Antlers as biomonitors of environmental pollution by lead and fluoride: A review

Antlers are periodically cast and re-grown cranial appendages of deer. Both endochondral and intramembranous ossification are involved in the formation of antler bone. After velvet shedding, antlers are completely bony structures which are referred to as hard antlers. Growing antlers accumulate substances with an affinity to mineralized tissues. Among these substances are lead and fluoride. Due to the seasonally limited life span of antlers, the concentrations of lead and fluoride in hard antlers reflect uptake by the forming bone during a defined, species-specific period of some months. Antlers can thus be viewed as naturally standardized environmental samples that are well suited as biomonitors of environmental pollution by bone-seeking contaminants. Because hard antlers are collected by hunters as trophies and kept in private or public collections, material for study can be obtained rather easily. So far, lead concentrations in hard antlers have been reported only from Europe, whereas data for fluoride are available from both Europe and North America. Some studies compared contaminant concentrations in antlers from different regions, while others analyzed time-trends in contaminant levels in antlers from a single region. Using the latter approach, a pronounced drop of lead concentrations during recent decades has been reported for antlers from various European countries. This indicates a marked decline of environmental lead levels that can be attributed mainly to the phase-out of leaded gasoline and, in addition, to a reduction of lead emissions also from stationary sources. In Germany, a corresponding drop has also been recorded for fluoride concentrations in antlers, which is attributed to a decline of fluoride emissions from stationary sources due to improved emission-control measures. There is some evidence that exposure to higher levels of fluoride may lead to an impaired antler mineralization. Using antlers as biomonitors has been shown to be an efficient method for assessing environmental pollution by lead and fluoride at low cost. Further studies using this now well established approach are therefore encouraged.This revised version was published online in May 2005. The following errors were eliminated:1. In the chapter Antler growth and mineralization in the last sentence of the first paragraph a slash was missing between the words reindeer and caribou; 2. In the second paragraph of the same chapter the word reiudees was corrected to reindeer; 3. In the chapter Accumulation of lead and fluoride in growing antlers the word lightest was corrected to highest.