EXPLANATION OF PARAMETERS

BIOLOGICAL PROPERTIES

Fecal Coliform Bacteria

Fecal coliform bacteria are a group of bacteria that live in the intestinal tract of animals.  High fecal coliform levels may indicate contamination from human or animal wastes and the potential presence of other disease-causing types of bacteria.  High fecal coliform levels may render rivers and streams unsafe for boating, swimming, drinking, or shellfishing.  Under the Federal Clean Water Act, ten percent of samples should have no more than 400 coliform colonies per 100mL of water sample.  Fecal coliform might be sampled for the hot spot program.

E. coli Bacteria

For some projects, we will be sampling for both fecal coliform and E. coli bacteria.  Current Massachusetts surface water quality standards require that no single sample have more than 235 colonies per 100mL.  The E. coli analysis will be conducted by the EPA Region I laboratory in Chelmsford, MA, or at the MyRWA lab on the Tufts campus.

Enterococcus spp. Bacteria

Like fecal coliform and E. coli, Enterococcus spp. is an indicator bacteria used to determine water safety. Enterococcus spp. is used primarily as an indicator in salt water and is currently used for MA beach swimming standards. Department of Public Health’s Minimum Standard for marine Bathing Beaches in the State Sanitary Code, Chapter VII (105 CMR 445.031) is based on Enterococcus spp. and states that “No single Enterococci sample shall exceed 104 colonies per 100 ml...”

CHEMICAL PROPERTIES

Nitrogen Compounds

Nitrate and ammonium are the forms of nitrogen that are available to plants and animals.  Most of the nitrogen in the environment is in gaseous form and makes up 80% of our air.  Inorganic nitrogen is found in aquatic systems as nitrates (NO₃), nitrites (NO₂), nitrogen gas (N₂), and ammonium (NH₄⁺).  Although ammonium is the preferred nitrogen source of autotrophs and bacteria, nitrates/nitrites are the most common.  Nitrates and nitrites enter rivers and streams from soil, animal wastes, and decomposing plants.  The major human sources are sewage, fertilizers, and animal waste.  Ammonia (NH₃) may accumulate in bottom sediments where oxygen levels are low.  Ammonia is a good indicator of the potential presence of sewage.  Ammonia together with amino acids, proteins, urea, and humic acids compose Kjeldhal Nitrogen, the organic part of nitrogen found in water bodies.  Nitrate+nitrite is measured for the baseline program, while nitrate, nitrite, ammonia, and Kjeldhal nitrogen may be measured for NPS Assessment projects.

Total Phosphorus

Phosphorus can enter rivers and streams from many sources: animal wastes, human wastes, fertilizer, detergents, erosion, and storm runoff.  The organic and inorganic, particulate and soluble forms of phosphorus undergo continuous transformations.  Phosphorus is frequently the limiting agent to plant and algal growth.  Therefore, elevated concentrations of phosphorus may stimulate aquatic plant growth and algal blooms.  The decomposition of plants or algae consumes dissolved oxygen, which decreases the amount of dissolved oxygen available to other organisms.  Total Phosphorus (TP) is a measure of all forms of phosphorus in the system.  Total Phosphorus is measured for the baseline program, and may be measured for NPS Assessment projects.

Orthophosphate

Orthophosphate is the form of phosphorus taken up by plants.  Sources include detergents (which end up in wastewater), fertilizers, and industrial discharges.  Samples may be tested for orthophosphates as an indicator of human sources of nutrient enrichment at NPS Assessment sites as needed. 

Chlorophyll a

Chlorophyll a is one of the types of chlorophyll used by aquatic plants, including algae, to conduct photosynthesis.  It is the dominant chlorophyll found in true algae and blue-green algae (Cyanobacteria), and is used as an estimate of algal biomass.  Although these important organisms form the base of the food chain, high levels of chlorophyll a can indicate excess nutrient input to a water body.  When massive quantities of algae die off, toxins can be released and decomposition can lead to reduced oxygen levels, causing fish kills.  Chlorophyll a may be measured for NPS Assessment projects.

Surfactants

Surfactants are organic chemicals used in such products as soaps, laundry detergents, and dishwashing soap.  As part of the NPS Assessment projects, measurement of surfactants can be used in bacterial source tracking efforts to indicate human sources of elevated bacterial levels. 

Optical Brighteners

Measuring optical brighteners is another technique that can be used to indicate human sources of bacterial pollution.  Optical brighteners are fluorescent white dyes that are added to most laundry detergents to make clothing look whiter.  Their presence indicates contamination by human waste waters.  Optical brighteners are typically measured by securing untreated cotton pads in a stream or pipe for several days.  The pad is then viewed under fluorescent light.  For NPS Assessment projects, we will follow the collection techniques and handling procedures outlined in the MyRWA Standard Operating Procedure (SOP).  If you are asked to help with this parameter, the SOP will be provided to you.

Oil and Grease

An accumulation of oil and grease forms a film over water which spreads and has different effects on organisms, including death, smothering, hypothermia, and inviability of eggs.  Oil and grease samples may be collected as part of NPS Assessment projects.  These samples must not be collected as composite samples (i.e., you cannot combine multiple samples into one bottle), because some grease may be lost on equipment

Total Petroleum Hydrocarbons

Total petroleum hydrocarbons (TPH) are a group of chemical compounds that are derived from crude oil.  The group includes jet fuels, mineral oils, benzene, toluene, naphthalene, and many others.  TPHs can affect the lungs, central nervous system, liver, and kidney of humans and other animals.  Samples may be collected and have constituents identified as part of NPS Assessment projects.  This parameter is called TPH-PHI (TPH-Petroleum Hydrocarbon Identification).

Potassium

If the ammonia to potassium ratio is greater than 1, it is likely to indicate the presence of sanitary wastewater.  Potassium will be measured in NPS Assessment projects when it is suspected that sanitary wastewater is contributing to high bacterial concentrations. 

Fluoride

As part of NPS Assessment projects, we may wish to assess water sources.  Fluoride is an indicator of tap and/or irrigation water sources. 

PHYSICAL PROPERTIES

Depth

This measurement gives an indication of the amount of water in the river.  Water quantity is vital to the health of the river ecosystem.  Sufficient amounts of water must exist for aquatic flora and fauna to survive.  Water quantity is also a component of water quality.  The effects of pollutants in a river are buffered by having a sufficient volume of water to dilute them.  As water quantity lessens, the concentration of pollutants may increase and adversely affect the water quality.  Depth is measured at the baseline sites that have stream gages.

Dissolved OxygenYouth Test for Dissolved Oxygen

Dissolved oxygen (DO) is the amount of oxygen dissolved in water.  This oxygen must be available for fish and other aquatic species.  Low DO values indicate excessive vegetative growth often brought on by the input of nutrient pollution (including sewage).  Dissolved oxygen is measured as milligrams of oxygen per liter of water (mg/L) or percentage of oxygen saturation.  The Mystic River should have more than 5.0 mg/L or between 60% and 100% saturation.  This parameter will be measured using a LaMotte Dissolved Oxygen kit for the baseline program, and using a YSI 85 meter for other programs.

Biochemical Oxygen Demand

Biochemical Oxygen Demand (BOD) measures the amount of oxygen used by microorganisms to break down organic matter.  When plants die and decompose, aerobic bacteria feed on them.  The metabolic processes of the bacteria use available oxygen.  When a water body receives excess nutrients (like nitrogen or phosphorus), plant growth is stimulated, which eventually leads to greater bacterial growth and higher BOD.  This leaves less oxygen available for other organisms like fish and aquatic invertebrates.  Samples for BOD analysis may be collected for NPS Assessment programs.

pH

pH is a measure of the acidity of water.  pH is important since water that is too acidic or, at the other extreme, too basic, can be toxic to fish and other aquatic life.  pH also plays an important role in how other pollutants, such as heavy metals, behave in the environment.  High or low pH levels can be the result of acid rain/snow, chemicals getting into the waterways, or certain natural conditions.  pH is measured on a scale from 1 to 14, with 1 being very acidic, 7 being neutral, and 14 being very basic.  The Mystic River and its tributaries should have pH levels between 6.0 and 8.3.  pH will be measured in the field with a hand-held pH meter.

Temperature

Water temperature may not seem like pollution, but it is critical for rivers and streams to remain relatively cool, in order for fish and other aquatic life to survive.  Water temperatures can get too hot from a lack of shade along the riverbanks, from discharges of cooling water, storm water running off hot pavement, or when cool water from underground aquifers is diverted from the stream by nearby wells.  Under the Clean Water Act, the Mystic River and its tributaries should have temperatures of less than 28.3⁰C.  Certain fish species that live in tributaries of the Mystic River need water that is even cooler.  This parameter will be measured in the field using a thermometer or a YSI 85 meter.

Total Suspended Solids

Total suspended solids (TSS) is a measure of dust, dirt, sand, and other particles stirred up in the water.  Excessive amounts of suspended solids can bury fish and aquatic plants, and can make rivers and streams unpleasant for recreation.  In addition, other pollutants, such as oil, heavy metals, and nutrients are frequently attached to suspended solids.  Thus, TSS can sometimes provide a very rough indication of where there might be problems with these other pollutants.  TSS is measured in mg/L; the Mystic River should have less than 25 mg/L.  TSS samples are collected as part of the baseline and NPS Assessment programs.

Clarity

Water clarity may be measured as turbidity or transparency for NPS Assessment projects.  Turbidity increases when there are a lot of suspended solids in the water, indicating low water clarity. The causes and effects of high suspended solids concentrations were discussed earlier.  Turbidity may be determined by commercial laboratories, while transparency data would be collected using a Secchi disk.  The Secchi disk would be lowered until you cannot see it.  This depth would be recorded, along with the depth at which the disk is again visible.

Specific Conductance

Specific conductance is a measure of how well water can conduct an electrical current.  This depends on the presence of ions and the temperature.  The ions, which come from the breakdown of compounds, conduct electricity because they are positively or negatively charged when dissolved in water. It is an indirect measure of dissolved solids; large changes in specific conductance could indicate that a discharge or other source of pollution has entered a river. Samples will be analyzed by the MWRA laboratory for the baseline program.  Specific conductance will be determined by a YSI meter for the hot spot program and NPS Assessment programs (or possibly by a laboratory for the latter).

MA Water Quality Standards:

Massachusetts Class B Surface Water Quality Standards (314 CMR 4.05). Please use this as a reference to the MMN water quality data.

Interested in learning more about the Clean Water Act? Check out the River Network's Clean Water Act online course.

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