Apr-2010

Greater environmental protection from monitoring lower levels of contaminents

A burgeoning world population and the industrialisation necessary to meet its needs have led to massive technological advances in all facets of human existence.

Stephen Harrison, Linde Gas

Article Summary

A burgeoning world population and the industrialisation necessary to meet its needs have led to massive technological advances in all facets of human existence — among them, food and textile production, the manufacturing of modern home wares and furnishings, medicine, infrastructure and transport. While bringing considerable benefits, these advances have sometimes had a negative impact on the environment.

Some chemicals hailed as scientific breakthroughs in the advancement of society, in time actually proved to be environmentally destructive. Chlorofluorocarbons (CFCs) are a prime example. First discovered in the 1920s, CFCs were the perfect solution for cooling refrigerators and air conditioners. They were easily turned into liquid at room temperature with application of just a small amount of pressure and they could just as easily be turned back into gas. At that time considered safe, inexpensive – and even eco-friendly CFCs were also completely inert and non-toxic to humans. They became ideal solvents for industrial solutions and hospital sterilants and could also be used to blow liquid plastic into various kinds of foams.

In the 1970s scientists studying the decomposition of CFCs in the atmosphere were appalled to discover that catalysing CFCs had begun to destroy the earth’s ozone layer. The environmental impact of CFCs and related compounds led to the Montreal Protocol in 1987, signed by many nations who pledged to reduce CFC production.  But with the phase-out of CFCs, industry was left with a need for a similar compound. CFCs were subsequently replaced by hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) which were later also found to either destroy the ozone layer and/or contribute to an unnatural warming of the planet's climate.

There are many other examples of chemicals developed with the best of intentions later being found to be environmentally harmful such as some pesticides, dyes and detergents.

Damaging at low levels
Once a chemical is found to be potentially hazardous, it is critical to determine at what level it is harmful, so it can be controlled or eliminated. Many contemporary chemicals are damaging at very low levels — down to sub parts per billion — and accurate, reliable methods and equipment are required to measure them once they have been released into the environment. Consequently, there have also been quantum leaps in the science of environmental testing and analysis.

Environmental toxicology highlights the potential effects upon organisms of compounds released into the natural environment. Using the latest technology in analytical instrumentation, air, water and soil samples can be analysed for the characterisation and assessment of an extensive range of harmful contaminants including Volatile Organic Compounds (VOCs), metals, petroleum based compounds, pesticide and herbicide residues and detergents, among others.

Sound analytical protocols are at the heart of work taking place at laboratories every day and in environmental analysis and testing, a range of sophisticated instruments and next generation gas chromatography and mass spectrometry techniques play a vital role in the identification and qualification of environmental pollutants. Both techniques and equipment require high quality specialty gases for instrument operation and/or calibration, in addition to dedicated high purity gas distribution systems. As the reliability of analysis is only as good as the quality of gas being used, distribution systems and equipment for high-purity and specialty gas mixtures have to be able to meet increasing demands for high standards of performance and new analysing methods. Impurities occurring in as low concentrations as parts per trillion (ppt) can have serious consequences.

For soil, gas and water, environmental analysis, monitoring and testing is done in the ambient environment where human development exists — where we plant our crops, source and drink water and breathe the air around us. This has resulted in testing stations being set up near roads and highways, on the top of tower blocks, in fields and at oceans. This testing is often sponsored by governments and national agencies and conducted by them, or on their behalf by universities or commercial contract laboratories.
 
For gas and water, environmental analysis and testing is also carried out at the point of emission — by the industrial concern at the emissions source or factory perimeter — to control and monitor what is being discharged into the environment.  There is an increasing trend to undertake measurement and analysis and to locate instruments where the potential contamination sample might be created.

Analysis can be facilitated either via a distributed or “remote” lab near the point of emission, or even situated directly into the process causing the emission, essentially “taking the lab to the product” rather than the product to the lab. Analysts are beginning to favour this “closer is quicker” approach, because it allows less opportunity for the integrity of the sample to be compromised or degraded.  To this end, more industrial concerns are undertaking their sampling in situ, analysing the sample in real time and feeding the results on line to a central database. 

Gases and their role in metrology and environmental protection
The gas industry plays a vital role in the metrological chain, producing several patterns that are used in the calibration and verification of instruments and equipment. With increasing regulatory requirements, more rigorous demands in measurement and even new contaminants to monitor, laboratories performing environmental analysis to detect and monitor our air quality are being constantly confronted with change and are under continuous pressure to expand their scope and expertise. Innovative, next generation calibration gas mixtures are essential to enable new air quality analysis technologies and meet the needs of laboratories researchers. Linde Gases plays a pioneering role in the global specialty gases market and through these highly innovative gas standards, Linde  provides some of the most advanced and technologically complex specialty gases to support environmental testing and analysis.