Lead in the Ohio River Basin The Ohio River Watershed Pollutant Reduction Program The Ohio River Valley Water Sanitation Commission November 1998 INTRODUCTION This report is prepared as part of the Ohio River Watershed Pollutant Reduction Program (ORWPRP) being conducted by the Ohio River Valley Water Sanitation Commission (ORSANCO) with funding assistance from the U.S. EPA and support from the Commission's member states. The goal of ORWPRP is to generate necessary information to evaluate the need for and achieve meaningful reductions of pollutants inhibiting the beneficial uses of the Ohio River and its tributaries. The purpose of this report is to present available information on lead pertaining to water pollution within the Ohio River Basin. Specifically, data is included on the geographic extent and severity of lead contamination in various aquatic media along with potential sources of such contamination. Lead is a naturally occurring metal that is found in small amounts within the earth's crust. Commonly, lead is used in the production of ammunition, batteries, metal products, pipes, and in a large variety of medical, scientific, and military equipment. While the element exists naturally, human activities have spread lead and substances that contain lead to all parts of the environment. Lead is found in drinking water as a result of pipes, faucets, and other plumbing equipment made of lead. In soils, lead comes from paint, or landfills that contain waste from lead ore mining, ammunition manufacturing and from industrial activities. Since the 1920's, the largest source of lead in the atmosphere was the burning of gasoline (USDHHS, 1993). However, in the 1980's the U.S. Environmental Protection Agency (USEPA) limited the use of leaded gasoline in automobiles thereby decreasing emissions. Currently, sources of lead to the atmosphere include burning fuel, such as coal or oil, industrial processes and burning of solid waste. Human exposure to lead can be particularly dangerous to young or unborn children since they are more sensitive to its effects. Health effects include premature birth or miscarriage in pregnant women, hearing problems, decreased IQ, and a retardation of physical growth in children. In adults, lead exposure can affect memory and decrease reaction time. In addition, exposure may cause or contribute to high blood pressure, anemia, and brain or kidney damage. METHODS Information contained in this report was generated through literature searches in libraries and on the World Wide Web. Data specific to the Ohio River Basin was obtained through personal communication and information requests with employees at federal, state and local government agencies. Agencies supplying information included the New York Department of Environmental Conservation, Pennsylvania Department of Environmental Protection, West Virginia Department of Environmental Protection, Ohio Environmental Protection Agency, Kentucky Division of Water, Indiana Department of Environmental Management, Illinois Environmental Protection Agency, U.S Environmental Protection Agency Region 5, U.S. Geological Survey, U.S. Army Corps of Engineers, and ORSANCO. Sediment and fish tissue data, and their sources of contamination were compiled through the Toxics Release Inventory (TRI) database, STOrage RETrieval (STORET) database, Aerometric Information Retrieval System (AIRS), Permit Compliance System (PCS), and the CERCLIS database. Where possible, data was assessed for trends on a spatial and temporal scale in order to quantify changes in contamination within the Basin. PHYSICAL AND CHEMICAL PROPERTIES Lead is a bluish-gray, soft metal that exists in several naturally occurring and man-made forms in the environment (see Table 1). While many compounds contain lead, these substances Lead Compounds Chemical Formula Metallic lead Pb Lead acetate PbC4H6O4 Lead chloride PbCl2 Lead bromide PbBr2 Lead oxide PbO Lead phosphate PbPO4 Lead sulfate PbSO4 Lead sulfide PbS Tetraethyl lead C8H20Pb Table 1. Common lead compounds and their chemical formulas (USDHHS, 1993). are not characteristic of lead in its metallic form. In its metallic form, lead is characterized as having a low melting point, high density, being insoluble.in water, and lacking any characteristic taste or smell (see Table 2). Lead also readily tarnishes in the atmosphere but is considered one of the most stable fabricated metals because of its resistance to corrosion. Property Value Molecular Weight 207.2 Melting Point 327.4 OC Boiling Point 1,740 -C Density 11.34 g/cm' @ 20 'C Water Solubility Insoluble Vapor Pressure 1.77 mmHg @ 1,000 'C Table 2. Summary of physical/chemical properties of lead (USDHHS, 1993). The ultimate fate of lead in the environment is terrestrial or aquatic sediments. Typically, the accumulation of lead in soil is a function of the rate of deposition from the atmosphere. Once in the atmosphere, lead exists primarily in the particulate form and can be carried long distances until it returns to the surface be wet or dry deposition. Approximately 40 to 70 percent of atmospheric deposition of lead is by wet fallout with the average residence time in the atmosphere being 10 days (USDHHS, 1993). However, an important factor in determining the atmospheric transport of lead is the particle size distribution. Large particles, with diameters greater than 2 um, settle out of the atmosphere fairly rapidly and are deposited relatively close to emission sources, whereas small particles may be transported thousands of kilometers (USDHHS, 1993). In soil, lead sorbs strongly to organic matter with very little being transported into ground water or surface water. Typically, atmospheric lead is retained in the upper 2 to 5 cm. of soil when the pH is greater than or equal to 5, and there is at least five percent organic matter content. Depending on soil type and organic matter content, lead becomes immobilized by forming insoluble lead complexes or precipitating out with carbonate or phosphate ions. However, when the soil becomes acidic, or has a pH of between 4 to 6, leaching to groundwater can occur. Under natural conditions the downward movement of lead from soil to groundwater by leaching is very slow unless in a highly acidic environment, such as a National Priority List (NPL) site. In addition, inorganic lead is bound into crystalline matrices of rocks and remains essentially immobile. Lead may enter rivers, lakes and streams when soil particles are displaced by rainwater and surface runoff. Lead can be present as sorbed ions or surface coatings on sediment mineral particles, or it may be carried as part of suspended living or nonliving organic matter in water. A significant fraction of lead carried by surface water is in the undissolved form and can consist of colloidal or larger-sized undissolved particles of lead carbonate, lead oxide, lead hydroxide or other lead compounds. Typically, the concentration of dissolved lead is low in groundwater and surface water because lead will form compounds with the anions in water, such as hydroxides, carbonates, sulfates and phosphates, and will precipitate out of the water column. The ratio of lead in suspended solids to lead in the dissolved form has been found to vary from 4:1 in rural streams to 27:1 in urban streams (USDHHS, 1993). Once in the environment, lead remains there for many years. Some of the chemicals that contain lead can be broken down by sunlight, air and water to other forms of lead however, the lead atom itself cannot be broken down. ENVIRONMENTAL AND HUMAN HEALTH CONCERNS Even though lead occurs naturally, the majority of lead dispersed throughout the environment is primarily the result of anthropogenic activities. Enviromnental fate processes may transform lead from one compound to another however, it is not degraded and is still available for human exposure. Individuals can be exposed to lead through ingestion, inhalation or dermal contact. Typically, inhalation and dermal contact with lead are associated more with occupational exposure whereas, ingestion of lead is a concern to the general population. Individuals can be exposed to lead by eating lead-based paint chips, drinking water that comes ftom lead pipes or lead soldered fittings, breathing tobacco smoke, breathing or ingesting contaminated soil, dust, air or water near waste sites, eating contaminated food grown on soil containing lead, and breathing fumes or ingesting lead from hobbies that use lead, such as ceramics. Children, especially those who are preschool age, are at risk for potentially high levels of lead because of their tendency to put hands, toys and other lead containing items, such as paint chips, into their mouths. The human body cannot distinguish between calcium and lead therefore, lead is assimilated in the bloodstream in the same manner as calcium. Once lead enters the body it is distributed in the blood to the "soft tissues", such as the liver, kidneys, lungs, brain, spleen, muscles and heart, and then transported to the bones where it can remain stored for decades and reenter the blood at a later time. The amount of lead remaining after storage is then removed from the body in urine and feces. Generally in adults, about 99 percent of the total amount of lead taken into the body is removed in wastes within a couple of weeks. However, since young children absorb more calcium to meet their extra needs, they also absorb more lead. Therefore, in children only 32 percent of the total amount of lead absorbed by the body is eventually removed (USDHHS, 1993). In all individuals, bonestores of minerals, including normally inert lead, can be mobilized back into the bloodstream and increase blood-lead levels at a later time. Lead can affect almost every organ and system in the human body and health effects can last for months or years following exposure. At high levels, exposure to lead can cause permanent brain and kidney damage and impair the central nervous system by decreasing reaction time, causing weakness and aching in arms and legs, and possibly effecting memory.