Comparison between lead levels in dandelions grown in an ultra-clean lab environment (baseline) and those collected from the San Francisco Bay Area

This study is aimed at establishing the baseline (natural) levels of lead in dandelions (Taraxacum officinale) grown in an ultra-clean environment. Dandelions have been used extensively as biomonitors of environmental lead levels since their distribution is global and they can be easily collected. However, industrial lead contamination is so pervasive that even dandelions from the most remote areas in the world may be contaminated with industrial lead. Therefore, this work will test the hypothesis that “natural” lead levels in dandelions are lower than any previously published values – by growing them in a HEPA filtered air (Class 100) trace metal clean room with high purity (18 MΩ cm) water.  Concentrations and isotopic compositions of lead in the clean-room grown dandelions will be compared to values in literature and to those of lead in dandelions collected from San Francisco Bay Area.   Lead is a dense, ductile, and highly malleable metal that is found naturally in our environment. Due to its properties it is currently highly used in building construction, in ceramic glazes, lead chromate and in PVC plastic used to coat electrical cords.  The uses of lead have included paint, leather tanning, and being used as an additive to gasoline prior to the mid 1970’s, as well as others.  Due to its many uses, humans are susceptible to lead regularly through various means of exposure from air, water and soil, often leading to lead toxicity.