Changes

====Arsenosis in China====

====Arsenosis in China====

[[File:UNN_Medical_Geology_Fig_5.png|thumb|400px|{{figure number|5}}Hyperkeratosis/Ulceration of the Foot and Hands and Hair Fall-Out (Wuyi et al, 2003).]]

[[File:UNN_Medical_Geology_Fig_5.png|thumb|400px|{{figure number|5}}Hyperkeratosis/Ulceration of the Foot and Hands and Hair Fall-Out.<ref name=Wuyi>Wuyi, W., Y. Linsheng, H. Shaofan, and T. Jian’an, 2003. Mitigation of Endemic Arsenocosis with Selenium: an Example from China. HCWSkinner ARBerger, 51–56.</ref>]]

Arsenosis refers to a range of adverse health effects caused by the intake of arsenic into the body system above the recommended values of 50μg/l.

Arsenosis refers to a range of adverse health effects caused by the intake of arsenic into the body system above the recommended values of 50μg/l.

In Guizhou Province, China, the cool, damp autumn weather forces villagers to bring their harvest of chili peppers and corn indoors to dry. They hang the peppers over unvented stoves which were formally fueled by wood. But, due to the destruction of forests, wood became scarce; so, the villagers turned to the plentiful outcrops of coal for heating, cooking and drying their harvests.<ref name=Fnklman2010a /> Unknowingly to them, mineralizing solutions in this area had deposited enormous concentrations of arsenic − up to 35,000 ppm − and other trace elements on the coals. It should be noted that normal coals have arsenic concentration of 20 ppm. Consumption of the chili peppers dried over these arsenic-rich coals exposed the natives to arsenosis. The dried chili peppers contained up to 500 ppm of arsenic whereas normal chili peppers contain less than 1 ppm of arsenic (Wuyi et al, 2003). In addition, inhalation of arsenic-laden indoor air derived from coal combustion has increased the toll of arsenic poisoning in the region.<ref name=Fnklman2005 />

In Guizhou Province, China, the cool, damp autumn weather forces villagers to bring their harvest of chili peppers and corn indoors to dry. They hang the peppers over unvented stoves which were formally fueled by wood. But, due to the destruction of forests, wood became scarce; so, the villagers turned to the plentiful outcrops of coal for heating, cooking and drying their harvests.<ref name=Fnklman2010a /> Unknowingly to them, mineralizing solutions in this area had deposited enormous concentrations of arsenic − up to 35,000 ppm − and other trace elements on the coals. It should be noted that normal coals have arsenic concentration of 20 ppm. Consumption of the chili peppers dried over these arsenic-rich coals exposed the natives to arsenosis. The dried chili peppers contained up to 500 ppm of arsenic whereas normal chili peppers contain less than 1 ppm of arsenic.<ref name=Wuyi /> In addition, inhalation of arsenic-laden indoor air derived from coal combustion has increased the toll of arsenic poisoning in the region.<ref name=Fnklman2005 />

Chemical and mineralogical tests conducted showed that there were many arsenic-bearing minerals in the coals, although, much of the arsenic is bound to the organic matrix of the coals. This observation presented two problems namely: (1) since arsenic is bound to the organic matrix, conventional reduction methods of removing arsenic was ineffective; (2) the visually observable pyrite on the coal samples was not reliable in establishing arsenic-rich samples.

Chemical and mineralogical tests conducted showed that there were many arsenic-bearing minerals in the coals, although, much of the arsenic is bound to the organic matrix of the coals. This observation presented two problems namely: (1) since arsenic is bound to the organic matrix, conventional reduction methods of removing arsenic was ineffective; (2) the visually observable pyrite on the coal samples was not reliable in establishing arsenic-rich samples.

To curtail IDD, salt iodization programme has been introduced, not only in this region but in all African countries. However, this project has not yielded maximum results due to the counteracting effect of goitrogens in the African diet. Goitrogenic effect comes from certain vegetables such as brassica. It proceeds by depressing the formation of thyroid hormone leading to increased secretion of thyroid stimulating hormone (TSH). The thyroid gland responds to this by enlarging itself as a compensating mechanism leading to the development of goiter ([[:File:UNN_Medical_Geology_Fig_6.png|Figure 6]]).<ref name=Dvies /> Another substance with goitrogenous effect is thiocyanate which is present in cassava consumed in many African countries. It inhibits the entrance of iodine into the thyroid gland.<ref name=Dvies />

To curtail IDD, salt iodization programme has been introduced, not only in this region but in all African countries. However, this project has not yielded maximum results due to the counteracting effect of goitrogens in the African diet. Goitrogenic effect comes from certain vegetables such as brassica. It proceeds by depressing the formation of thyroid hormone leading to increased secretion of thyroid stimulating hormone (TSH). The thyroid gland responds to this by enlarging itself as a compensating mechanism leading to the development of goiter ([[:File:UNN_Medical_Geology_Fig_6.png|Figure 6]]).<ref name=Dvies /> Another substance with goitrogenous effect is thiocyanate which is present in cassava consumed in many African countries. It inhibits the entrance of iodine into the thyroid gland.<ref name=Dvies />

In China, about 425 million people are at risk of IDD. In iodine deficiency areas, a serious shortage of iodine intake by pregnant women would affect the development of the nervous system of the fetus and newborn infants would likely suffer from cretinism and related health problems (Zheng et al, 2010). Endemic cretinism prevailed in Chinese regions with acute iodine shortage. Analysis showed that places with iodine threshold of 25μg suffer from endemic cretinism whereas places with only goiter usually have iodine threshold of 50 μg. This triggered off a research into the relationship between goiter and cretinism in 25 provinces on 750,000 persons. The research showed that goiter had an average prevalence rate of 24.92% while cretinism had an average prevalence rate of 3.15% (Zheng et al, 2010). Fortunately, inhalation of iodine volatized from coal has contributed to increased reduction in the goiter cases.

In China, about 425 million people are at risk of IDD. In iodine deficiency areas, a serious shortage of iodine intake by pregnant women would affect the development of the nervous system of the fetus and newborn infants would likely suffer from cretinism and related health problems.<ref>Zheng, B., B. Wang, and R. B. Finkelman, 2010. Medical Geology in China: Then and Now. In: Selinus, O., Finkelman, R.B. and Centeno, J.A., (eds), Medical Geology: A Regional Synthesis, 303–319.</ref> Endemic cretinism prevailed in Chinese regions with acute iodine shortage. Analysis showed that places with iodine threshold of 25μg suffer from endemic cretinism whereas places with only goiter usually have iodine threshold of 50 μg. This triggered off a research into the relationship between goiter and cretinism in 25 provinces on 750,000 persons. The research showed that goiter had an average prevalence rate of 24.92% while cretinism had an average prevalence rate of 3.15% (Zheng et al, 2010). Fortunately, inhalation of iodine volatized from coal has contributed to increased reduction in the goiter cases.

===Health effects resulting from the deficiency and excessiveness of selenium===

===Health effects resulting from the deficiency and excessiveness of selenium===

===Health effects of Cadmium, Cd===

===Health effects of Cadmium, Cd===

<gallery mode=packed heights=300px widths=300px>

<gallery mode=packed heights=300px widths=300px>

UNN_Medical_Geology_Fig_8.png|{{figure number|8}}Distribution of Cadmium in the central districts of Jamaica (after Wright et al, 2010).

UNN_Medical_Geology_Fig_8.png|{{figure number|8}}Distribution of Cadmium in the central districts of Jamaica<ref name=Wright>Wright, P. R. D., R. Rattray, and G. Lalor, 2010, A Regional Perspective of Medical Geology– Cadmium in Jamaica. In: O. Selinus, R. B. Finkelman, and J. A. Centeno, (eds), 2010, Medical Geology: A Regional Synthesis, 36–45.</ref>

UNN_Medical_Geology_Fig_9.png|{{figure number|9}}Correlation between yam Cd concentration and soil Cd concentration (Wright et al, 2010).

UNN_Medical_Geology_Fig_9.png|{{figure number|9}}Correlation between yam Cd concentration and soil Cd concentration.<ref name=Wright />

</gallery>

</gallery>

Cadmium is highly toxic to humans. According to Hutton,<ref name=Htton /> it mainly accumulates in soft tissues such as the kidneys and liver. In Japan, it is the cause of a disease known as itai-itai–a disease that affects mainly women.<ref name=Hisashi>Hisashi, N., F. Kunio, and K. Takashi, 2010, Medical Geology in China. In: Selinus, O., Finkelman, R.B. and Centeno, J.A., eds, Medical Geology: A Regional Synthesis, 329–338.</ref> Its symptoms include: backaches, pain in the limbs, arthralgia and pain in the pubic bones. This is the direct result of the loss of calcium in bones. The loss makes the bones to be fragile and causes the development of fractures. The victim remains in pain until death. In a particular autopsy conducted, 72 fracture points were seen.<ref name=Hisashi />

Cadmium is highly toxic to humans. According to Hutton,<ref name=Htton /> it mainly accumulates in soft tissues such as the kidneys and liver. In Japan, it is the cause of a disease known as itai-itai–a disease that affects mainly women.<ref name=Hisashi>Hisashi, N., F. Kunio, and K. Takashi, 2010, Medical Geology in China. In: Selinus, O., Finkelman, R.B. and Centeno, J.A., eds, Medical Geology: A Regional Synthesis, 329–338.</ref> Its symptoms include: backaches, pain in the limbs, arthralgia and pain in the pubic bones. This is the direct result of the loss of calcium in bones. The loss makes the bones to be fragile and causes the development of fractures. The victim remains in pain until death. In a particular autopsy conducted, 72 fracture points were seen.<ref name=Hisashi />

Health issues arising from high cadmium concentration has also been established in the central parts of Jamaica ([[:File:UNN_Medical_Geology_Fig_8.png|Figure 8]]). It occurs in the soil of a region with limestone and an overlying aluminum-rich bauxite deposit (Wright et al, 2010). Cadmium exists in a phosphatic band that forms the interface between the two lithologies. Further research indicates that the phosphatic band contains fossilized fish bones and teeth suggesting a marine origin. The processes of weathering release cadmium from the phosphatic band into the soil.

Health issues arising from high cadmium concentration has also been established in the central parts of Jamaica ([[:File:UNN_Medical_Geology_Fig_8.png|Figure 8]]). It occurs in the soil of a region with limestone and an overlying aluminum-rich bauxite deposit.<ref name=Wright /> Cadmium exists in a phosphatic band that forms the interface between the two lithologies. Further research indicates that the phosphatic band contains fossilized fish bones and teeth suggesting a marine origin. The processes of weathering release cadmium from the phosphatic band into the soil.

This has drastically increased the cadmium level in Jamaican soil to maximum values of 900 mg/kg against cadmium levels in other parts of the world which range from 0.1 mg/kg to 0.5 mk/kg (Wright et al, 2010).

This has drastically increased the cadmium level in Jamaican soil to maximum values of 900 mg/kg against cadmium levels in other parts of the world which range from 0.1 mg/kg to 0.5 mk/kg.<ref name=Wright />

The cadmium storage ability varies greatly in the various parts of plants, namely: the fruit, roots and the leaf as shown by tests conducted on food crops root crops, legumes and vegetables (Wright et al, 2010) (Table 5).

The cadmium storage ability varies greatly in the various parts of plants, namely: the fruit, roots and the leaf as shown by tests conducted on food crops root crops, legumes and vegetables (Table 5).

{| class="wikitable"

{| class="wikitable"

|-

|-

|+ Table 5: Concentrations of Cadmium in various plant species in Jamaica (Wright et al, 2010).

|+ Table 5: Concentrations of Cadmium in various plant species in Jamaica.<ref name=Wright />

|-

|-

! Food Category || Number of Samples || Range (Conc. in mg/kg)

! Food Category || Number of Samples || Range (Conc. in mg/kg)

Amongst the above plant species, yam and carrot show the greatest ability to store cadmium. The concentration of cadmium in yam increases as the soil Cd level increases; it, however, decreases at low levels indicating toxicity as shown in [[:File:UNN_Medical_Geology_Fig_9.png|Figure 9]].

Amongst the above plant species, yam and carrot show the greatest ability to store cadmium. The concentration of cadmium in yam increases as the soil Cd level increases; it, however, decreases at low levels indicating toxicity as shown in [[:File:UNN_Medical_Geology_Fig_9.png|Figure 9]].

Toxicity effects of cadmium occurred in Jamaica as a result of food intake from Cd- contaminated food crops, legumes and vegetables. The mean Cd intake was 9.3 μg/kg bodyweight/week above WHO guideline of 7 μg/kg bodyweight/week while the drinking water standard for cadmium is 5μg l-1 (Wright et al, 2010).

Toxicity effects of cadmium occurred in Jamaica as a result of food intake from Cd- contaminated food crops, legumes and vegetables. The mean Cd intake was 9.3 μg/kg bodyweight/week above WHO guideline of 7 μg/kg bodyweight/week while the drinking water standard for cadmium is 5μg l-1 .<ref name=Wright />

===Health effects of radon gas===

===Health effects of radon gas===

   

   

*  

*  

* Wright, P.R.D., Rattray, R. and Lalor, G., 2010. A Regional Perspective of Medical Geology– Cadmium in Jamaica. In: Selinus, O., Finkelman, R.B. and Centeno, J.A., (eds) 2010. Medical Geology: A Regional Synthesis, 36–45.

*  

* Wuyi, W., Linsheng, Y., Shaofan, H. and Jian’an T., 2003. Mitigation of Endemic Arsenocosis with Selenium: an Example from China. HCWSkinner ARBerger, 51–56.

*  

* Zheng, B., Wang, B. and Finkelman, R.B., 2010. Medical Geology in China: Then and Now. In: Selinus, O., Finkelman, R.B. and Centeno, J.A., (eds), Medical Geology: A Regional Synthesis, 303–319.

*  

* Zumdahl, S.S., 2009. Chemical Principles. Houghton Miffin Company, 120p.

* Zumdahl, S.S., 2009. Chemical Principles. Houghton Miffin Company, 120p.