Water Pollution Chapter 14 Friday, April 8 th, 2016

Water Pollution  Refers to degradation of water quality.  Generally look at the intended use of the water  How far the water departs from the norm  Its effects on public health  Or its ecological impacts

Water Pollution  Water pollutants includes  Heavy metals  Sediment  Certain radioactive isotopes  Heat  Fecal coliform bacteria  Phosphorus  Nitrogen  Pathogenic bacteria and viruses

Water Pollution  Primary water pollution problem is the lack of clean, disease free drinking water.( Sanitary water)  Outbreaks of waterborne disease affects several billion people worldwide  E.g. cholera, Crytosporidium  Quality of water determines its potential uses.  All segments of society may contribute to water pollution.

Pollution Sources  Water pollution is the contamination of water by substances produced by human activities and that negatively affect organisms  Point source pollution comes from a distinct location that can easily be traced (factory, pipe)  Nonpoint source pollution cannot easily be traced to the source (urban areas, farms). More difficult to control and more common

Nutrient pollution  Nutrient pollution comes from fertilizers, farms, sewage, lawns, golf courses, and leads to eutrophication  Fertilizers add phosphorus to water, which boosts algal and aquatic plant growth  Spreading algae cover the surface, decreasing sunlight  Bacteria eat dead algae, reducing dissolved oxygen  Fish and shellfish die  Solutions include:  Treating wastewater  Reducing fertilizer application  Using phosphate-free detergents/fertilizers  Planting vegetation to increase nutrient uptake

Human Wastewater  Human wastewater is water produced by human activities (sewage, laundry water). High in nutrients. Leads to 3 concerns 1. Oxygen demanding waste is organic matter that enters water and feeds the growth of microbes that are decomposers.  The more waste in the water, the more microbes. More microbes, the more they demand oxygen  Biological oxygen demand (BOD) is the amount of oxygen microbes use when breaking down waste (measures odw)  High BODs typically mean more wastewater. Eventually leads to dead zones because not enough oxygen to support life

Continued… 2. When organic matter is decomposed, nutrients are released  Eutrophication – nutrients added to water which brings algae blooms. These die and bacteria increases and uses up oxygen  Cultural eutrophication is caused specifically by humans 3. Wastewater can carry parasites and bacteria that can make humans ill. These are called pathogens  Cholera, typhoid fever, flu, diarrhea  3.1 million deaths per year caused by unsafe drinking water  We only test for certain bacteria in our water since there are so many different kinds

Eutrophication  Oligotrophic lake (BOD is low)  Lake w/ relatively low concentration of chemical elements required by life  Clear water  Low abundance of life – animals are diverse (mosquitos, fish, aquatic insects and bugs)  Eutrophic lake - (BOD is high)  Lake w/ high concentration of chemical elements  Often w/ mats of algae and murky water  Abundance of life, but few animals – only algae, bacteria, and some other higher plant species

Cultural Eutrophication  Human processes that add nutrients to water  Solution fairly straightforward  Ensure that high concentrations of nutrients do not enter water  Accomplished by  use of phosphate-free detergents  controlling nitrogen runoff  disposing or reusing treated wastewater  advanced water treatment methods

Treatment of Wastewater  Septic systems are sewage treatment systems found in rural areas. Has two major components  Septic tank takes wastewater in one end, and releases it out the other  Leach field are pipes where the septage (clear layer full of bacteria) moves out. Septage slowly leaks out of pipes into the ground  Sewage treatment plants are used for urban areas  Primary treatment lets solid stuff settle and become sludge. From there it can be taken to landfill, farms, etc  Secondary treatment uses bacteria to break down remaining organic matter. Also has a settling tank  Water gets released to nature, but contains high N and Ph levels  During times of heavy rain, treatment plants are overloaded and release raw sewage into nearby bodies of water

A typical wastewater treatment facility  Sludge = solid material resulting from treatment  Is decomposed microbially  Then landfilled, incinerated, or used as fertilizer on cropland  Methane-rich gas created by decomposition can be burned to generate electricity

Heavy Metals and Acid Deposition  Lead enters water through old lead pipes. Can damage brain, kidneys, and nervous system (especially babies)  Arsenic occurs naturally in rocks, but is increased by humans breaking up rocks. Leads to various cancers.  Mercury is natural and is also increased by human activities. Most human related mercury comes from burning ff.  Attacks central nervous system and fetuses. Often found in fish, mostly top consumers (bioaccumulation)  Acid deposition comes from burning fossil fuels. Leads to death of trees and aquatic ecosystems. Coals scrubbers and static help

Synthetic Organic compounds  SOC are man-made organic compounds  Pesticides help control pests, but lead to other problems  Don’t only kill pest they are designed to kill  Affect organisms down the food chain that eat these pests  Cancer, birth defects, bioaccumulation  Other common compounds found in water include military compounds, pharmaceutical drugs, and industrial compounds

Oil Spills  Toxic to many species, including algae which starts aquatic food webs  Surface oil is sucked up, skimmed up, chemicals are applied that break it up, bacteria is applied that eats it up, or coagulate it  No easy way to clean up underwater plumes

Not All Pollutants are Chemicals  Solid waste production  Plastic rings strangle animals  Medical waste hazardous to humans  Coal ash, which contains heave metals  Sediment pollution comes from small particles carried in rivers  Occurs from land erosion (mostly in agricultural areas)  Reduce sunlight, this reducing photosynthesis  Clog gills  Thermal pollution is when human activity causes water temp to change (power plants)  Dissolved oxygen decreases as temperature increases  Noise pollution can affect animal communication (SONAR)

Pathogens and waterborne diseases  Enter water supplies through inadequately treated human waste and animal waste from feedlots  Fecal coliform bacteria indicate fecal contamination  They are not pathogenic organisms  But the water may also hold other disease-causing pathogens (e.g., giardiasis, typhoid, hepatitis A)  Bacterial pollution causes more human health problems than any other type of water pollution  Conditions are improving  86% of people now have safe water

Dissolved Oxygen (DO)  DO (measured in PPM) is necessary for aquatic life  Most comes from atmosphere  Rapidly moving water has higher DO levels  Stagnant water with high levels of organic matter can contain oxygen consuming bacteria that leads to eutrophication  As water temp increases, DO levels decrease, thus eutrophication is worse in summer

Laws  Clean water act (1972)  Supports the protection and propagation of wildlife and recreation in and on the water  Defined standards of acceptable limits of various pollutants  Control how much discharge industries and put in water  Safe drinking water act (1974, 1986, 1996)  Established max contaminant level for 77 different elements or substances in surface and ground water

Problem: In 2010, the South Anna River had a largemouth bass population of 25,000 individuals over a 10–mile stretch. In early 2011, a chemical spill occurred and the population of largemouth bass decreased to only 5000 individuals over the same area. Calculate the percent change in largemouth bass in the South Anna River.