When it comes to analysing water, soil and air samples, how you collect and present your sample can affect the outcome of your results. To get the most accurate test results, you must collect, store and transport to the lab all water, soil and air samples. Therefore, we’ve outlined the basic requirements for the collection of soil, water and air samples below: 

Collecting water samples 

Before collecting water samples, prepare by making sure you have the correct equipment. You will need collection bottles, field equipment and preservatives. The type of water collection bottle you’ll need depends on the method followed and sample type. Usually, you would use a plastic collection bottle for metal analysis samples. Glass containers are typical for volatile organics and pesticide analysis samples. Leave no headspace when filling the containers to keep the analytes dissolved in the water and prevent them from escaping into the air. 

Depending on the analysis, the preservation techniques may differ. One of the possible preservatives is sodium thiosulfate. This is a dechlorinating agent used to preserve bacteria analysis and volatile organics. Temperature, also, is an important preservation technique. Keep the samples cool and transport them to the lab between four and six degrees Celsius. 

Tests used to determine the water quality commonly include temperature, pH, chloride, salinity, dissolved oxygen, turbidity, pesticides, nitrate and nitrite fluoride sulphate, arsenic, total coliforms, manganese, zinc, iron, potassium, sodium, calcium, magnesium and legionella testing. 

Soil sampling 

For accurate soil analyses and reliable nutrient recommendations, you need proper soil sampling. In general, soil samples should be representative of the whole area. To get a representative soil sample, one should consider several factors. These include the timing of sampling, tools used, sampling depth and proper handling. Sampling depth is particularly important. Take the samples from 0 to 15 cm,15 to 30 cm, and 30 to 60 cm to get the most accurate level of soil nutrients. If the sample is moist, keep it cool and send to the lab immediately for analysis. However, if it’s impossible to send the sample immediately, be sure to store it dried or frozen. 

Soil analyses may include extractable nitrate nitrogen, potassium and phosphorus, sulphate sulphur, pH, salinity (electrical conductivity), and micronutrients such as boron, chloride, copper, iron, manganese or zinc. 

Testing air quality 

It is important to test air quality for hazardous substances and microorganisms in the environment. There are several different types of air sampling techniques, including the following: 

Whole air sampling: Used for volatile organic compounds, reduced sulphur compounds and permanent gases present in the air. The sample can be collected in an inert canister of the gas bag.  X-LAB would normally transfer the sample to an intermediate trap before analysis.

Active air sampling and passive air sampling: Used for collecting volatile and semi-volatile organic compounds. X-LAB can provide kits suitable for the collection of samples tailored for customer needs.  X-LAB is also the first laboratory in South Africa to offer US EPA 325 analysis and kits for fenceline VOC measurement.

Filter sampling: Used for collecting contaminants in mist or particulate form. 

One can use air testing to find the concentrations of VOCs, actively growing mould, toxic formaldehyde, and fixed gases including methane, hydrogen, oxygen, nitrogen, carbon dioxide, carbon monoxide and BTEX. Do you need your water, soil or air samples tested? Get in touch to arrange a visit.