In this investigation of water quality that the club made Planet Guardians took several samples of parameters that will dictate whether that body of water is contaminated is by contaminated or is already polluted. As you know Vernier technology used to measure the following parameters: temperature, pH, conductivity, dissolved oxygen, current velocity, and concentrations of ammonium, nitrate, chloride and calcium.
Research tells us that most of the parameters are expected and normal levels, but we have to watch some of these which are the maximum allowed or are already at higher levels than expected. The parameters are:
Turbidity
Sabana Llana - Site 1
According to the USGS, the turbidity of surface water is usually between 1 NTU and 50 NTU. Water is visibly turbid at levels above 5 NTU. The standard for drinking water is 0.5 NTU to 1.0 NTU. The average turbidity in this site of the Sabana Llana Stream is 45.8 NTU. The water is visibly turbid and in the standard range. It can’t be used for drinking water.
Sabana Llana - Site 2
The average turbidity in this site of the Sabana Llana Stream is 55.4 NTU. The water is visibly turbid and in the standard range.
Possible causes of high Turbidity
Many factors can contribute to the turbidity of water. An increase in stream flow due to heavy rains or a decrease in stream-bank vegetation can speed up the process of soil erosion. This will add suspended particles, such as clay and silt, to the water.
Conductivity
Sabana Llana - Site 1
TDS values in lakes and streams are typically found to be in the range of 50 to 250 mg/L. Drinking water will tend to be 25 to 500 mg/L TDS. The average conductivity of the Sabana Llana Stream is 403 μS/cm. There is little amount of metals because the standard levels of conductivity are low.
Sabana Llana - Site 2
Llana Stream is 432 μS/cm. This measurement is of our concern because is in the maximum limit of this parameter. We have to watch very carefully the conductivity of the Sabana Llana Stream.
Possible Causes of high Conductivity - Site 2
Solids are found in streams in two forms, suspended and dissolved. Suspended solids include silt, stirred-up bottom sediment, decaying plant matter, or sewage-treatment effluent. Total dissolved solids, or TDS, can be determined usinig a Vernier Conductivity Probe
Ammonium Ion Selective Electrode
Sabana Llana - Site 2
While levels of ammonium nitrogen in drinking water should not exceed 0.5 mg/L, streams or ponds near heavily fertilized fields may have higher concentrations of this ion. The average of the concentration of ammonium ion are 6.29mg/L. These amounts of ammoniumare above the expected values. The amount of ammonium in this water isn’t accepted for drinking water.
Possible causes of high Ammonium concentrations –Site 2
Ammonium-nitrogen levels are usually quite low in moving surface waters. This is because there is little decaying organic matter collecting on the bottom. If there is a high level of ammonium nitrogen in a moving stream, it may be an indication of pollution of some kind entering the water.
Nitrate Ion Selective Electrode
Sabana Llana - Site 2
The nitrate level in freshwater is usually found in the range of 0.1 to 4 mg/L . Unpolluted waters generally have nitrate levels below 1 mg/L. The average concentration of nitrate ion in this site of the Sabana Llana stream is of 4.6 mg/L. This body of water has a high amount of nitrate which can’t permits life for many organisms.
Possible causes of high Ammonium concentrations –Site 2
Nitrates are an important source of nitrogen necessary for plants and animals to synthesize amino acids and proteins. Although nitrate levels in freshwater are usually less than 1 mg/L, manmade sources of nitrate may elevate levels above 3 mg/L. These sources include animal feedlots, runoff from fertilized fields, or treated municipal wastewater being returned to streams. Levels above 10 mg/L in drinking water can cause a potentially fatal disease in infants called methemoglobinemia, or Blue-Baby Syndrome.
