A Closer Look at Environmental Monitoring Sample Methods
Sep 08 2014
Environmental monitoring has emerged as a key component of governmental and private organisation policies across the globe. But how exactly do specialists draw samples and determine results? Given the fact that environments vary from project to project, a wide range of techniques are used to gather material. To help shed light on the matter, we’ve put together this useful guide offering an overview of some of the most commonly used sampling methods.
For homogeneous materials such as water, a grab sample offers quick and accurate insight into the quality of the environment. Samples are collected in a single vessel which is then transported back to a lab for analysis. This technique is one of the most commonly used sampling methods and is great for establishing base measurements such as chemical composition and salinity. That said, grab samples are also limited in that they only offer a snapshot of a certain area at a certain time. As a dynamic substance, water quality can rapidly fluctuate due to changes in flow, evaporation and other external factors.
Semi-continuous and continuous monitoring
For projects that require ongoing analysis, semi-continuous and continuous monitoring is the sampling technique of choice. Sophisticated equipment can be programmed to draw samples at pre-determined intervals. This is particularly useful for safeguarding vital water sources where immediate detection of any issues is critical.
When budgets are low and infrastructure is limited, passive sampling is a cost effective solution. The semi-disposable equipment is budget friendly which allows for maximum coverage and data collection at the lowest possible cost.
While on-site data collection is the most commonly used technique, many projects also employ the use of remote surveillance equipment. This involves using a communications network to link on-site equipment to a base station. As a result, environmental monitors can store and analyse multiple data feeds and micromanage individual sites.
For sophisticated projects, aircraft and satellites can use multi-channel sensors to record environmental quality. Remote sensing comes in two forms – passive and active. The first is used to track reflection levels of natural radiation such as sunlight. This is particularly useful for detecting changes in plant based environments that can’t be seen by the naked eye. The latter is primarily used to gather topographical information and is ideal for use in remote or dangerous areas such as the Arctic. It involves actively releasing energy and using a passive device to record the amount of radiation that is reflected back. While remote sensing is complex, it does help to shed light on issues such as deforestation, climate change, depth sounding and conservation.
Analysing living organisms can offer invaluable insight into environmental quality. Plants and animals with a tendency to absorb the contents of their natural habitats are of particular value. For example, thanks to their predisposition to absorbing heavy metals, mosses are often used as a tool for determining the presence of cadmium, mercury and lead.
At the end of the day, what’s most important is that scientists choose the right sampling method for the given area and carry out the process with as little environmental impact as possible. Regular improvements to wireless technology is making the monitoring processes and environmental conditions in many locations much easier and safer. Personnel are no longer exposed to dangerous or unpleasant environments and access to the data is possible at any time without sending personnel on site. This article, Added Value of Wireless Data Transmission in Environmental Applications, Automated Compost Temperature Monitoring, looks at this topic in more detail.
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