International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 4, April 2017, pp. 2238–2245, Article ID: IJCIET_08_04_253 Available online at http://iaeme.com/Home/issue/IJCIET?Volume=8&Issue=4 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 © IAEME Publication Scopus Indexed QUANTIFICATION OF HEAVY METALS IN AGRICULTURAL SOILS OF SWARNA RIVER BASIN, UDUPI Hanna Soosan George Environmental Engineering, Manipal University, Manipal, Karnataka, India H.N Udayashankar Geology, Manipal University, Manipal Institute of Technology, Manipal, Karnataka, India ABSTRACT Udupi district is essentially an agriculture district with more than 80% of population depends on agriculture for their livelihood whereas only 40% of the available land is used for agriculture. Paddy is the main crop raised by 75% of the cultivated area in kharif season. Swarna is one of the important west flowing rivers of Karnataka and the major source of agricultural land in Udupi. Heavy metal contamination is a major problem in the agricultural field nowadays. Hence, a study was conducted to analyze the heavy metal contamination of agricultural soils of Swarna river basin in Udupi. The studied soils were under paddy cultivation. The soil samples were found to be slightly acidic. Key words: AAS, Microwave Digestor, heavy metals, soil, paddy. Cite this Article: Hanna Soosan George and H.N Udayashankar, Quantification of Heavy Metals in Agricultural Soils of Swarna River Basin, Udupi. International Journal of Civil Engineering and Technology, 8(4), 2017, pp. 2238–2245. http://iaeme.com/Home/issue/IJCIET?Volume=8&Issue=4 1. INTRODUCTION Heavy metal is a general term given to a group of elements that includes not only metals but also metalloids. They are the elements whose density is greater than 4g.cm-3. Heavy metals most commonly found at contaminated sites are lead (Pb), chromium (Cr), zinc (Zn), cadmium (Cd), copper (Cu), mercury (Hg), and nickel (Ni). In the environment many forms of heavy metals are generally stable, that is, they do not degrade chemically or biologically over time. So they accumulate in the soils reaching dangerous concentrations. (João P. Vareda et al). In spite of their natural occurrence, they get accumulated in the soil due to emissions from rapidly expanding industrial areas, mining tails, disposal of metal wastes etc. http://iaeme.com/Home/journal/IJCIET 2238 [email protected] Quantification of Heavy Metals in Agricultural Soils of Swarna River Basin, Udupi This study is to quantify the heavy metal concentration in agricultural soils of Swarna River basin, West Coast, India. As far as agricultural soils are concerned the pesticides and insecticides used in crops will also contribute to the heavy metal concentration. 2. EFFECTS OF HEAVY METALS IN SOIL Heavy metals can lead to harmful effects on soil ecosystem, agricultural production, ground water quality, food safety and human health through food chain. (Yuan Chai et al) Therefore it is important that the heavy metal concentration in the soil does not exceed the acceptable levels. The increase in heavy metal content can lead to deterioration of soil health. From soil, heavy metals are taken up by crops. Even though metals like Cr, Co, Cu etc. are required for plants, it becomes dangerous when they exceed the safety limits and can cause severe health hazards in humans and plants. 3. ANALYZED HEAVY METALS The heavy metals analyzed in this study are Chromium, Copper, Cobalt, Manganese, Cadmium, Nickel and Lead. 4. EFFECTS OF HEAVY METALS ON PLANTS AND HUMANS 4.1. Chromium Intake of Cr can cause skin rashes, upset stomachs and ulcers, respiratory problems, weakened immune systems, kidney and liver damage, alteration of genetic material, lung cancer and death. In plants excess Cr causes alterations in the germination process as well as in the growth of roots, stems and leaves. 4.2. Copper Intake of Cu can cause irritation of the nose, mouth and eyes and it causes headaches, stomachaches, dizziness, vomiting and diarrhea. Intentionally high uptakes of copper may cause liver and kidney damage and even death. Whether copper is carcinogenic has not been determined yet. Plants that are affected by copper toxicity appear stunted, are usually bluish in color, and eventually turn yellow or brown. 4.3. Cobalt Co is beneficial for humans because it is a part of vitamin B12, which is essential for human health. The total daily intake of Co is variable and may be as much as 1 mg, but almost all will pass through the body unadsorbed, except that in vitamine B12. Health effects that are a result of the uptake of high concentrations of cobalt are vomiting, vision problems, heart problems & thyroid damage. In plants increase of Co causes leaf fall, inhibition of greening, discolored veins, premature leaf closure, and reduced shoot weight. 4.4. Cadmium Excess intake of Cd Diarrhea, stomach pains and severe vomiting, bone fracture, reproductive failure and possibly even infertility, damage to the central nervous system, damage to the immune system, psychological disorders, possibly DNA damage or cancer development. http://iaeme.com/Home/journal/IJCIET 2239 [email protected] Hanna Soosan George and H.N Udayashankar Chlorosis, leaf rolls and stunting are the main and easily visible symptoms of cadmium toxicity in plants. 4.5. Manganese Mn is an essential nutrient for the human body but intake off excess Mn may cause hallucinations, forgetfulness and nerve damage. Manganese can also cause Parkinson, lung embolism and bronchitis. In plants manganese toxicity results in dark-brown, necrotic spots on lower leaves, distortion of expanding leaves and chlorosis of young leaves. 4.7. Lead Pb is highly toxic and may cause disruption of the biosynthesis of hemoglobin and anemia, rise in blood pressure, kidney damage, miscarriages and subtle abortions, disruption of nervous systems, brain damage, declined fertility of men through sperm damage, diminished learning abilities of children, behavioral disruptions of children, such as aggression, impulsive behavior and hyperactivity. Symptoms of Pb toxicity in plants are rapid inhibition of root growth, stunted growth of the plant and chlorosis. 4.8. Nickel Intake of nickel develops higher chances getting of lung cancer, nose cancer, larynx cancer and prostate cancer, sickness and dizziness after exposure to nickel gas, lung embolism, respiratory failure, birth defects, asthma and chronic bronchitis, allergic reactions such as skin rashes, mainly from jewelry and heart disorders. Toxic effects of nickel on plants include alterations in the germination process, in the growth of roots, stems and leaves. 5. MATERIALS AND METHODS 5.1. Study Area The Swarna basin forms the wettest part of the Western Ghats located in coastal Karnataka. It is mainly a rain fed river. It is the major source of agricultural land in Udupi. The soil and paddy samples were collected from the agricultural soils of Swarna-Madisal river basin in Udupi district of Karnataka. 5.2. Sampling Points 20 soil samples were collected from the agricultural plots of Swarna-Madisal river basin, Udupi. 5.3. Sample Preparation The soil samples were first dried in the shade for 5 to 7 days. Then they were sieved in a 2mm sieve and out of that 250 gms of soil was weighed out. 5.3.1. Microwave Digestion Digestion is done to achieve total sample decomposition. In recent years, microwave digestion method has become more common. It has many advantages, such as fast dissolving, good dissolving effect, simple, safe, easy to control, low evaporation losses, multiple samples digestion and good reproducibility. http://iaeme.com/Home/journal/IJCIET 2240 [email protected] Quantification of Heavy Metals in Agricultural Soils of Swarna River Basin, Udupi For the digestion of soil 5ml of hydrofluoric acid, 3ml hydrochloric acid and 2ml nitric acid is added to 0.2 mg of soil sample. The samples are taken in Teflon vessels and are kept in the digester for an hour. The sample is treated in high temperature and pressure. After the digestion it was diluted to 30 ml with distilled water and was stored. 5.3.2. Atomic Adsorption Spectrometer It is a method for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state. AAS relies on Beer-Lamberts law. The electrons of the atoms in the atomizer can be promoted to excited state for a short period of time (nanoseconds) by absorbing a defined quantity of energy (radiation of a given wavelength). This amount of energy, i.e., wavelength, is specific to a particular electron transition in a particular element. In general, each wavelength corresponds to only one element. The radiation flux without a sample and with a sample in the atomizer is measured using a detector, and the ratio between the two values (the absorbance) is converted to analyte concentration or mass using the Beer-Lambert Law. Nitrous oxide acetylene is used as a fuel for chromium and arsenic in AAS since they requires high temperature and pressure. For other heavy metals air acetylene is used as the fuel. In this project I have determined eight elements Cr,Cd, Co, Cu, Ni, Pb and Mn. Soil was analyzed using this method. 6. CALCULATION After the results were obtained the concentration of heavy metals were calculated using the following formulas. (1) CONCENTRATION OF ELEMENTS (mg/kg) = ((Concentration of metals in mg/l)*Dilution Factor)/Sample weight (2) DILUTION FACTOR = (Vi + Vf)/Vi Vi = Volume of digested sample Vf = Volume of distilled Water 7. RESULTS AND DISCUSSIONS 7.1. Basic parameters- pH and Electrical Conductivity of Soil Table 1 pH and Electrical Conductivity of soil Samples Ph Electrical Conductivity (mhos/cm) 1 4.96 0.035 2 5.05 0.040 3 4.95 0.041 4 5.05 0.030 5 4.83 0.030 6 5.12 0.030 7 5.03 0.026 8 5.50 0.033 9 5.30 0.020 10 5.24 0.042 11 4.90 0.116 12 5.45 0.075 13 5 0.056 14 6 0.061 http://iaeme.com/Home/journal/IJCIET 2241 [email protected] Hanna Soosan George and H.N Udayashankar 15 5.95 0.023 16 5.80 0.022 17 4.95 0.034 18 4.86 0.032 19 5.40 0.042 20 5.10 0.053 7.2.