Research ethics in pediatric environmental health: lessons from lead.

From my perspective, the ethical problems in pediatric environmental health research stem from a profound societal lack of understanding about the role that environment plays on health. An Institute of Medicine report states the environmental health hypothesis as follows: ‘‘Healthy environments promote individual and community health; unhealthy environments can create substantial morbidity, mortality, and disability, in addition to sapping economic welfare of societies’’ [16]. The connection between the environment and health is amply illustrated by lead. The purpose of my contribution is to describe empirical research findings as they pertain to lead and to explore the ethical consequences for failing to apply the environmental health hypothesis toward treating this preventable disease. Empirical research about the connection between community lead contamination and environmental health is from a series of studies conducted in New Orleans, LA, beginning in 1989 and being concluded in 2002. The exceptional sensitivity of young children to lead is related to their crawling and hand-to-mouth behavior plus their physiological need for minerals such as calcium and iron [1]. Children are super efficient absorbers of environmental minerals, and excessive lead absorption is one of the manifestations of these childhood characteristics. In addition to neurotoxicity, childhood exposure has long-term consequences to the immune and respiratory systems [3]. The total tolerable daily intake for lead is about 6 mg/day for very young children [2]. One of the first empirical studies we conducted was on the amount of lead children pick up on their hands during indoor and outdoor play at daycare centers of New Orleans. The usual approach for studying lead exposure is to screen children’s blood lead. Inserting needles into veins is traumatic to many children, and for this and other reasons, studies involving blood lead screening have been prohibited by most daycare centers. As an alternative approach for evaluating environmental health we developed a protocol for a hand wipe study of children that was benign and provided direct information to the owners of the daycare center about environmental trouble spots on their property [19]. Each child was its own control. First children’s hands were wiped after playing indoors. Then, the children went outdoors. Finally, the children’s hands were wiped a second time as they were returning inside from the outdoor play area. At private daycare centers in the inner city, the indoor play resulted in an average of 4 mg lead per hand, while outdoor play resulted in 28 mg lead per hand. In the outer city, children had an average of 3 mg lead per hand inside and 4 mg per hand after outdoor play. It is important to note that private daycare centers had bare soils. The study also included public daycare (Head Start) centers where the outdoor play areas had rubberized ground cover and no bare soils. In that situation there was only a small increase (from 1.4 to 1.9 mg lead averages per hand) between indoor and outdoor play [19]. We reasoned that on ordinary inner-city private properties children pick up and ingest more lead than children living in outer-city locations because the inner-city environment, especially outdoor play areas, contained larger quantities of accessible lead. While daycare centers may differ from ordinary homes, the findings are suggestive of the broader environmental health situation; lead-contaminated environments are linked with unhealthy levels of lead exposure by children. Further empirical research was conducted to test the environmental health hypothesis. Our studies focused on surveying the distribution of lead in the residential environment of the entire city of New Orleans located on the Mississippi River delta. New Orleans soils are of alluvial origin, meaning that they were transported as sediments by the Mississippi River from the entire watershed and were subsequently deposited (as alluvium) during annual flooding in the river delta. The fresh alluvium deposited along the river provides a measure of the modern background. The median background of alluvial soil lead is about 5 mg/g