Red Rain in Kerala - Chemical Composition

Chemical Composition

Several groups of researchers analyzed the chemical elements in the solid particles, and different techniques gave different results. The particles were composed mostly of carbon and oxygen with lesser amounts of hydrogen, nitrogen, silicon, chlorine and metals.

Some water samples were brought to the Centre for Earth Science Studies (CESS) in India, where they separated the suspended particles by filtration. The pH (acidity) of the water was found to be around 7 (neutral). The electrical conductivity of the rainwater showed the absence of any dissolved salts. Sediment (red particles plus debris) was collected and analyzed by the CESS using a combination of ion-coupled plasma mass spectrometry, atomic absorption spectrometry and wet chemical methods. The major elements found are listed below. The CESS analysis also showed significant amounts of heavy metals, including nickel (43 ppm), manganese (59 ppm), titanium (321 ppm), chromium (67ppm) and copper (55 ppm).

Louis and Kumar used energy dispersive X-ray spectroscopy analysis of the red solid and showed that the particles were composed of mostly carbon and oxygen, with trace amounts of silicon and iron. A CHN analyzer showed content of 43.03% carbon, 4.43% hydrogen, and 1.84% nitrogen.

J. Thomas Brenna in the Division of Nutritional Sciences at Cornell University conducted carbon and nitrogen isotope analyses using a scanning electron microscope with X-ray microanalysis, an elemental analyzer, and an isotope ratio (IR) mass spectrometer. The red particles collapsed when dried, which suggested that they were filled with fluid. The amino acids in the particles were analyzed and seven were identified (in order of concentration): phenylalanine, glutamic acid/glutamine, serine, aspartic acid, threonine, and arginine. He concluded that the results were consistent with a marine origin or a terrestrial plant that uses a C4 photosynthetic pathway.

In April 2013, Wickramasinghe published that the 2013 Sri Lankan red rain cells have outer cell walls unusually rich in uranium, and a nuclear region with a strong deficit or absence of phosphorus, which he interprets as evidence of an unusual organism, and arguable evidence of a meteorite/cometary origin of the cells.