Nonpoint Source Pollution: Understanding the Causes, Impacts, and Solutions, Study notes of Agricultural engineering

Download Nonpoint Source Pollution: Understanding the Causes, Impacts, and Solutions and more Study notes Agricultural engineering in PDF only on Docsity! 1 Nonpoint Source Pollution Outline What is it? Where does it come from? What problems does it cause? How big of a problem is it? What is being done about it? What can be done about it? How do Point and Nonpoint sources differ? Point Sources Come from a readily identifiable single source Can generally be Nonpoint Sources Come from diffuse sources that are difficult to identify collected and treated Controlled by regulation through permits Collection and treatment is generally not feasible Controlled through Best Management Practices (BMPs) Common Nonpoint Source Pollutants Fertilizers and Pesticides Hydrocarbons and other toxic chemicals Metals Sediments (soil erosion) Pathogens and nutrients from livestock and septic systems ‘Emerging Contaminants’ etc! Agriculture Crop Fertilization Animal manures Soil erosion Forestry Urban and residential runoff Septic systems Construction sites Common Nonpoint Sources of Pollution: There are many sources of NPS. Our focus will be on agriculture. NPS is not just an issue with agriculture Nonpoint source (NPS) pollution is also an issue in the urban- residential landscape Several of the pollutants are the same (e.g. nutrients) As with agriculture, most of the issue is due to how we design and manage the landscape 2 Problems caused by NPS pollutants Pollutant Pesticides/other toxic compounds Threat posed Human/wildlife health Metals Bacteria Sediment Human/wildlife health Human health Habitat degradation Often a vector of other pollutants Why are only N and P of concern? One or the other is often the Limiting Nutrient in a water body (Limiting biological growth) Eutrophication: process by which a water body b i h i di l d t i t ftecomes r c n sso ve nu r en s, o en leading to algal blooms, low dissolved oxygen, and changes in community composition. Eutrophication occurs naturally, but can be accelerated by human activities that increase nutrient inputs to the water body. http://suwanneeho.ifas.ufl.edu/newspapers/ Gainesville_com%20%205-14-04%20all.htm STREAMLINES – WINTER 2005 THE BATTLE AGAINST ALGAE By Teresa Monson PALATKA -- The phones at the St. Johns River Water Management District began ringing in mid-August when concerned homeowners and recreational enthusiasts first spotted bright pea-green algae in the last 100 miles of the St. Johns River. Concern turned into alarm as the algae grew into a dense sheet that covered much of the river and, most especially, when scientists identified it as a type of toxic blue-green http://sjr.state.fl.us/progr ams/outreach/pubs/stre algae called Microcystis aeruginosa. In their work to understand where nutrients are coming from, District staff have identified many sources, including stormwater runoff from urban and agricultural areas. But the single greatest source of nutrients to the lower St. Johns River is effluent from industrial and wastewater treatment plants. The District has recommended reducing specific pollutants that may prevent the worst of the impacts that the current "pollution loads" are having on the river. The state's goal: to achieve 30 percent less nitrogen and phosphorus in the freshwater portion of the river, and 22 percent less nitrogen in the saltwater reaches. amln/streamln.html Problems caused by Nutrients in Water Cultural eutrophication Hypoxia (low oxygen content) Pfiesteria piscicida (toxic dinoflagellate) Ammonia (Nitrogen form toxic to fish) Methemoglobinemia (Blue Baby disease) Caused by the nitrogen form – nitrate Drinking water limit of 10 mg/L of nitrate-N Primarily a problem in rural areas. Hypoxia (Low Oxygen Content) Two causes: 1. Day/Night changes in Dissolved Oxygen (DO) • Plants and algae produce oxygen during the day (photosynthesis) and consume oxygen at night (respiration) 2. Decomposition of organic material consumes oxygen (oxidation)