Matt Dibbs, Managing Director Meteor Communications Ltd., explains how the Coronavirus pandemic presented significant challenges to the collection of environmental data. However, by utilising novel technology, British water companies and the Environment Agency have been able to continue gathering water quality data in locations from Cornwall to Cumbria. Matt believes that this provides a template for environmental monitoring on the future.

The Coronavirus pandemic presented significant challenges to the collection of environmental data. However, by utilising novel technology, water companies and the Environment Agency have been able to continue gathering key data in locations from Cornwall to Cumbria.

Water quality monitoring
The British Environment Agency and water utilities have statutory obligations to protect and enhance water resources; and in order to fulfil these obligations they undertake large numbers of measurements to establish baseline data, detect trends, monitor mitigation measures, and identify sources of pollution from both point and diffuse sources. This involves making a range of measurements; either collecting samples for laboratory analysis or employing portable instruments in the field. To support these activities, rapidly deployable, automatic, remote monitoring systems have also been developed to provide real-time access to data 24/7.

The Environment Agency’s Environmental Sensor Network (ESNET) is operated by the National Laboratory Service. This agile monitoring capability of over 150 sites is providing a template for sustainable, resilient, environmental monitoring. ESNET is comprised of modular water quality monitoring systems that can be quickly and easily deployed at remote sites. The telemetry modules and website capability are developed and supplied by Meteor Communications Ltd.

The laboratory analysis of samples is vitally important and allows industry and regulators to analyse for an extensive array of parameters. These samples inform a better understanding of longer term trends and facilitate the monitoring of trace and emerging pollutants. However, water bodies are highly dynamic environments. Precipitation, flow and the intermittent or diurnal nature of process and agricultural effluents mean that in some circumstances it is necessary to employ enhanced high-resolution monitoring techniques to provide evidence upon which informed operational and policy decisions can be made.

Real-time, high-resolution water quality monitoring systems
The Environment Agency uses two main types of continuous water quality monitors; a fixed, cabinet or kiosk based system (right), and a portable version which is housed in a rugged case (below). Evidence from these systems is utilised by environment planners, ecologists, fisheries and environment management teams across the agency. These continuous water quality monitoring systems have been developed and refined over the last 20 years, so that they can be quickly and easily deployed at almost any national location; delivering data via telemetry within minutes of installation. This high-intensity monitoring capability substantially improves the temporal and spatial quality of data. The rapid deployment of these monitors now enables the agency to respond more quickly to pollution events.

Each system is built around a battery-powered multi-parameter water quality sonde; situated in the river or located in a bankside flow-through chamber, with samples being taken at 15 minute intervals. Typically, the sondes are loaded with sensors for measuring parameters such as dissolved oxygen, temperature, pH, conductivity, turbidity, ammonium, Blue Green Algae and chlorophyll. Additionally, the systems can incorporate an automatic sampler which can be triggered when pre-determined conditions arise. This means that event-triggered samples can be made available for subsequent laboratory investigation.

Measured data is transferred securely to the Meteor Data Cloud, where stakeholders access graphical, tabular and geospatial views to see live readings and retrieve recorded data. With this customisable data presentation, managers are able to communicate evidence in a form which is more accessible and meaningful to public representatives, interest groups and stakeholders. This also enables bodies such as the Environment Agency to promote the use of open data, providing live data links, advice and services to a diverse range of public groups and organisations such as flood awareness groups, rivers trusts and angling organisations.

During the coronavirus pandemic the Environment Agency collected over 16,000 samples per day using ESNET and the cloud-based viewer was made available to all water quality practitioners across the Defra family, as well as a wide range of external bodies.

The advantages of remote monitoring networks
By collecting data automatically; the volume of evidence increases dramatically, furthermore, such systems are resilient to the effects of issues such as a lockdown; because monitoring practitioners are able to collect and assess data; even if they are isolated at home.

In recent years, sensors and water quality sondes have undergone significant development to improve reliability and extend the period between service and calibration. Meteor Communications provides a comprehensive maintenance program for customers on a monthly basis and freshly calibrated units are constantly in circulation within the ESNET system.

Continuous monitoring enables the detection of transient spikes that can arise from pollution incidents; helping to raise timely alarms and identify ongoing sources of pollution. This evidence can be used to develop informed interventions by stakeholders in industry and agriculture, and to enable the adoption of practices that improve water quality.

Integrated systems such as those operated in the Thames Valley catchment are able to track pollution events as they move with the river, which means for example, that water treatment plants can adjust their intakes accordingly.

Tidal water presents a major monitoring challenge because large volumes of saline water are constantly moving back and forth, which significantly complicates the comparison of measurements at one point on the river. So, for example, a measurement at one location at 9am is not directly comparable with another measurement at 9am a week later, because one might be taken at low tide and the other at high tide. The transient effects of CSO’s and algal activity further complicate the picture. Water quality scientists at the Environment Agency have therefore worked closely with Meteor Communications to develop a software-based monitoring system, known as ‘Half Tide Correction’ (HTC). In simple terms, this corrects for the effects of the tide and allows assessment of the underlying water quality.

Continuous, accurate and robust data allows managers to assess the impact of developments and remediation measures. Good data, used as evidence, informs the evaluation of investments and leads to better decision making.

The ESNET network also provides image acquisition, and the Environment Agency and others have deployed over 600 ESNET camera sites. These remote cameras are used to continuously monitor a wide range of flood defence infrastructure and assets; rapidly detecting blockages or overflows and avoiding the need for unnecessary and costly site visits.

ESNET systems also provide an essential tool for measuring the effectiveness of Natural Flood Management (NFM) schemes. In Oxfordshire for example, working with a wide range of partners in the Evenlode catchment, the systems are helping to evaluate the effectiveness of NFM measures for the local community and other stakeholders.

Utilities – final effluent monitoring
The flexibility of the ESNET systems makes them ideal for monitoring water quality at waste water treatment works. The responsibility for monitoring discharges rests with the operators themselves under the terms of operator self-monitoring (OSM) agreements. OSM is now delivered by a spot sampling regime supported by real time monitors, so an opportunity exists for all stakeholders to benefit from the advantages of continuous monitoring.

A British water company is now operating 130 ESNET final effluent monitoring systems across their business. These sites have continued to operate during the COVID-19 lockdown providing operators and managers with vital data with which to assess performance and compliance during this challenging period.

Summary
Recent advances in technology have enabled the development of continuous monitoring systems that are quick and easy to install. The portable ESNET system is routinely commissioned in less than an hour, and the pumped kiosks can usually be installed within half a day.

With little or no capital works necessary prior to the installation of an ESNET system, continuous, easily accessible, multi-parameter data can be established quickly and cost effectively. Real-time monitoring means less travel, less time on site and a lower carbon footprint. Real time data can also be provided to stakeholders, timely alarms triggered and monitoring can continue unaffected by the impact of viral pandemics.

@MeteorComms @_Enviro_News #PAuto #Water #coróinvíreas #COVID19 #coronavirus

The Dutch horticultural sector aims to be climate-neutral by 2040. Scientists at Wageningen University & Research have therefore recently built a new demonstration greenhouse ‘Greenhouse 2030’ in an effort to find ways to reduce CO2 emissions as well eliminating the need for crop protection chemicals and optimizing the use of water and nutrients.

Greenhouses helping to reduce greenhouse gas emissions

Scientists at Wageningen University & Research (WUR) in the Netherlands have employed Vaisala carbon dioxide sensors in their research greenhouses for over a decade. Carbon dioxide is an extremely important measurement parameter in plant science, not just because plants need carbon dioxide to grow, but also because environmental emissions contribute to climate change, so enormous threats and opportunities surround this gas. As a world renowned research organisation, the value of the institute’s work is partly dependent on the accuracy and reliability of sensors, so it is important that its researchers do not compromise on sensor quality.

Wageningen has been one of the driving forces in research and technology development for greenhouse horticulture in the Netherlands. The institute’s expertise in the greenhouse cultivation of ornamental, fruit and vegetable crops is unique, and together with growers and technology partners, it has developed new cultivation systems, climate control systems, revolutionary greenhouse cover materials and other innovations. The application of these new technologies has made greenhouse horticulture in the Netherlands a world leader.

The Plant Research Institute operates over 100 greenhouse compartments at its Bleiswijk site, which means that researchers are able to generate a wide variety of environmental conditions. Typical environmental variables include light, water, growing medium, nutrients, (biological) pest/disease control, temperature, humidity and of course carbon dioxide (CO₂); all of which have significant effects on crop yields.

The Dutch horticultural sector aims to be climate-neutral by 2040. The Wageningen researchers have therefore recently built a new demonstration greenhouse ‘Greenhouse 2030’ for the cultivation of vegetables, fruit and flowers in an effort to find ways to reduce CO₂ emissions as well eliminating the need for crop protection chemicals and optimizing the use of water and nutrients. Pests and diseases are preferably tackled biologically, and the energy-efficient greenhouse reuses water and nutrients as much as possible; leading to cleaner cultivation and improved yields.

Carbon Dioxide in Greenhouses
Carbon dioxide is a by-product of many processes in the oil, gas and petrochemical industries, but it is also required by plants to grow through photosynthesis, so Dutch greenhouse operators have collaborated with the country’s industrial sector to utilise this byproduct and thereby contribute in the fight against climate change by lowering the country’s net CO₂ emissions. Globally, many greenhouse operators burn natural gas to generate CO₂, but this also generates heat that may not be needed in the summer months, so the utilisation of an industrial byproduct is significantly preferable.

Carbon dioxide was first delivered to Dutch greenhouses in 2005 via a pipe network established by the company Organic Carbon Dioxide for Assimilation of Plants (OCAP). Commercial greenhouse operators pay for this CO₂ supply, which is largely derived from a bio ethanol plant. A key feature of the Institute’s research is work to optimise the utilisation of CO₂, along with other plant growth variables. For example, the Institute has developed a simulation tool for CO₂ dosing: the “CO₂-viewer.” This programme monitors and displays the effects of a grower’s dosing strategy. For instance, it enables the evaluation of CO₂ dosing around midday compared with dosing in the morning. The computational results of such an evaluation take all relevant greenhouse building characteristics and climate control settings into account.

Monitoring Carbon Dioxide

CO₂ Probe

After around 10 years of operation, the institute is replacing around 150 of the older model probes with a newer model. The calibration of all probes is checked prior to the commencement of every project, utilizing certified reference gases. It is important that calibration data is traceable, so each probe’s calibration certificate is retained and subsequent calibration checks are documented. A portable CO₂ monitor (a Vaisala GM70) with a GMP252 CO₂ probe are also used as a validation tool to check installed probes, even though further calibration is not necessary.

Currently, the Institute’s installed probes provide 4-20 mA signals which feed into ‘climate computers’ that are programmed to manage the greenhouses automatically. This system also raises alarms if CO₂ levels approach dangerous levels for any reason.

CO₂ Sensor Technology
Carbon dioxide absorbs light in the infrared (IR) region at a wavelength of 4.26 μm. This means that when IR radiation is passed through a gas containing CO₂, part of the radiation is absorbed, and this absorbance can be measured. The Vaisala CARBOCAP® carbon dioxide sensor features an innovative micro-machined, electrically tunable Fabry-Perot Interferometer (FPI) filter. In addition to measuring CO₂ absorption, the FPI filter enables a reference measurement at a wavelength where no absorption occurs. When taking the reference measurement, the FPI filter is electrically adjusted to switch the bypass band from the absorption wavelength to a non-absorption wavelength. This reference measurement compensates for any potential changes in the light source intensity, as well as for contamination or dirt accumulation in the optical path. Consequently, the CARBOCAP® sensor is highly stable over time, and by incorporating both measurements in one sensor, this compact technology can be incorporated into small probes, modules, and transmitters.

The CARBOCAP® technology means that the researchers don’t have to worry about calibration drift or sensor failure.

Carbon Dioxide Plant Science Research
Two projects are currently underway evaluating the effects of different CO₂ levels on plant production. One is studying soft fruit and the other tomatoes; however with CO₂ playing such an important role in both plant growth and climate change, the value of accurate measurements of this gas continues to grow. Most of the greenhouses are now connected to the institute’s Ethernet and a wide variety of new sensors are continually being added to the monitoring network; providing an opportunity to utilise new ‘smart’ sensors.

Summary
The accuracy, stability and reliability of the CO₂ sensors at Bleiswijk are clearly vitally important to the success of the Institute’s research, particularly because data from one greenhouse are often compared with data from others.

The CO₂ supply has a cost; it is therefore important that this resource is monitored and supplied effectively so that plant production can be optimized.

Clearly, moves to lower the use of fossil fuels and develop more efficient energy management systems will help to reduce CO₂ emissions from the greenhouse sector. However, the importance of CO₂ utilization is set to grow, given the 2040 climate-neutral target and the world’s need to find new and better ways to capture CO₂ emissions in ways that are both sustainable and economically viable.

#Hortoculture #Environment @VaisalaGroup @_Enviro_News

Critical Environment Technologies Canada Inc. (CETCI) was founded by Frank and Shirley Britton in 1995. Since that time, the company has expanded considerably and now employs around 35 people; developing and manufacturing gas detection equipment for global markets. One of the keys to the company’s success has been the relationship that it has built with sensor supplier Alphasense.

Frank’s career in gas detection stretches back to 1982, and when he was first visited by a sales person from Alphasense in 2003, he was immediately impressed with the representative’s technical knowledge. “It was clear that he understood the issues that manufacturers face, and had a good knowledge of the challenging applications in which our equipment is commonly deployed. This was important, because it helped to build trust.”

Following that initial meeting, it was agreed that CETCI would trial some of Alphasense’s electrochemical gas detection sensors, and Frank was pleased to see how well they performed. “It was also very encouraging to note the high level of service that we enjoyed,” he adds. “Even though there were 5,000 miles between us and 8 hours in time difference, we have always received very prompt and useful responses to our service requests.

“In fact, I would go so far as to say that Alphasense has delivered superb levels of service from day one, and as a consequence is one of our best suppliers. It is also very useful that Arthur Burnley from Alphasense visits us every year to review progress and explore new ways for us to work together in the future.”

YesAir portable

As the relationship with Alphasense has grown the range of sensor technologies employed has expanded to include electrochemical, catalytic, optical, metal oxide and PID. For example, some of these sensors are deployed in portable indoor air quality instruments such as the YESAIR range. Available in two models (pump or diffusion) and battery powered with onboard datalogging, the YESAIR instruments have been designed for intermittent or continuous indoor air quality monitoring of temperature, RH, particulates and up to 5 gases. Each can be configured with parameter selection from more than 30 different plug and play gas sensors, as well as a particulate sensor.

CETCI also manufactures fixed gas detection systems, controllers and transmitters that are deployed to monitor hazardous gases; protecting health and safety in confined spaces and indoor environments. Customers are able to select from a range of target gases including Ammonia, Carbon monoxide, Chlorine dioxide, Chlorine, Ethylene, Ethylene oxide, Fluorine, Formaldehyde, Hydrogen, Hydrogen sulphide, Hydrogen chloride, Hydrogen cyanide, Hydrogen fluoride, Nitric oxide, Nitrogen dioxide, Oxygen, Ozone, Phosphine, Silane, Sulfur dioxide, Methane, Propane, Hydrogen, TVOCs and Refrigerants. The company’s products are employed in commercial, institutional, municipal and light industrial markets, and in a wide variety of applications. These include refrigeration plants, indoor swimming pools, water treatment plants, ice arenas, wineries and breweries, airports, hotels, fish farms, battery charging rooms, HVAC systems, food processing plants, vehicle exhausts and many more.

One of the main reasons for CETCI’s success is its ability to develop gas detectors that meet the precise requirements for specific markets. “We are large enough to employ talented people with the skills and experience to develop products that meet the latest requirements,” Frank explains. “But we are not so large that we are uninterested in niche applications – in fact we relish the challenge when a customer asks us to do something new, and this is where our relationship with Alphasense, and the technical support that they can provide, comes into its own.”

The market for gas detection equipment is constantly changing as new safety and environmental regulations are created around the world, and as new markets emerge. Again, the close relationship with Alphasense is vitally important; as new sensors are being developed, CETCI is moving into new markets that are able to utilise these technologies.

New market example – cannabis cultivation
Following the legalisation of marijuana in Canada and some other North American regions, greenhouses and other plant growth rooms have proliferated. These facilities can present a variety of potential hazards to human health. Gas powered equipment may be a source of carbon monoxide; carbon dioxide enrichment systems may be utilised; air conditioning systems can potentially leak refrigerants, and propane or natural gas furnaces may be employed for heating purposes. All of these pose a potential risk, so an appropriate detection and alarm system is necessary.

Responding to market demand, CETCI developed monitoring systems that met the requirements of the market. This included appropriate gas detectors connected to a controller with logging capability and a live display of gas levels. In the event of a leak or high gas concentration, the system can provide an audible or visual alarm, and relays can be configured to control equipment such as the ventilation system or a furnace.

Developing market example – car parking facilities

Car park installation

In recent years, the effects of vehicular air pollution on human health have become better understood, and received greater political and media attention. As a result, the owners and operators of parking facilities have become more aware of the ways in which they can protect their customers and staff.

Carbon monoxide is a major component of vehicle exhaust, and nitrogen dioxide levels are high in the emissions of diesel powered engines. In more modern facilities, hydrogen may accumulate as a result of electric car charging stations. CETCI has therefore developed hazardousgas detection systems to protect air quality in parking locations. This equipment includes output relays which can minimise energy costs by controlling the operation of ventilation systems.

Summarising the secrets to a long and successful partnership in gas detection, Frank says: “One of the most important issues is of course the quality of the products, and we have always been impressed with the fact that Alphasense differentiates itself from other sensor manufacturers by testing every sensor.

“The next important issue is the quality of service; we need sensors to be delivered on time and in perfect condition, and when we have a technical query we have become accustomed to a very prompt response.

“We also value highly the opportunity to develop our businesses together – through regular conversations with Arthur and his colleagues we are able to plan our future product development and marketing strategies, so that we can meet the ever changing needs of the market. This has worked extremely well for the last 17 years and we foresee it doing so for many years to come.”

#Environment #Alphasense @cetci @_Enviro_News

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#PAuto #TandM

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In this article, Josh Thomas from instrumentation specialist Ashtead Technology, discusses the risks associated with dust at quarries, and highlights the vital role of monitoring.

Josh Thomas

Background
Almost all quarrying operations have the potential to create dust. Control measures should therefore be established to prevent the generation of levels that cause harm. These measures should be identified in the health and safety document, and measurements should be taken to monitor exposure and demonstrate the effectiveness of controls.

Many minerals contain high levels of silica, so quarrying activities of these materials generate silica dust known as respirable crystalline silica (RCS) and particular care must be taken to control exposure. Guidance is available from the British Health & Safety Executive (HSE); see document HS(G) 73 Respirable crystalline silica at quarries. Sandstone, gravel and flint typically contain over 70% crystalline silica, shale contains over 40% and granite can contain up to 30%. Inhaling RCS can lead to silicosis which is a serious and irreversible lung disease that can cause permanent disablement and early death. There is an increased risk of lung cancer in workers who have silicosis, and it can also be the cause of chronic obstructive pulmonary disease (COPD).

The British Control of Substances Hazardous to Health Regulations 2002 (COSHH) requires employers to ensure that exposure is prevented or, where this is not reasonably practicable, adequately controlled. The COSHH definition of a substance hazardous to health includes dust of any kind when present at a concentration in air equal to or greater than 10 mg/m³ 8-hour time-weighted average of inhalable dust, or 4 mg/m³ 8-hour TWA of respirable dust. This means that any dust will be subject to COSHH if people are exposed to dust above these levels. Some dusts have been assigned specific workplace exposure limits (WELs) and exposure to these must comply with the appropriate limits. For example, the WEL for RCS is 0.1 mg/m³ 8-hour TWA.

The Quarries Regulations 1999 (GB) cover all surface mineral workings, and include tips and stockpiles, as well as areas used for crushing, screening, washing, drying and bagging. Buildings and other structures are also included, as are common areas and prospecting sites. The Regulations were created to protect the health and safety of quarry staff, as well as others that may be affected by quarrying activities, such as those living, passing or working nearby, or visiting the site.

The role of monitoring
In order to assess the risks posed by dust, it is necessary to undertake both workplace monitoring – inside buildings, vehicle cabs etc., as well as environmental monitoring in and around the quarry. The technology for doing so is similar but different instruments are available for every application. Ashtead supplies personal air sampling pumps when it is necessary to conduct compliance monitoring, or when the identification and measurement (in a laboratory) of a specific dust type, such as RCS, is required.

Once the dust risks at a quarry have been assessed, ongoing monitoring is more often conducted with direct reading instruments that employ optical techniques to measure the different particulate fractions. Portable battery-powered instruments such as the TSI SidePak and the DustTrak are ideal for this purpose and feature heavily in Ashtead’s fleet of instruments for both sale and rental.

Installed TSI DTE

The same dust monitoring technology is employed by the TSI DustTrak Environmental (DTE), which has been developed specifically for applications such as dust monitoring at quarries. Fully compliant with stringent MCERTS performance requirements, the DTE employs a ‘cloud’ based data management system, which provides users with easy access to real-time data on dust levels, with the optional addition of other sensors. Alarm conditions can be set by users so that text and email alerts are issued when threshold levels arise. The DTE monitors PMTotal, PM₁₀, PM_2.5 and PM_1.0 mass fractions simultaneously, which provides detailed information on the type of dust present, and means that alarms can be set for specific fractions.

Clearly, dust monitors can perform a vital role in helping to protect safety at working quarries. However, a TSI DTE was recently hired from Ashtead Technology to perform monitoring prior to the commencement of quarrying operations, so that baseline dust levels could be established for comparison once the quarry is operational. Monitoring prior to operations is important, because airborne dust at a quarry is not necessarily derived from the quarry alone; local agricultural or industrial activities may also contribute to the particulate burden. This also highlights the advantages of 24/7 monitoring because dust pollution may be intermittent, so continuous monitors such as the DTE are able to identify peaks and thereby assist in the attribution of sources.

Ashtead Technology fitted the DTE mentioned above with a solar panel and rechargeable battery so that it could operate unattended for extended periods in a remote location. With web-based access to the data, site visits were minimised and costs lowered. This equipment was hired from Ashtead to avoid capital expenditure, and looking forward, the client is planning to add a Lufft wind monitor to the rental, because data on wind speed and direction helps with modelling and with the identification of dust pollution sources.

Summary
Ideally, quarry site monitoring should be undertaken prior to the commencement of operations to establish baseline levels for that site. Risk assessments can then be undertaken around the site and within buildings and vehicles/machinery. However, conditions can change significantly, so continuous monitoring is preferable. Changes in quarry practices and weather can affect environmental conditions, and workplace exposure can be affected by a wide range of factors such as broken filter bags, spillage, insufficient cleaning, filter blockage and dry (instead of wet) drilling or cutting.

With a variety of applications for dust monitoring, it is important that appropriate technology is employed, so the Ashtead Technology instrument fleet has been developed to meet almost every need, and technical advice is available to help consultants and quarry operators ensure that dust hazards and effectively managed.

#Environment @ashteadtech @_Enviro_News

Ten hospitals in the most polluted areas of London (GB) are to be equipped with new air quality monitors to measure levels of toxic air and help protect patients and staff. Hospital patients, including young children and the elderly, are most vulnerable to the harmful health effects of air pollution, especially those suffering with respiratory conditions.

Breath London Pod

The air quality instruments will be supplied and installed by Air Monitors, one of the Breathe London partners. Air Monitors MD Jim Mills said: “Air quality improvement measures should be targeted to protect the most vulnerable people. Therefore, I’m delighted to be expanding the network of AQMesh pods to include hospital sites. Data from these locations will help to highlight pollution hotspots and ensure the solutions that our partners put in place are working.”

A recent study found 60 per cent of hospitals and NHS facilities in inner London are located in areas that exceed the legal limit for air quality pollutants*.

The Mayor’s new hospital monitors will support the NHS by providing real-time air quality measurements that will allow health professionals to take appropriate action to protect patients and employees – for example, warning patients about high pollution episodes and advising which hospital entrances have the lowest levels of pollution.

The first monitor is already up and running at St. Bartholomew’s Hospital, with others due to be installed shortly at the Trust’s other three hospitals The Royal London, Whipps Cross and Newham Hospitals, as well as at Great Ormond Street Hospital, the Royal Free Hospital, Guy’s Hospital and St Thomas’ Hospital and other NHS sites in London.

The monitors are part of Sadiq’s work to deliver the world’s most advanced and comprehensive network of air quality monitors in London to help investigate and improve London’s toxic air.

Sadiq Khan – Mayor of London

The Mayor of London, Sadiq Khan said: “Vulnerable hospital patients are more susceptible to the harmful effects of our toxic air pollution health crisis that harms lung growth and is linked to asthma, cancer and dementia. I am working with London’s leading hospitals to install air pollution monitors and help find new ways to reduce pollution and protect patients.

“I’m doing everything in my power to protect Londoners from polluted air including cleaning up our bus and taxi fleet, and establishing the largest air quality monitoring network of any major city. We are now counting down to the world’s first 24-hour seven-day-a-week Ultra Low Emission Zone in the central London congestion charge zone, which will help clean our air and reduce NOx road transport emissions in central London, including around many hospitals, by 45 per cent.”

The ULEZ will begin in central London on 8^th April. The Mayor’s Breathe London project is using a range of more than 100 cutting-edge fixed and mobile sensors, including two dedicated Street View cars and backpacks for school children, to provide an unprecedented level of detail about London’s air quality crisis and deliver new insight into the sources of pollution. The new hospital monitors will help:

• NHS staff to be better informed about air pollution, associated health risks and able to give vulnerable patients appropriate advice.
• Hospitals and NHS facilities to measure the impact of measures they take to improve air quality (for example cleaning up their vehicle fleet or running no idling schemes)
• Researchers to use on site air pollution concentrations alongside patient records to better understand the relationship between air pollution and health effects

Great Ormond Street Hospital (GOSH) and Global Action Plan have published their new Clean Air Hospitals Framework and recommended installing air quality monitoring at NHS sites.

Matthew Shaw, Chief Executive of GOSH said, “Great Ormond Street Hospital (GOSH) is delighted to be supporting the Mayor’s Breathe London project. As a specialist children’s hospital, we see a number of patients in our hospital who are impacted by air quality. The ability to get real time air quality data will mean patients and staff will be able to make informed decisions about how they can help reduce their exposure to poor quality air. The project compliments delivery of the GOSH Clean Air Hospital Framework, a pioneering strategy aimed at creating a healthy environment for patients, staff and the surrounding community. We hope other hospitals will be inspired to adopt the Clean Air Hospital Framework so that patients and communities across the UK may benefit.”

Dr Penny Woods, Chief Executive of the British Lung Foundation, said: “Air pollution is a public health emergency – it can cause lung cancer, respiratory and heart disease and stunt the growth of children’s little lungs. So it’s not right patients – especially children, the elderly and those with heart and lung problems – are exposed to dirty air that may make their symptoms worse when going to hospital.

“It’s fantastic to see the Mayor’s announcement to install air quality monitors at London’s most polluted hospitals; it will help to protect some of the most vulnerable people in the city. However, our research shows that across the UK, a quarter of hospitals and a third of GP surgeries are in areas exceeding safe limits of particulate pollution. We must now see the rest of the country start to follow London’s lead with ambitious plans such as a national system of air pollution alerts and clean air zones in our most polluted towns and cities.”

Nicky Philpott, Director of the UK Health Alliance on Climate Change (UKHACC) said: “Air pollution is a public health emergency. Estimates of the mortality burden are as high as 40,000 deaths per year and by 2035 the health and social care costs of air pollution have been estimated to be £18.6 billion. The UK Health Alliance on Climate Change, representing over 650,000 health care professionals, support efforts to both monitor and reduce air pollution, this is especially important around hospitals, both because the people visiting them are often the most vulnerable to poor air quality, but also because this is the workplace of our doctors, nurses and other health professionals.“

Chris Large, Senior Partner at Global Action Plan said, “Every year, millions of the most poorly Londoners visit hospitals that are sadly located in air pollution hotspots. Monitoring the peaks in pollutants is an incredibly important tool to help hospitals identify, and tackle the activity that causes dangerous pollution levels to accumulate.”

• Study on Climate Change King’s College London and the UK Health Alliance

• The Clean Air Hospital Framework, launched by Great Ormond Street and Global Action Plan is freely available to download here.

@airmonitors #BreathLondon

Measuring soil carbon flux gives an insight into the health of forest ecosystems and provides feedback on the effects of global warming. This article, from Edinburgh Instruments, outlines how soil CO₂ efflux is determined and the applications of soil carbon flux research.

Soil is an important part of the Earth’s carbon cycle.
Pic: pixabay.com/Picography

The Earth’s carbon cycle maintains a steady balance of carbon in the atmosphere that supports plant and animal life. In recent years, concerns about the increasing levels of CO₂ in the atmosphere, indicating a problem in Earth’s carbon cycle, has been a prominent global issue.^1,2

As a part of a stable carbon cycle, carbon is exchanged between carbon pools including the atmosphere, the ocean, the land and living things in a process known as carbon flux. Carbon exchange typically takes place as a result of a variety of natural processes including respiration, photosynthesis, and decomposition.

Since the industrial age, humans have begun to contribute to carbon exchange with activities such as fuel burning, and chemical processes, which are believed to be responsible for increasing atmospheric CO₂ concentrations and increasing global temperatures.^1-3

Soil carbon flux provides feedback on environmental conditions
Soil is a vital aspect of the Earth’s carbon cycle, containing almost three times more carbon than the Earth’s atmosphere. Carbon is present in soil as ‘solid organic carbon’ including decomposing plant and animal matter. Over time, microbial decomposition of the organic components of soil releases carbon into the atmosphere as CO₂.^4,5

The amount of carbon present in soil affects soil fertility, plant growth, microbial activity, and water quality. Studying the carbon flux of soil gives an insight into an ecosystem as a whole and specific information about microbial activity and plant growth.^4-6

Soil carbon flux can also help us to understand and predict the effects of global warming. As global temperatures increase, is it expected that microbial activity will also increase, resulting in faster plant decomposition and increased CO₂ efflux into the atmosphere.^5,6

Measuring soil CO₂ efflux
Determining soil-surface CO₂ efflux can be challenging. Researchers commonly employ a chamber combined with CO₂ concentration measurements to determine CO₂ efflux. A variety of chambers have been designed for such research, some of which are commercially available.^7-10

Closed-chamber systems typically pump air through a gas analyzer, which measures CO₂ concentration, before returning the air to the chamber. Soil CO₂ efflux is then estimated from the rate of increase of CO₂ concentration in the chamber.

Open-chambers pump ambient air into the chamber and measure the change in CO₂concentration between the air entering the chamber and the air leaving the chamber to determine the soil CO₂ efflux.

Of the two chamber types, open chambers are considered more accurate. Closed chambers tend to underestimate CO₂ efflux as increased CO₂ concentrations in the chamber cause less CO₂ to diffuse out of the soil while the chamber is in place.^10,11.

Often, CO₂ concentrations in chambers are measured periodically and then extrapolated to give an estimation of CO₂ efflux. This method can be inaccurate because CO₂ efflux can vary significantly between measurements with changes in environmental conditions.

A further limitation of using chambers for CO₂ efflux measurements is that chambers typically only provide measurements in one location, while CO₂ efflux has been found to vary widely even in relatively homogeneous environments. The overall result is CO₂ efflux data with limited temporal and spatial resolution, that does not reflect the environmental situation as a whole.^10,12,13

Naishen Liang

A group of researchers from the National Institute for Environmental Studies (Japan) led by Naishen Liang has designed an automated, multi-chamber chamber system for measuring soil-surface CO₂ efflux.

As CO₂ concentrations are measured automatically using an infrared gas sensor, CO₂ efflux can be determined accurately throughout the experiment. The improved temporal resolution, combined with increased spatial detail resulting from the use of multiple chambers gives a better overview of how CO₂ efflux varies with time, location, and environmental conditions within an ecosystem.¹⁰

Liang and his team have applied his method to gather information about a range of forest ecosystems. Their automated chambers have been used in a variety of forest locations combined with heat lamps to provide high-resolution, long-term data about the effects of warming on microbial activity and CO₂ efflux.

Liang’s research has shown that soil temperatures have a significant effect on CO₂ efflux in a wide range of forest environments, information that is vital for understanding how global warming will affect forest ecosystems and the Earth’s carbon cycle as a whole.^14-17

All chamber systems for determining CO₂ efflux rely on accurate CO₂ concentration analysis. Infrared gas analyzers are the most widely used method of instrumentation for determining CO₂ concentrations in soil CO₂ efflux measurement chambers.^8,10,18

Infrared gas sensors, such as gascard sensors from Edinburgh Sensors, are well suited to providing CO₂ concentration measurements in soil chambers, and are the sensors of choice used by Liang and his team.

The gascard sensors are robust, low-maintenance, and easy to use compared with other sensors. They provide rapid easy-to-interpret results and can be supplied as either complete boxed sensors (the Boxed Gascard) or as individual sensors (the Gascard NG) for easy integration into automated chambers.^19,20

Notes, References and further reading
1. ‘The Carbon Cycle’
2. ‘Global Carbon Cycle and Climate Change’ — Kondratyev KY, Krapivin VF, Varotsos CA, Springer Science & Business Media, 2003.
3. ‘Land Use and the Carbon Cycle: Advances in Integrated Science, Management, and Policy’ — Brown DG, Robinson DT, French NHF, Reed BC, Cambridge University Press, 2013.
4. ‘Soil organic matter and soil function – Review of the literature and underlying data’ — Murphy BW, Department of Environment and Energy, 2014
5. ‘The whole-soil carbon flux in response to warming’ — Hicks Pries CE, Castanha C, Porras RC, Torn MS, Science, 2017.
6. ‘Temperature-associated increases in the global soil respiration record’ — Bond-Lamberty B, Thomson A, Nature, 2010.
7. ‘Measuring Emissions from Soil and Water’ — Matson PA, Harriss RC, Blackwell Scientific Publications, 1995.
8. ‘Minimize artifacts and biases in chamber-based measurements of soil respiration’ — Davidson EA, Savage K, Verchot LV, Navarro R, Agricultural and Forest Meteorology, 2002.
9. ‘Methods of Soil Analysis: Part 1. Physical Methods, 3rd Edition’ — Dane JH, Topp GC, Soil Science Society of America, 2002.
10. ‘A multichannel automated chamber system for continuous measurement of forest soil CO2 efflux’ — Liang N, Inoue G, Fujinuma Y, Tree Physiology, 2003.
11. ‘A comparion of six methods for measuring soil-surface carbon dioxide fluxes’ — Norman JM, Kucharik CJ, Gower ST, Baldocchi DD, Grill PM, Rayment M, Savage K, Striegl RG, Journal of Geophysical Research, 1997.
12. ‘An automated chamber system for measuring soil respiration’ — McGinn SM, Akinremi OO, McLean HDJ, Ellert B, Canadian Journal of Soil Science, 1998.
13. ‘Temporal and spatial variation of soil CO2 efflux in a Canadian boreal forest’ — Rayment MB, Jarvis PG, Soil Biology & Biochemistry, 2000.
14. ‘High-resolution data on the impact of warming on soil CO2 efflux from an Asian monsoon forest’ — Liang N, Teramoto M, Takagi M, Zeng J, Scientific Data, 2017.
15. ‘Long‐Term Stimulatory Warming Effect on Soil Heterotrophic Respiration in a Cool‐Temperate Broad‐Leaved Deciduous Forest in Northern Japan’ —Teramoto M, Liang N, Ishida S, Zeng J, Journal of Geophysical Research: Biogeoscience, 2018.
16. ‘Sustained large stimulation of soil heterotrophic respiration rate and its temperature sensitivity by soil warming in a cool-temperate forested peatland’ — Aguilos M, Takagi K, Liang N, Watanabe Y, Teramoto M, Goto S, Takahashi Y, Mukai H, Sasa K, Tellus Series B : Chemical and Physical Meteorology, 2013.
17. ‘Liang Automatic Chamber (LAC) Network’
18. ‘Interpreting, measuring, and modeling soil respiration’ — Ryan MG, Law BE, Biogeochemistry, 2005.
19. ‘Boxed Gascard’
20. ‘Gascard NG’

@edinsensors #Environment #NIESJp

Josh Thomas of Ashtead Technology discusses the reasons for monitoring dust in the workplace.

Almost any place of employment can present a potential threat to health and safety from airborne particulates and aerosols. It is important to note, however, that dust hazards are not necessarily visible to the human eye and that the finest particles can represent the greatest threat because of their ability to travel deepest into the lungs. Effective monitoring is therefore key to the implementation of an effective risk management strategy.

There are two major reasons for monitoring dust in the workplace; to enable air quality management, and for regulatory compliance. The immediate effects of dust can be irritation to eyes, headaches, fatigue, coughing and sneezing. As such, poor indoor air quality can lower employee performance and cause increased absenteeism through sickness. In addition, particulates are known to create long-term deleterious effects, contributing to serious illnesses. In combination with outdoor exposure (to pollution form vehicles for example), the Government has estimated that 29,000 premature deaths occur in the UK every year as a result of particle pollution. This means that, particularly in urban areas, natural ventilation may not necessarily improve indoor air quality.

Employers are responsible for ensuring that staff and visitors are not exposed to poor air quality in the workplace, so it is necessary to conduct monitoring. Accurate and effective monitoring data can be used to check exposure levels and to help identify safe working practices.

Monitoring also helps to demonstrate compliance with relevant regulations. COSHH is the law that requires employers to control substances that are hazardous to health. According to the Health & Safety Executive (HSE), employers can prevent or reduce workers’ exposure to hazardous substances by finding out what the health hazards are; by deciding how to prevent harm to health; by providing effective control measures; by providing information and training; by providing monitoring and health surveillance, and by planning for emergencies.

In order to evaluate workplace safety, monitoring data is compared with Workplace Exposure levels (WELs) which prescribe the maximum exposure level to a hazardous substance over a set period of time. Failure to comply with COSHH and WELs can result in financial penalties, prosecutions and civil claims.

Indoor air quality is affected by both internal and external factors. Air pollution may arise from external sources such as neighbouring factories, building and development activities, or from vehicles – especially those with diesel engines. Internally, air quality is affected by working practices and business processes. For example, dust may arise from raw materials such as powders, or it may be produced by processes that generate particulates; including dust, mist, aerosols and smoke. In all cases, internal and external, it is important to identify both the source and the seriousness of the problem, so that appropriate and effective mitigation measures can be implemented. These might include, for example, ventilation, process dust prevention, the management of shift patterns, personal protection equipment (PPE) and alarm systems.

Regulatory requirements to monitor
Under the British Workplace (Health Safety and Welfare) Regulations 1992, employers have a legal duty to ensure, so far as is reasonably practicable, the health, safety and welfare of employees. Furthermore, the Management of Health and Safety at Work Regulations 1999 (GB) require employers to assess and control risks to protect their employees. A key element of this is the requirement to comply with the COSHH Regulations. The HSE says that exposure measurement is required:

• For COSHH assessment, to help select the right controls
• Where there is a serious risk to health from inhalation
• To check that exposure limits are not exceeded
• To check the performance of exposure controls
• To help select the right respiratory protection equipment
• To check exposure following a change in a process
• To show any need for health surveillance; or
• When an inspector issues an ‘Improvement Notice’ requiring monitoring

The COSSH Regulations include dust, mist, vapour, fumes and chemicals, but they do not cover Lead or Asbestos. Specific requirements exist for certain industries such as construction. Generally, WELs relate to particulate diameter because the health effects of particulates are heavily influenced by their size.

Inhalable dust is that which enters the nose or mouth during breathing and is available for deposition in the respiratory tract. It includes particles with a width between 2.5 and 10 microns (PM_2.5 – PM₁₀), and the WEL for this fraction is 10 mg/m³ as an 8-hour Time Weighted Average (TWA).

Respirable dust is the fraction that penetrates deep into the gas exchange region of the lungs. It includes particles with a width between 1 and 2.5 microns (PM₁– PM_2.5), and the WEL for this fraction is 4 mg/m³ as an 8-hour TWA. Lower specific WELs exist for particulates that present a greater threat to health. For example, Silica dusts have a WEL of just 0.1 mg/m³ respirable dust as an 8-hour TWA.

The costs of non-compliance
In addition to the enormous numbers of premature deaths that result from exposure to outdoor air pollution, there are also numerous well-documented instances demonstrating the harm caused by exposure to indoor pollution from dust, smoke, aerosols and vapour. For example, a 46-year-old cook developed breathing problems after working with flour in a school kitchen with poor ventilation. Her breathing problems became so severe that she could hardly walk and had to sleep sitting up. She became severely asthmatic and had to retire early on health grounds. With the support of her Union she made a compensation claim on the basis that decent working conditions were not provided, and the council admitted that it had not taken sufficient action despite repeated complaints. Consequently, the courts awarded the cook £200,000 (€230k) in damages.

In another example, between 1995 and 2004, a solderer was exposed to rosin based solder fumes and suffered health deterioration and breathing problems including asthma. An investigation conducted by the HSE found that the company did not have adequate control measures in place and failed to install fume extraction equipment. Furthermore, the company did not employ rosin-free solder until December 2003, despite an assessment having identified the need in 1999. The company was subsequently fined £100,000 (€116k) with £30,000 (€35k) costs, a punishment which attracted both local and national media attention.

Monitoring dust
A wide variety of methods exist for the measurement of dust, and the choice of equipment is dictated by the application. For example, it is obviously important to employ a technology that is able to measure the particulates that will be present. In addition, it will be necessary to determine whether monitoring should be continuous, at a single point, or whether portable instruments are necessary to check multiple locations. Monitoring might be conducted in a work space, or personal sampling might be undertaken in order to assess the exposure of an individual over an entire shift.

Personal Sampling Pumps represent the preferred method for workplace exposure monitoring where it is necessary to demonstrate regulatory compliance or where legal dispute is a possibility. An HSE document (MDHS 14/4) provides workplace exposure monitoring guidance for collecting respirable, thoracic and inhalable aerosol fractions. The samples collected by this process are analysed in a laboratory, which means that chemical analysis is also possible. However, the sampling method incurs a delay and incurs extra cost.

In response to the wide variety of applications and monitoring requirements, Ashtead Technology stocks a comprehensive range of monitors for both sale and rental, providing customers with complete financial and technical flexibility. As a TSI Gold Partner, Ashtead Technology provides a comprehensive range of maintenance and calibration services; helping customers to ensure that their monitoring equipment remains in optimal condition. Ashtead’s fleet of rental equipment includes large numbers of the latest TSI instruments, supported by the highest levels of service and technical assistance. Employing advanced light-scattering laser photometers, the TSI products are supplied with a calibration certificate and provide real-time, direct-reading aerosol monitoring and analysis of different particulate fractions in workplace, cleanroom, HVAC, fugitive emissions and environmental monitoring applications.

The TSI range of dust monitors is continually being developed to bring new levels of functionality to the market. For example, the new lightweight AM520 Personal Dust Monitor is able to measure and log PM₁₀, Respirable (PM₄), PM₅ (China Respirable), PM_2.5, PM₁ or 0.8μm Diesel Particulate Matter (DPM), providing real-time audible and visual alarms, and running from a rechargeable battery for up to 20 hours. For outdoor applications, the MCERTS approved Environmental DustTrak is web-enabled, providing a quick and easy dust monitoring solution for applications such as building and development projects.

@ashteadtech #PAuto @TSIIncorporated

In North Ayrshire, Scotland, monitoring activities have demonstrated that the main local air quality issues are related to traffic congestion caused by a section of the High Street in Irvine, which is being used as a bus terminus, and by queuing traffic at New Street in Dalry. In both locations the pollutant of most concern is Nitrogen Dioxide.

Sensor on street in Irvine.

North Ayrshire Council operates a fixed continuous air quality monitoring station (AQMS) in Irvine High Street which supplies data to Scottish Air Quality website.

“Data from the AQMS is supplemented by portable monitoring equipment that is installed at key locations,” reports the Council’s Willie McNish. “Passive diffusion tubes provide approximate monthly average data, but over the last 2-3 years we have started using AQMesh air quality monitors. Three ‘pods’ have been installed in pollution hotspots and a further AQMesh pod is used as a mobile device; installed temporarily in key locations to assist with air quality strategy development, and planning and development control.”

AQMesh air quality monitoring pods, from Air Monitors, are small, lightweight, wireless, battery or solar -powered air quality monitors that are quick and easy to install. They are able to monitor the main pollutants simultaneously, delivering accurate cloud-based data wirelessly via the internet. “We use the AQMesh pods for air quality screening,” reports Willie McNish, one of the Council’s Officers responsible for air quality monitoring. “The beauty of these monitors is that they provide almost real-time data that we can access via PC. This is really useful for detecting and predicting trends. For example, I can look at the current air quality measured by a pod and then look at the Met Office website for information on wind speed and direction, and this helps us to better understand the factors that affect air quality.”

The ease and speed with which AQMesh pods can be installed in almost any location is a major advantage in air quality investigations related to planning applications. For example, Willie says: “Concerns about dust and fumes from trucks were raised in connection with an application to extend the life of a landfill site by ten years (as less waste is being landfilled more time was required to fill it), but by locating an AQMesh pod (measuring gases and particulates) in an appropriate location, we were able to support the planning decision by demonstrating that air quality would not be harmed by the extension.”

Monitoring is also informing the development of traffic management strategies to reduce exposure to air pollution. In Irvine, Willie says: “The prevailing wind direction is from the South West, which creates a canyon effect, whereby air pollution accumulates within streets that are confined by buildings on both sides. This effect is exacerbated by queuing double-decker buses, so we plan to undertake remedial measures and monitor their effects.”

As a consequence of the elevated levels of Nitrogen Dioxide in Irvine, the Council will undertake public realm works (streetscape improvements) to widen the pavement, and one of the bus stops will be relocated. This will not only move the source of pollution away from the receptor, but also allow better dilution and dispersion of pollutants, without affecting the frequency of service or convenient access to public transport. In Dalry, a new bypass is due to be constructed and it is anticipated that this will lower Nitrogen Dioxide levels. In both locations, modelling has indicated that air quality will improve, but existing monitoring data will be compared with data once the work is complete, so that an effective evaluation of the effects on air quality can be performed.

Summarising the advantages of the Council’s air quality monitoring strategy, Willie says: “The AQMS in Irvine employs standard reference methods or equivalent, to measure air quality, so it is able to provide definitive data for comparison with EU limits. The station is serviced and maintained by Air Monitors and delivers extremely high levels of data capture. Since 2015 it has also included a FIDAS 200 particulate monitor, so we are now able to monitor TSP, PM₁₀, PM₄, PM_2.5, PM₁ and Particle Number simultaneously, which provides greater insight into the types of pollution and their likely sources.

“To complement the AQMS we also operate 4 AQMesh pods which provide the flexibility we need to monitor air quality in precisely the location of greatest importance. Web connectivity combined with Air Monitors’ reliability of service provides us with continuous access to accurate air quality data, which means that we are able to fulfil our statutory obligations as a Council, and also find ways to protect the health of people in North Ayrshire.”

@airmonitors #Pauto @scotairquality @_Enviro_News #Environment

A train derailment in Mississippi resulted in ground contamination by large quantities of hazardous chemicals, and environmental investigators have deployed sophisticated on-site analytical technology to determine the extent of the problem and to help formulate an effective remediation strategy. Here Jim Cornish from Gasmet Technologies discusses this investigation.

Jim Cornish

On March 30^th 2015 a long freight train, transporting a variety of goods including lumber and chemicals, wound its way through the state of Mississippi (USA). At around 5pm, part of the train failed to negotiate a curved portion of the track in a rural area near Minter City, resulting in the derailment of nine railcars, one of which leaked chemicals onto agricultural farmland and woodlands. Emergency response and initial remediation activities were undertaken, but the remainder of this article will describe an environmental investigation that was subsequently conducted by Hazclean Environmental Consultants using a portable multiparameter FTIR gas analyzer from Gasmet Technologies.

Background
Over 17,000 gallons of Resin Oil Heavies were released from the railcar, and the main constituent of this material is dicyclopentadiene (DCPD). However, in addition to DCPD, Resin Oil Heavies also contains a cocktail of other hydrocarbons including ethylbenzene, indene, naphthalene, alpha-methyl styrene, styrene, vinyl toluene, 1, 2, 3-trimenthylbenzene, 1, 2, 4-trimethylbenzene, 1, 3, 5-trimethylbenzene and xylenes.

DCPD is highly flammable and harmful if swallowed and by inhalation. Its camphor-like odor may induce headaches and symptoms of nausea, and as a liquid or vapor, DCPD can be irritating to the eyes, skin, nose, throat or respiratory system. DCPD is not listed as a carcinogen, however DCPD products may contain benzene, which is listed as a human carcinogen. DCPD is not inherently biodegradable, and is toxic to aquatic organisms with the potential to bioaccumulate.

It is a colorless, waxy, flammable solid or liquid, used in many products, ranging from high quality optical lenses through to flame retardants for plastics and hot melt adhesives. As a chemical intermediate it is used in insecticides, as a hardener and dryer in linseed and soybean oil, and in the production of elastomers, metallocenes, resins, varnishes, and paints. DCPD-containing products are also used in the production of hydrocarbon resins and unsaturated polyester resins.

Emergency Response
Emergency response phase activities were performed from March 31 through May 2, 2015. Response objectives and goals were formally documented by utilizing Incident Action Plans for each operational period. Activities between April 11 and April 28, 2015 were summarized in weekly reports and submitted to the Mississippi Department of Environmental Quality (MDEQ) and the Environmental Protection Agency (EPA).

Approximately 10,189 gallons of the leaked product was recovered, leaving 5,458 gallons to contaminate the farmland surface and subsurface soil, surface waters, groundwater and ambient air. The site contamination problem was exacerbated due to heavy rainfall and associated stormwater runoff which caused the unrecovered product to migrate from the spill site.

Taking account of the high rainfalls levels that followed the event, it was calculated that contaminated stormwater runoff from the immediate project site (10 acres with 8.7 inches of rainfall) was 2,362,485 gallons less that retained by emergency retention berms. Approximately 207,000 gallons of contaminated stormwater were collected during the emergency response, in addition to approximately 7,870 tons of impacted material which were excavated for disposal. Following removal of the gross impacted material, the site was transferred into Operation and Maintenance status, conducted in accordance with a plan approved by MDEQ.

Ongoing site contamination
Groundwater and soil samples were collected and analyzed in 2015 and 2016, producing analytical data which confirmed that widespread soil and groundwater contamination still existed at the site. Further remediation was undertaken, but the landowners were extremely concerned about the fate of residual chemicals and contracted Hazclean Environmental Consultants to conduct a further investigation.

“The affected land is used for agricultural purposes, producing crops such as soybeans and corn,” says Hazclean President, E. Corbin McGriff, Ph.D., P.E. “Consequently, there were fears that agricultural productivity would be adversely affected and that chemicals of concern might enter the food chain.
“This situation was exacerbated by the fact that the landowners could still smell the contamination and initial investigation with PID gas detectors indicated the presence of volatile organic compounds (VOCs).”

Hazclean’s Joseph Drapala, CIH, managed and conducted much of the site investigation work. He says: “While PID gas detectors are useful indicators of organic gases, they do not offer the opportunity to quantify or speciate different compounds, so we spoke with Jeremy Sheppard, the local representative of Gasmet Technologies, a manufacturer of portable FTIR (Fourier Transform Infrared) gas analyzers.

Soil Vapor Analysis with FTIR

“Jeremy explained the capabilities of a portable, battery-powered version of the Gasmet FTIR gas analyzer, the DX4040, which is able to analyze up to 25 gases simultaneously, producing both qualitative and quantitative measurements. Gasmet was therefore contacted to determine whether this instrument would be suitable for the Mississippi train spill application.

“In response, Gasmet confirmed that the DX4040 would be capable of measuring the target species and offered to create a specific calibration so that these compounds could be analyzed simultaneously on-site.”

Site investigation with FTIR analysis
A sampling zone was defined to capture potential contamination, and measurements were taken for surface and subsurface soil, groundwater, and surface and subsurface air for a range of VOCs.

Vapor Well

The area-wide plan resulted in the installation of four permanent monitoring wells for groundwater sampling, twenty vapor monitoring wells, and twenty test borings for field screening. The test borings indicated the presence of VOCs which were further characterized by sampling specific soil sections extracted from the parent core.

In addition to the almost instantaneous, simultaneous measurement of the target compounds, the Gasmet DX4040 stores sample spectra, so that post-measurement analyses can be undertaken on a PC running Gasmet’s Calcmet™ Pro software, providing analytical capability from a library of 250 compounds. “The Gasmet DX4040 was manufacturer-calibrated for dicyclopentadiene, benzene, ethylbenzene, naphthalene, styrene, toluene, 1,2,3-trimenthylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene and m, o, and p and total xylenes at a detection range of 0.01 ppm to 100 ppm in air,” Joseph reports, adding: “The ability to compare recorded spectra with the Calcmet Pro library is a major advantage because it enables the measurement of unknown compounds.”

The operating procedures for the DX4040 indicate a simple, convenient requirement for daily calibration with zero gas prior to each monitoring activity. However, in addition to the use of nitrogen as the zero gas, Joseph also employed specialty gas (DCPD) certified for 1 ppm and 5 ppm as a calibration check and a response (akin to bump testing) gas.

Site screening
The test borings provided soil samples that were vapor-tested on-site as part of the screening process. Vapor from the extracted soil samples was analyzed by placing the soil samples in vessels at ambient temperature and connecting the DX4040 in a closed loop from the vessel, so that air samples could be continually pumped from the vessel to the analyzer and returned to the vessel. This screening activity helped to determine the location for vapor wells.

All soil samples were screened with the DX4040 and those with the highest reading from each boring were sent for laboratory analysis.

Vapor wells were fitted with slotted PVC liners and capped. Before monitoring, the cap was replaced with a cap containing two ports to enable the DX4040 to be connected in a similar closed-loop monitoring system to that which was employed for the soil samples.

Conclusions
As a result of this investigation it was possible for Hazclean to determine that the release of DCPD in the vapor state, as measured in the vapor monitor wells, is a result of surface and subsurface contamination in the soil and groundwater, and that this contamination will remain in the future.

Vapor analysis data provided by the DX4040 identified DCPD, benzene, styrene and xylene previously adsorbed on soil and/or wetted surfaces undergoing diffusion and evaporation. The adsorption, diffusion and evaporation of DCPD et al. released and spread across the farmland is a mechanism to explain the vapor concentrations found in vapor monitor wells as well as the ambient malodor problem.

The long term release of DCPD and other VOCs will continue to occur in the impact area unless a larger remediation project is conducted to remove soil and groundwater contamination. Furthermore, Hazclean recommends that, as a result of the effectiveness of the Gasmet DX4040 in this investigation, the same technology should be employed in any subsequent screening activities, using the same Gasmet calibration configuration.

Summarizing, Joseph Drapala says: “The Gasmet DX4040 was an essential tool in this investigation. Screening activities should have the ability to detect and identify the target compounds, as well as any secondary compounds that may have already been present on-site or could have been produced as a result of chemical interactions.
“As an FTIR gas analyzer, the DX4040 meets these requirements, providing enormous analytical capability through Gasmet’s Calcmet software. However, the instrument is also small, lightweight and battery powered which makes it ideal for field investigations.”