BUILT HERITAGE SERIES: AN INTRODUCTION TO SIMPLE ANALYSIS METHODS FOR: LEAD-BASED PAINT (PART 1 OF 1)

BUILT HERITAGE SERIES: AN INTRODUCTION TO SIMPLE ANALYSIS METHODS FOR: LEAD-BASED PAINT (PART 1 OF 1)

Mrs. Emilia Zambri, MSoc Sci Tangible Heritage Conservation.

PREFACE

Welcome to this series of techniques for managing change and assessing the condition of architectural heritage structures and historic heritage fabric. This newsletter aims to provide professionals, including Heritage Consultants, Architects, Archaeologists, and Conservators, with practical and effective methods to determine the most appropriate approaches to management, conservation, and restoration.

Inspired by the challenges encountered in safeguarding historic heritage, especially in under-resourced areas, particularly in Africa, this series has been developed to assist colleagues globally. The goal is to present simple and easy-to-use frameworks, case studies, and tests that can be employed to evaluate the preservation, conservation, and restoration needs of historic heritage, ensuring their safeguarding for future generations.

By utilising these techniques, the objective is to empower heritage professionals with the knowledge and tools necessary to make informed decisions about the preservation of our shared cultural heritage. Join us as we embark on a journey to protect and preserve the historical structures that define our shared identity.

1. INTRODUCTION

This Lead Analysis Article examines the efficacy and benefits of 3M? LeadCheck? Swabs, a reliable qualitative spot test kit designed to detect lead in paint. The LeadCheck? Swabs are a self-contained, user-friendly, and cost-effective solution for identifying lead-based paint hazards prior to carrying out Renovation, Repair, and Painting (RRP) activities.

To ensure the accuracy and reliability of the LeadCheck? Swabs, 3M contracted Battelle, an independent testing organization, to conduct laboratory tests on plaster and drywall substrates in accordance with the Test/QA Plan for Verification of LeadCheck? approved by the U.S. Environmental Protection Agency (EPA). The testing was carried out under strict quality assurance protocols, generating data of known and adequate quality, and the results are scientifically defensible.

In addition to providing a detailed overview of the LeadCheck? Swabs, this article delves into the history of lead-based paint and the critical importance of identifying and managing lead-based hazards before embarking on RRP activities. The use of LeadCheck? Swabs has profound implications for lead paint management and public health.

2. HISTORY OF LEAD-BASED PAINT

Prior to 1978, lead-based paints were commonly used for interior and exterior applications to buildings. The US government subsequently banned the use of lead-based paint in residential and commercial applications due to its hazardous nature. However, despite the bans, such paints still exist in many built heritage sites across the world.?Approximately 24 million US dwellings are at risk for lead-based paint hazards, according to a report by the President's Task Force on Environmental Health Risks and Safety Risks to Children.

The identification of lead-based paint in built heritage sites is of utmost importance to both the Federal government and private individuals living in residences that contain such paints. Renovation, repair, and painting (RRP) activities may disturb painted surfaces and produce a lead exposure hazard.?

The removal of lead paint can create two potential health hazards: the inhalation or ingestion of lead paint particles by workers, the public near the structure, and the deposition of lead paint particles on nearby surfaces where they can be resuspended and tracked into buildings. Repeated inhalation or ingestion of lead paint particles can lead to lead poisoning, which can cause a range of health issues, including nervous system damage, stunted growth, reproductive problems, high blood pressure, and memory and joint pain. This exposure can be especially harmful to children and pregnant women as lead exposure can cause neurological and developmental problems in both children and fetuses.?

Protective equipment can help keep workers safe during paint removal and analysis, while preventing public access to the work site can protect the public. However, managing lead paint deposition can be complex, depending on the size, shape, and location of the building.

To address the issues of RRP activities on lead-based paints, lead-based paint test kits are available to help heritage specialists in identifying lead-based paint hazards before any RRP activities take place. This allows proper health and safety measures to be taken. It is noteworthy that in Australia, lead-based paint was commonly used until 1997, and while many heritage buildings have been repainted, some still contain lead paint beneath multiple layers. Buildings constructed and painted prior to 1970 often contain high levels of lead, which can be found in the paint on the walls or absorbed in the soil.

To detect lead-based paint, a lead analysis report is necessary. The report must be conducted according to procedures specified in the EPA-approved Test/QA Plan for Verification of LeadCheck?, a Qualitative Spot Test Kit for Lead in Paint. The LeadCheck? Swabs are a self-contained, easy-to-use, and inexpensive test kit for the qualitative spot detection of lead in paint.?

3. 3M LEAD CHECK SWABS

The LeadCheck? Swabs are a highly effective, self-contained, and cost-efficient test kit for detecting lead in paint. The kit contains two sealed ampoules with a buffered aqueous solution and a proprietary lead-indicating dye mixture. The swab assembly is enclosed by a protective cardboard tube that needs to be crushed at designated points to start the test. To conduct the test, the user rubs the swab on the test area for 30 seconds, and the presence of lead is indicated by a red or pink color change at the swab's tip.

The LeadCheck? Swabs have been tested and confirmed to be non-interfering with other metals and highly specific to lead detection. Furthermore, the swabs are non-toxic, and the results are generally visible within seconds of testing. The test confirmation cards included in the kit allow for individual test result verification.

The LeadCheck? Swabs are EPA-recognized for use in determining the presence of lead-based paint on wood and metal. The product is widely available nationwide in hardware, paint, and home centers, as well as online. The cost of the swabs is less than $5 per swab, making it an affordable option for lead detection in paint.

4. METHODOLOGY

Preparation of Paint Sample: A utility knife will be used to prepare the paint sample. Two nickel-sized half-circle slits will be made at approximately 5 degrees into the substrate. A flap will form which will expose all paint layers, and the flaps will be folded down, forming a pocket.

Activation of LeadCheck Swab: The LeadCheck Swab will be activated by crushing ampoules labeled A and B. The reactant solutions will be gently mixed by shaking the swab a few times.

Applying LeadCheck Swab: The swab will be positioned above the pocket and a drop or two of the solution will be squeezed into the pocket so that all layers of the paint are exposed to the solution. ForPerformance Evaluation Materials (PEM) with a red topcoat of paint, the swab tip will then run along the edge of the folded down flap while avoiding contact with any plaster or gypsum surfaces, other than the paint.

Waiting Time: A 30-second timer will be activated, and the swab will then be placed on a clean surface while the reaction occurs. This will be repeated with a new swab for each test site. If no red or pink color is detected at the end of the 30 seconds on either the PEM or the swab, a drop of the reactant solution will be placed onto the test confirmation card (a QC check supplied with the test kit) to validate the accuracy of the swab. This should turn red immediately.

Observation Period: If the indicator card does not turn red, then a new swab will be obtained, and a new cut placed on the PEM for a new sample to be tested. In all cases, the indicator card will turn red. If no color is detected on the swab or sampling surface after the initial 30 seconds, both the swab and the PEM will be retained and observed for an extended period of up to 5 minutes and longer.

Recording Results: A sample that generates an instant response (30 seconds or less) will be considered positive for lead. If the sample does not generate an instant positive response, it will be observed for an initial time of 5 minutes. If a color change occurs during the 5 minutes, the sample will be recorded as positive for lead, and the time of the color change will be recorded. If no color change is seen after 5 minutes, the PEM and corresponding swabs will be placed in a polyethylene bag and sealed. The sample will then be observed at various times throughout the day for up to 20 hours (overnight) for any color changes, and the results will be recorded.

4.1 ETHICS

Samples?are only taken by a trained Analyst when absolutely necessary for understanding, conservation, or restoration of a historical monument or building. Taking even a small sample for a cross-section means removing and destroying a portion of the original structure of the heritage building or monument. While non-destructive analyses do not damage the original during the examination, destructive analyses must take samples and, to some extent, damage the painted surface. Before performing any 'destructive' sampling, all nondestructive methods of analysis should be first considered.

4.2 PERSONAL PROTECTIVE WEAR

To ensure protection during analysis, always wear an AS-1716-approved respirator with P1 or P2 filters, secure coveralls, gloves and other appropriate Personal Protective Equipment. It is the employer's responsibility to provide and maintain this equipment. Wash hands and face before meals and smoking, and avoid carrying cigarettes where lead dust is present. Clean up and change out of work clothes to reduce the risk of taking lead dust home, especially for vulnerable individuals. Wash work clothes separately and rinse the washing machine afterwards and decontaminate all tools and equipment with D-Lead wipes.

4.3 SAMPLING PROCEDURE

Identification of Sampling Sites: The sampling sites will be identified based on the project's scope and the applicable regulations. The sampling locations will include areas where lead-based paint is suspected, such as windows, doors, and trim.

Selection of Sampling Equipment: The LeadCheck Swabs and the utility knife will be used to collect the paint samples.

Collection of Samples: The sample collection process will follow the methodology outlined above.

Sample Handling: The collected samples will be labeled and kept in a secure and appropriate container to avoid cross-contamination.

Transportation of Samples: The samples will be transported to the laboratory for analysis in a secure and appropriate container to avoid breakage and leakage.

Analysis of Samples: The laboratory will analyze the samples and provide a report of the results.

Reporting of Results: The report will include the identification of the sample, the methodology used for sample collection and analysis, and the results of the analysis. The report will be prepared in a format suitable for the project's requirements and any applicable regulations.

5. PERFORMANCE SUMMARY

The performance summary for the LeadCheck? Swabs on PEMs shows that the false positive rate was 70% for the technical operator and 98% for the non-technical operator for lead levels of ≤ 0.8 mg/cm2, and false negative rates were 1% for the technical operator and 0% for the non-technical operator for lead levels of ≥1.2 mg/cm2. The observed false positive rates were 75% for the technical operator and 98% for the non-technical operator for lead levels <1.0 mg/cm2, and false negative rates were 1% for the technical operator and 0% for the non-technical operator for lead levels of ≥ 1.0 mg/cm2. The LeadCheck? Swabs were consistent for both technical and non-technical operators for all lead levels except for the combined results at 0.0 mg/cm2.

The LeadCheck? Swabs were sensitive down to 1.0 mg/cm2 lead across both operator types and lead levels, and provided positive responses to lead concentrations <1.0 mg/cm2. The modeled probability curve results indicate that at 0.8 mg/cm2, the upper prediction bound does not provide a false positive rate of ≤10%. A false negative rate of ≤5% is predicted. The actual predicated false negative rate for the LeadCheck? Swabs is 4.9%. An overall false positive threshold value with 95% confidence could not be established at any lead level. A false negative threshold value with 95% confidence of 1.2 mg/cm2 could be established for the LeadCheck? Swabs.

Both the technical and non-technical operator found the LeadCheck? Swabs instructions to be clear, informative, and easy to follow. The swabs were generally quick to use and cost less than $5 per swab. The testing solution is self-contained within each swab, and a single swab and possibly a test confirmation card were produced as waste for a single test. No special disposal conditions were noted in the test kit instructions. However, the use of the LeadCheck? Swabs on drywall and plaster require that a drop of activated solution be released from the swab into the notched paint pocket that was formed with a utility knife.

6. CONCLUSION

In conclusion, the 3M LeadCheck Swabs is an efficient, affordable, and non-intrusive solution for detecting the presence of lead in paint. Lead-based paints, which were widely used before 1978, can be a health hazard to individuals during repair, renovation, and painting activities. It is crucial to identify lead-based paint in built heritage sites to preserve both the structures and public health. The LeadCheck Swabs, a self-contained kit with two sealed ampoules containing a buffered aqueous solution and a proprietary lead indicating dye mixture, are EPA-recognized for use in determining the presence of lead-based paint on wood and metal. The simple test is easy to use, and the results are generally visible within seconds of testing. The low cost of the swabs makes it an affordable option for lead detection in paint. Therefore, for heritage specialists, architects, archaeologists, and conservators, the LeadCheck Swabs can help identify lead-based paint hazards and provide assistance in evaluating the conservation needs of architectural heritage.