Sample collection and determination in soil analysis
The collection of soil environmental samples is a technical action for the design, layout, and distribution of soil environmental surveys, and the implementation of the site layout plan. The quality of soil environmental samples is the basis for obtaining reliable soil measurement results. It directly affects the accuracy of test analysis. And precision. In the investigation of soil pollution in Yunnan Province, a series of control measures were adopted. 1 Workflow (see Figure 1) 2 sampling equipment To effectively control the various system errors and human errors brought about by sampling, a suitable sampling tool is selected. The sampling tools selected for the survey include topographic maps, digital cameras, earth drills, aluminum boxes, ring knives, and sampling boxes. , cloth bags and so on. 3 point determination 3.1 Determination of points Using the points provided (this survey, the point is provided by the national unity), first find the approximate location of the sampling points on the map, for example, which county and which village are located. Then enter the latitude and longitude of the point into GPS, and use the navigation function of GPS to find the detailed position. 3.2 Sample Point Requirements (1) Sampling of sites with relatively flat terrain and uniform vegetation distribution is generally selected; (2) Samples should not be taken at places where residential and large industrial and mining enterprises are around, roadsides, excreta pits, graves, etc., where human interference is obvious and lacks representativeness; (3) Not sampling in remote areas where soils, various parent materials, and parent rocks are staggered and where the area is small; (4) Profile points should be selected for soils with relatively complete sections and clear intervals. Soil profile can take advantage of naturally occurring, developed soil profiles. 4 Sample Types and Sampling Methods 4.1 Individual samples Individual samples are soil samples used to analyze organic contaminants. There are special requirements for sampling tools, holding containers, and environmental conditions for storage. (1) After determining the sampling point, remove defoliation, weeds, stones, roots and other debris on the surface, but ensure the topsoil (0cm); (2) Use a shovel or a wooden shovel to dig the soil to a depth of 0 to 20cm. , Load 1l brown glass bottle to protect from light, the sample should fill the container. (3) Stick the brown glass bottle in the sampling box and store it in a refrigerator. Separate samples should be sent to the laboratory for sample preparation as soon as possible (preferably within 7 days); and during the transport process, the temperature of the sample box should be kept below 4e. 4.2 Mixed Samples In soil environmental quality monitoring work, mixed soil samples are generally collected, that is, in a sampling area, the soil samples collected from multiple points are mixed into one sample. On the one hand, the amount of analysis can be reduced, and on the other hand, the sampling area can be inhomogeneous. The impact is minimized. Sampling should follow a certain route, according to the principle of / random 0, / equal 0 and / multi-point mixing 0. In this sub-soil survey, several sampling points commonly used are the diagonal sampling method, the snake sampling method, and the quincunx sampling method. The applicable conditions and sampling points are shown in Table 2. 4.3 profile samples In this survey, separate samples and profile soil samples were collected from the background points. Section soil samples are taken after section observation and recording. Samples are generally collected according to the natural occurrence level of the soil. In the sampling of the soil profile where the soil is naturally not obvious, in order to reduce the error in determining the depth of the section, the section depth (0 to 20 cm) is used. 20~50cm, 100~120cm) sampling. When collecting profile samples, they should be stratified from the bottom to the top in order to avoid mixed contamination of the underlying soil when the upper sample is taken. In addition, in order for the sample to clearly reflect the characteristics of each layer, it is usually taken in the most typical middle of each layer, which can overcome the transition between layers, thereby increasing the typicality or representativeness of the sample. 5 sampling depth In this survey, the sampling depth of individual samples and mixed samples was 0-20 cm. The profile samples were sampled according to the soil's naturally occurring level or according to the profile depth (0-20 cm, 20-50 cm, 100-120 cm). When sampling, pay attention to the sampling depth and sampling depth of each sampling point should be uniform, the proportion of the upper and lower soil samples should be the same. The sampler should be earthed perpendicular to the ground and have the same depth. 6 sample weight In this survey, 5kg were taken from the mixed sample and the profile sample, and the collected soil samples were discarded using the quaternary method. The soil sample to be collected is placed on a plastic sheet or board, broken, mixed, and squared. Divide the soil sample into four parts diagonally. Combine the two opposite corners into one, and keep one. Discard one. If the resulting sample is still large, it can be treated by quartering until the required amount. Separate samples taken 1l. 7 sample label The collected samples were placed in cloth bags or brown ground glass bottles with a sample label inside and outside. Labels should indicate the sample number, latitude and longitude of the sampling site, collection location, sampling time, sampling depth, elevation, and collectors. 8 inspection After each point of the sample is collected, the contents of the record, type and quantity of the sample shall be checked and checked one by one. If the missing item is found, it shall be filled in, and any misconduct shall be corrected. 9 Summary (1) Different sampling methods should be adopted according to the location of sampling site; (2) When collecting mixed samples, adequate sampling points should be provided regardless of the method used; (3) Past practice shows that in soil monitoring, sampling errors have a greater effect on the results than sample preparation errors and analysis errors. Therefore, each sampling personnel should strictly follow the principle and scheme of sampling layout during the sampling process, control the sampling quality from each step in the sampling process, minimize the sampling error as much as possible, and ensure that the collected soil The samples are fully representative and can truly reflect the actual conditions of the soil. Graphite Parts,Gasket Graphite,Graphite Heating Elements,Graphite Exhaust Gasket Material CARBONS TECH&CREATION(HENAN) INDUSTRY CO.,LTD , https://www.kyedmgraphite.com
