Domestic dogs as sentinels of children lead exposure: Multi-pathway identification and source apportionment based on isotope technique

Environmental lead exposure poses risks to children’ health, thus exposure sources and pathways identification remain important concern and research scope. Due to sharing the same environment, domestic animals, especially dogs, have been used as useful sentinels to identify human lead exposure. However, more evidence is needed on whether domestic dogs could be used to identify the lead exposure pathways and sources of children. Thus, this study investigated the dietary habits, behaviors, and household environment of children and dogs in a typical coal-fired area in China. The lead levels and lead isotope ratios (Acronym: LIRs, expressed as 208Pb/206Pb and 207Pb/206Pb) in dogs' and children's blood, as well as in environmental media (food, PM2.5, indoor/outdoor dust, drinking water and soil) were measured to explore the predominant lead pollution sources and exposure pathways of children. The results showed that the LIRs of children's blood (208Pb/206Pb = 2.0703 ± 0.0076, 207Pb/206Pb = 0.8501 ± 0.0052) were similar to those of dogs' blood (208Pb/206Pb = 2.0696 ± 0.0085, 207Pb/206Pb = 0.8499 ± 0.0052), as well as similar to the LIRs of environmental media, i.e. children's food (208Pb/206Pb = 2.0731 ± 0.0057, 207Pb/206Pb = 0.8491 ± 0.0036) and coal (208Pb/206Pb = 2.0683 ± 0.017, 207Pb/206Pb = 0.8515 ± 0.01). Children and dogs had similar lead exposure pathways, but the contributions of each exposure pathway were different, i.e., 83.1% vs. 76.9% for children and dogs via food ingestion, 1.4% vs. 5.6% via particulate matter exposure, and 15.5% vs. 17.5% via household dust exposure, respectively. The contribution of food via ingestion to lead exposure remains dominant, and coal combustion is a main lead exposure source for children and domestic dogs. [Display omitted] •Behavior patterns of children and dogs were investigated through questionnaires.•Lead levels and isotope ratios in blood samples and environmental media were measured.•Children and dogs were exposed to lead in similar pathways and sources.•Food, PM2.5 and dust were the main media of lead exposure for children and dogs.•Food ingestion contributed 83.1% and 76.9% to children's and dogs' lead exposure.