Section 1: What is Water Pollution? Unit 12: Water Pollution Section 1: What is Water Pollution?

What is Water Pollution? Water pollution is any change in the quality of water that can cause harm to organisms or make the water unusable to humans Types of Pollution: Point-source – drain pipes (usually) discharge pollutant directly into bodies of surface or underground water Nonpoint-source – broad, diffuse areas of pollution where rainfall runs pollutants into water from land (ex. Agricultural fields, parking lots, logged forests, livestock pens, lawns, etc.)

Leading Causes of Water Pollution Agricultural Activities – sediment erosion = #1; others include fertilizer, pesticide, fecal bacteria, salts, etc. Industrial Facilities – emit harmful inorganic and organic chemicals Mining – surface = erosion, toxic metal runoff; also, acid drainage

Types of Water Pollution Type/Effects Examples Major Sources Infectious agents – cause diseases Bacteria, Viruses, Parasites Human/Animal Waste Oxygen-demanding waste – Deplete DO needed by aquatic organisms Animal waste and plant debris Sewage, animal feedlots, food processing plants, paper mills Plant nutrients – cause excessive growth of algae Nitrates (NO3-) and Phosphates (PO43-) Sewage, animal waste, inorganic fertilizers Organic chemicals – Add toxins to water Oil, gasoline, plastic, pesticides, cleaning solutions Industry, farms, homes Inorganic chemicals – Add toxins to water Acids, bases, salts, metal compounds (oxides, etc.) Industry, homes, surface runoff, mining Sediments – Disrupt photosynthesis, food webs, etc. Soil, silt Land erosion (mostly agricultural) Heavy metals - Cause cancer, disrupt immune, nervous, and endocrine systems Lead, Mercury, Arsenic, etc. Unlined landfills, households, mining, industries Thermal – Increase vulnerability to disease and decrease DO Heat Industrial and Power plants

Oxygen-Demanding Wastes Flowing streams and rivers can recover from moderate levels of oxygen-demanding waste through dilution and bacterial biodegradation Leads to depletion of oxygen Oxygen sag curve!!!!

Plant Nutrient Pollution Leads to eutrophication (and subsequent decrease in DO) In marine ecosystems, can lead to harmful algal blooms (Red/Green/Brown Tides) Release water and air poisons and can deplete DO, leading to oceanic dead zones

Groundwater Pollution Pollution can leak from landfills, agricultural land, industry, and other sources into groundwater. Must be purified prior to use and in some cases, it is permanently contaminated and the aquifer is abandoned

Clean Water Policies Preservation of Clean water Clean Water Act (1972, 1977) established the basic structure for regulating direct discharges of pollutants into the waters of the United States. It gave EPA the authority to implement pollution control programs such as setting wastewater standards for industry. Preservation of Clean water Safe Drinking Water Act of 1974 established to protect the quality of drinking water in the U.S. This law focuses on all waters actually or potentially designed for drinking use, whether from above ground or underground sources. Allowed EPA to set tap water standards. Originally, Congress enacted the Soil Conservation Act of 1935 on April 27, 1935 in an attempt to address farm erosion problems by bringing within its policy and purposes, the improvements and preservation of national soil resources.   Dust Bowl The CRP program originally began in the 1950s as the conservation branch of the Soil Bank Program which was enacted by the Agriculture Act of 1956.

Oceans: The Ultimate Destination Most pollutants ultimately end up in the ocean Ocean currents can transport this pollution all around the planet Currents are driven by: Density differences Temperature differences Gravity Or, Wind

Ocean Gyres Warm and cool currents can influence climate along the coasts Sections of the oceans’ currents create circular, clockwise (Northern) or counter-clockwise (Southern) patterns These are called gyres Pollutants (especially garbage and plastics) can collect in the middle of them

Currents Drive Water Movement Water has the property of cohesion So when currents diverge in an area, water beneath is drawn up This is known as upwelling and generally brings cool, nutrient-rich water to the surface Upwelling can also occur when wind blows across the surface, parallel to a coastline Water can also converge, or sink in an area This is referred to as downwelling and transports surface water rich in dissolved gases such as Oxygen and Carbon dioxide These areas of differing movement of water leads to the earth’s thermohaline circulation Warm, fresher water moves along surface, sinks/cools, and cool, saltier water moves deeper beneath the surface