MNA PROGRAMME AT CHLORINATED SOLVENT CONTAMINATED SITE IN CENTRAL ENGLAND
For the past 5 years Ford Consulting Group Ltd has been retained to assist a multinational chemical manufacturing client to understand and address residual organic solvent and other chemical contamination at a former chemical blending facility located in central England. The work programme has included operational history review (production ceased in ~1990), site investigations/monitoring plus detailed numerical modelling of local and regional groundwater flow and contaminant fate and transport. This was designed to characterise residual soil and groundwater contamination and its migration down gradient within a major aquifer.
The risk to off-site receptor wells has been characterised by detailed quantitative groundwater risk assessment. Whilst the site is associated with a wide range of contaminants including a range of VOCs, petroleum hydrocarbons, trace metals and metalloids, high pH (caustic input) and phosphate, it is the chlorinated solvent species PCE, TCE and TCA and their breakdown products that were the potential risk drivers, because of their mobility and persistence. The mass flux of contamination (including residual contamination) from the site from the mid-1970s onward has been modelled in detail and found to be limited due to natural attenuation (2 orders of magnitude reduction).
An EA approved Monitored Natural Attenuation (MNA) programme has been in place since 2007 and includes quarterly monitoring for a wide range of organic and inorganic contaminants and associated environmental and NA indicators. Ongoing predictive modelling is included. The expected time period for improvement in groundwater quality to <EQS beneath the site boundary in the main aquifer has been predicted to be 10-25 years. Some proactive enhancement of the NA process via residual source area remediation is being considered with a view to reducing this time frame.
TERM CONTRACT AS CONTAMINATED LAND EXPERTS FOR EPA (IRELAND)
In 2009 Ford Consulting Group Ltd was awarded a 2 year Framework Contract to provide expert contaminated consultancy support to the Irish EPA, related to licensed industrial and waste management sites and also other problem sites or areas. In being awarded the contract Ford Consulting Group was awarded full marks for qualifications and work experience, report writing, communication and training skills, work programme design and expected reliability and continuity of service.
The work has so far involved review of contaminated land and groundwater related issues at between 50-100 sites across Ireland, working with the relevant Inspector and sometimes the sites themselves. When site visits are required these usually are to allow greater context to be gained designed to ensure the findings and recommendations made are appropriate. Sometimes it has been used to allow direct communication of findings to the problem holder to allow interaction and discussion of the same.
CORRECTIVE ACTION AT 3 CHLORINATED SOLVENT CONTAMINATED SITES IN SOUTHERN ENGLAND, SCOTLAND & WALES
Ford Consulting Group Ltd has been retained to assist a multinational chemical distribution business in understanding and addressing contaminated land liabilities at their UK facilities. The work programme has included detailed ground contamination source audits coupled with intrusive site investigations and monitoring to characterise residual soil and groundwater contamination.
Where risk assessment has indicated issues of potential concern, further intrusive investigations, remedial feasibility and design studies have been undertaken. Remedial solutions implemented or currently under consideration include soil vapour extraction, groundwater treatment and insitu bioremediation of chlorinated solvents in both soil and groundwater. One remedial system has been in place for 2 years, with the other two sites currently at the final feasibility and design phase.