A novel method for the quantification of tire and polymer-modified bitumen particles in environmental samples by pyrolysis gas chromatography mass spectroscopy.

Tire and road wear particles may constitute the largest source of microplastic particles into the environment. Quantification of these particles are associated with large uncertainties which are in part due to inadequate analytical methods. New methodology is presented in this work to improve the analysis of tire and road wear particles using pyrolysis gas chromatography mass spectrometry. Pyrolysis gas chromatography mass spectrometry of styrene butadiene styrene, a component of polymer-modified bitumen used on road asphalt, produces pyrolysis products identical to those of styrene butadiene rubber and butadiene rubber, which are used in tires. The proposed method uses multiple marker compounds to measure the combined mass of these rubbers in samples and includes an improved step of calculating the amount of tire and road based on the measured rubber content and site-specific traffic data. The method provides good recoveries of 83-92% for a simple matrix (tire) and 88-104% for a complex matrix (road sediment). The validated method was applied to urban snow, road-side soil and gully-pot sediment samples. Concentrations of tire particles in these samples ranged from 0.1 to 17.7 mg/mL (snow) to 0.6-68.3 mg/g (soil/sediment). The concentration of polymer-modified bitumen ranged from 0.03 to 0.42 mg/mL (snow) to 1.3-18.1 mg/g (soil/sediment).

The Distribution of Essential, Trace, and Nonessential Minerals in Weanling Male Rats Fed Sheep or Cow Milk.

SCOPE: The aim of the study is to determine the effects of sheep milk consumption in comparison to cow milk on the mineral distribution in the soft organs and serum in a growing animal model system. As the mineral composition of cow and sheep milk differs, different effects on the bio-accumulations in the body may be observed. Differences in the mineral composition of cow and sheep milk may lead to different bioavailability or accumulation of minerals in the body. Newly weaned rats were fed either cow milk, sheep milk, or sheep milk diluted so that it had the same solid content as cow milk. At the end of the feeding trial, the concentration of minerals in the organs and plasma of the rats was assessed. The results indicate that the consumption of the high level of minerals in sheep milk does not have any negative effects in the rat model. METHODS AND RESULTS: Newly weaned male rats were fed ad libitum for 28 days on either cow milk, sheep milk, or sheep milk diluted to have the same concentration of milk solids as cow milk. Animals were euthanized and the soft organs and serum were harvested and then analyzed for mineral composition by inductively coupled plasma MS. Rats fed sheep milk had lower iron concentrations in the liver and higher concentrations of rubidium and cesium in all of the soft organs. The growth rate of the rats was not affected by the type of milk consumed. CONCLUSION: The concentration of essential and trace minerals in the liver is found to be significantly different between rats fed sheep milk compared to those fed cow milk (p < 0.05). The consumption of sheep milk does not affect the growth of animals.