The Centers for Disease Control and Prevention began funding states as part of the national Environmental Public Health Tracking (EPHT) program in 2002. While the South Carolina (SC) Department of Health and Environmental Control (DHEC) was not funded in the first round of states, DHEC began efforts to build capacity for a SC EPHT program at that time. The national EPHT program identified blood lead records as one of the first nationally consistent data and measures (NCDM) for states to track. Lead is a ubiquitous environmental contaminant, as well as a potential source of exposure for workers in certain types of industries (eg, smelting, construction, and battery manufacture). Exposure to lead can have a number of detrimental health effects.1–7 Therefore, tracking lead exposure consistently among grantee states was a priority for the national EPHT program. The SC EPHT began development of a database and internal Web application for blood lead test records in SC, which was finalized in 2011.
Per SC Law §44-29-10, all blood lead test records are reportable to DHEC, regardless of test value or the age of the individual being tested. However, prior to SC EPHT, there was not an internal Web application in place to allow for ease of entering paper test records, nor for import of electronic laboratory records in a standard format. Because of SC EPHT efforts and the associated Centers for Disease Control and Prevention funding, blood lead data from 2010 to the present for both children and adults in SC are considered highly valid. The SC EPHT program has worked diligently to improve data quality and increase reporting of blood lead test records from both primary care providers and laboratories in the most recent 3-year grant cycle.
South Carolina currently receives no federal funding from either the Childhood Lead Poisoning Prevention Program or the Adult Blood Lead Epidemiology and Surveillance (ABLES) program. Only national EPHT funds support child and adult blood lead surveillance in SC specifically related to data collection and data quality. Given this, SC EPHT has played a primary role in both children and adult blood lead surveillance. The SC EPHT employs data entry staff to key paper records, and the SC EPHT data manager closely monitors the data for duplicates, helps oversee import of electronic laboratory records, and initiates geocoding of addresses. The SC EPHT also funds staff with experience in epidemiology and analysis of both environmental and occupational exposure data. For children, SC EPHT ensures that high-quality data are available in a timely fashion, so appropriate DHEC staff can follow up with children and perform environmental assessments, as needed. However, the role of SC EPHT in adult blood lead surveillance is more direct.
Most adult blood lead testing in SC is to fulfill occupational regulations for high-risk workers, is conducted if unintentional occupational exposure was thought to have occurred, or for potential exposure through cultural practices or traditional medicines used by certain subpopulations. In 2012, the ABLES program was moved to SC EPHT. As part of this programmatic change, SC EPHT began providing the Centers for Disease Control and Prevention with semiannual reports of adult blood lead test records and continues to do so despite the end to federal ABLES funding in 2013. The same year the ABLES program became part of SC EPHT, a memorandum of understanding (MOU) was entered into by SC EPHT and the SC Occupational Safety and Health Administration (SC OSHA), which is part of the SC Department of Labor, Licensing and Regulation. Per this MOU, SC EPHT provides quarterly reports of elevated (≥25 μg/dL) blood lead test records for adults (≥16 years of age) to SC OSHA, including employer information and North American Industry Classification System (NAICS) codes. This information is utilized by SC OSHA for workplace inspections. In relation to the information provided by SC EPHT as part of this MOU, SC OSHA has completed 14 inspections that have resulted in fines and corrective actions to protect the health and safety of employees exposed to lead. The SC EPHT has, in turn, written a number of public health actions (PHA) based on this collaboration, 3 of which were selected by the national EPHT program.
The objectives of this review were to provide results of descriptive analyses on adult blood lead data in SC from 2010 to 2015, summarize PHA that have been produced from the collaboration between SC EPHT and SC OSHA, and to outline future directions for SC EPHT with regard to adult blood lead surveillance. While lead exposure in children generally receives much attention due to the well-documented health impacts of early life lead exposure,6 , 8 , 9 it is important to also monitor exposure in adults, which generally is the result of occupation.10 , 11 Health effects from lead exposure can impact a number of body systems in adults,12–14 as well as fertility in males and pregnancy outcomes in females.15 , 16 Occupational exposure in adults has also been identified as the exposure source for children living in that same home.17 , 18 In addition, it is thought that there is no safe level of exposure to lead, as low levels of exposure (<5 μg/dL) have been found to be associated with negative health outcomes.5 Therefore, SC EPHT's role in adult blood lead surveillance in SC is important to the general health of all South Carolinians.
De-duplicated blood lead test records for adults 16 years of age or older for the years 2010 to 2015 were obtained (n = 31 251). Besides demographics (age, race/ethnicity, and sex), records also contained test type (venous, capillary, and unknown), blood lead test value (in μg/dL), and county of residence, which was based on the geocoded address associated with the record. Age was categorized into the following groups: 16-24, 25-34, 35-44, 45-54, 55-64, and older than 65 years. Race/ethnicity was categorized as non-Hispanic white, non-Hispanic black, and other, which included all other race/ethnicity combinations. County was used to assign test records to a DHEC public health region (Figure 1). In addition, a subset of blood lead test records also had a corresponding 2012 NAICS code based on employer information. North American Industry Classification System code categories were identified in the data set that had at least 10 or more tests associated with them; all other NAICS codes were combined into an “other” category.
All statistical analyses were performed with SAS 9.2 (SAS Institute, Cary, North Carolina). The percentage of records that had an elevated blood lead level (EBLL; ≥25 μg/dL) was calculated by year. The mean blood lead level (BLL) was calculated and compared for year of test, type of test, age group, race/ethnicity, sex, DHEC region, and NAICS code using analysis of variance; for these comparisons, only the first test (temporally) for an individual was used to ensure independence between observations. First tests made up the majority of records in the data set (56%). These comparisons were also limited to test records not missing the demographic variable of interest. For analysis of variance comparisons, pairwise comparisons of least squares means were examined, and a Tukey adjustment was made to account for the number of categories compared.
Three nationally accepted PHA from SC have been directly related to the collaboration between SC EPHT and SC OSHA. Two were based on inspection reports from SC OSHA related to SC EPHT's reporting of EBLL in adults; 2 employers (bridge contractors and a gun shop) were identified and cited. An additional PHA was related to an analysis that utilized 2011 to 2015 adult blood lead surveillance data, restricted only to first test records that were both elevated and had an associated NAICS code. Summaries of these PHA are provided.
Adult blood lead surveillance in SC: 2010-2015
From 2010 to 2015, 31 251 adult blood lead test records were received by DHEC and the SC EPHT program from 21 674 unique adults; 17 473 (80.6%) adults had only 1 blood lead test record during the time period examined, and the maximum number of test records for an adult was 25. Generally, 4000 to 5000 adult blood lead test records were reported annually, and the percentage of EBLL records by year ranged from 1.8% to 2.7% (Figure 2). In addition, there were 365 unique adults with at least 1 EBLL (≥25 μg/dL).
Missing information was an issue with most blood lead test records received from 2010 to 2015. When restricted to first test records for adults, almost 90% were missing race/ethnicity and 32.4% were missing test type, though only 2.6% and 0.8% were missing age and gender, respectively. Summarized demographics of test records (restricted to only first tests temporally) are shown in Supplemental Digital Content Table 1, available at http://links.lww.com/JPHMP/A340, along with P values for comparisons of mean BLL by category. Most adult blood lead first test records were associated with males (65.0%) and the majority of tests were categorized as venous (65.4%; see Supplemental Digital Content Table 1, available at http://links.lww.com/JPHMP/A340). The mean BLL was significantly higher for males than for females (P < .001), with males having a mean first test BLL twice as high as females in the sample (see Supplemental Digital Content Table 1, available at http://links.lww.com/JPHMP/A340). Mean BLL was also higher for those in age groups ranging from 16 to 64 years than for those older than 65 years (P < .001; see Supplemental Digital Content Table 1, available at http://links.lww.com/JPHMP/A340). The mean first test BLL for the Pee Dee and Midlands DHEC public health regions was also significantly higher than those for the Lowcountry and Upstate regions (P < .001), though first tests with associated geographic information were generally dispersed evenly among DHEC public health regions in SC (see Supplemental Digital Content Table 1 available at http://links.lww.com/JPHMP/A340).
The top NAICS categories for records with that information are shown in the Table, along with the mean BLL and percentage of EBLL records for each. The “other” category included industry classifications with less than 10 total first tests in the time period, and industry types in that category were varied (Table). The highest percentage of EBLL was found in the building finishing contractors category (77.8%; Table), though only 18 tests were associated with that category from 2010 to 2015. Seventy-one percent of first blood lead test records were elevated in the “other” category, but this group consisted of only 31 first tests. The mean BLL was highest for the remediation and other waste services category (Table). In addition, mean BLL values were significantly different by NAICS codes (P < .001).
PHA for the SC EPHT program related to MOU and SC OSHA collaboration
Two nationally accepted PHA from SC were related to EBLL employee records from different industries. Based on the quarterly reports supplied by SC EPHT, SC OSHA conducted inspections classified as referrals from another state agency. While these reports have led to several inspections, 2 specific investigations by SC OSHA are summarized here as part of the nationally accepted PHA. The first (2012) was associated with bridge contractors in SC. The SC OSHA discovered violations that included employees not wearing proper personal protective equipment when handling lead abatement equipment and failure to properly clean surfaces of lead abatement equipment. In this case, citations were issued under US OSHA standard 1926.62, which pertains specifically to construction work where an employee may be exposed to lead.
The second (2013) was associated with gun shop employees in SC. Again, reporting from SC EPHT led to inspections that identified a number of violations, including overexposure of 2 employees to lead. Specifically, one measured exposure level of 139 μg/m3 was above the 8-hour time-weighted average of 50 μg/m3. For the other employee, the measured exposure level of 616 μg/m3 was found to be above the adjusted time-weighted average of 30 μg/m3. These observations led to 2 citations, 1 under US OSHA personal protective equipment respiratory standard 1910.134 and the other under US OSHA lead exposure standard 1910.1025.
The third PHA involved the production of a fact sheet as part of a quarterly SC EPHT series, “Putting Tracking to Work for You.” This series focuses on epidemiological investigations that utilize environmental and/or health data tracked by SC EPHT. In this analysis, adult EBLL records with associated NAICS codes from 2011 to 2015 that were shared with SC OSHA were examined (n = 300), and mean EBLL values were compared by NAICS codes. The mean EBLL for remediation services industries and other amusement/recreation industries was found to be significantly higher than for other NAICS codes examined. Further investigation revealed that employees of only 1 remediation service company was represented in that category, and that specific company focused on cleanup and lead recovery activities at shooting ranges.
Based on SC EPHT surveillance of adult blood lead test records from 2010 to 2015, the number of tests received, as well as percentage of those tests that were elevated, have varied by year. Alarcon19 reported a 2013 EBLL rate of 5.2 per 100 000 employed population for 30 reporting ABLES states. This is similar to what was observed in SC from 2010 to 2015 utilizing the same calculation, suggesting that adult occupational exposure in SC is comparable with what has been observed nationally. Although prevalence of EBLL due to occupational exposure has been decreasing nationally since the mid-1990s,19 continued identification of adults with EBLL is vital to their individual health, given the numerous negative health effects associated with lead.4 , 8 , 12 , 16 In addition, it is of note that in SC, data associated with blood lead records were not being collected in a manner that streamlined tracking and surveillance until the SC EPHT program helped develop and implement the internal Web application for the collection of this vital public health data, and began collaborating with SC OSHA.
As part of continuous improvement related to blood lead surveillance in SC, SC EPHT is currently working to implement a new Web application as part of the South Carolina Infectious Disease and Outbreak Network (SCION). Since blood lead tests are a reportable condition in SC (like many infectious diseases), SC EPHT is developing a lead-specific module for this network. This module will allow primary care providers to enter blood lead test results manually, will tie in to the current DHEC electronic laboratory record reporting system, and will streamline reporting of results and follow-up for both children and adults with an EBLL. Implementation of this new SCION lead module is planned for the first half of 2017. The SC EPHT program has been responsible for funding the lead module, and SC EPHT staff have been heavily invested in programming the SC-specific lead question packages for both children and adults in order to meet program area needs related to follow-up and environmental assessments.
As mentioned previously, missing demographic information remains an issue with all blood lead test records DHEC receives. Even so, demographic differences were noted for adult records when that information was available. Most studies reviewed did not examine demographic differences, but those observed related to age and geographic location in SC as part of this study may be important. Individuals of younger age (16-64 years of age) had higher mean BLL values than those older than 65 years, though adults older than 65 years made up the largest percentage of the study population as compared to the other age groups examined. While those of younger age are likely employed at a higher rate, adults older than 65 years made up a quarter of both audio and video equipment manufacturing and architectural and structural metals manufacturing NAICS categories. Further investigation may be warranted regarding these observed age differences in the examined records, as well as differences by both age and industrial category. In addition, given that an adult may have a number of test records within the database, looking at trends over time by individual, or associations between BLL and age for those with multiple tests, may provide additional insight regarding occupational exposure to lead in SC.
Geographically, records with county information were generally dispersed evenly between the 4 DHEC regions. However, the mean BLL was higher for those in the northeast and central parts of SC than for those in the northwest and southeast. This may be a function of where industries associated with the potential for occupational lead exposure are located within SC, though additional investigation would be necessary to verify this. Another confounding factor is that the address used for geocoding to county may be the location of employment, the employee's residence, or the address of the laboratory or physician's office performing the analysis. Which address is reported would likely vary by year, laboratory performing the test, and patient demographics. Teasing out these address differences would improve lead surveillance in SC and allow for more complex spatial analyses; methods to improve address reporting and categorization for adults are currently in development.
One recent step aimed at addressing missing demographics involved the issuance of a notice by DHEC on the Health Alerts and Notifications Web resource to remind primary care providers that all blood lead test results are reportable in SC, and that certain demographic information is required as a part of this reporting. This update was released in July 2016, and analyses of completeness of records prior to and after the Health Alerts and Notifications release are forthcoming for both children and adults. As an agency, DHEC is also examining other ways to increase reporting and screening, as well as to increase data quality in blood lead test records beyond implementation of the SCION lead module.
North American Industry Classification System codes that were associated with significantly higher mean BLL were identified. The category with the highest mean BLL (remediation and other waste services) was also identified by Alarcon19 as the top service sector NAICS codes associated with EBLL nationally. Since NAICS codes are only obtained or provided for a subset of records, a goal of SC EPHT is to examine additional ways to gather more complete information on industrial categories for all adult blood lead test records. This is an important factor for the type of lead a worker can be exposed to, gives insight on the potential for lead exposure and testing for different NAICS categories, and is an important piece of information for SC OSHA staff related to their follow-up with industries. It is also hoped that the new SCION lead module, in combination with targeted education and training for providers, will increase reporting of employer information on blood lead test records associated with occupational exposure.
The collaboration between SC EPHT and SC OSHA has led to specific PHA for SC. These PHA are vital to the national EPHT program, as they show successes in grantee states and provide a quantifiable way to measure a grantee's performance. They are important to SC as they directly impact the health of citizens of our state. The EBLL records that SC EPHT provides to SC OSHA are used to initiate inspections. This means that follow-up on elevated adult blood lead records comes from both the primary care provider and the state organization targeted with protecting the health and safety of employees in SC. The adult blood lead surveillance that SC EPHT does for SC is vital to identification of EBLL in adults, citation of industries putting their employees at risk, and mitigation of exposure to these employees to protect their health. Also, the information gleaned from the “Putting Tracking to Work for You” fact sheet regarding the remediation services company and the specific remediation work they were doing was informative and important, since shooting ranges are a well-documented source of lead exposure.20 The SC EPHT program hopes to use this information to provide further education to employers and employees on the ways to reduce exposure to lead in the workplace.
The Department of Health and Environmental Control is committed to improving the health of those living and working in SC. Quality data collection and population surveillance are a vital part of that responsibility. This in-depth examination of adult blood lead records in SC from 2010 to 2015 has provided SC EPHT with additional insight on ways to enhance surveillance and improve data quality. It is hoped that the new SCION lead module will assist with this, along with continued monitoring of data completeness to help reduce missing information in records. In addition, the collaboration between SC EPHT and SC OSHA has resulted in inspections, citations, and mitigation for employers putting their employees at undue risk for occupational exposure to lead. Not only has this information provided PHA for the national EPHT program to showcase the work of SC EPHT, but this collaboration has directly impacted the health of those working in SC. The SC EPHT is committed to continued surveillance of all SC blood lead records and to the collaboration with SC OSHA in order to positively impact the health of all those living and working in SC.
Implications for Policy & Practice
- Increased surveillance of adult blood lead levels in SC can help identify demographic and regional differences related to both elevated lead levels and reporting, which can then be used to provide focused education and outreach around occupational testing and reporting requirements to appropriate audiences.
- Continued provision of elevated blood lead level test records to the SC Occupational Safety and Health Administration by the SC Department of Health and Environmental Control will ensure the safety of those at risk for occupational exposure to lead.
1. Hicken M, Gragg R, Hu H. How cumulative risks warrant a shift in our approach to racial health disparities: the case of lead, stress, and hypertension. Health Aff. 2011;30(10):1895–1901.
2. Jelliffe-Pawlowski LL, Miles SQ, Courtney JG, Materna B, Charlton V. Effect of magnitude and timing of maternal pregnancy blood lead (Pb) levels on birth outcomes. J Perinatol. 2006;26:154–162.
3. McFarlane AC, Searle AK, Van Hooff M, et al Prospective associations between childhood low-level lead exposure and adult mental health problems: the Port Pirie cohort study. Neurotoxicology. 2013;39:11–17.
4. Liao LM, Friesen MC, Xiang Y, et al Occupational lead exposure and associations with selected cancers: The Shanghai Men's and Women's Health Study cohorts. Environ Health Persp. 2016;124(1):97–103.
5. Xie X, Ding G, Cui C, et al The effects of low-level prenatal lead exposure on birth outcomes. Environ Pollut. 2013;175:30–34.
6. Yang H, Huo X, Yekeen TA, Zheng Q, Zheng M, Xu X. Effects of lead and cadmium exposure from electronic waste on child physical growth. Environ Sci Pollut Res. 2013;20:4441–4447.
7. Zhang A, Hu H, Sanchez BN, et al Association between prenatal lead exposure and blood pressure in children. Environ Health Persp. 2012;120(3):445–450.
8. Chatham-Stephens K, Caravanos J, Ericson B, Landrigan P, Fuller R. The pediatric burden of disease from lead exposure at toxic waste sites in low and middle income countries. Environ Res. 2014;132:379–383.
9. Magzamen S, Amato MS, Imm P, et al Quantile regression in environmental health: early life lead exposure and end-of-grade exams. Environ Res. 2015;137:108–119.
10. Ji JS, Schwartz J, Sparrow D, Hu H, Weisskopf MG. Occupational determinants of cumulative lead exposure: analysis of bone lead among men in the VA Normative Aging Study. J Occup Environ Med. 2014;56(4):435–440.
11. Julander A, Lundgren L, Skare L, et al Formal recycling of e-waste leads to increased exposure to toxic metals: an occupational exposure study from Sweden. Environ Int. 2014;73:243–251.
12. Grashow R, Spiro A, Taylor KM, et al Cumulative lead exposure in community-dwelling adults and fine motor function: comparing standard and novel tasks in the VA Normative Aging Study. Neurotoxicology. 2013;35:154–161.
13. McElvenny DM, Miller BG, MacCalman LA, et al Mortality of a cohort of workers in Great Britain with blood lead measurements. Occup Environ Med. 2015;72(9):625–632.
14. Sommar JN, Svensson MK, Björ BM, et al End-stage renal disease and low level exposure to lead, cadmium and mercury; a population-based, prospective nested case-referent study in Sweden. Environ Health. 2013:12;9.
15. Bellinger DC. Teratogen update: lead and pregnancy. Birth Defects Res A. 2005;73:409–420.
16. Joffe M, Bisanti L, Apostoli P, et al Time to pregnancy and occupational lead exposure. Occup Environ Med. 2003;60:752–758.
17. Baker EL, Folland DS, Taylor TA, et al Lead poisoning in children of lead workers—home contamination with industrial dust. New Engl J Med. 1977;296:260–261.
18. Longhman-Adham M. Renal effects of environmental and occupational lead exposure. Environ Health Persp. 1997;105(9):928–938.
19. Alarcon WA. Elevated blood lead levels among employed adults—United States, 1994-2013. MMWR Morb Mortal Wkly Rep. 2016;63:59–65.
20. National Research Council. Potential Health Risks to DOD Firing-Range Personnel From Recurrent Lead Exposure. Washington, DC: The National Academies Press; 2013.