What is polluting Oregon's rivers?
Arsenic
In
Oregon, the
principle source of arsenic in surface water and groundwater is believed to be
native rocks and soil. Arsenic residues also come from industrial processes, paints
and pesticides. Arsenic has been used as a poison for centuries, and at low
levels over a long period of time it can cause cancer.
Aquatic Weeds & Algae
Weeds or algae can be so rampant that they interfere with using a stream or significantly reduce its surface area. Excessive algae can also contribute to other water quality impairments, such as pH or dissolved oxygen.
Biological Criteria
Rivers are listed for biological criteria when there is significant damage to fish and it is suspected that the cause is pollution-related. For example, sections of the Willamette River are listed due to skeletal deformities in fish.
Chlorophyll
Chlorophyll is a green pigment found in plants. It absorbs sunlight and converts it to sugar during photosynthesis. High chlorophyll levels indicate the excessive growth of algae. While chlorophyll levels naturally fluctuate over time, longterm persistence of high chlorophyll levels can indicate poor water quality and excess nutrient levels.
Dioxin
Dioxins are some of the most toxic and carcinogenic compounds known. In addition to causing cancer, they act like a hormone in the body, disrupting the endocrine system (the glands that produce hormones) and suppressing the immune system. Dioxins break down very slowly, so they tend to accumulate in aquatic life, from algae to fish. Dioxins are produced as a byproduct from the manufacture of chlorinated herbicides, the combustion of domestic and industrial wastes, and chlorine bleaching of wood pulp and paper.
Dissolved Oxygen (DO)
Just like it sounds, this is the amount of oxygen dissolved in water. Dissolved oxygen (DO) is not a pollutant; on the contrary, fish need oxygen to breathe through their gills. Streams are listed when dissolved oxygen levels are dangerously low. A number of factors impact dissolved oxygen levels. Aquatic plants produce oxygen through photosynthesis, and it is removed from the water by plant and animal respiration and decomposition of organic material. Cold, fast-flowing water holds more oxygen than warm, still water. Wastewater from sewage treatment plants, storm water runoff, and failing septic systems can cause low DO levels.
Fecal Coliform
Fecal coliform is a type of bacteria, including E. coli, which is found in the intestines of mammals. Its presence indicates that feces is in the water, so it is used as an indicator of pathogens dangerous to human health. DEQ had been testing for fecal coliform in general, and it is now switching to testing specifically for E. coli as a bacteria indicator. Most strains of E. coli do not cause serious illness, but when E. coli is detected it may indicate the presence of more harmful bacteria, such as salmonella or giardia. Sources of E. coli and other fecal coliform include the fecal matter of birds and wildlife, domestic dogs and cats, livestock, and sewer overflows.
Iron & Manganese
Iron and manganese are natural minerals dissolved from rocks. They can affect the taste, odor, color, and staining properties of water, but do not cause illness or hazards to aquatic life.
Legacy Toxics (PCBs, DDT & DDE, Dieldrin & Aldrin)
DDT
and its byproduct DDE, and aldrin and its byproduct dieldrin are pesticides
that were banned in the 1970s and can still be found in river sediments. They
have toxic effects on wildlife, take a long time to break down, and can have
harmful effects on human health. These legacy pesticides are washed into rivers
from agricultural soils where they were once used. PCBs were widely used as
coolants and lubricants until they were banned in the 1970s. Consumer products
that may contain PCBs include old fluorescent lighting fixtures, electrical
devices or appliances containing PCB capacitors, and hydraulic fluids. DDT,
DDE, PCBs, dieldrin and aldrin persist in the environment for long periods of time
and become concentrated as they move up the food chain. Fish advisories have
been issued for PCBs in the Willamette and Columbia rivers.
Mercury
Mercury is a naturally occurring element that has many industrial commercial uses. However, it is highly toxic, persists for years in the environment and can accumulate to higher concentrations as it moves up the food chain. Mercury is a neurotoxin that can slow fetal and child development and cause irreversible deficits in brain function. People are exposed to mercury primarily through fish consumption, and mercury is the number one reason for fish consumption advisories in Oregon and nationwide. A significant amount of mercury enters Oregon's waterways from global air deposition and erosion of native soil. It also comes from abandoned mines, mercury-added products (such as thermostats and automotive switches) and dental amalgam. Industrial sources such as cement plants and coal-fired power plants emit mercury into the air, which eventually is deposited on the ground and picked up by runoff water.
Nutrients (Phosphorous & Ammonia)
Phosphorous is an essential nutrient for plant and animal growth, but too much phosphorous (or phosphate) can cause accelerated plant growth, algae blooms, low dissolved oxygen, and the death of certain aquatic organisms. Ammonia is one form of nitrogen, which is also an essential nutrient for plant growth. Like phosphorous, nitrogen can cause excessive plant growth and other associated water quality problems. Excessive nutrients can come from wastewater treatment plants, fertilizer runoff, faulty septic systems, livestock confinement areas or manure storage facilities and phosphate-containing detergents.
PAHs
Polycyclic aromatic hydrocarbons (PAHs) come from vehicle emissions, the smoke and soot from power plants, or material left behind by tires. They also can leach from asphalt-based and coal tarbased sealants used on paved lots. PAHs are suspected carcinogens and they have adverse ecological effects on aquatic organisms.
Pentachlorophenol
Pentachlorophenol is a pesticide and wood preservative. Since 1984, the purchase and use of pentachlorophenol has been restricted to certified applicators. It is no longer available to the general public, but it is still used industrially as a wood preservative for utility poles, railroad ties, and wharf pilings. Pentachlorophenol can cause cancer, damage to the central nervous system, reproductive effects and damage to liver and kidneys.
pH
pH is a measure of acidity or alkalinity on a scale from 0 to 14, with low numbers being more acidic and 7 being neutral. Exposure to very low or high pH may cause death or reproductive problems for fish and other aquatic life. Dissolved minerals from rocks and soil contribute to pH, as do photosynthesis and respiration of plants. Sources of abnormal pH levels include mine drainage, industrial effluent, acid rain, sewage, and livestock containment areas. Fertilizers can indirectly lead to high pH levels by causing excessive plant growth.
Sediment
Sedimentation is the formation of significant bottom or sludge deposits. Some sediment is natural, but high sediment levels are harmful to macroinvertebrates (such as crustaceans and water insects) and to fish because sediment can smother fish eggs. In addition, sediment can bind with a number of persistent, toxic pollutants. Soil erosion contributes to sediment, and common sources include exposed streambanks, roads, agricultural and forestry practices, construction and urban runoff.
Temperature
The most common impairment in Oregon rivers is temperature. High water temperatures can be deadly to fish and other river critters, even though warm water may not sound scary if you're planning to take a swim. High water temperatures are often caused by the removal of shade-providing streamside trees and vegetation. Warm water can also enter streams from industrial processes and urban stormwater runoff. Dam-created reservoirs can increase river temperatures by holding water in place and allowing it to be warmed by the sun more than it would if it were flowing naturally. However, some deeper reservoirs discharge from the bottom and can be a source of cool water.
Total Dissolved Gas
Extreme aeration of the river under certain types of spillways on dams can lead to supersaturation of dissolved gasses that can be harmful to fish.
Turbidity
Turbidity is a measure of how clear the water is. Suspended particles such as soil, algae, plankton and microbes contribute to turbidity. High turbidity levels may increase temperatures, lower dissolved oxygen levels, reduce photosynthesis, clog gills, and smother fish eggs and macroinvertebrates.
