Elemental status of grazing animals located adjacent to the London Orbital (M25) motorway.

This research examined the amount of different elements (including metals potentially harmful to health) found in the blood and wool or hair of animals grazing near the M25 motorway in London, using advanced laboratory techniques. It found that some of these elements, particularly lead and cadmium, were significantly higher in animals living near the motorway than in control animals.

Experimental Setup and Techniques

• The researchers studied lead (Pb), bromine (Br), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), selenium (Se), vanadium (V), and zinc (Zn) content in the blood and wool or hair of animals (sheep, horses and alpacas) living alongside the M25 motorway in London.
• Their measurements were performed with an analytical method called inductively coupled plasma mass spectrometry (ICP-MS), which provides high-precision quantitative analysis of element concentrations.
• Quality control was ensured through means such as comparing measurements with flameless atomic absorption spectroscopy and considering the results from the analyses of the international reference material IAEA A13 Animal Blood.

Findings

• The research showed that lead (Pb) and cadmium (Cd) levels in the blood of sheep grazing near the M25 were significantly higher compared to control animals. Lead levels ranged from 0.15-0.51 micrograms per milliliter in M25 sheep, whereas in control group the range was 0.04-0.18 micrograms per milliliter.
• The study also found higher levels of several elements (Br, Cd, Cr, Cu, Ni, Pb, V, Zn) in the wool of animals living near the motorway compared to the control group.
• There were also higher amounts of cadmium and lead in the blood or hair of the horses and alpacas that lived by the M25.

Interpretation and Implications

• A highly significant correlation was observed between the amounts of lead in the blood and in the wool or hair for all three types of animals. This suggests that such external samples (e.g. wool or hair) could potentially be used as indicators of lead exposure in such animals in the future. The correlation was particularly strong for sheep (r=+0.89).
• The increased levels of certain elements, particularly lead and cadmium, in animals living near the motorway may imply potential health risks due to exposure to vehicle emissions. Such findings address the environmental impact of motor vehicle emissions and underscore the potential risks to animals and, by extension, to human health due to bioaccumulation through the food chain. Further studies may be needed to elucidate these possible health implications.