Attachment 06 - NIH Total Suspended Solids.1714658486096.docx

Attachment 06: NIH Total Suspended Solids (TSS) (Standard Methods (2005) 2540D and EPA (1983) Method 160.2)

Summary The procedure described here follows Standard Methods (2005), 2540D and EPA (1983) Method 160.2 (Residue, non-filterable). A well-mixed, measured volume of a water sample is filtered through a pre-weighed glass fiber filter. The filter is heated to constant mass at 104 ± 1º C and then weighed. The mass increase divided by the water volume filtered is equal to the TSS in mg/L.

Maintenance of the Instrument The Contractor shall perform maintenance on their equipment as outlined per the manufacturer’s instructions.

The maintenance protocol shall be available and be delivered to NIH upon request.

Sample Collection and Preservation NIH shall collect samples, and the Contractor shall pick up the samples from NIH Bethesda, Building 11. The Contractor’s personnel assigned to pick up the samples shall be trained in sampling procedures, such as wearing gloves and eye protection when collecting samples. Samples shall be analyzed as soon as possible after collection. If storage is required, samples maintained at 4°C may be held for up to 48 hours. No chemical preservation is required. Cool sample to 4°C.

In the event that the Contractor also collects the sample, they shall follow the following procedure:

Samples shall be collected in plastic or glass bottles. All bottles must be thoroughly cleaned and rinsed with turbidity-free water. Volume collected shall be sufficient to ensure a representative sample, allow for replicate analysis (if required), and minimize waste disposal.

Calibration and Standardization A. The balance shall be level, clean and calibrated prior to use.

B. Perform a balance check prior to each batch of analyses:

C. Select a test weight (or combination of test weights) and place on the balance pan.

D. Record values on the bench sheet and in the balance instrument logbook.

Procedure The Contractor shall follow the procedure detailed below:

A. The sample must be thoroughly mixed, shaking through inversion (10) times B. A measured volume of sample is passed through a prepared, preweighed 1.5-micron filter paper, and the initial weight is recorded. A vacuum pump and vacuum flask are used for the filtration C. Wet the filter with a small amount of reagent water to seal it, and secure the funnel to the base D. While the sample is filtering, record the total sample volume filtered E. Wash the filter and collect solids with three successive 10 mL portions of reagent water, to remove any dissolved solids trapped in and on the filter.

F. The vacuum pump needs to continue to operate for three minutes after filtration is complete G. The filter is dried in a drying oven at 104 °C for at least one hour H. Remove filter from the oven and place in a desiccator until they reach room temperature I. The filter is then reweighed on a balance to the nearest 0.0001 g and the weight recorded J. Repeat steps F through H at least one more time to obtain a reading of ±0.0005 g from the previous weight K. The final weight is the weight of the filter plus the dried residue, and the initial weight is the weight of the unused filter.

L. The total suspended solids is calculated as follows:

(Final Weight (g)−Initial Weight (g)) ∗1,000,000Sample Volume (mL)=mg TSS/LFinal Weight g−Initial Weight g∗1,000,000Sample Volume (mL)=mg TSS/L

Safety and Prevention The analysis involves handling of freshwater samples that may contain live microorganisms and therefore pose some threat of infection. Laboratory personnel who are routinely exposed to such water samples are encouraged to protect themselves from water borne illnesses by wearing clean disposable gloves and washing their hands frequently. This analytical procedure uses a vacuum pump for the filtration steps. There is a risk of implosion under some circumstances. The analyst should ensure that the receiving flask is free from cracks or other imperfections.

References Standard Methods for the Examination of Water and Wastewater. Method 2540 D, APHA, 21st Edition, 2005 “Residue, Non-Filterable – Method 160.2 (Gravimetric, Dried at 103 – 105ºC).” EPA Methods for Chemical Analysis of Water and Wastes. EPA publication 600/4-79/020. March 1983.