Metal Pollutants
Cadmium
Used in manufacture of batteries, paints and plastics. Used to plate iron products such as nuts and bolts for corrosion prevention.
Human-caused Sources: Tire wear, vehicle exhaust, insecticide application.
Effects on Watershed / Health: Heavy metals cause a variety of problems including interfering with vitamin uptake, neurological disorders, and disruption of renal function. These problems result from chronic and cumulative exposure. Cadmium is a cumulative toxicant that replaces zinc in the body; it is toxic to both humans and fish.
Copper
Used as alloy component. Sulphate salt used as algicide in water supply reservoirs. Component of fungicide. Used in electroplating industry. Found in coolant, brake fluid, motor oil, gasoline.
Human-caused Sources: Metal plating, bearing wear, engine parts, brake lining wear, vehicle exhaust, fungicides and insecticides use.
The most common sources of copper found at industrial facilities include the following:
- Vehicle brake pads
- Architectural copper
- Electrical wire & equipment
- Copper-containing Pesticides
- Marine antifouling coatings
- Vehicle servicing and cleaning
Other less common and often overlooked sources of copper include:
- Air emissions (gas and diesel combustion)
- Wood preservatives
- Welding Sticks
- Asphalt sealcoat
Effects on Watershed / Health: Heavy metals cause a variety of problems including interfering with vitamin uptake, neurological disorders, and disruption of renal function. These problems result from chronic and cumulative exposure.
Lead
Human-caused Sources: Used as an additive to gasoline, motor oil, vehicle exhaust, brake fluid and coolant. Component of pipes, paints and dyes. Used in manufacture of batteries, insecticide, caulking and plastics.
Effects on Watershed / Health: Heavy metals cause a variety of problems including interfering with vitamin uptake, neurological disorders, and disruption of renal function. These problems result from chronic and cumulative exposure. Lead causes a variety of neurological disorders in humans, particularly inhibiting brain cell development in children. It also prevents the uptake of iron in the body leading to anemia.
Zinc
Human-caused Sources: Galvanized surfaces (roofs, gutters, flashing, fencing, guard rail, and downspouts and drainage system/pipes, etc.), and wear debris from vehicle tires, motor oil and grease.
Used in electroplating industry. Component of bronze, rubber, enamel, glass and paper. Component of automobile tires, vehicle exhaust, road salt and paint.
Other local sources, can be very important if they occur at or near a location, such as
- Wood treated with preservatives containing zinc (AZCA or zinc naphthenate)
- Anticorrosion paint (often used on exterior steel)
- Zinc moss killers applied on walkways, decks, and roofing (and sometimes impregnated into non-metallic roofing materials)
- Fertilizers (most likely if over-applied or an unusually high-zinc material)
- Cleaners/surface preparation chemicals used before painting (particularly metal surfaces)
- Marine antifouling coatings (usually used primarily in or near salt water)
- Zinc-content de-icing chemicals
- Air deposition from local air emissions sources (e.g., galvanizers, glow-in-the-dark product manufacturers)
The following list includes commonly galvanized items:
- Roofs
- Roof HV AC, ductwork, turbines, equipment boxes
- Downspouts
- Roof gutters
- Storm sewer pipe
- Chain-link fence
- Light poles
- Bay doors
- Steps
- Truck trailer panels
Effects on Watershed / Health: Zinc toxicity is not generally a problem, but heavy metals cause a variety of problems including interfering with vitamin uptake, neurological disorders, and disruption of renal function. These problems result from chronic and cumulative exposure.
Want more on Zinc Sources? Check out this report CASQA put out.
Both motor oil and hydraulic fluid contain high concentrations of zinc, about 0.1% by weight (1,000,000 μg/L). To get a sense of the extent these fluids can add zinc to runoff, when 1⁄2 cup of motor oil is added to an area 100 feet x 100 feet of paved surface, the runoff is calculated to be about 250 μg/L or parts per billion. This is for a depth of water of 0.02 inch rain, typically sufficient rainfall to cause runoff. WA DOE Report on Common Sources of Zinc
COD
Description: Chemical oxygen demand (COD) does not differentiate between biologically available and inert organic matter, and it is a measure of the total quantity of oxygen required to oxidize all organic material into carbon dioxide and water.
Chemical Oxygen Demand (COD) is similar to Biochemical Oxygen Demand (BOD) in that they are both used to calculate the oxygen demand of a water sample. The difference between the two is that chemical oxygen demand (COD) measures everything that can be oxidized, whereas biochemical oxygen demand (BOD) only measures the oxygen demanded by organisms.
Natural Sources: Leaves and Woody Debris, Dead Plants and Animals, and Animal Manure
Human-caused Sources: Effluents from Pulp and Paper Mills, Wastewater Treatment Plants, Feedlots, and Food-Processing plants; Failing Septic Systems; and Urban Stormwater Runoff
Chlorine dosages above 10 mg l−1 resulted in increased BOD and COD levels of the effluent, with chlorine dosages above 30 mg l−1 resulted in almost double the original BOD and COD values.
Additionally: Residual food waste from bottles and cans, antifreeze, emulsified oils are all high in COD and are common sources of COD for industrial stormwater. Water with high COD typically contains high levels of decaying plant matter, human waste, or industrial effluent.
Effects on Watershed / Health: COD directly affects the amount of dissolved oxygen in rivers and streams. The greater the COD, the more rapidly oxygen is depleted in the stream. This means less oxygen is available to higher forms of aquatic life. The consequences of high COD are the same as those for low dissolved oxygen: aquatic organisms become stressed, suffocate, and die.
Possible Solutions: Aeration should help reduce the COD in 2 ways. First it may evaporate some volatiles like hexane. Second it will add oxygen to the water speeding up any biological oxidation of the less volatile organics by the bacteria (microbial growth).
BOD
Description: Biochemical Oxygen Demand (BOD) measures the amount of oxygen consumed by microorganisms in decomposing organic matter in water under aerobic conditions.
Natural Sources: Leaves, Grass and Woody Debris, Dead Plants and Animals, and Animal Manure
Human-caused Sources: Effluents from Pulp and Paper Mills, Wastewater Treatment Plants, Feedlots, and Food-Processing plants; Failing Septic Systems; and Grass Clippings.
Effects on Watershed / Health: BOD directly affects the amount of dissolved oxygen in rivers and streams. The greater the BOD, the more rapidly oxygen is depleted in the stream. 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.
Biochemical Oxygen Demand (BOD) is a measure of the dissolved oxygen that is consumed as organic contaminants decay or break down in waterways. An excess of organic contaminants can use up dissolved oxygen faster than it can be replaced. Low levels of dissolved oxygen can be harmful to fish and other aquatic life.
Other Potential Sources of BOD
- Deicing aircraft or pavements
- Storing food waste or other waste material outdoors
- Managing landscaping waste
- Leaks from dumpsters
- Fertilizer, herbicide, or pesticide use
- Sanitary facilities, such as portable toilets
- Washing equipment with soap containing biodegradable solutions
- Spills of biodegradable material
WHAT ARE THE DIFFERENCES BETWEEN COD & BOD?
Many people tend to confuse these two metrics since they are used for the same purpose – to find out the degree of water contamination. However, unlike BOD, COD measures all oxidizable matter in a sample of water, and not just organic compounds. Thus, BOD is typically lower than COD for the same sample.
Moreover, a standard COD test can be done in a few hours, unlike a BOD test which requires a standard 5-day incubation period.
Fecal Coliform including E. Coli (Escherichia coli)
Description: Bacteria found in the digestive systems of warm blooded organisms
Natural Sources: Human, Wildlife, and Livestock Waste
Human-caused Sources: Pet Waste, Failing Septic Systems, Sanitary Sewer Overflows, Animal Feeding Operations, and Animal/Bird Droppings.
Effects on Watershed / Health: Fecal coliform does not pose a health threat but serves as an indicator for bacteria that can cause illness in humans and aquatic life. High bacteria levels can limit the uses of water for swimming or contaminate drinking water in groundwater wells.
Motor Oil
Motor oil is known to contain high levels of zinc. Every major brand of motor oil contains zinc from 0.11 - 0.20 % zinc by weight (Hackett, 1999). This corresponds to 1,000,000 – 1,800,000 μg per /L of motor oil of 0.88 density. This concentration is high enough that motor oil diluted 1:2,500 with water results in a total zinc concentration higher than the action level of 372 μg/L specified in the ISGP.
Hydraulic Fluid
Hydraulic fluids contains zinc to reduce wear, at approximately the same concentration as in motor oil. The dividing line between hydraulic fluid considered to be high or low in zinc is 0.07% or more zinc by weight. Environmental concerns are beginning to drive hydraulic fluid manufacturers away from zinc, but at this time, the technology and interest have not been well developed (Travell, 2003).
Hydraulic fluid can leak from forklifts or other hydraulic equipment onto paved surfaces, becoming entrained in stormwater flow. Like motor oil, hydraulic fluids can build up on paved surfaces.
Tire Particles
Zinc is used as a filler material for tires and is found in tire material at 1% by weight. Tire tread material is released with tire wear in the form of particulate dust or deposits onto pavement. Zinc released from tire wear on roadways has been found to be a source in stormwater runoff.
The potential for considerable zinc inputs to industrial stormwater from tire dust has been pointed out by Jeff Davis, an engineer with the fruit processor, Tree Top, Inc. Fine black powder has been found coating top rails of storage shelf racking, and there has been a problem with tire dust depositing on finished goods.
At areas of Tree Tops facilities where flatbed trucks are loaded and unloaded, there is heavy 24-hour forklift traffic. Stormwater from the facilities has been reported to be inky-black in color. Davis suggested that considerable short-radius turning results in tire-dragging and a high rate of tire wear. To counter the problem, Tree Top has employed the use of non-marking forklift tires and increased ventilation (Davis, 2005a). The problem of a fine black powder or dust collecting upon warehouse inventory has been reported by other firms (Concrete News, 2005).
At the suggestion of the project lead for this study, both total recoverable (TR) and dissolved zinc concentrations were analyzed for runoff at Tree Top facilities (Davis, 2005b) . Analyses of grab samples at their Selah and Cashmere facilities from a storm event on November 1, 2005 showed the following zinc concentrations:
Selah: 181 μg/L zinc total 85 μg/L zinc dissolved (53% of zinc as particles) Cashmere: 256 μg/L zinc total 125 g/L zinc dissolved (51% of zinc as particles)
A strong relationship between sideways friction and tire wear has been found in roadway situations. Estimates of tire particles released on straight sections of typical roadways are 0.01 – 0.05 g-tread/km; Councell et al., 2004; Pierson et al., 1974). This compares with much higher rates of 7 - 40 g-tread/mi (4 – 25 g-tread/km) on a 40 mph roadway curve (Pierson et al., 1974). The rate of tire wear for forklifts and trucks making tight turns on grounds and loading docks may be considerably greater. Although this source of zinc in industrial stormwater runoff is not generally recognized, it should not be assumed that the contribution of tire wear to zinc in industrial stormwater is insignificant or even small.
Nitrogen
Description: Nitrates are a form of nitrogen, which is found in several different forms in terrestrial and aquatic ecosystems. These forms of nitrogen include ammonia (NH3), nitrates (NO3), and nitrites (NO2). Nitrates are essential plant nutrients, but in excess amounts they can cause significant water quality problems.
Natural Sources: Leaves and Woody Debris, Dead Plants and Animals, and Animal Manure
Human-caused Sources: Fertilizers, Failing Septic Systems, Waste Water Treatment Plant (WWTP) Discharges, Pet Waste, Livestock and Farm Animals, Industrial Discharges
Effects on Watershed / Health: Together with phosphorus, nitrates in excess amounts can accelerate eutrophication, causing dramatic increases in aquatic plant growth and changes in the types of plants and animals that live in the stream. This, in turn, affects dissolved oxygen, temperature, and other indicators. Excess nitrates can cause hypoxia (low levels of dissolved oxygen) and can become toxic to warm-blooded animals at higher concentrations (10 mg/L or higher) under certain conditions. The natural level of ammonia or nitrate in surface water is typically low (less than 1 mg/L); in the effluent of wastewater treatment plants, it can range up to 30 mg/L.
Total Phosphorus
Description: Phosphorus is a nutrient, along with nitrogen, necessary for the growth of algae and other plants. It aids in photosynthesis and usually is found in low levels in surface waters.
Human-caused Sources: Fertilizers, Failing Septic Systems, Waste Water Treatment Plant (WWTP) Discharges, Pet Waste, Livestock and Farm Animals, Disturbed Land Areas, Drained Wetlands, and Commercial Cleaning Preparations
Effects on Watershed / Health: Since phosphorus is the nutrient in short supply in most fresh waters, even a modest increase in phosphorus can, under the right conditions, set off a whole chain of undesirable events in a stream including accelerated plant growth, algae blooms, low dissolved oxygen, and the death of certain fish, invertebrates, and other aquatic animals.
Total Phosphorus
Phosphorus is a naturally occurring nutrient essential to the growth of plants. It is a component of fertilizers, pesticides and detergents and it can also accumulate in high concentrations in septic systems. Phosphorus can be harmful when it is introduced into waterways due to its ability to cause algae blooms.
Additional Potential Sources of Phosphorus
- Landscaping activities including:
- Fertilizer or pesticide application
- Surface erosion
- Leaf and grass clipping disposal
- Construction and building maintenance activities including:
- Surface erosion
- Washing buildings
- Prepping buildings for painting, particularly using trisodium phosphate (TSP)
- Septic systems
Turbidity
Description: Turbidity is a measure of water clarity. Suspended materials, including soil particles (clay, silt, and sand), algae, plankton, microbes, and other substances, impact clarity in the water. These materials are typically in the size range of 0.004 mm (clay) to 1.0 mm (sand). Turbidity is an approximation of the amount of TSS in water.
Natural Sources: Soil Erosion, Excessive Algae Population, Large Numbers of Bottom Feeding Fish
Human-caused Sources: Waste Discharge, Land Development and Urban Runoff
Effects on Watershed / Health: Higher turbidity increases water temperatures because suspended particles absorb more heat. This, in turn, reduces the concentration of dissolved oxygen (DO) because warm water holds less DO than cold. Higher turbidity also reduces the amount of light penetrating the water, which reduces photosynthesis and the production of DO. Suspended materials can clog fish gills, reducing resistance to disease in fish, lowering growth rates, and affecting egg and larval development. As the particles settle, they can blanket the stream bottom, especially in slower waters, and smother fish eggs and benthic macroinvertebrates.
PFAS
What Are PFAS? Per- and polyfluoroalkyl substances (PFAS) are chemicals that resist grease, oil, water, and heat. They were first used in the 1940's and are now in hundreds of products including stain- and water-resistant fabrics and carpeting, cleaning products, paints, and fire-fighting foams. (EPAs Explanation of PFAS)
PAHs
PAHs are organic compounds commonly associated with petroleum products or the combustion of fossil fuels.
Potential Sources of PAHs
- Coal-tar based sealants on paved surfaces
- Pavement maintenance including grinding or sealcoating asphalt surfaces
- Diesel equipment maintenance
- Used motor oil
- Tire wear
- Burning fossil fuels in equipment or vehicles
- Creosote treated wood products
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