Field instrumentation is often necessary for environmental testing due to ever-changing conditions and the difficulty associated with transporting samples back to the lab. In addition to field instruments, fully equipped mobile laboratories may be driven to test sites for ongoing analysis. Advances in field instrumentation have enabled extensive analysis outside the traditional laboratory setting. Given the constraints of fieldwork, these instruments must be compact, easy to transport, durable, and have portable power options. There also has been a shift toward wireless monitoring systems that transmit data for cloud storage and remote computer and cell phone access. These systems reduce the cost and time required for repeated trips to a test site.
Soil and water analyses are performed to ensure human, animal, and ecosystem health and to comply with environmental regulations. Many large-scale industrial operations such as mines and oil refineries as well as animal agriculture can contaminate the soil and water. Environmental contaminants range from heavy metals to pesticides, herbicides, hormones, and pharmaceuticals, among many others. Regular field-testing enables users to monitor water and soil quality; however, instrumentation must be easily portable and provide rapid, accurate results. Advances in field instrumentation have helped overcome the challenges outside the laboratory and have brought powerful technology into the field.
Contaminated soil can impact human health, especially when agricultural land is affected. Different portable solutions enable the detection and identification of contaminants in soil samples. Testing may be performed prior to new construction on previously used land as well as to monitor the effects of industrial activities such as mining.
Portable X-ray fluorescence (PXRF) instruments can now be used to identify unique chemical elements in a soil sample. PXRF devices emit X-rays to excite electrons in the sample. The secondary X-ray emitted by the sample is detected and is specific to the individual element. Earlier in 2018, Bruker released a new portable XRF analyzer, weighing less than seven kilograms, that is ideal for field testing and mobile laboratories. In a recent study, portable XRF and geographic information systems data were combined to produce a map of soil contaminated by heavy metals in abandoned mine sites.1 This method enabled more rapid mapping compared to conventional methods and demonstrated accuracy similar to that of inductively coupled plasma atomic emission spectroscopy (ICP-AES).
Related Article: Study Reveals How Soil Bacteria Are Primed to Consume Greenhouse Gas
Gas chromatography coupled with mass spectrometry (GC-MS) is widely used in the laboratory setting, as it is considered the gold standard for compound identification. The development of portable units brings GC-MS into the field, enabling rapid compound identification. The PerkinElmer Torion T-9 Portable GC/MS is a self-contained, rechargeable, battery-operated system that packs the power of benchtop GC-MS into a portable, 32-pound instrument. Portable GC-MS has been used to detect polychlorinated biphenyl (PCB) in soil samples. PCB is an organic chlorine compound with potential carcinogenic effects, and its production was banned by the United States. Portable GC-MS has been used in the field to assess PCBs in soil matrices.2 Using on-site analysis reduces the cost and potential complications associated with transporting samples back to a laboratory, such as changing conditions during sample transport. In this study, the instrument was powered by an internal battery and helium cylinder, and the detection limit was approximately 10 ppm, considered useful for remediation efforts of these sites.
There are multiple applications for field instrumentation in water testing, including quality assessment for aquaculture, drinking water, and wastewater management, among others. As with soil, ensuring water is free of contaminants is important to animal and human health, and there are multiple tools available for field testing.
Aquaculture, the cultivation of different species of fish and other aquatic organisms, relies on accurate water testing in the field to ensure animal health. Ammonia is a toxic metabolic waste product excreted by fish, and it can be fatal in high concentrations. Osmo Systems has developed the Osmobot, an affordable aquaculture sensor that enables monitoring of dissolved oxygen, pH, ammonia, and temperature. Unlike other sensors consisting of multiple ion sensors connected to a sonde, this device is constructed with photochemical sensor patches. The sensor uses light-reader chips as opposed to expensive spectrometers, which eliminates the need for recalibration. The device connects to a cloud-based platform for continuous remote monitoring and data storage, with options for alerts and alarms. Realtime Aquaculture also provides sensors that wirelessly transmit data pertaining to salinity, dissolved oxygen, algae, and turbidity and that sync for cloud-based data storage. These systems make aquaculture water quality monitoring simpler, reducing the amount of time spent manually obtaining measurements.
Related Article: LC-MS-MS and GC-MS for Water Quality Monitoring
Fifty-one percent of the United States population relies on groundwater for drinking water. Groundwater is also important for industrial processes, irrigation, and recharging of rivers and wetlands. Field-testing is essential to ensure adequate groundwater quality and supply. For example, groundwater with high salinity may damage crops when used for irrigation. Testing water conductance (the ability to pass electrical flow due to ion concentration) in the field can provide an indication of salinity. Further, measuring groundwater levels is important, as fluctuations can influence habitat sustainability. Groundwater must be accessed through wells for testing, and systems that can be deployed to transmit data for remote monitoring reduce the amount of time spent traveling to and from sites. OTT HydroMet has developed systems including the ecoLog 500 that can be deployed and left unattended in groundwater wells. All instrument components are inserted in the groundwater well to measure water temperature, pressure, and, optionally, conductivity. Data can be stored and transmitted by text or email for remote access. Bentek Systems offers satellite telemetry systems for groundwater monitoring that consist of a satellite modem and weatherproof enclosure. The system can be supplied with a sensor or configured with industry-standard sensors and is linked to a server to provide web and smartphone access to site data.
Environmental testing in action
Dr. Mark McMaster is a scientist at the Canadian Centre for Inland Waters at Environment and Climate Change Canada in Burlington, Ontario. Nancy Glozier is an aquatic ecosystems scientist at Environment and Climate Change Canada in Saskatoon, Saskatchewan. They are involved with the Oil Sands Monitoring (OSM) Program, a joint federal and Alberta government initiative to determine whether environmental indicators are changing in the Alberta oil sands region as a result of oil sands development. The program monitors water quality in the Athabasca River and its major tributaries.
In addition to water sample analysis, “water quality data sondes are used at all the sites on the mainstream Athabasca River as part of our water quality monitoring program,” they say. These sites are selected specifically because they are above and below major tributary inflows, water intakes, and outfalls. Sondes collect “continuous, high frequency information on standard water quality parameters (i.e., dissolved oxygen, pH, temperature, conductivity, and turbidity).” According to McMaster and Glozier, work with remote autonomous water quality monitoring systems has begun, including “automated river platforms and instrumented lake buoys systems at key locations.” While there are several advantages to remote monitoring, there are still some challenges to overcome when implementing these new systems, specifically, changing weather and environmental conditions. “We are actually having a bit of difficulty with these, as they have been washed out by large trees, etc., during storms and large rain events,” says Dr. McMaster.
In his work with the OSM Program, Dr. McMaster is focused on the fish health monitoring program, which involves “sampling fish for health endpoints.” Data collection often occurs on-site, where different species of fish are caught and sampled for specific health markers. Using a mobile laboratory trailer setup enables researchers to power balances, centrifuges, and other equipment used during testing and eliminates the challenges of working outside prior to sending samples back to a laboratory.
Environmental testing is essential to human, animal, and ecosystem well-being. Field instruments and mobile laboratories have been designed to reduce the need to transport samples back to the laboratory (sometimes a great distance) for later analysis. Field instruments enable rapid, accurate data collection at the test site and can alert scientists to potentially dangerous environmental contamination. The shift toward remote and mobile monitoring—for example, instrumented buoys in lakes—reduces travel to the test site and enables continuous monitoring. As field instrumentation continues to become more sophisticated, scientists will be able to complete highly accurate analysis outside the laboratory. While various environmental factors create challenges for scientists and technology, durable and compact devices are being developed to withstand these forces and obtain valuable data.
1. Suh, J., Lee, H. & Choi, Y. A Rapid, Accurate, and Efficient Method to Map Heavy Metal Contaminated Soils of Abandoned Mine Sites Using Converted Portable XRF Data and GIS. Int. J. Environ. Res. Public Health 13, (2016).
2. Zhang, M., Kruse, N. A., Bowman, J. R. & Jackson, G. P. Field Analysis of Polychlorinated Biphenyls (PCBs) in Soil Using Solid-Phase Microextraction (SPME) and a Portable Gas Chromatography–Mass Spectrometry System. Appl. Spectrosc. 70, 785–793 (2016).
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