(Cauvery) River, India - ACS Publications - American Chemical Society

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Chapter 7

Organochlorine Pesticide Contamination in the Kaveri (Cauvery) River, India: A Review on Distribution Profile, Status, and Trends Nikhil Nishikant Patil, Krishna Kumar Selvaraj, Vimalkumar Krishnamoorthy, Arun Elaiyaraja, and Babu Rajendran Ramaswamy* Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli - 620024, Tamil Nadu, India *E-mail: [email protected].

Numerous studies have reported organochlorine pesticides (OCPs) in water resources such as rivers and lakes, etc. Agricultural and vector control activities contribute significantly to the contamination of persistent OCPs in rivers. In India, monitoring studies on rivers are limited. This chapter deals with OCPs contamination profile, status and trends in the Kaveri River, which is one of the longest rivers in southern India that serves as a water source for agriculture, drinking water and industrial purposes for centuries. The reported OCPs in this river includes hexachlorocyclohexane (HCH), dichloro-diphenyltrichloroethane (DDT), endosulfan, aldrin, dieldrin, heptachlor epoxide etc. The concentrations of HCHs, DDTs and endosulfan residues in Kaveri River water were observed up to 2,300 ng/L, 3,600 ng/L and 15,400 ng/L, respectively, while in sediment, HCHs and DDTs were reported with the maximum concentration of 158 ng/g dw and 9.15 ng/g dw, respectively. Biota (fish, shrimp) samples collected from the river were found to contain significant levels of HCHs (228 ng/g) and DDTs (2,805 ng/g). The levels of some OCPs in the Kaveri River environment exceeded safety guideline values, therefore we cannot rule out the threat to resident organisms

© 2015 American Chemical Society In Water Challenges and Solutions on a Global Scale; Loganathan, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.

because of continuous exposure. Future monitoring studies are warranted to understand the contamination status, effects on biota, and to design control measures to protect the Kaveri River ecosystem.


Introduction Indiscriminate usage of pesticides in agriculture and public health purposes to meet the demand for food and to prevent insect borne diseases in many countries has resulted in ubiquitous occurrence of the pesticide residues in abiotic and biotic components globally (1). Despite the remarkable economic benefits (enhanced agricultural productivity and the control of vector-borne diseases), some of the pesticides may cause environmental contamination that lead to adverse health effects in wildlife and on the human population, including cancer, endocrine disruption, developmental deformities, etc. (2, 3) Among various synthetic organic chemicals, organochlorine pesticides (OCPs) were highly used in the last century and are still used sparingly in developing countries. Persistent, bioaccumulative and toxic properties of organochlorines prompted researchers for continuous monitoring of OCPs in the environment and ecotoxicological evaluation even in post-usage era. The tropical climate in India is favorable for breeding of various types of pests and thereby frequent use of pesticides in agricultural and malarial vector control practices is inevitable. At present, India ranks second in pesticide production among the Asian countries and fourth globally (4, 5). In 1985, the Indian government banned the use of pesticides listed in the Stockholm Convention dirty dozen, with an exception of DDT, which is still used to control malaria (6). The pesticide consumption has increased a few orders of magnitude, from 154 MT (metric tonnes) in 1954 to 41,822 MT in 2009-2010. In India, 67% of pesticides are consumed in agriculture and horticulture (7), whereas about 8.5% is utilized for public health (8). Among the pesticides in India, insecticide usage (80%) is much higher than herbicide (15%) and fungicide (2%) unlike the global scenario where herbicide (47.5%) and fungicide (17.5%) usage predominates (9). In terms of volume, OCPs still constitute a major fraction (40%) of pesticide used in India, followed by organophosphates (30%), carbamates (15%), synthetic pyrethroids (10%) and others (5%) (Figure 1) (2, 10). Therefore, monitoring of OCPs is still considered important. In India, information on OCPs occurrence in environmental matrices such as air, water, soil is limited. Especially in southern India, only few reports were available pertaining to riverine ecosystem to date. Among the states in southern India, Tamil Nadu, with an area of 1,30,000 km2, uses a higher proportion (12,500 MT) of pesticides annually than other Indian states (11). In fact, the Kaveri River delta region has the highest rate of pesticide consumption for rice (29%), followed by cotton (27%), vegetables (9%) and pulses (9%). This chapter deals with the Kaveri River basin (Figure 2), a major river basin in Tamil Nadu state for assessing the fate of OCPs. 116 In Water Challenges and Solutions on a Global Scale; Loganathan, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.


Figure 1. Pattern of pesticides usage in India.

Figure 2. Map showing the Kaveri River and its tributaries, south India. indicates major sampling locations. 117 In Water Challenges and Solutions on a Global Scale; Loganathan, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.


Among the twenty peninsular rivers in India, Kaveri is one of the longest rivers flowing in southern India. Rising in Karnataka state at Talacauvery (11°9’N, 79°52’E) in the Western Ghats, it flows 800 kilometers southeast and exits in the Bay of Bengal (Figure 2). The river covers a basin of about 72,000 km2 in Karnataka and Tamil Nadu state. The tributaries of the Kaveri includes Shimsha, Hemavati, Arkavati, Honnuhole, Lakshmana Tirtha, Kabini, Bhavani, Lokapavani, Noyyal and Amaravati Rivers. The Kaveri River delta is one of the most developed and populated regions (350 people/km2) supporting agriculture for centuries and serves as lifeline for southern India. The river receives a multitude of pollutants through the release of untreated wastewater and agricultural runoff (12). Although, the river has many tributaries, studies on pesticide residue are limited to the main river.

OCPs in River Water The agricultural drainage, urban and rural runoff form a major source of pesticides in rivers. Babu Rajendran and Subramanian (13) first reported OCPs residues in Kaveri River (Manikaranai - 11°06′N; 79°42′E and Melaiyur - 11°07′N; 79°45′E) and its tributary Coleroon (Kollidam - 11°21′N; 79°50′E). Water samples were analysed using GC-ECD and the results showed ubiquitous presence of HCHs and DDTs with higher levels of HCHs (3.2-182 ng/L) in pre-monsoon (July to September) and monsoon seasons (October to December). Among HCH isomers, α, β, and γ-HCH were reported up to 101.3, 79.3 and 73 ng/L, respectively. Increased HCH levels during pre-monsoon and monsoon seasons than post-monsoon season indicates the use of HCH (10% BHC dust) for rice, pulses and cotton in the Kaveri delta region. In the case of DDT and its metabolites, they did not observe any clear differences with respect to seasons. The reported levels of DDTs were (0.75-4.17 ng/L) one order of magnitude lower than HCHs and this may be due to continuing use in only vector control. Further, Babu Rajendran and Subramanian (13) reported that DDT levels were below Eurpean Commision (Council Directive 98/83/EC) maximum acceptable concentration (100-500 ng/L) and lower than USA water quality guidelines (2,000 ng/L). Begum et al. (14) reported pesticide (HCHs, DDTs and endosulfan) residues in upper reaches of the Kaveri River in Karnataka state and found at least one of the OCPs in all the locations. The HCHs (50-2,430 ng/L) and DDTs (50-1,750 ng/L) concentrations were higher than reported in an earlier study by Babu Rajendran and Subramanian (13) (Table 1) from the lower reaches of the river. Although HCHs were forbidden for agricultural use in 1997, the Indian government has allowed the use of the γ-isomer (lindane) for some crops in addition for use in the health sector (15, 16). Other than HCHs and DDTs, endosulfan was reported in the Kaveri river for the first time up to 840 ng/L by Begum et al. (14)

118 In Water Challenges and Solutions on a Global Scale; Loganathan, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.

119


Table 1. Concentration of OCPs in Water, Sediment, and Biota Samples from Kaveri River and Other Indian Rivers OCPs

River

ΣDDT

Σ3HCH

Heptachlor

Heptachlor epoxide

Endosulfan

Reference

Water (ng/L) Kaveri

3.2-182

0.75-4.17

-

-

-

(13)

Kaveri

50-2,430

50-1,750

-

-

< 10-840

(14)

Kaveri

ND-47.4

ND-49

260

-

-

(17)

Kaveri

2300

3600

-

-

15,400

(18)

Kabini*

BDL-7.2

BDL-0.4

BDL-0.75

BDL-2.4

-

(19)

Tamiraparani

(Cauvery) River, India - ACS Publications - American Chemical Society

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