Community- and family-level factors influence care-giver choice to screen blood lead levels of children in a mining community

Addressing systemic problems with exposure assessments to protect the public's health

BACKGROUND

Understanding, characterizing, and quantifying human exposures to environmental chemicals is critical to protect public health. Exposure assessments are key to determining risks to the general population and for specific subpopulations given that exposures differ between groups. Exposure data are also important for understanding where interventions, including public policies, should be targeted and the extent to which interventions have been successful. In this review, we aim to show how inadequacies in exposure assessments conducted by polluting industries or regulatory agencies have led to downplaying or disregarding exposure concerns raised by communities; that underestimates of exposure can lead regulatory agencies to conclude that unacceptable risks are, instead, acceptable, allowing pollutants to go unregulated; and that researchers, risk assessors, and policy makers need to better understand the issues that have affected exposure assessments and how appropriate use of exposure data can contribute to health-protective decisions.

METHODS

We describe current approaches used by regulatory agencies to estimate human exposures to environmental chemicals, including approaches to address limitations in exposure data. We then illustrate how some exposure assessments have been used to reach flawed conclusions about environmental chemicals and make recommendations for improvements.

RESULTS

Exposure data are important for communities, public health advocates, scientists, policy makers, and other groups to understand the extent of environmental exposures in diverse populations. We identify four areas where exposure assessments need to be improved due to systemic sources of error or uncertainty in exposure assessments and illustrate these areas with examples. These include: (1) an inability of regulatory agencies to keep pace with the increasing number of chemicals registered for use or assess their exposures, as well as complications added by use of 'confidential business information' which reduce available exposure data; (2) the failure to keep assessments up-to-date; (3) how inadequate assumptions about human behaviors and co-exposures contribute to underestimates of exposure; and (4) that insufficient models of toxicokinetics similarly affect exposure estimates.

CONCLUSION

We identified key issues that impact capacity to conduct scientifically robust exposure assessments. These issues must be addressed with scientific or policy approaches to improve estimates of exposure and protect public health.

A Pilot Study of Children's Blood Lead Levels in Mount Isa, Queensland

Mount Isa, Queensland, is one of three Australian cities with significant lead emissions due to nonferrous mining and smelting. Unlike the two other cities with lead mines or smelters, Mount Isa currently has no system of annual, systematic, community-wide blood lead level testing; and testing rates among Indigenous children are low. In previous screenings, this group of children has been shown to have higher average blood lead levels than non-Indigenous children. The first aim of this study was to assess whether parents and children would participate in less invasive, rapid point-of-care capillary testing. The second aim was to measure blood lead levels among a range of children that roughly reflected the percentage of the Indigenous/non-Indigenous population. This pilot study is based on a convenience sample of children between the ages of 12 and 83 months who were recruited to participate by staff at a Children and Family Centre. Over three half-days, 30 children were tested using capillary blood samples and the LeadCare II Point-of-Care testing system. Rapid point-of-care capillary testing was well tolerated by the children. Of 30 children tested, 40% (n = 12) had blood lead levels ≥5 µg/dL and 10% had levels ≥10 µg/dL. The highest blood lead level measured was 17.3 µg/dL. The percentage of children with blood lead levels ≥5 µg/dL was higher among Indigenous children compared to non-Indigenous (64.2% compared to 18.8%) as was the geometric mean level (6.5 (95% CI, 4.7, 9.2) versus 2.4 (95% CI, 1.8, 3.1)), a statistically significant difference. Though based on a small convenience sample, this study identified 12 children (40%) of the sample with blood lead levels ≥5 µg/dL. Due to historical and ongoing heavy metal emissions from mining and smelting in Mount Isa, we recommend a multi-component program of universal blood lead level testing, culturally appropriate follow-up and intervention for children who are identified with blood lead levels ≥5 µg/dL. We further recommend focused outreach and assistance to the Indigenous community, and further control of emissions and remediation of existing environmental lead contamination in children's play and residential areas.

Managing hazards in place: The risks of residual risks

Managing hazards in place (MHP) is a policy instrument in environmental health that allows less than complete removal, abatement, or remediation of environmental hazards. The practice of minimizing exposure to hazards rather than removing them is widely recognized as part of the toolbox of environmental protection for human and ecosystem health. The concept of managing hazards in place is embedded in several environmental statutes and regulations in the US notably the waste management regulations, as well as in the Safe Drinking Water Act and the Clean Water Act. While this commentary focuses largely on applications of MHP in the US, this policy is also utilized by agencies in many other countries for managing hazardous waste sites, lead in housing and drinking water systems, and environmental contamination of rivers and estuaries. The rationale for this concept is not difficult to understand: MHP policies can reduce the costs of meeting environmental goals; it can provide opportunities for access to resources that have been contaminated by past actions such as waste disposal, and it can enhance land and property values as well as tax revenues all of which are important to home owners and communities. The concerns related to this concept are also not difficult to understand: an incompletely abated or contained hazard may present future exposure risks to humans and environmental biota. Further, the compromise implicit in MHP is the assurance of indefinite oversight and monitoring to detect any releases. To that extent, MHP involves both sociology as well as toxicology and the exposure sciences. Because of the prevalence of managing hazards in place, this commentary suggests that evaluation of its performance is needed.

Principal components analysis to identify influences on research communication and engagement during an environmental disaster

OBJECTIVES

To discern community attitudes towards research engagement in Libby, Montana, the only Superfund site for which a public health emergency has been declared.

STUDY DESIGN

Survey study of convenience samples of residents near the Libby, Montana Superfund site.

PARTICIPANTS

Residents of the Libby, Montana area were recruited from a local retail establishment (N=120, survey 1) or a community event (N=127, survey 2).

MEASURES

Two surveys were developed in consultation with a Community Advisory Panel.

RESULTS

Principal components of survey 1 showed four dimensions of community members' attitudes towards research engagement: (1) researcher communication and contributions to the community, (2) identity and affiliation of the researchers requesting participation, (3) potential personal barriers, including data confidentiality, painful or invasive procedures and effects on health insurance and (4) research benefits for the community, oneself or family. The score on the first factor was positively related to desire to participate in research (r=0.31, p=0.01). Scores on factors 2 and 3 were higher for those with diagnosis of asbestos-related disease (ARD) in the family (Cohen's d=0.41, 0.57). Survey 2 also found more positive attitudes towards research when a family member had ARD (Cohen's d=0.48).

CONCLUSIONS

Principal components analysis shows different dimensions of attitudes towards research engagement. The different dimensions are related to community members' desire to be invited to participate in research, awareness of past research in the community and having been screened or diagnosed with a health condition related to the Superfund contaminant.

Effectiveness of introducing point of care capillary testing and linking screening with routine appointments for increasing blood lead screening rates of young children: a before-after study

Background

Lead has significant neuro-toxic effects, particularly for young children. Voluntary screening of pre-school aged children for elevated blood lead levels has been an important part of the lead management program in the mining town of Broken Hill (NSW, Australia) since 1991, where lead remains a significant public health issue for young children despite average blood lead levels having fallen by two-thirds. The annual proportion of children screened declined to 0.39 in 2008. The objective of this study was to determine the impact of changing to capillary screening and linking screening with existing routine health programs on participation in blood lead screening by young children in the community.

Methods

We used a before-after study. Screening rates were determined from routinely collected service data and analysed using cross-sectional and cohort analyses.

Results

The proportion of children screened annually increased from 0.39 in 2008 to 0.75 in 2012, with the greatest increases among 11–23 and 48–59 month old children. The proportion of children screened at least once by 24 months increased from 0.63 for children born in 2007 to 0.98 for children born in 2010. Attendance stabilized after capillary screening was introduced, and increased markedly after screening was offered at immunization.

Conclusons

Changing from venous to capillary screening stabilized attendance and improving convenience was associated with dramatically increased screening. Linking screening with well-accepted mainstream child health programs is an effective strategy to improve participation in blood lead screening programs. The findings have implications for improving participation in other health screening programs.

Ethical issues in using children's blood lead levels as a remedial action objective

The Environmental Protection Agency measures the success or failure of Superfund site remediation efforts against remedial action objectives (RAOs). RAOs are frequently based on environmental contaminant concentrations, but with lead exposure, blood lead levels from the population at risk are often used. Although childhood lead screening is an important public health tool, an RAO based on child blood lead levels raises ethical concerns: public health efforts that are more reactive than preventive, a blood lead standard (10 μg/dL) that may not be fully protective, the use of a measure whose validity and reliability may be easily compromised, and exacerbation of environmental injustice and systematic disadvantages. The example of Bunker Hill mine, Kellogg, Idaho, allowed an examination of these ethical concerns.

Effectiveness of a household environmental health intervention delivered by rural public health nurses

OBJECTIVES

Parents need meaningful and actionable information if they are to reduce household environmental health risks to their children. To address this issue, we tested the effectiveness of a multi-risk social/cognitive intervention on rural low-income parents' (1) environmental health self-efficacy and (2) stage of environmental health precautionary adoption.

METHODS

Biomarker (lead, cotinine) and household samples (carbon monoxide, radon, mold/mildew, and drinking water contaminants) were collected from 235 families (399 adults, 441 children) in Montana and Washington states. Families were randomly assigned to intervention or control groups; intervention families received 4 visits from public health nurses who provided tailored information and guidance to parents; controls received usual and customary public health services.

RESULTS

At 3 months, the intervention group had significantly higher scores on (1) all 6 risk-specific self-efficacy subscales (P < .01), (2) general environmental health self-efficacy (P < .001), (3) 5 of 6 risk-specific precaution adoption subscales (P < .05), and (4) general environmental health precaution adoption (P < .001).

CONCLUSIONS

The intervention yielded significant improvements in both outcomes. This evidence supported the need for a policy discussion addressing the added value that broadbased public health nurse interventions might bring to children's environmental health.

Community-based participatory research (CBPR) approach to study children's health in China: experiences and reflections

BACKGROUND

Community-based participatory research principles have been successfully applied to public health research in U.S. settings. While there is a long history of collaboration between government and communities in China, to date, community-based participatory research has not been used in children's environmental health studies.

METHOD

This article describes how community-based participatory research principles were applied by an international research group to the China Jintan Child Cohort Study, a longitudinal study of malnutrition and lead exposure on cognitive and neurobehavioral development. Challenges emerged and lessons learned from implementing the study were discussed and recommendations were presented.

CONCLUSION

We conclude that the community-based participatory research model can be applied in conducting and promoting environmental health research in China and researchers should be prepared for special challenges and cultural constraints in the implementation of the research in regards to human subject regulations, information dissemination, and culture.

Childhood lead poisoning from the smelter in Torreón, México

Lead concentrations and isotopic compositions in blood samples of 34 children (ages 2-17 years) living within a 113 km(2) area of a silver-zinc-lead smelter plant in Torreón, México were compared to those of associated environmental samples (soil, aerosols, and outdoor and indoor dust) to identify the principal source(s) of environmental and human lead contamination in the area. Lead concentrations of soil and outdoor dust ranged 130-12,050 and 150-14,365 μg g(-1), respectively. Concentrations were greatest near the smelter, with the highest levels corresponding with the prevailing wind direction, and orders of magnitude above background concentrations of 7.3-33.3 μg g(-1). Atmospheric lead depositions in the city varied between 130 and 1350 μg m(-2) d(-1), again with highest rates <1 km from the smelter. Blood lead (PbB) concentrations (11.0±5.3 μg dl(-1)) levels in the children ranged 5.0-25.8 μg dl(-1), which is 3-14 times higher than the current average (1.9 μg dl(-1)) of children (ages 1-5 years) in the US. Lead isotopic ratios ((206)Pb/(207)Pb, (208)Pb/(207)Pb) of the urban dust and soil (1.200±0.009, 2.467±0.003), aerosols (1.200±0.002, 2.466±0.002), and PbB (1.199±0.001, 2.468±0.002) were indistinguishable from each other, as well as those of the lead ores processed at the smelter (1.199±0.007, 2.473±0.007). Consequently, an elevated PbB concentrations of the children in Torreón, as well as in their environment, are still dominated by industrial emissions from the smelter located within the city, in spite of new controls on atmospheric releases from the facility.