|Year : 2020 | Volume
| Issue : 1 | Page : 44-48
Dynamics of heavy metal accumulation in an endosulfan affected area of Kasaragod district, southwest coast of India
VV Sayooj, V Vineethkumar, Sreerag Ramesh, V Prakash
Department of Physics, Payyanur College, Kannur, Kerala, India
|Date of Submission||08-Jun-2019|
|Date of Decision||06-Mar-2020|
|Date of Acceptance||13-Mar-2020|
|Date of Web Publication||12-May-2020|
Department of Studies and Research in Physics, Payyanur College, Edat, Kannur-670 327, Kerala
Source of Support: None, Conflict of Interest: None
The heavy metal accumulation study on bed sediments of Kodangari stream situated in Enmakaje panchayath of Kasaragod district, Kerala, has been carried out. A total of 20 sediment samples along the stream were collected and analyzed for the concentration of heavy metals, namely manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe), using a flame atomic absorption spectrometer. The observed concentration of Mn varies in the range of 0.14–32.80 ppm, the concentration of Zn varies in the range of 0.15–10.80 ppm, the concentration of Cu varies in the range of 1.80–12.20 ppm, and the concentration of Fe varies in the range of 19.12–378 ppm. The physicochemical parameters, namely pH, moisture content, organic matter content, and electrical conductivity, associated with the samples were also measured and correlated with the concentration of heavy metals. There exists a good correlation between the concentration of heavy metals and various physicochemical parameters. The results obtained are presented and discussed in detail in the manuscript.
Keywords: Concentration, endosulfan, heavy metal, sediments
|How to cite this article:|
Sayooj V V, Vineethkumar V, Ramesh S, Prakash V. Dynamics of heavy metal accumulation in an endosulfan affected area of Kasaragod district, southwest coast of India. Radiat Prot Environ 2020;43:44-8
|How to cite this URL:|
Sayooj V V, Vineethkumar V, Ramesh S, Prakash V. Dynamics of heavy metal accumulation in an endosulfan affected area of Kasaragod district, southwest coast of India. Radiat Prot Environ [serial online] 2020 [cited 2021 Feb 26];43:44-8. Available from: https://www.rpe.org.in/text.asp?2020/43/1/44/284225
| Introduction|| |
The study on heavy metal content of selected samples from an environment assumes great significance because of their association with environmental issues and the health of plants, animals, and humans. These are found mainly in terrestrial rocks, sand, water, air, living matter, limestones, seawater, etc., in varying concentrations. The sources of these metals in the atmosphere can be natural and/or anthropogenic. The natural sources include erosion, weathering of rocks and soils, volcanism, sea spray, thermal springs, lake and river sediments, vegetation, forest fires, biological methylation, and plant growth. Anthropogenic sources include mining operations, smelting and other industrial activities, combustion of wood, oil, coal, waste incineration, agricultural operation, and cremation. The assessment of heavy metal concentration in general and toxic heavy metals in particular is important for the prediction of risk to the environment and public. The distribution of heavy metals in various environmental matrices depends on the nature of the element itself and the site of specific characteristics such as soil type and its physicochemical properties. The most important variables of soils which affect the distribution are soil pH, texture, organic matter quantity and quality, mineral composition, and electrical conductivity. Increased human population, industrialization, use of fertilizers, and human-made activities may also affect the ecosystem. The industrial activities and the use of fertilizers will affect both physical and chemical soil properties and will lead to changes in the behavior of heavy metals in the soil. The effluents that are removed from every industry and the fertilizers that we use for crop development will be polluted with heavy metals and, in turn, lead to the contamination of soil, air, and/or water.
The Kodangari stream is the selected location for the present study and is situated in Enmakaje panchayath of Kasaragod district, Kerala. The Enmakaje panchayath is one of the most endosulfan-affected areas in Kerala. Endosulfan was aerially sprayed by the Plantation Corporation of Kerala Ltd. from 1976 to 2000 in the cashew plantations to control tea mosquitoes. Later, several abnormalities and various health issues were found and reported among the residents in and around the present study location. This has stressed the need to undertake an in-depth study in the location to envisage the reason and to implement mitigation mechanisms. Several studies conducted by both the government and private agencies in the endosulfan-affected area of Kasaragod district could not form a clear-cut conclusion regarding the health issues prevailing in the region. Some of the reports say that health issues are due to endosulfan and some other reports stress the contribution of heavy metals and radionuclides in the environment. Even though it is speculated that endosulfan is the reason for these health issues, no studies were able to prove it.
Dr. Y. S. Mohankumar, a physician who has been practicing in Vani Nagar of Enmakaje panchayath since 1982 has tried to bring out the health issues prevailing in the region. In 1997, he wrote to the Kerala Medical Journal about the endosulfan issue, in order to draw the attention of medical researchers to this specific issue. He reported that, in 4 km area of Padre village with a population of about 2000, there were cases of 51 cancer deaths for a period of 5 years. These cases were reported among the occupants of 126 houses near to the Kodangari stream and pointed out that the health issues may be due to the enrichment of heavy metals or radionuclides in the endosulfan-affected area. He has also suggested that an epidemiological survey needs to be carried out for the proper identification of the reasons for the health issues prevailing in the study area. The specialists' medical camps organized at Vani Nagar, Enmakaje panchayath, by the Kerala Government reported many cases of central nervous system anomalies, congenital anomalies, mental retardation, cancer, and infertility. The number of reported cases was high in the occupants near to the Kodangari stream. Among the schoolchildren, reported cases of congenital anomalies were high.
In this context, the investigation on heavy metal accumulation in environmental matrices in and around the endosulfan-affected area assumes great significance. Hence, it has been planned to analyze the sediment samples collected in and around the banks of Kodangari stream in Enmakaje, an endosulfan-affected area with a large number of residents, to understand the contribution of heavy metals toward the health issues among the residents. Sediment samples were collected from various parts of the Kodangari stream about 2-km stretch. The concentration of heavy metals, namely manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe), was analyzed using a flame atomic absorption spectrometer (FAAS).
| Materials and Methods|| |
Location of the study
The sediment samples were collected from the banks of the Kodangari stream [Figure 1] situated in Enmakaje panchayath, Kasaragod, Kerala. The length of the stream is about 2 km, and finally, it joins the Chandragiri river. The Chandragiri river is in Kasaragod district and is also known as Payaswini. It stretches about 100 km in Kasaragod district and flows west to join the Arabian Sea.
A total of 20 sediment samples (S1–S20) each weighing ~2–3 kg were collected from the study area. The unused and undisturbed surface area was selected for sampling, and the grass, root mat, stones, pebbles, plant materials, and other wastes were removed from the samples. The sample collection was done at 30-cm depth, after thorough mixing. The samples were collected in polythene bags and brought to the laboratory for further analysis.
Sample processing and analysis
The samples were processed following standard procedures. Samples were air-dried and sieved through the 250-μm standard mesh and then taken to the laboratory for the preparation and chemical processing. Diethylenetriaminepentaacetic acid (DTPA) is a chelating agent that extracts the available forms of Fe, Mn, Zn, and Cu when buffered at pH 7.3. Weigh 10 g of sediment into a 150-ml conical flask, add 20 ml of DTPA extractant, and shake the constituents on a horizontal shaker for 2 h. Then, filter the solution using Whatman No. 40 filter paper. Finally, feed the clear sample to the instrument having an appropriate hollow cathode lamp, and the concentration of these elements in the solution was determined using an atomic absorption spectrometer (model: novAA 350, Analytik Jena). The physicochemical parameters of the samples, namely moisture content, pH, electrical conductivity, and organic matter, were also determined using well-established techniques/instruments.
| Results and Discussion|| |
Trace element concentration
The results of trace element concentration in sediment samples are given in [Table 1]. The descriptive statistical data contents of the metals and the threshold levels of metal concentration as per the World Health Organization (WHO) guidelines are summarized in [Table 2]. The median values of concentration of heavy metals, namely Mn, Zn, Cu, and Fe, in the sediment samples were 10.66 ppm, 3.40 ppm, 5.59 ppm, and 181.00 ppm, respectively. It can also be seen from the table that the trace element concentrations for Mn, Zn, Cu, and Fe vary within the range of 0.14–32.8 ppm, 0.152–10.8 ppm, 1.82–12.2 ppm, and 19.1–378 ppm with a mean value of 11.66 ppm, 3.99 ppm, 5.77 ppm, and 162.33 ppm, respectively. The results clearly show that the concentration of heavy metals is comparable with the reported values elsewhere and within the permissible threshold prescribed by the WHO.
The sediment samples in the study area contain Mn with an average value of 11.66 ppm, which is well within the threshold limit of 150 ppm. The average value of Zn in the sediment samples from the area is found to be 3.99 ppm and is well within the threshold value of 200 ppm suggested by the WHO. The average concentration of Cu in the collected samples is found to be 5.77 ppm, which is also well within the threshold value of 30 ppm. The sediment samples contain Fe with an average value of 162.33 ppm and are well within the threshold limit of 380 ppm. The results indicate that, accumulation of heavy metals in sediment samples collected from the banks of Kodangari stream is not significant to contribute the health issues of the inhabitants near to the stream. It can be concluded that the health issues arising in the endosulfan spread area cannot be directly attributed to the heavy metal accumulation in the region. There is no direct influence on the accumulation of heavy metals in the health issues prevailing in the region.
The physicochemical parameters associated with the collected sediment samples are summarized in [Table 3]. The moisture content in the sediment samples varies with a minimum value of 0.15% to a maximum value of 21.86%. The pH value of the samples varies from a minimum value of 4.14 to a maximum of 6.46, and it is clear that all the samples are acidic. The electrical conductivity of the samples varies from 0.04 mS to 0.14 mS. The organic matter content in the samples varies from 0.03% to 1.74%.
|Table 3: Physicochemical parameters associated with the sediment samples|
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The Pearson correlation of heavy metal concentration and physicochemical parameters is given in [Table 4]. The correlations between the concentration of Mn, Zn, Cu, and Fe with physicochemical parameters, namely moisture content, pH, electrical conductivity, and organic matter, were studied. A significant negative correlation is observed between the concentration of Cu and pH, and a significant positive correlation is observed between the concentration of Fe and organic matter content. A significant negative correlation is observed between the concentration of Fe and the physicochemical parameters, namely pH and electrical conductivity.
|Table 4: Pearson correlation between heavy metals and physicochemical parameters|
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In order to validate the results, intercomparison measurements were carried out for the heavy metal concentration in some of the samples using an inductively coupled plasma-mass spectrometer (ICP-MS) at Sophisticated Test and Instrumentation Centre, Cochin University. The results obtained from FAAS have been compared with the results obtained by the ICP-MS. A good correlation with a correlation coefficient (r = 0.98) was observed between the results of the two measurements, indicating that the results obtained were in good agreement.
| Conclusions|| |
The reported health issues and chronic diseases from the endosulfan spread area, near the bank of Kodangari stream, may not be directly attributed to the accumulation of heavy metals in the location. There is no direct influence on the accumulation of heavy metals in the health issues prevailing in the region. The effects of physicochemical parameters on the concentration of heavy metals were significant in many cases as it was evident from the Pearson correlation study. The study indicates that endosulfan effects are more significant in the location compared to heavy metal accumulation. However, many other factors can also contribute to the health issues, and combined effect may be observed. Hence, periodic monitoring and an in-depth study are needed to get a clear-cut conclusion on the health issues prevailing in the endosulfan spread areas.
The first author acknowledges Dr. Mohan Kumar and Mr. Ambikasudhan Mangad for providing detailed information of the sampling location and Dr. Binitha N. K. for permitting the analysis at the College of Agriculture, Padannakkad. Mr. Shimod K. P. has been thankfully acknowledged for mapping the study location at the Department of Geography, Kannur University. The help received from Mr. Amal Raj, Mr. Sai Krishna Nayanar, Mr. Anjith Kumar, Mr. Mithun Raj P. R., and Mr. Abin P. Binoy during sample collection is also acknowledged. Thanks are due to the natives of Enmakaje panchayath, Kasaragod district, who have helped to understand the geology of the location and endosulfan-related issues.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]