Economically and Environmentally Sustainable Enhanced Oil Recovery. M. R. Islam

“evil spirit” has been known to imply inexplicable ailments, including mental illness (Islam et al., 2017). There have been reports of improvement of lungs and hearts owing to ‘moistening actions’ of cinnabar while consumed orally or even applied externally. Most significantly, cinnabar was known to be a cure of convulsion and epilepsy, as well as fetal toxicity and pox virus. It was also considered to prevent malaria (Wang, 2015).

      One such compound is mercury sulphide (cinnabar), which is known in ancient Chinese (called zhūshā, 朱砂), Greek and Arabic (called zinjafar, ) culture with universal use in medicine as well as general alchemy. Cinnabar has been used in traditional Chinese medicine as a sedative for more than 2000 years (Huanga et al., 2007). In addition to being used for insomnia, cinnabar is thought to be effective for cold sores, sore throat, and some skin infections.

Cinnabar is generally found in a massive, granular or earthy form and is bright scarlet to brick-red in color, has the highest refractive index of any mineral (King, 2002).

      It turns out that mercury compounds continued to be used in Europe during 15^th through 20^th century. In the era before synthetic antibiotics, sexually-transmitted diseases were of great concern. In search for a cure, various forms of mercury were tried. As such, mercury was the remedy of choice for syphilis in Protestant Europe. Paracelsus (1493-1541) formulated mercury as an ointment because he recognised the toxicity and risk of poisoning when administrating mercury as an elixir. Mercury was already being used in Western Europe to treat skin diseases.

      The dominating medical use of Hg, (in metallic form and as calomel, Hg₂Cl₂), in Sweden in the second half of the 19th century indicates that some persons were highly exposed to Hg, mainly for treatment of syphilis, and 0.3-1% of the population of 3.5-5 millions were treated for venereal diseases (10,000-50,000 patients).

      Sublimate (HgCl₂) is in certain countries still used as an antiseptic for wounds. It was used in large quantities during the World Wars, triggered by the largely increased use of Hg in explosives. Sublimate was also used for preserving wood.

      In the 1830′s, dental restorative material, called ‘amalgam’ was introduced to the United States. This amalgam was developed in England and France and contained silver, tin, copper, zinc and mercury. The amalgam fillings were not openly embraced by organized dentistry in America, and in 1840, members of the American Society of Dental Surgeons were required to sign pledges not to use mercury fillings. By this time, the current methods of refining metals (including mercury) have been in place. Mercury and its compounds used in dental practice may be responsible for release of mercury into the oral cavity. Compounds of mercury tend to be much more toxic than the element itself, and organic compounds of mercury (e.g., dimethyl-mercury) are often extremely toxic and may be responsible in causing brain and liver damage.

      Recently, Wang et al. (2013) conducted an interesting study. They orally administered various doses of cinnabar for 10 consecutive days, then studied the mercury levels. They discovered that the mercury level in serum and tissues are significantly higher than that of vehicle control (Table 2.2). The serum mercury levels in the cinnabar groups were increased in a dose-dependent manner. However, the serum mercury content for the cinnabar group was only about 1/100 of that of the HgCl₂ group at the same dose. The mercury levels in the brain tissue of the cinnabar group were raised slowly with the increasing dose and were about 1/19 of HgCl₂ group at the same dose. Similar to the pattern of the HgCl₂ group, mercury accrued more in kidney than in liver. However, in the HgCl₂ group, mercury accumulation was about 330 times higher than that of the cinnabar group.

      Table 2.2 Mercury contents after cinnabar and HgCl₂ administration for 10 days (From Wang et al., 2013).

Group	Serum (ng/ml)	Brain (ng/g)	Liver (ng/g)	Kidney (ng/g)
Vehicle	1.39 ± 0.05	2.96 ± 1.24	11.19 ± 4.31	14.24 ± 2.97
HgCl2 0.01 g/kg	401.94 ± 30.3	190.25 ± 11.8	5571.91 ± 1211	23592.40 ± 446
Cinnabar 0.01 g/kg	4.10 ± 0.47	10.63 ± 2.53*	25.58 ± 5.97	70.00 ± 18.02
Cinnabar 0.05 g/kg	14.63 ± 0.59	11.07 ± 2.10	32.73 ± 6.96	82.69 ± 20.02
Cinnabar 0.1 g/kg	26.75 ± 6.98	12.20 ± 1.44	84.75 ± 9.47	271.10 ± 49.25
Cinnabar 1 g/kg	75.30 ± 9.24	13.27 ± 2.22	89.47 ± 10.02	455.88 ± 76.93

      Meanwhile, there were no significant differences in the tissue distribution patterns between the cinnabar and pure HgS groups (Table 2.3) except that the pure HgS group accumulated mercury in the kidney ~2 times higher than that of the cinnabar group.

      Table 2.3 Mercury contents after cinnabar and HgS administration for 10 days (From Wang et al., 2013).

Group	Serum (ng/ml)	Brain (ng/g)	Liver (ng/g)	Kidney (ng/g)
Vehicle	1.52 ± 0.02	1.83 ± 0.49	5.71 ± 1.69	16.29 ± 1.19
Cinnabar 0.1 g/kg	24.62 ± 1.55	12.12 ± 1.19	77.57 ± 10.17	206.21 ± 33.76
HgS 0.1 g/kg	27.44 ± 3.29	8.03 ± 1.98	41.39 ± 9.78	454.56 ± 70.68

This study indicates that cinnabar is remarkably different from HgCl₂ in mercury absorption and tissue distribution. This finding is profound because up until recently synthetic chemicals were considered to be the same as natural chemicals (Khan and Islam, 2016). As will be discussed in latter chapters, this marks a bifurcation point in terms of natural chemicals following a different pathway from artificial chemicals.

      2.2.2 Sal Ammoniac

      Sal ammoniac is a naturally occurring substance, mainly containing NH₄Cl.