Chapter 1THE PROBLEM AND ITS SETTINGIntroduction Until today, contamination of heavymetals in the environment is a major global concern due of its toxicity to thehuman life and ecosystem.
Human exposure to these heavy metals throughinhalation, skin contact and even ingesting contaminated food and beverages mayintroduce some adverse effects to the body. These effects may either be toxic(acute, chronic or sub-chronic), neurotoxic, or even carcinogenic, mutagenic orteratogenic. Arsenic (As), considered to be a naturally occurring component ofthe earth’s crust is a carcinogenic heavy metal of the Nitrogen group. Known tobe the King of Poisons, this environmental intoxicant is highly toxic in itsinorganic form and contributes to the contamination of air, agricultural soils,and water supplies. Its presence in water irrigation and agricultural soilsincreases Arsenic’s capability of finding their way in the human food chain.
Rice(Oryza sativa), considered to be astaple food of over half of the world’s population is one of the food cropsthat are at high risk of Arsenic contamination. Being grown in water-flooded conditions where high levels of wateraccumulation is needed for plant’s survival, rice roots has the tendency to absorb toxic heavy metalscontained in soil and water much more effectively than most plants. Allowingheavy metals to be more easily taken up by its roots and stored on the grains.
Innumerous areas where rice is cultivated, the use of As-contaminated irrigationwater results to the build-up of Arsenic (As) levels in soil. Excessiveaccumulation of this element, particularly inorganic As in rice poses apotential health risks to population with high rice consumption such as thePhilippines.Thepresence, consumption, and long-term exposure to inorganic arsenic, mainlythrough drinking-water and food, including rice can lead to chronic arsenicpoisoning that may be observed by to pigmentation changes, skin lesions andhard patches on the palms and soles of the feet (hyperkeratosis). These occurafter a minimum exposure of approximately five years and may be a precursor toskin cancer. In addition to skin cancer, long-term exposure to arsenic may alsocause cancers of the bladder and lungs (World Health Organization, 2017).Theaforementioned cases influenced the researchers to study about the toxicitylevel of Arsenic in rice grains and irrigation waters. Determining the levelsof this carcinogenic metal will aid the proponents of this study to producebaseline data for future research. Statement of the Problem This study aimed to determine the level oftoxicity in rice grains and irrigation waters at Maco, Compostela Valley.
Specifically, it seeks to answer the following questions:1. What is the role of irrigation water onArsenic contamination in rice grains?2. How can Arsenic be contained in irrigationwaters?3. Is there a significant difference betweenthe levels of Arsenic on rice grains and irrigation waters? Theoretical Framework Arsenic is ametalloid, a natural element that is not actually a metal but which has some ofthe properties of metal. It is a natural component of the Earth’s crust,generally found in trace quantities in all rock, soil, water and air.
However, issignificant when concentrations are higher leading in acute to chronicdiseases. Presence of Arsenic is more prominent in certain areas in theindustrial zone where factories and mining industries are present. Contaminatedwater used for drinking, food preparation and irrigation of food crops posesthe greatest threat to public health from arsenic (World Health Organization,2017).
Ingestion of low dose via food orwater is the main pathway of this metalloid into the organism, where absorptiontakes place in the stomach and intestines, followed by the released in thebloodstream. In chronic poisoning, arsenic is then converted by the liver to aless toxic form, from where it is eventually largely excreted in the urine. The incidence of arsenic contaminationof both rice grains and irrigation water has taken the dimension of anepidemiological problem. It has been established that arsenic is extremelytoxic in the body when found in concentrations higher than 1 ppm (Agency forToxic Substances and Disease Registry, 2009).
It enters into the human bodythrough ingestion, inhalation or skin absorption. After entering into the bodyit is distributed in the large number of organs including the lungs, liver,kidney and skin. The clinical manifestation of arsenic poisoning are myriad,and the correct diagnosis depends largely on awareness of the problem. Conceptual FrameworkIndependentVariable DependentVariable Figure 1: Conceptual Framework The figure shown above depicts thedetermination of the amount of Arsenic in rice grains and irrigation waters asthe independent variable having effect to the levels of Arsenic in rice grainsand irrigation waters as the dependent variables.Significance of the Study The study aimed to measure the levelsof toxicity brought by Arsenic in Maco, Compostela Valley and would dwell onthe possible arsenic contents of rice grains and irrigation waters in the saidarea. In addition, the study would provide awareness on the toxicity level ofthis heavy metal in our most consumed food and how threatening is its effectsin our body. Furthermore the study would provide data on the arsenic content inrice grains that could be used in future arsenic related studies.
The result ofthis study would be important to the following:To the government : Theresult of this study may be used by the government in checking whether the varietiesof rice that would be examined in this study is safe for human consumption. To the society :The result of this study would give awareness to the society about the possiblearsenic content of rice grains and irrigation waters.To the future researchers : Thisstudy will lay the recommendations that may bridge the current research andfuture research about the determination of heavy metal Arsenic in other foodsource of humans to avoid any serious health conditions that it might bring. Scope and Delimitations This study will be focusing and delimiting only to selectedrice fields in Maco, Compostela Valley. Irrigation waters and rice grainssamples will then be utilized as the source of As in this study. Both water andrice samples will be processed at the Chemistry Laboratory of the UIC MainCampus and would be examined and read using the silver diethyldithiocarbamatespectrophotometric method at the Science Resource Center of the University ofthe Immaculate Conception located at Fr. Selga St.
, Davao City. Definition of TermsThefollowing are terms that are being defined as per its operational use in thestudy.Atomic Absorption Spectrometry (AAS) –A spectroanalytical procedure whose principle involves the absorption ofoptical radiation by free atoms in the gaseous state, that would be used inthis study to identify and quantify the presence of Arsenic in the samples ofrice grains and irrigation waters that would be utilized in this research.Rice grains –A crop that would be utilized in this study as a source of ArsenicIrrigation water – Apotential source of Arsenic that would be tested in this study for its ArseniccontentInorganic arsenic-A toxic form of Arsenic naturally found in ground and surface water however canbe at higher concentrations due to mining and industrial wastes.