Studies on the Heavy Metal Content of Coastal Waters Adjacent to Kadiyapattanam Estuary, South West Coast of India
Sreekala . S1, H. Mary Helen2
1Research Scholar, P.G and Research Department of Chemistry, S.T. Hindu College, Nagercoil, Kanyakumari District, Tamil Nadu, India
2Assistant Professor, P.G and Research Department of Chemistry, S.T. Hindu College, Nagercoil, Kanyakumari District, Tamil Nadu, India
*Corresponding Author E-mail: ssreekala473@gmail.com
ABSTRACT:
Valliyar is one of the main river systems in Kanyakumari District, originates from Velimalai Hills in Western Ghats and enters into Arabian Sea through Kadiyapattanam estuary. The concentration of heavy metals was analysed from water samples collected at different location in coastal waters adjacent to Kadiyapattanam estuary in Kanyakumari District, Tamil Nadu, south west coast of India. Samples were collected continuously throughout the year during monsoon, post monsoon and pre- monsoon seasons in the year 2015-2016.To carry out present study 5 sampling stations were selected and 7 heavy metals such as lead, zinc, copper, cadmium, iron manganese and Mercury were estimated following standard methods and procedures. Study area is situated near Indian rare earth limited corporation in Manavalakurichi. Mercury was found absent in the samples throughout the year in the present study. Concentration of iron was found higher compared to other metals. The metal concentration in samples was determined using Perkin Elmer A Analyst 200 Atomic absorption spectroscopy. The order of heavy metal content in the study area was Fe > Cd > Pb > Cu > Mn > Zn > Hg. In the present study the concentration of Zinc, copper, and manganese are within the permissible limit in all seasons. Lead and cadmium shows higher values in some season. The result of the study indicates that the river Valliyar and coastal waters of kadiyapattanam estuary are polluted due to the discharge of toxic heavy metals, agro chemical waste runoff and anthropogenic activities.
KEYWORDS: Water, heavy metals, river, analysis, estuary.
Water is an important natural resource which plays a vital role in the existence of life on earth. Since it is directly linked with the welfare of human beings. About 97.2% of water is salty and remaining 2.8% of fresh water is used for human existence and other activities1. Water has great role in the wealth of a nation particularly Indian economy mainly depend on agriculture growth2. The analysis of water both in term of quality and quantity is essential for the very existence of mankind 3,4. Polluted river water contains the presence of several inorganic elements, thereby causing harmful effects on aquatic biota and human health. The indiscriminate use of heavy metal containing fertilizers and pesticides in agriculture resulted in deterioration of water quality and cause serious environmental problem5. Heavy metal cannot be biodegradable and accumulate into the tissues of aquatic animals and consequently enter into animals and human body who depend on aquatic product as food. Heavy metals concentration in aquatic environment is a critical issue due to the toxicity of metals6. Anthropogenic activities represent the major contributor to the contamination of aquatic environments7. Among heavy metals certain dangerous metals like lead, zinc, cadmium, copper, iron and mercury are toxic. Due to the toxic nature of these heavy metals, their presence will lead to adverse effect on living beings. If the amount of these metals is higher than permissible limits causes serious health problems like kidney damage, cardio vascular system, neurological problems and hypertension. Such water systems are considered as undesirable for drinking purpose.
Description of the study area
Kanyakumari district is a coastal district situated at the southernmost tip of India. It is situated between77015’and 77036’east latitude and 8003’and 8035’ north longitude. This district receives rain fall during monsoon seasons, both south west (June to September) and north east monsoon (October to December). Rivers also collects maximum amount of water during this season and get flooded. Kadiyapattanam is one of the minor estuaries in Kanyakumari District. Valliyar is the one of the main river systems in the district. Valliyar along with its tributary Thoovalar originates from Velimalai Hills in Western Ghats and travels about 29kms before entering into Arabian Sea through Kadiyapattanam estuary near manavalakurichi. Station 1 Kadiyapattanam Estuary is the bar mouth of the river Valliyar. Kadiyapattanam estuary situated about 32 kilometers northwest of Cape Comorin falling within the latitude 8o121N and longitude 77o291E and 77o311E. This is the place where river meets the sea. Natural radiation levels in this region are higher than normal which are believed to be emitted from the rich deposits of the monazite bearing beach sands. Station II Manavalakurichi Bridge is situated approximately 2 kms from estuary station. Station III Thiruninarkurichi is a very beautiful place situated 3 kms away from station II. The surrounding area of this location is mainly agriculture field mostly paddy field. Station IV Keezhekalkurichi is situated approximately 4.5kms away from station III. In this station where it’s tributary Thoovalar joins with Valliyar. Some small canals were also joins with river nearby this location. Station V Puliyoorkurichi is situated approximately 3kms away from station IV.
MATERIALS AND METHODS:
The present investigation deals with the analysis of heavy metal content in Valliyar river water adjacent to kadiyapattanam estuary. The work was carried out over a period of one year from June 2015 to May 2016, covering pre- monsoon (February-May), the monsoon (June-September), and post-monsoon (October-January) season. Samples from 5 selected sampling stations were collected in pre cleaned two litre plastic bottles every month. Collection of samples was done between 8 am to 10am. Samples were acidified with 1-2ml of concentrated nitric acid per litre of the sample at the point of collection and transported to laboratory for analysis. From the collected water samples 7 heavy metals such as zinc, copper, lead, cadmium, iron, manganese, and Mercury were estimated following standard methods8,9 The metal concentration in samples was determined using Perkin Elmer A Analyst 200 Atomic absorption spectroscopy.
RESULTS AND DISCUSSION:
To estimate the content of heavy metals like lead, zinc, copper, cadmium, Iron manganese and Mercury in river water samples, 5 different stations were selected and samples were collected throughout the year. Collected samples were analysed using Atomic absorption spectroscopy. Result obtained for water samples at 5 different sampling stations was represented in the following figures. The source of heavy metals in river water is from weathering of mineral rocks, chemical fertilizers, pesticides, organic remains, human activities and due to industrial effluents. Due to their toxic nature, when they enter into food chain leads to bio accumulation.
Figure I Concentration of Zinc (ppm)
Zinc has been found to be low toxic to man compared to other metals. At higher concentration it leads to health problems. Estimated value of zinc is shown in figure I. Observed values are found to be well below the acceptable limits throughout the study period in all seasons. Highest amount of zinc was found in station III (0.038 ppm) in the month of June in monsoon season and lowest value was found in station 1 (0.00 ppm) kadiyapattanam estuary in the month of December in post monsoon season.
Figure II Concentration of Copper (ppm)
Lower concentration of copper is essential to maintain the metabolism of human body, however higher concentration leads to poisoning. Amount of copper observed is shown in figure II. Highest amount of copper was found in station III (0.356 ppm) in the month of February and lowest value was found in station IV&V (0.000 ppm) in the month of April in pre-monsoon season. January and February shows higher values compared to other months, but values are under permissible limit.
Figure III Concentration of Lead (ppm)
Lead enter in to the environment from automobile exhaust, effluence from manufacturing industries like lead acid batteries, paint and dyes etc. Estimated values of Lead are shown in figure III. Highest amount of lead was found in station III (1.883 ppm) in the month of September and lowest value was also found in station III (0.163 ppm). Concentration of lead was below detected level in pre- monsoon season and some months on post-monsoon season. Higher concentration of lead may be due to erosion and flood water carrying terrigenenous matter
Figure IV concentration of Cadmium (ppm)
Concentration of Cadmium observed is shown in figure IV. The toxic heavy metal cadmium enters into the water source are mainly of anthropogenic origin, sewage material and waste dumping9. Highest amount of cadmium was found in station IV (2.231 ppm) in the month of October and lowest value was found in the month of January. In all seasons some station shows lower value that is values are below detectable level.
Figure V concentration of Iron (ppm)
Iron is most abundant metal in the earth crust. It is an essential micro nutrient for the life process in animals and plants. Concentration of Iron observed is shown in figure V. Concentration of Iron is found to be high in all station throughout the year. Highest concentration of iron was found in station IV (3.45 ppm) in the month of October and lowest value was seen in station V (0.206 ppm) in the month of November in post-monsoon season. Higher concentration may be due to the weathering of iron containing minerals and rocks, Industrial effluence, sewage and landfill leaches.
Figure VI concentration of manganese (ppm)
Concentration of manganese is shown in figure VI. In the case of manganese almost all station shows values under desirable limits of Indian standard. Highest amount of manganese was found in station II (0.29 ppm) in the month of April in pre-monsoon season and lowest value (0.00 ppm) was found in almost all stations in the month of July during monsoon season.
Mercury was not detected in water samples collected from the selected location throughout the year in the present study
CONCLUSION:
Accumulation of heavy metals in ecosystem is of global importance. Metals generally enter the aquatic environment through atmospheric deposition, corrosion of geological matrix or due to anthropogenic activities caused by industrial effluents, domestic sewage and mining wastes. Present studies on heavy metals, water samples were collected from 5selected station in Valliyar including Kadiyapattanam estuary. Station III shows higher values of zinc and copper compared to other stations and the values are under permissible limits. Monsoon season shows lowest values of Manganese compared to other seasons. Lead and Cadmium shows higher concentration during monsoon season. Concentration of lead was below detected level in pre- monsoon season and some months on post-monsoon season. Iron shows higher concentration almost in all station in all seasons. Mercury was found absent in all seasons in the study area. Metal concentration is increased in river water may be due to their role in carrying municipal and industrial waste waters and runoff from agricultural land. The order of heavy metal content in the study area was Fe > Cd > Pb > Cu > Mn > Zn > Hg. Thus we can conclude that the river valliyar and coastal waters of kadiyapattanam estuary are polluted due to the discharge of toxic heavy metals and agro chemical waste runoff from agricultural field.
ACKNOWLEDGEMENT:
The authors are thankful to the Management and staff of S.T. Hindu College Nagercoil, Kanyakumari District,
Tamil Nadu.
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Received on 18.08.2016 Modified on 11.09.2016
Accepted on 06.10.2016 © AJRC All right reserved
Asian J. Research Chem. 2016; 9(10):479-484.
DOI: 10.5958/0974-4150.2016.00072.9