Water Woes -Part 3

Inorganics

As a general rule that not all chemists agree on, inorganic compounds are composed of two or more elements, except those containing only carbon and hydrogen bonds, which are known as organic compounds.

Examples of inorganic compounds tested in water tests are biological oxygen demand, chemical oxygen demand, cyanide, anions, solids and nutrients.

Two tests that labs may do on your water are for BOD and COD, short for biological oxygen demand and chemical oxygen demand. The tests are more applicable to sewage and industrial waste water but can apply to shallow wells which may take in some surface groundwater and surface water from a lake or stream because there may be a new cause of pollution from runoff or upstream.

BOD or biochemical oxygen demand is the amount of oxygen that microorganisms require to break down organic materials. In contrast, chemical oxygen demand (COD) is the amount of oxygen required to break down the organic material by oxidation.

BOD is tested by incubating a sealed water sample at 20^oC for five days, then comparing the measurement of the difference in oxygen content before and after incubation. COD measures how much dissolved oxygen (DO) is consumed by the chemical oxidation of organic matter under controlled conditions. COD is measured by a laboratory assay in which a sample is incubated with a strong chemical oxidant for a specified time interval and at constant temperature (usually 2 h at 150°C).

The biochemical oxygen demand (BOD) represents the amount of dissolved oxygen (DO) consumed by biological organisms when they decompose organic matter in water. The greater the BOD, the more rapidly oxygen is depleted in the stream or lake. This means less oxygen is available to higher forms of aquatic life. The consequences of high BOD are the same as those for low dissolved oxygen: aquatic organisms become stressed, suffocate, and die. Streams and lakes which are unpolluted usually have BOD levels below 1 part per million (equivalent to 1 mg/L), while untreated sewage has between 200 and 600 ppm. The amount of pollution in a water body is directly proportional to the BOD.

COD or chemical oxygen demand is the amount of oxygen consumed when the water sample is chemically oxidized. COD is usually greater than BOD in treated water systems because more organic compounds can be chemically oxidized than biologically oxidized. This includes chemicals toxic to biological life, which can make COD tests very useful when testing industrial sewage because BOD testing will not detect them. Chemical oxygen demand is an indicator of the seriousness of pollution of water by organic matter. The higher the COD, the more pollution. The most common application of COD testing is for surface water (lakes and rivers) and wastewater. (Davidson, 2001; Sara and Goncaloglu, 2008).

COD also increases if inorganic compounds susceptible to oxidation by the oxidant are present. Water with high COD typically contains high levels of decaying plant matter, human waste, or industrial effluent. If water treatment facilities do not reduce the organic content of wastewater before it reaches natural waters, microbes in the receiving water will consume the organic matter. As a result, these microbes will also consume the oxygen in the receiving water as part of the breakdown of organic waste. This oxygen depletion along with nutrient-rich conditions is called eutrophication, a condition of natural water that can lead to the death of animal life.

Nutrients such as ammonia, nitrogen and phosphorous are considered essential for plant growth and are often used as fertilizers, but the overuse of nutrients in water can have many harmful health and environmental effects.
Ammonia can be toxic to fish and is easily transformed into nitrate (NO₃^–) in waters that contain sufficient dissolved oxygen or into nitrogen gas in waters that have no dissolved oxygen.
Nitrogen or nitrate is very soluble in water and is stable over a wide range of environmental conditions. It is readily transported in groundwater and streams. An excessive amount of nitrate in drinking water can cause health problems.
Phosphates are the most common form of phosphorus in natural waters. Phosphates are only moderately soluble and compared to nitrate are not very mobile in soils and groundwater. Phosphates usually remain attached to soil particles, but erosion or sudden heavy rain can wash the phosphate to streams and lakes.

An overabundance of nutrients, typically nitrogen and phosphorous, can run into the water and starts eutrophication. Nitrogen and phosphorus occur in a variety of forms, or species, and the species present can change as they move between the air, water, and soil.

Algae feed on the nutrients, growing and spreading quickly, turning the water green. Algae blooms can block sunlight and release toxins in some cases. When the algae die, they are decomposed by bacteria. This process consumes the remaining oxygen in the water that is needed by fish and other aquatic life to “breathe”. If too much oxygen is removed, the water can become hypoxic and there is not enough oxygen to sustain life, creating a “dead zone”.

AMMONIA (NH₃) and AMMONIUM (NH₄⁺) are among the primary forms of nitrogen in natural waters. Ammonia can be toxic to fish. It is also soluble in water and relatively unstable in most environments. Ammonia is easily transformed into nitrate (NO₃^–) in waters that contain sufficient dissolved oxygen or into nitrogen gas in waters that have no dissolved oxygen.
NITRATE (NO₃^–) is another primary form of nitrogen in lakes and streams. Nitrate is very soluble in water and is stable over a wide range of environmental conditions. It is readily transported in groundwater and streams. An excessive amount of nitrate in drinking water can cause health problems.
PHOSPHATES (containing PO₄³⁻) are the most common form of phosphorus in natural waters. Phosphates are only moderately soluble and, compared to nitrate, are not very mobile in soils and groundwater. Phosphates tend to remain attached to soil particles, but erosion can transport considerable amounts of phosphate to streams and lakes.
USGS Circular 1350

Image: Collecting Water Nutrient Data — *Sources/Usage: Public Domain.*
A scientist collects water-quality sample to better understand the role of nutrients in the overabundance of duckweed and algae. Too much nitrogen and phosphorus in water can lead to an overgrowth of free-floating plants such as duckweed and filamentous algae, resulting in dense layers of scum on the surface of the water. This can damage aquatic plants, fish, and other lake organisms by depriving them of the oxygen and sunlight they need to survive. (Credit: James Fischer)

Now for some good news in our area:

We should be very grateful for the wonderful water that naturally occurs here and we get from wells, streams, ran water harvesting and small water systems. Other than in the Jordan River area where there are pockets of environmental degradation from industry, our water is generally natural and healthy. A group called Jordan River Watershed Awareness Coalition. From their website – The Jordan River Watershed Awareness Coalition (JRWAC) is a not-for-profit society dedicated to working collaboratively with diverse interests and rights holders to raise awareness about complex interactions that limit the flourishing of life within di:ti:dah/the Jordan River watershed.

We should also beware of certain “convenience” items in our lives that our grandparents would not recognize. We should choose to use a china plate and cast iron frying pan rather than two items listed below. This recent report from an official US Government website is pretty grim.

PFAS :“At least 45% of the nation’s tap water is estimated to have one or more types of the chemicals known as per- and polyfluorinated alkyl substances, or PFAS, according to a new study by the U.S. Geological Survey. There are more than 12,000 types of PFAS, not all of which can be detected with current tests; the USGS study tested for the presence of 32 types.

PFAS are a group of synthetic chemicals used in a wide variety of common applications, from the linings of fast-food boxes and non-stick cookware to fire-fighting foams and other purposes. High concentrations of some PFAS may lead to adverse health risks in people, according to the U.S. Environmental Protection Agency. Research is still ongoing to better understand the potential health effects of PFAS exposure over long periods of time. Because they break down very slowly, PFAS are commonly called “forever chemicals.” Their persistence in the environment and prevalence across the country make them a unique water-quality concern.”

A scientist wearing black gloves is collecting a sample of tap water from the kitchen sink using small plastic vials. — *Sources/Usage: Public Domain.* *Visit Media* *to see details.*
A USGS scientist wearing black gloves is collecting a sample of tap water from the kitchen sink using small plastic vials to test for PFAS.

“USGS scientists tested water collected directly from people’s kitchen sinks across the ( USA) nation, providing the most comprehensive study to date on PFAS in tap water from both private wells and public supplies,” said USGS research hydrologist Kelly Smalling, the study’s lead author. “The study estimates that at least one type of PFAS – of those that were monitored – could be present in nearly half of the tap water in the U.S. Furthermore, PFAS concentrations were similar between public supplies and private wells.”

This USGS research marks the first time anyone has tested for and compared PFAS in tap water from both private and government-regulated public water supplies on a broad scale throughout the country. Those data were used to model and estimate PFAS contamination nationwide. This USGS study can help members of the public to understand their risk of exposure and inform policy and management decisions regarding testing and treatment options for drinking water.

Scientists collected tap water samples from 716 locations representing a range of low, medium and high human-impacted areas. The low category includes protected lands; medium includes residential and rural areas with no known PFAS sources; and high includes urban areas and locations with reported PFAS sources such as industry or waste sites.”

We need to be aware of any potential changes to our area, industrial or otherwise, which may adversely affect our water. It is a gift not to be taken for granted. Recently we heard from a family who get their licensed water from a creek. They went upstream one day and found an old mattress and a deer carcass had been dumped in the water.

B.C. References for more information (click on links):

Well water testing Well Water Testing | HealthLinkBC File 05b

How to take a water sample Water Quality Testing | RDN

Arsenic in drinking water Arsenic in Drinking Water – HealthLinkBC File #49c – Printer-friendly version

Island Health staff can be consulted for further advice on water quality issues and interpretation of water testing results. Island Health Gateway Village Victoria: 250-519-3401 (gateway_office@islandhealth.ca)

References:

Agency for Toxic Substances and Disease Registry (.gov)

Government of Canada Food Inspection Agency

https://inspection.canada.ca/food-safety-for-consumers/fact-sheets/specific-products-and-risks/fruits-and-vegetables/natural-toxins/eng/1332276569292/1332276685336

h2olabcheck.com

https://www.h2olabcheck.com/blog/view/biological-oxygen-demand-bod#:~:text=High%20BOD%20is%20harmful%20to,matter%20loading%20present%20in%20wastewaters.

HANNA Instruments

https://blog.hannainst.com/cod-testing

Know your H2O water research centre

https://www.knowyourh2o.com/indoor-6/cyanide

This site has some easy self tests on it.

Proteus Instruments