USDA LTAR Common Experiment measurement: Total suspended solids (TSS)

At a minimum, collect 1mg of TSS residue. At a maximum, TSS should not impede the flow rate of the filter media (slow filtration is more time-consuming but does not impact results).

Return samples to the laboratory On ice and filter them on collection day if possible.

Analyze the samples as soon as possible after collection.

If storage is required, refrigerate the samples at 4°C or store On ice to minimize decomposition of solids.

Store water samples for TSS analyses until data certification (QA/QC verification) as this is common practice.

Assemble the vacuum filtration apparatus with a new filter.

Apply the vacuum.

Rinse the filter three times with distilled water.

Maintain the vacuum for a few seconds to remove excess water, then remove the vacuum.

Using forceps, carefully remove the rinsed filter to an aluminum weighing dish.

Dry in an oven at 103°C - 105°C for 1 hour.

Store dried filters in a desiccator until needed.

Using forceps, select a prepared glass fiber filter. Weigh it and record the mass to the nearest 0.1 mg in a lab notebook.

Unless filtering the entire sample, shake it vigorously before dividing it into a volume suitable for analysis.

Select a water sample, weigh the sample + bottle mass, and record the mass in a lab notebook.

Assemble the filtration apparatus and apply a vacuum.

Pre-moisten the filter with a small volume of distilled water.

Shake the sample vigorously and pour it into the filtration apparatus funnel.

Maintain the vacuum until all sample water has passed through the filter.

Using a wash bottle with distilled water, rinse the sample bottle and sides of the filter funnel three times (for a 4.7 cm filter, each rinse should be roughly 10 ml).

Weigh the empty sample bottle and record the mass in a lab notebook.

Remove the vacuum.

Using forceps, carefully remove the filter paper and place it in a labeled and weighed aluminum weighing dish.

Dry the filter paper + sample at 105°C for 1 hour or longer, if necessary, to remove all water.

Remove the samples from the oven and immediately store them in a desiccator or weigh them. Record the mass in a lab notebook.

Store the weighed and recorded filters in a desiccator until ready for disposal.

Sample the covariate metrics (Total N (TN) and total P (TP) concentrations) concurrently.

Perform the calculations using the following formula:

Total suspended solids in a sample (mg/L) = (A-B) * 1000 / C

Table 1. Summary of recommendations for the collection and measurement of TSS concentration.

A	B	C	D
Attribute	Preferred	Minimum	Comments
Spatial scale	Field	Plot
Frequency	Event-driven	Event-driven	Sample collection frequency will depend on site-specific flow chracteristics and experimental goals
Covariate metrics	TN, TP	TN, TP
Sample preservation and storage	Analyze on collection day	Refrigerate at 4°C or store on ice for up to 7 days
Sample analysis	Total suspended solids dried at 103-105°C
Water quantity	Discharge or flow rate	Discharge or flow rate	Calculate TSS loads by linking this metric to the water quantity metric “flow"

Covariate metrics = other metrics to sample concurrently. TN = total nitrogen; TP = total phosphorus.