How will& surface water and sediment samples be collected?

Understand the 5 steps for performing the surface water and sediment collections in the Paraopeba River during the Brumadinho UFMG Project.

Published on 09/11/2020

Surface water and sediment collections will be performed at 44 points, following the sampling design of those specified in Calls no 09/2019 and 11/2019 of the Brumadinho UFMG Project. The sampling points are located in the Paraopeba River, Ferro-Carvão stream, and the Retiro Baixo HPP. 

Five steps are required to perform the collections:  

Stage 1 - Procedures preceding the start of field sampling.

This stage starts immediately, all the initial procedures that precede the collections will be done, such as mobilizing the team and organizing the material to be used.

Step 2 - Validation of the sample points

Pilot campaign for validation and, if necessary, readjustment of the sampling points. Thus, a previous investigation by the team about the accesses to the roads is fundamental for the boat transport and to carry out the collection in an effective way, with quality and in safety. A report on the pilot campaign will be issued, with all the photographic records, observations and documented justifications, for presentation and discussion with the technical scientific committee, for later definitive marking of the sampling points.

Stage 3 - Field team training

To ensure the quality and standardization of sampling and sample preservation and handling procedures, training will be conducted with all team members in the field soon after the sample points are defined and validated. The team training will take place near Brumadinho, with an estimated 3 days of activities.

Stage 4 - Preparation and collection of surface water and sediment samples

● Sampling frequency:

Surface water sampling will be conducted monthly for 11 months. Sediment collections will be performed twice a year, once in the dry period and once in the rainy period.

● Preparation for the collections:

All the logistics for the collections will be started 10 days in advance, such as hotel reservations, car rental, definition of the members of each team, cleaning of the vials, and separation of the material for collection. The bottles will go through cleaning procedures and, when necessary, solutions will be added for preservation, according to what is established by the National Guide for Sample Collection and Preservation of the National Water Agency (ANA, 2011). After cleaning, the flasks will be properly labeled according to the chain of custody methodology. In addition to the flasks, buckets, ropes, Van Dorn bottles, dredges, syringes and other utensils used during collection will be decontaminated. Solutions for preservation of the samples will be prepared, transferred to the bottles and properly identified. The multiparameter probe will be checked and calibrated according to the manufacturer's instructions. The field forms will be prepared with initial information (georeferenced location). Before the start of each sampling campaign the team will check the separate items.

● Georeferencing the information collected in the field:

We will use a collection of integrated, geo-location-based applications from the ArcGIS Platform (Collector, Survey123, Navigator, ArcGIS Pro) to optimize the efficiency of field activities and to improve the way we document the work performed. Specifically, (1) we will create robust forms from the Survey123 application about the information to be collected in the field (e.g., identifier following the chain of custody, effective field staff, physicochemical parameters, collection date, sampling point, collection date, delivery date); (2) we will plan field logistics using geographic location intelligence, including defining guided routes with the help of the Navigator tool; (3) we will collect data in the field from GPS-equipped tablets, filling in the forms created in (1). The field data will be entered directly into the ArcGIS Platform through a cloud system. Therefore, field data will be able to be shared among all those involved in the project in an agile manner, thus facilitating the traceability of each step of the process, as well as improving the monitoring of the work performed

● Execution of surface water sample collections:

Samples for analyses of metals, metalloids, and organic compounds will be collected according to the standards described in the National Guide for Sample Collection and Preservation of the National Water Agency (ANA, 2011). For ecotoxicological tests, water samples will be collected according to the ABNT NBR 15469 (2007) standard.

Surface water samples will be collected at a depth of 30 cm using a stainless steel bucket (AISI 316L) or through a horizontal Van Dorn bottle. The sample preservation techniques involve chemical addition, freezing and/or refrigeration, depending on the parameter collected, according to the standards described in the National Guide for Sample Collection and Preservation of the ANA (Agência Nacional de Águas, 2011). To avoid cross-contamination problems during sampling, all equipment used will be washed in the field with distilled water and set at each sampling point. The total depth of the sampling site will be checked in the field with the aid of a metered rope with a pointer. Physicochemical parameters of turbidity, temperature, pH, dissolved oxygen and conductivity will be measured in situ with a multiparameter probe.

Samples for analyses of metals, metalloids and organic compounds in sediment will be collected according to the standards described in the National Guide for Sample Collection and Preservation of the National Water Agency (ANA, 2011). For ecotoxicological tests, sediment samples will be collected according to the ABNT NBR 15469 (2007) standard.

Stage 5 - Product delivery (samples and reports)

The georeferenced samples collected monthly will be delivered to a location defined by the scientific technical committee for proper storage in refrigerators or freezers. All samples will be checked through a checklist, signed and dated by the recipient and the deliverer. Due to the large volume of samples collected per campaign, and the short time of validity of analysis for some parameters (7-14 days), a car will be sent to pick up the samples every 3 collection days, followed by their delivery as soon as possible to UFMG. Thus, 2 or 3 partial deliveries of samples per collection month are expected.

A partial technical report will be prepared and delivered for all the campaigns carried out, being 1 for the pilot campaign for validation of the points, 11 for the surface water collections and 2 for the sediment collections, totaling 14 partial reports. These reports will detail all the activities involved in the campaigns carried out. A final report will be delivered, containing the synthesis of the entire project completed at the end of the 12 months.

 

Interested and want to learn more? Go to Subproject 09 + 11.