Chesapeake Bay Basin Toxics Loading and Release Inventory
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Chesapeake Bay Basin Toxics Loading and Release Inventory May 1999 Chesapeake Bay Program 410 Severn Avenue, Suite 109 Annapolis, Maryland 21403 1-800 YOUR BAY http://www.chesapeakebay.net Printed by the U.S. Environmental Protection Agency for the Chesapeake Bay Program Executive Summary I. WHAT IS THE PURPOSE OF THIS To address that goal, the Bay Program has INVENTORY? been following these steps (Figure 1): This Toxics Loading and Release Inventory 1. Identifying areas of the Bay impacted is one of many tools the Chesapeake Bay by toxics. Program is using to set more targeted 2. Determining chemicals causing the source reduction and pollution prevention toxic impacts. goals to reduce and eliminate toxic impacts 3. Determining the origin of those in the Bay. The overall goal of the 1994 chemicals. Chesapeake Bay Basinwide Toxics 4. Implementing management actions to Reduction and Prevention Strategy is “a reduce inputs of those chemicals to Chesapeake Bay free of toxics by reducing levels that will result in no toxic or or eliminating the input of chemical bioaccumulative impacts on the Bay’s contaminants from all controllable sources living resources or on human health, to levels that result in no toxic or based on available data and current bioaccumulative impact on the living state of science. resources that inhabit the Bay or on human health.” 3. Identify the chemical sources. Point source loads 4. Reduce chemical inputs. (industries; federal facilities; wastewater treatment plants); urban runoff loads; atmospheric deposition loads, etc. 1. Identify the toxics impacts 2. Identify the chemicals on living resources. causing the impacts. WATER Benthic community SEDIMENT Figure 1. Chesapeake Bay Program process for managing chemical contaminant-related problems in the Bay and its rivers. This figure illustrates that the loading data reported in this inventory are only one piece of the overall toxics management picture. The inventory must be used in conjunction with data on toxics impacts and impairing chemicals in order to identify sources to control. i-1 Executive Summary Since the signing of the 1994 strategy, the identify the greatest data needs to Bay Program has made significant progress improve future loads estimates. in identifying toxic impacts in the Bay and < The public can use this inventory to chemicals causing the impacts. In early learn about their waterbodies of interest 1999, the Bay Program completed its – the types of chemicals entering these characterization of toxic impacts in all tidal waters, the magnitude of the loads, and rivers of the Bay. This toxics chemical sources. This information, characterization will supplement existing coupled with the toxics characterization characterizations carried out by Bay of these waters, will help the public Program partners and will provide a identify how and when to act to reduce scientifically-based description of the chemical loads to these waters. distribution and extent of chemical contaminant impacts in the Bay. This This inventory reports chemical contaminant characterization and other state efforts have loads to the Bay and its rivers but does not identified chemicals which cause problems report what the loads mean to the Bay’s in localized areas of the Bay’s rivers. In living resources or which specific sources addition, the Bay Program has developed a and chemicals are causing impacts. A big Chesapeake Bay Toxics of Concern List of load of a chemical contaminant does not chemicals which cause, or have the potential necessarily mean a big impact, nor does a to cause, adverse impacts on the Bay system. small load always indicate a small impact. The information on impacts and A big load of chemical contaminants from a chemicals causing impacts, coupled with particular source also does not mean that the this updated 1999 Chesapeake Bay source is uncontrolled. For example, point Basinwide Toxics Loading and Release source dischargers may be in compliance Inventory, will enable managers, with their permits, but may still produce a scientists, and stakeholders to target their substantial load to the Bay and tidal rivers. toxics reduction and prevention activities This is often the case with large flow toward specific sources and chemicals in facilities (i.e., wastewater treatment plants) impacted areas of the Bay. that emit a very low concentration of a chemical into the Bay and tidal rivers, but This inventory can be used by managers, their flow is so large that it results in a large scientists, and the public in the following load. As stated previously, this inventory can ways: be used in conjunction with the toxics characterization to help managers target < Scientists, managers, and stakeholders management actions toward specific can use this inventory, coupled with the geographic areas, chemicals, and sources. toxics characterization, to set reduction targets for sources of chemicals causing Toxicity of a chemical depends on many factors toxic impacts in the Bay’s tidal rivers. such as the concentration, chemical/physical < Managers can use the assessment of the form, and persistence of the chemical; the relative importance of point and chemical/physical properties of the waterbody nonpoint sources of chemical it is entering (i.e., pH, sediment type, etc.); and the type and life stage of the living resources contaminants to better target their exposed to the chemical. management programs to the most important sources. < Scientists can use this inventory to i-2 Executive Summary II. WHAT IS THE FOCUS FOR THIS Bay. This inventory mainly reports chemical INVENTORY? contaminant loads to the Bay and its tidal rivers, as opposed to non-tidal waters, Loads and Releases because tidal waters are the focus of the Bay Program’s toxics efforts. The sites of many This inventory reports both loadings and of the known toxics problems are in tidal releases to the Bay watershed. Loadings are waters and most of the urban areas and estimates of the quantity of chemical toxics-related land use activities are adjacent contaminants that reach the Bay and tidal to tidal waters. However, it is important to rivers, from sources such as point sources note that non-tidal waters -- above the fall discharging into the Bay or its rivers, urban line -- are also sources of chemical runoff, atmospheric deposition on the Bay or contamination. Chemical contaminant loads its rivers, shipping and boating, and acid can enter the Bay and its rivers above the fall mine drainage. Releases are the estimates of line (non-tidal waters) or below the fall line the quantity of chemical contaminants (tidal waters). Measurements taken at the fall emitted to the Bay’s watershed that have the line are used to represent the fraction of potential to reach the Bay. The only release upstream loads (whether from point or information in this inventory is for pesticide nonpoint sources) that make it to the tidal usage. waters. Upstream sources can originate from point sources such as industries, federal Loads to Tidal Rivers and Bay facilities (e.g., military bases), and wastewater treatment plants or nonpoint The Chesapeake Bay has a direct connection sources such as agricultural or urban runoff. with the Atlantic Ocean. Because of the In this inventory, chemical contaminant loads ocean tides, saltwater from the Atlantic is entering the rivers above the fall line are mixed in the Bay with freshwater derived reported for point sources, urban runoff, and from land runoff. The part of the Bay and acid mine drainage only. Loads to the tidal its rivers that is influenced by the tide is rivers, below the fall line, are reported for referred to as the “tidal Bay” and “tidal point sources, urban runoff, atmospheric rivers.” Moving upstream, there comes a deposition, and shipping and boating spills. point at which the rivers are no longer (Figure 2) influenced by the ocean tide. The portions of the rivers that are not under the influence of the tide is referred to as “non-tidal.” The boundary between the non-tidal and tidal portions of a river is called the “fall line.” The fall line is the physiographic boundary representing the natural geographic break between the non-tidal and tidal regions of the Bay watershed. For example, in the Potomac River, the fall line is at Great Falls. The tidal portions of rivers appear to be efficient traps for chemical contaminants, which may be a reason why only low levels of chemical contaminants are detected in the i-3 Executive Summary Watershed (land) Point Source Loads Urban Stormwater Runoff Loads Acid Mine Drainage Loads River Fall line Fall line loads Above Fall Line Point Source Loads NON-TIDAL Urban Stormwater Runoff Loads Atmospheric Deposition Loads Shipping and Boating Loads Below Fall Line TIDAL River Figure 2. The sources of chemical contaminant loads to the Bay, above the fall line and below the fall line, reported in this inventory. Chemicals Reported Loadings are reported for chemicals on the Chesapeake Bay Toxics of Concern List (TOC) and the Chemicals of Potential Concern List. These chemicals cause or have the potential to cause adverse effects on the Bay’s living resources. Other chemicals that are not on these lists, but having very high loads, are also reported. The TOC list represents inorganic contaminants such as metals (copper, lead, mercury) and organic contaminants such as polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Metals come from both point and nonpoint sources from a variety of activities. PAHs come from the combustion of fossil fuels and from oil and grease used in cars. PCBs were used as fire retardants and can be found in older electric transformers and other machinery. Although PCBs are banned, they are still found in the environment and we still report them where found. i-4 Executive Summary Controlling Toxic Inputs: Concentrations accumulate in the environment, while some Versus Cumulative Loads degrade or are flushed out of the Bay and tidal rivers.