Abstract Derivation of seawater quality criteria (SWQC) is based on ecotoxicological testing is commonly accepted practice because it is one of the important regulatory tools to set the seawater quality regulations for the protection of aquatic life. SWQC for metals in the coastal and coral reef ecosystems of Gulf of Mannar, India have not been derived and notified. To fill the gap, the present study was undertaken and derived the SWQC for copper (Cu), cadmium (Cd), zinc (Zn), and mercury (Hg) based on LC50/EC50, no observed effect concentration and lowest observed effect concentration, and chronic values calculated through ecotoxicological testing with marine food chain organisms. The calculated chronic values showed that mercury was highly toxic and zinc was least toxic to all the tested marine organisms. It is concluded that clam Donax faba, oyster Magallana bilineata, finfish Chanos chanos, and finfish Terapon jarbua showed similar order of toxicity (Hg > Cu > Cd > Zn) while it was Hg > Cd > Cu > Zn for post larvae of shrimp Penaeus monodon. The range of chronic values for Cu were varied from 5.0 (clam Donax faba) to 270.0 μg L−1 (Chanos chanos); Cd were ranged from 8.0 (shrimp P. monodon PL) to 590.0 μg L−1 (Terapon jarbua), Hg were found to be 0.11 (oyster Magallana bilineata) to 2.35 μg L−1 (clam Donax faba), and Zn were between 130.0 (shrimp Penaeus monodon) to 1200.0 μg L−1 (fish Terapon jarbua). Further, the criterion maximum concentration (CMC) and criterion continuous concentration (CCC) were derived based on LC50/EC50 values and final chronic values (FCV), respectively. The CMC values derived for Gulf of Mannar are 39.4 μg L−1 for Cu, 11.4 μg L−1 for Cd, 0.072 μg L−1 for Hg and 340 μg L−1 for Zn and the CCC values are 4.319, 0.909, 0.0044, and 37.226 μg L−1 for respective metal. It is suggested that the above values are recommended as SWQC for the protection of 95% of organisms in the coastal and coral reef environments of Gulf of Mannar, India. Research highlights <OrderedList> <ListItem> <ItemNumber>1.</ItemNumber> <ItemContent> Derivation of seawater quality criteria was a pioneer one in the Indian context since the release of metal pollution affects the coastal marine ecosystem’s health including coral reefs. </ItemContent> </ListItem> <ListItem> <ItemNumber>2.</ItemNumber> <ItemContent> This study was carried out using various ecotoxicological testing for prescribing SWQC for Cu, Cd, Zn, and Hg. </ItemContent> </ListItem> <ListItem> <ItemNumber>3.</ItemNumber> <ItemContent> Specific acute values (LC50/IC50/EC50) and chronic values (NOEC/LOEC/CV) of Cu, Cd, Hg, and Zn for each organism were derived for the protection of the Gulf of Mannar waters. </ItemContent> </ListItem> <ListItem> <ItemNumber>4.</ItemNumber> <ItemContent> This study prescribed specific SWQC in terms of CCC for all four metals such as Cu, Cd, Zn, and Hg such as 4.319, 0.909, 37.226, and 0.0044 µg L−1, respectively. </ItemContent> </ListItem> <ListItem> <ItemNumber>5.</ItemNumber> <ItemContent> This study will support to derive the safe limits and frame the policy for the protection and conservation of organisms inhabiting the coastal and coral reef ecosystems of the Gulf of Mannar, India. Since SW-I defines ecologically sensitive areas such as coral reef islands, the recommended criteria would be included in the same SW-I category but it may be considered as a site-specific criteria for the Gulf of Mannar region. </ItemContent> </ListItem> </OrderedList>

Derivation of seawater quality criteria for copper, cadmium, zinc, and mercury for the coastal and coral reef ecosystems of Gulf of Mannar, India

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发表日期：

2026年4月29日

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C M Ramakritinan,
M Anand,
L Palanikumar,
Manoj Singh,
S Manikandan,
G Jayanthi,
A K Kumaraguru,
D Mohan,
T Balasubramanian,
B R Subramanian

摘要

Abstract

Derivation of seawater quality criteria (SWQC) is based on ecotoxicological testing is commonly accepted practice because it is one of the important regulatory tools to set the seawater quality regulations for the protection of aquatic life. SWQC for metals in the coastal and coral reef ecosystems of Gulf of Mannar, India have not been derived and notified. To fill the gap, the present study was undertaken and derived the SWQC for copper (Cu), cadmium (Cd), zinc (Zn), and mercury (Hg) based on LC₅₀/EC₅₀, no observed effect concentration and lowest observed effect concentration, and chronic values calculated through ecotoxicological testing with marine food chain organisms. The calculated chronic values showed that mercury was highly toxic and zinc was least toxic to all the tested marine organisms. It is concluded that clam Donax faba, oyster Magallana bilineata, finfish Chanos chanos, and finfish Terapon jarbua showed similar order of toxicity (Hg > Cu > Cd > Zn) while it was Hg > Cd > Cu > Zn for post larvae of shrimp Penaeus monodon. The range of chronic values for Cu were varied from 5.0 (clam Donax faba) to 270.0 μg L⁻¹ (Chanos chanos); Cd were ranged from 8.0 (shrimp P. monodon PL) to 590.0 μg L⁻¹ (Terapon jarbua), Hg were found to be 0.11 (oyster Magallana bilineata) to 2.35 μg L⁻¹ (clam Donax faba), and Zn were between 130.0 (shrimp Penaeus monodon) to 1200.0 μg L⁻¹ (fish Terapon jarbua). Further, the criterion maximum concentration (CMC) and criterion continuous concentration (CCC) were derived based on LC₅₀/EC₅₀ values and final chronic values (FCV), respectively. The CMC values derived for Gulf of Mannar are 39.4 μg L⁻¹ for Cu, 11.4 μg L⁻¹ for Cd, 0.072 μg L⁻¹ for Hg and 340 μg L⁻¹ for Zn and the CCC values are 4.319, 0.909, 0.0044, and 37.226 μg L⁻¹ for respective metal. It is suggested that the above values are recommended as SWQC for the protection of 95% of organisms in the coastal and coral reef environments of Gulf of Mannar, India.

Research highlights

Derivation of seawater quality criteria was a pioneer one in the Indian context since the release of metal pollution affects the coastal marine ecosystem’s health including coral reefs.

This study was carried out using various ecotoxicological testing for prescribing SWQC for Cu, Cd, Zn, and Hg.

Specific acute values (LC₅₀/IC₅₀/EC₅₀) and chronic values (NOEC/LOEC/CV) of Cu, Cd, Hg, and Zn for each organism were derived for the protection of the Gulf of Mannar waters.

This study prescribed specific SWQC in terms of CCC for all four metals such as Cu, Cd, Zn, and Hg such as 4.319, 0.909, 37.226, and 0.0044 µg L⁻¹, respectively.

This study will support to derive the safe limits and frame the policy for the protection and conservation of organisms inhabiting the coastal and coral reef ecosystems of the Gulf of Mannar, India. Since SW-I defines ecologically sensitive areas such as coral reef islands, the recommended criteria would be included in the same SW-I category but it may be considered as a site-specific criteria for the Gulf of Mannar region.