Introduction to Chemistry Activity

SJWP June 18, Fish Kill Scenario There has been a massive fish kill in Lake St. Louis. Your team has been dispatched to investigate the possible source(s) of the fish kill. Prior to the fish kill there were rainsand the low lying areas in the watershed were flooded. A sample has been collected in a one gallon plastic jug from Lake St. Louis. You need to compare the lab results to the Missouri Department of Natural Resources Water Quality Standards (10 CSR ) to determine which pollutant(s) may have caused the fish kill. A survey of the watershed has been performed and the following activities and potential pollution sources have been identified: Construction activity with soil erosion Golf course with fertilizer and pesticide application Wastewater treatment plant with a treated effluent discharge that is in compliance with BOD and ammonia limitations Residential areas with pets and road salt application for ice control Farm land with an animal waste lagoon, row crops and a gasoline underground storage tank Industrial plant with outside bulk chemical storage (acid and Methylene Chloride) Using the provided data, try to answer the following questions: 1. Which pollutant(s) caused the fish kill? 2. What is (are) the most likely source(s) of the pollutant(s) that caused the fish kill? 3. Are there any other pollutants that exceeded water quality standards? 4. Which water quality standards are exceeded? 5. What is (are) the most likely source(s) of these pollutants? 6. What most likely caused these pollutants to be released to the environment? 7. Are there any problems with the sample collection or analytical results? 8. What are the most likely cause(s) of these problems? 9. Are there any problems with lab analytical detection limits? 10. Would you recommend any follow-up investigations or analyses?

Division of Environmental Compliance (DEC) data notes Station 1 – Organic Analysis Atrazine, DDT (4-4’ dichlorodiphenyldichloroethane), Chlordane and Pentachlorophenol are all pesticides. Atrazine is commonly used for agricultural purposes. Bis(2-ethylhexyl) phthalate is commonly found in plastics. Benzene, Toluene, and Xylene are solvents commonly found at industries and in gasoline. Dimethyl phthalate is commonly found in plastics. Methylene Chloride is a solvent commonly found at industries and laboratories. PCBs were commonly used in electrical transformers Station 2 – Wet Chemistry Analysis Ammonia is commonly found in fertilizers, human waste and animal waste. Chloride is commonly found in road salt for ice control. Hardness is a measure of the buffering capability of water. pH is a measure of the acidity of water. Total dissolved solids - (TSS) is a measure of the amount of particulates suspended in water. Most municipal wastewater treatment plants have an effluent discharge limit of 30 mg/L of TSS. Station 3 – Metals Metals are commonly used in a wide variety of consumer and industrial products and can be naturally occurring in rock and soil. Station 4 – BOD/COD/DO Biochemical oxygen demand or BOD is a chemical procedure for determining is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. It is not a precise quantitative test, although it is widely used as an indication of the quality of water. In environmental chemistry, the chemical oxygen demand (COD) test is commonly used to indirectly measure the amount of organic compounds in water. Most applications of COD determine the amount of organic pollutants found in surface water (e.g. lakes and rivers), making COD a useful measure of water quality. It is expressed in milligrams per liter (mg/L), which indicates the mass of oxygen consumed per liter of solution. Older references may express the units as parts per million (ppm). Oxygen saturation or dissolved oxygen (DO) is a relative measure of the amount of oxygen in a given medium, water in this case. It can be measured with a dissolved oxygen probe such as an oxygen sensor in liquid media, usually water. BOD and COD are indications of waste strength including animal, human and industrial wastes. Most municipal wastewater treatment plants have an effluent discharge limit of 30 mg/L of BOD.

Please complete the questions and summarize your conclusions