Lead bioaccumulation in emydid turtles of an urban lake and its relationship to shell disease

Urban runoff contributes significant amounts of heavy metals into receiving waters in which turtles make up a large portion of the biodiversity. Turtles accumulate heavy metals in their body and shell bone, yet little is known about how it affects their health. Studies in vertebrates have shown bioaccumulation of lead to have several deleterious effects such as immunosuppression, impairment of skeletal calcification and competition with calcium ion uptake. This study surveys the bioaccumulation of lead in emydid turtles of an urban lake and investigates the differences based on species, sex, size and its possible relationship to shell disease. Shell disease was quantified and small sections of shell were collected from each specimen and analyzed for lead content using Graphite Furnace Atomic Adsorption Spectrometry. Significant differences of lead accumulation were found between species, yet not with sex or body size. Linear regression comparison of lead concentration and shell disease showed no positive correlation.