Research Paper Sample on Arsenic Exposure: Health Risks and Long-Term Effects

Introduction

Arsenic is a chemical compound that is classified as a metalloid whose common oxidation states in the atmosphere are arsenite (AsIII) and arsenate (AsV), which exhibit various toxicity grades (Stueckle et al., 2012). Arsenic compounds exist in organic form when combined with hydrogen and carbon as well as inorganic form when combined with sulfur, chlorine, or oxygen. Long term exposure to arsenic has always been connected to various human health concerns such as skin cancer. Moreover, there are various sources of arsenic such as water, air, and food, which possess different threat levels to human health. Due to the element’s physical characteristics such as no flavour, colour, nor odour, its exposure is always unnoticed especially when consumed continuously through drinking water (Hughes et al., 2011).

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Save 25%

The delicate balance between ROS scavenging and balance is often distributed by various stress factors like pathogen infection, high irradiance, pollution, heavy metals, extreme temperatures, drought, and salinity (Hughes et al., 2011). Thus, plant survival relies on various significant factors such as duration and severity of stress conditions, conditions of growth, and their capacity to quickly adapt to the changing equation of energy. However, only 2% of the oxygen consumption by plant tissues results in ROS formation making some plants to be remedies of ROS. The paper, therefore, expounds on the carcinogenic effects of occupational exposure of Arsenic on human skin as well as how the molecules of Hibiscus flower can be used as a remediation effect to reduce Reactive Oxygen Species that decreases carcinogenicity.

Arsenic Occupational Exposure

Arsenic gets construed as a naturally occurring element that is vastly distributed in the crust of the earth. The element is chemically classified as a metalloid as it has both properties of a nonmetal and a metal. Elemental arsenic, is, however, a grey solid steel material (Surdu et al., 2013). Arsenic is distributed in the earth’s environment combined with other elements such as sulfur, chlorine, and oxygen. Thus, when arsenic combines with the depicted elements, it is referred to as inorganic arsenic. Organic arsenic is formed when arsenic combines with hydrogen and carbon that forms arsenocholine and arsenobetaine that are nontoxic as opposed to the toxic inorganic forms. The commonly known toxic inorganic compounds are arsenate (As5+/AsV) and arsenite (As3+/AsIII) (Surdu et al., 2013).

The inorganic Arsenate is chemically readily reduced to arsenite that is further broken down to the subsequently less toxic methylated metabolites dimethylarsinic acid (DMA) and monomethyl arsenic acid (MMA) (Boffetta et al., 2011). Additionally, soluble inorganic arsenic is considered to be toxic as its consumption for a long period can result in arsenicosis (chronic arsenic poisoning). The effects, which take long to develop depending on the exposure level, include cancer, cardiovascular disease, renal system effects, diabetes, gastrointestinal symptoms, peripheral neuropathy, and skin lesions (Chung et al., 2014). Organic arsenic compounds, that are vastly found in seafood, are, however, less harmful to human health as they are rapidly excreted or eliminated by the body.

Ethically, arsenic is classified as a first-class human carcinogen by various national and international health agencies, which implies that there is enough carcinogenicity evidence to humans (Hughes et al., 2011). However, despite various proofs in humans, models of animals still fail to replicate the observed effects that hinder exact action mode elucidation underlying in the arsenic-related carcinogenicity.

Skin and various kinds of internal cancers such as lung, prostate, liver, kidney, and bladder are associated with the ingestion of arsenic. The most common neoplasm form associated with arsenic ingestion is skin cancer while other types of cancer such as lung cancer correspond to deadly arsenic (Hong et al., 2014). Interestingly, As2O3 or arsenic trioxide is often used as an agent for chemotherapy for different types of cancer, with studies showing a high response percentage in patients with APL (Acute Promyelocytic Leukemia) (Hughes et al., 2011).

Routes of Arsenic Exposure

Arsenic is vastly distributed in the earth’s crust as metal arsenides and arsenates or an arsenic sulfide. The compound can be released to the atmosphere as trioxide by processes of high temperature. As it reaches the atmosphere, it is adsorbed by various particles then dispersed by wind and deposited on water or land. Moreover, arsenic can find its way into water and atmosphere through natural activities such as mineral dissolution especially into groundwater, wind-blown dust, exudates from vegetation, and volcanic activity (Hughes et al., 2011). Historic sources remobilization like mine drainage water and drinking water mobilization from deposits of geology by drilling of tube wells.

Industrial Processes

The primary occupational exposure route is through inhalation of particles containing arsenic, but dermal exposure and ingestion might also be significant in some situations such as during the preparation of wood treated with arsenate of chromate copper (Poreba et al., 2011). Moreover, the greatest arsenic occupational exposure takes place in the smelting of various non-ferrous metal where the arseniferous ores are often used. Arsenic is used in the glass and pharmaceutical industries, manufacture of poison baits, antifouling paints, arsenic-containing pigments, leather preservatives, sheep dips, and alloy. The compounds are also employed in optical and microelectronics industries. Additionally, arsenic is widely used in pesticides and insecticides due to its germicidal power (Reichard and Puga, 2010).

The inorganic compounds, especially sodium arsenite, is used as a non-selective soil sterilant and a weed killer. Nevertheless, in smelting industries, workers are always exposed to arsenic as the used heavy metals are dangerous to human health. Although the metals are naturally present in the ecosystem, their exposure to mankind is via numerous anthropogenic actions of human (Karami et al., 2011). In the crust, heavy metals exist in the form of ores which are always recovered during mining. In most ores, heavy metals like cobalt, silver, nickel, gold, zinc, copper, lead, iron, and arsenic exist as sulfides while aluminum, antimony, selenium gold, and manganese exits as oxides. Certain heavy metals like cobalt, iron, and copper exist both as oxide and sulfide ores. Nevertheless, some sulfides might contain more than two heavy metals such as chalcopyrite that has both iron and copper (Poreba et al., 2011).

When mining takes place, heavy metals are released from the depicted ores and scattered open in the sites, which are then transported by water and air to other areas. When the heavy metals are used for various industrial purposes, some of the depicted compounds are released into water bodies or soil as effluents or to the air during combustion (Chung et al., 2014). Additionally, industrial products such as herbicides, pesticides, cosmetics, and paints serve as heavy metals’ sources which might be transported through acid rain and erosion to various locations on water bodies and soils (Lu et al., 2014).

The depicted heavy metals cause toxicity in living cells, especially the human skin, by following an ionic mechanism as well as oxidative stress. The oxidative stress in the living cells found in the human skin is caused by the imbalance between free radicals’ production and antioxidants generation to repair the resulting damage or detoxify the reactive intermediates. Moreover, antioxidants like glutathione that is always present in the skin cells products it from free radicals like hydrogen peroxide (Surdu, 2014). However, under the influence of the metals, the ROS level increases, decreasing the antioxidants level. Since glutathione exists in oxidized and reduced states, its reduced form gives its reducing equivalents of (H+ + e−) from the thiol cysteine groups to ROS to stabilise. Since free radicals collect electrons from molecules of lipids inside the cell membrane, lipid peroxidation is caused. ROS, at high concentrations, causes structural damage to skin cells, lipids, and membranes leading to a stressed cellular situation level (Reichard and Puga, 2010).

Carcinogenic Effects of Arsenic Occupational Exposure on Human Skin and Its Detrimental Effects

Carcinogenesis is considered as a multistage process that involves inappropriate normal cellular genes activation to become oncogenes such as ras genes as well as the inactivation of other cellular genes referred to as the tumour suppressor genes (Ren et al., 2011). The prototypic suppressor genes of tumors are often suited as molecular links between cancer causes, that is, carcinogenic physical and chemical agents, specific viruses, and clinical cancer development. The crucial variation between cancerous and normal cells often stem from discrete alterations in specific genes that control tissue homeostasis and proliferation (Dopp et al., 2010). Nevertheless, progress in the fields of molecular epidemiology and carcinogenesis often raises people’s ability to assess the risks of cancer.

Skin Cancer

Skin cancer is the primary malignancy connected with the ingestion of arsenic via drinking water. The pathological cell types of skin cancer include malignant melanoma, squamous cell carcinoma (SqCC), and basal cell carcinoma (BCC) (Wong and Wang, 2010). The relationship between skin cancer and arsenic has always been a health concern for many decades. The first made inferences were through observations of increased frequency cases of skin cancer following treatment with 1% of potassium arsenite (Fowler’s solution) (Cao et al., 2010), formerly used for various haematological and skin disorders. Squamous cell carcinoma (SqCC), basal cell carcinoma (BCC), and Bowen’s disease (carcinoma in situ or intraepithelial carcinoma) are the most common malignancies found in patients who have been exposed to arsenic for a long period (Cao et al., 2010).

Nonetheless, arsenic-related skin squamous cell carcinoma can progress from Bowen’s disease or develop de novo, whereas arsenic-related basal cell carcinoma often develops in areas of the body covered from the exposure of the sun and multiple foci, opposing cases that originate from other skin carcinogens like ultra-violet light. Bowen’s disease that is related to arsenic, in most cases, often appears ten years after being continually exposed to arsenic, while the latency period of other types of skin cancer is 20 or 30 years (Martinez et al., 2010).

Conclusion

Thus, arsenic is classified as a first-class human carcinogen as it has various evidential carcinogenicity to humans. The common effects of arsenic include cancer of the skin, lung, liver, kidney, prostate, bladder, to mention but a few. Moreover, molecular oxygen is introduced to the atmosphere by oxygen-evolving photosynthetic organisms, causing the Reactive Oxygen Species (ROS) advent as unwanted byproducts. ROS is constantly generated by aerobic respiration that is confined to different cellular of plant compartments such as peroxisomes, mitochondria, and chloroplast.