WHAT DID WE ASK?
“Can you confirm what capabilities or equipment the Environment Agency have had available for testing for phosphine gas emission analysis since its creation in 1996? Are front line staff able to carry out phosphine analysis readings on specific sites?”
The request was further clarified on request.
“To clarify my request relates to historic landfill sites and monitoring of phosphine from such sites which are known to be historically contaminated with material likely to generate this highly toxic gas.”
and “if front line staff have ever had any means of being able to detect phosphine emissions regardless of whether they do not routinely monitor for this gas and what apparatus/equipment may be at their disposal within the Environment agency to detect
Could you also clarify how the agency may be able to detect releases of phosphine from sources such as aluminium and zinc phosphides should these substances be released into the environment?”
WHY DID WE ASK THIS?
The generation of phosphine gas from historic p4 contaminated lagoons has been demonstrated in the United States. Following this link gives some background about one such site.
With capping of the rattlechain lagoon sediment, the generation of this gas is made more likely than less likely. Phosphine was detected in analysis carried out by Cramer and Warner in 1991, and subsequently reported in additional studies after this. However the HPA human health risk assessment claimed that ERM, Rhodia’s consultants, had not detected any above detection limit. We do not accept these claims, as phosphine is always associated with white phosphorus breakdown. We know white phosphorus is in the sediment.
In terms of long term monitoring does the regulatory authority have the ability to detect releases of this harmful chemical, or is it reliant on the honesty of a company and their paid environmental contractor to self regulate by carrying out their own analysis?
Aluminium and zinc phosphides are rodenticides, whose active ingredient is phosphine produced in contact with acids in the digestive system of the animal unfortunate to have ingested it.
WHAT DID THEY KNOW
A fairly good response was received.
“As previously stated, we do not carry out any routine monitoring for phosphine in landfill gas, nor do we require landfill operators to monitor for phosphine as part of their annual analysis of landfill gas for trace components. Our ‘front line’ staff do not have the capability to analyse for phosphine, however our National Laboratory Service (NLS) do have the capability to detect and monitor for phosphine gas, should we need to carry out monitoring on a site specific basis.
The NLS have a handheld electrochemical instrument and Draeger tubes which can be used to detect the presence of phosphine in either the landfill gas or in the atmosphere. Both these methods will give a concentration reading in the range of 0.1 to 4 parts per million (ppm), however they are both prone to interference from other trace components in landfill gas. In order to quantitatively analyse for phosphine we would need to take samples of the landfill gas onto sample tubes in accordance with NIOSH method 6002: Phosphine. The principle of this analysis method is to pass a sample of air through a sampling tube containing mercuric cyanide. Any phosphine will react with mercuric cyanide and the concentration of phosphine can be determined back at the laboratory using uv-vis spectroscopy. These sample tubes have a limited shelf life and would need
to be specially ordered for any sampling exercise.
In order to detect emissions of phosphine, it would be necessary to set up a sampling tube and pump and sample the air over a known period of time and pumping rate. The concentration of phosphine retained in the tube could subsequently be determined in the laboratory and the concentration in the air back-calculated. The method will tell us the concentration of phosphine gas but will not tell us whether the gas was generated from
aluminium or zinc phosphide (or similar phosphide compounds).”
To determine the concentration of phosphine within landfill gas, a similar procedure would take place. On the assumption that there would be a greater concentration of phosphine in the gas within the landfill, we would first determine the approximate concentration of phosphine using a handheld meter or Draeger tube. This would be to ensure that an appropriate volume of sample was taken without overloading the capacity of the sampling tubes. A sample of known volume would then be passed through the tube and the concentration determined back in the laboratory. ”
nb NIOSH (national institute of Occupational safety and health) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the Centers for Disease Control and Prevention (CDC) within the U.S. Department of Health and Human Services.
WHAT DOES THIS MEAN?
The EA frontline staff, i.e those whose job it is to “monitor and inspect” cannot monitor for phosphine in situ at Rattlechain lagoon, nor have they ever attempted to.
Phosphine analysis is a complex laboratory led exercise. The US EPA appear to have a more stringent approach to monitoring such contaminated sites, and it is unfortunate that their British cousin relies on the self regulation of a business which has a less than excellent record of transparency with the local community concerning it’s toxic p4 lagoon.
We find this situation rather intolerable with regard to public health scrutiny and safety.