EPA Certified Lead Risk Accessor
Consulting, Testing, and Inspections
Breathe Easy LP is at the forefront of reducing this health concern to America’s children and workers. Close attention to the needs of our clients, proper training, certification of our technical staff, and monitoring of changing technology have enabled Breathe Easy LP Environmental to continue to be a leader in lead-based paint consulting. We provide XRF Inspections, Risk Assessments, In-place Management, Remediation Design, Remediation Monitoring, Clearance Sampling, Waste Disposal Consultation and Waste Stream Analysis.
In 1978, the U.S. banned lead-based paint for use in houses, but many houses built before then contain lead-based paint. Some renovations and repairs can create lead dust in houses that have lead in their paint. If not done properly, this can cause people and pets to be lead poisoned. Lead dust also can contaminate your house and yard. Lead dust can remain long after the work is done.
Breathe Easy Environmental is licensed in Texas by the D.S.H.S. for Lead Risk Accessing, Mold Assessment Consultant, and Asbestos Inspections.
Lead is a naturally occur soft and heavy metal. Over the years lead has been mined and used in many products that were found in and around our homes and buildings. Exposure to lead should be avoided since it is highly toxic to humans, especially young children.
Lead in many household products has been banned or its use limited in many parts of the world over the last several decades. Despite these laws there are millions of homes and buildings across the nation that was constructed prior to these regulations.
The risk associated with lead comes from occupants inhaling, ingesting or drinking lead contaminated materials. In some circumstances if the lead has not been aerosolized, and is not chipping or flaking, there may be minimal risk to people. It is when lead containing products are disturbed or begin to decay that they typically pose the greatest risk to health.
Lead is typically impossible for occupants and building owners to detect using their normal senses. Affordable testing procedures are available by qualified professionals and accredited laboratories to determine if lead is present.
The information presented on this Web page is for risk assessors, site managers, and members of the general public who are familiar with risk assessment.
The science of risk assessment encompasses analysis of site data; development of exposure and risk calculations; and preparation of human health and ecological impact reports. For more information on EPA risk assessment, visit EPA's Waste and Cleanup Risk Assessment Web page . The four steps for conducting a risk assessment are: data collection and data evaluation, exposure assessment, toxicity assessment, and risk characterization. EPA's approach to lead risk assessment follows these four steps in the use of the Integrated Exposure Biokinetic and Uptake Model (IEUBK):
EPA's risk assesment for lead is unique because a Reference Dose (RfD) value for lead is not available. An RfD is typically derived from a concentration below which no adverse effects have been observed. Existing evidence indicates that adverse health effects occur even at very low exposures to lead (e.g., subtle neurological effects in children have been observed at low doses).
Since the toxicokinetics (the absorption, distribution, metabolism, and excretion of toxins in the body) of lead (Pb) are well understood, lead is regulated based on blood lead concentration (PbB). EPA and the Centers for Disease Control and Prevention (CDC) have determined that childhood blood lead concentrations at or above 10 micrograms of lead per deciliter of blood (µg/dL) present risks to children's health. The EPA risk reduction goal for contaminated sites is to limit the probability of a child’s blood lead concentration exceeding 10 µg/dL (the P10) to 5% or less after cleanup.
Blood lead concentration can be correlated with both exposure and adverse health effects. To predict blood lead concentration and the probability of a child’s blood lead concentration exceeding 10 µg/dL (the P10) based on a given multimedia exposure scenario, one can apply a model which considers lead exposure and toxicokinetics in a receptor -- i.e., a child (using the IEUBK model) or fetus (using the Adult Lead Methodology [ALM]) to derive an exposure level that satisfies the risk reduction goal.
Data Collection and Data Evaluation
Although the IEUBK model may be run using default values, it is preferable to obtain site-specific data for soil and dust lead concentrations. Site data may also support refined estimates for other model parameters such as bioavailability variables.
For each potential exposure medium (soil, dust, food, water, air) at a site, there are several strategies that may be employed for sample collection. The sampling strategy must be appropriate for it to be used in the risk assessment. For this reason, risk assessors should be involved in the development of the sampling strategy. The following areas are of major concern: sample size, location, and type; temporal and meteorological factors; field analyses; and sampling costs [see the Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (Part A), 1989].
Consistent with current EPA guidance, the Technical Review Workgroup for Metals and Asbestos (TRW) recommends that consideration be given to the collection of blood lead concentration data when feasible. If such human health monitoring is planned to assess current and/or historical exposures, the Agency for Toxic Substances and Disease Registry (ATSDR) should be consulted to ensure that any collected human site-specific data are of sufficiently high quality to be used for human health risk assessment. The Guidance Manual for the Integrated Exposure Uptake Biokinetic Model for Lead in Children provides more information pertaining to the comparison of measured and predicted blood lead concentrations.
Once collected, the entire data set must be evaluated. The data quality may depend on the analytical method used and sample quantitative limits. The evaluation allows for selection of a subset of the data to be used in the risk assessment.
Exposure may be defined as the contact of a receptor with a chemical or physical agent. Exposure assessment is the estimation or determination of the magnitude, frequency, duration, and route of exposure. The exposure assessment incorporates intake and uptake in quantifying the magnitude of the exposure. Exposure assessments should consider not only the current population, but also potential future populations.
For assessing lead exposure for lead risk assessment, EPA currently recommends two models, depending upon the age of the receptor population:
Both account for intake and uptake components of lead exposure, and allow the user to input site-specific data (e.g., exposure frequency, sources of lead) and predict blood lead concentrations (PbBs). Predicted blood lead concentrations provide one indication of the associated lead exposure for both current and potential future populations.
The toxicity assessment weighs all the available evidence and estimates the potential for the occurrence of adverse health effects. The CDC has identified a blood lead concentration level of 10 µg/dL as the level of concern above which significant health risks occur. For lead, the toxicity assessment is based on exceeding the 10 µg/dL blood lead concentration. Both the IEUBK model and EPA's 1996 ALM generate predicted blood lead concentrations and provide information on the percentage of the population exceeding 10 µg/dL. For lead risk assessment purposes, the IEUBK model and the ALM can provide information necessary to determine the probability of adverse health effects associated with lead exposures.
Risk characterization is the key step in the risk assessment process because it serves as the bridge between risk assessment and the information needs of risk management. Risk characterization is a combination of all the information gathered during the three phases of the risk assessment and relates toxicity and exposure assessments and can include the development of preliminary remediation goals.
It is important to identify and understand all the assumptions and uncertainties associated with the risk assessment in order to place conclusions in the proper perspective. Moreover, uncertainty analysis may identify areas at a site where additional data collection could aid in the selection of a more suitable remedy. This is especially true for model parameters that are very sensitive to site-specific input (e.g., bioavailability). When conducting a risk assessment, it is more important to identify the key site-related variables and assumptions that contribute most to the uncertainty than to precisely quantify the degree of uncertainty in the entire risk assessment.
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