solvents, heavy metals, and polychlorinated biphenyls (PCBs)
Controls at the time were less rigorous than they are today.
The main focus has been to find out if the waste deposited at the quarry during the 60s and 70s is migrating into surface water, groundwater, air or the surrounding rock.
Environmental studies and our monitoring confirm pollution of deep groundwater and intermittent pollution of surface waters.
The local authority, Rhondda Cynon Taf County Borough Council (RCT), has the lead statutory duty to investigate potential contaminated land in their borough under the Environmental Protection Act 1990. We became the regulatory authority once the site was designated as a ‘special site’ by the local authority under Part 2A of the Act in March 2005.
The site was determined as contaminated land because of pollution of controlled water linkages only.
Our aim is to fully understand the current risks to ground and surface waters, to determine the most cost-effective way forward to protect the local environment, and to recover costs from those liable.
Both the local authority and ourselves have been working in partnership with the Local Public Health Director to ensure a co-ordinated approach to the issues at Brofiscin Quarry.
Residents have been kept updated on progress by local drop in ‘surgeries’, newsletters, personal contacts and a hotline number.
We have started a long term surface and groundwater monitoring programme to deal with groundwater pollution at the site. The information we have gathered to date shows that natural processes occurring in the ground over the last 40 years are breaking the contaminants down naturally. The monitoring programme allows us to check the effectiveness of those processes and that they continue to occur quickly enough to protect local streams and springs.
Monitoring work in the nearby stream over the last 24 months has confirmed previous studies that there is no impact on the nearest streams and tributaries. The remaining affected area is confined to the ditch in the privately owned quarry.
Site Investigations and Remediation Options
In January 2005, prior to the determination of the site, we undertook a Preliminary Remedial Options Appraisal (ROA). The review recommended a list of Further Investigation Actions (FIA), that led to the installation of multilevel boreholes and a programme of sampling of vapour, groundwater and surface water in and around the site.
During February and March 2006 we drilled boreholes through the limestone bedrock that surrounds the quarry. In a few boreholes to the north of the quarry, some evidence of contamination was detected in thin clay bands about 40 metres below the ground surface on the quarry high wall.
The next phase of works involved collecting samples of vapour, soil and water directly from these boreholes and nearby surface waters. Four monitoring visits were completed to obtain data over 12 months, to take account of seasonal variations.
The work was fully completed in July 2007. and significantly improved the understanding of the Conceptual Site Model (CSM) and site conditions.
The full report is too large to publish online. However, the Executive Summary is available here:
Brofiscin Quarry: Executive Summary (PDF, 86811KB)
Brofiscin Quarry Executive Summary Overview (PDF, 121703KB)
You can also read the full report at our office in St Mellons, Cardiff and at the Rhondda Cynon Taf Council offices in Ty Elai., Williamstown.
You can get a copy of the report on CD by calling 029 2024 5330.
We then commissioned environmental consultants Enviros to update the ROA (May 2008), which helped us identify ways to remediate the site. Any remediation must take into account practicality, durability, effectiveness and reasonableness (including costs).
The ROA looked at the full range of remedial techniques available for the contaminants present at the site and highlighted a number of civil engineering and biological based processes. These included excavation and disposal, containment cover systems, surface water treatment and monitored natural attenuation.
A wide range of chemical, solidification and stabilisation, and thermal based remedial processes were also identified, which would involve excavating the waste prior to treating it on site.
The ROA identified three remedial packages from which a remediation scheme was recommended, subject to the collection of additional site specific information.
The preferred package identified was surface water treatment and Monitored Natural Attenuation (MNA) for groundwater pollution. This would involve monitoring pollution levels and other parameters within the groundwater and streams to check that natural processes are degrading contamination at the same rate as its migrating off site. It would also involve treating the contaminated surface water that currently discharges from the site. It includes the collection of information such as flow rates and the undertaking of ‘treatability’ studies on site. Groundwater and surface water quality monitoring would also continue as part of this package. Costs were estimated to range from £0.8 million to £2.0 million spread over a 25 year period.
Environmental monitoring
Environment Agency Wales' Monitoring team have carried out two separate biological surveys of streams close to the Broficsin Quarry site in September 2009 and January 2010.
The surveys found that the water flowing out of the quarry, as well as the springs flowing into Mwyndy Brook, are not having a detrimental effect on the streams’ ecology.
We have implemented a long term surface and groundwater monitoring programme to deal with groundwater pollution at the site. Information gathered to date demonstrates that natural attenuation processes occurring in the ground over the last 40 years are breaking the contaminants down naturally. The monitoring programme allows us to check the effectiveness of those processes and that they continue to occur quickly enough to protect local streams and springs. Monitoring work conducted over the last 24 months in the nearby stream has confirmed the conclusion of earlier studies, in that there is no impact on the nearest streams and tributaries, with the affected area being limited to the receiving ditch within the privately owned quarry.
We have also completed a water balance calculation for the site. This looks at inputs (for example rainfall) and losses (including evaporation) against changes in the volume of water in the quarry over the last 10 years. This will assist in the remedial design process.
Copies of the monitoring reports can be obtained by calling us on 029 2024 5330.
