Annamalai Subramanian

Mussel watch: marine pollution monitoring of butyltins and organochlorines in coastal waters of Thailand, Philippines and India

Contamination by butyltin (BTs) and organochlorine compounds (OCs) in green mussels collected along the coastal areas of Thailand, Philippines and India during the period of 1994–1997 was examined. The BT residues in green mussel were widely detected, suggesting a widespread contamination along the coastal waters of Asian developing countries. Relatively high concentrations of BTs in green mussel were found in high boating activity and coastal aquaculture areas, implying the usage of TBT as a biocide in antifouling paints used on boat hulls and marine aquaculture facilities. The composition of BT derivatives in mussel was in the order of TBT>DBT>MBT, suggesting also the presence of significant butyltin source in Asian coast. BT residues pattern in green mussels from Thailand revealed higher levels in aquaculture than in boating activity sites. This result may indicate that the developing countries showing high economic growth rate (like Thailand) tend to increase the usage of TBT for aquaculture activities. BT contamination levels in Asian developing countries were lower than those in developed nations. However, considering the fact that the unregulated usage of organotins in Asian developing countries and the increasing demand for antifouling paints in Asia–Pacific regions, BTs contamination in aquatic environment may be serious in future. Concentrations of OCs detected in green mussels were lower than BTs. Considerable residues of p,p′-DDT found in mussel indicated the current usage of DDTs in Asian regions. HCHs and DDTs contamination in India is apparently higher than in other Asian developing countries. The present study clearly indicates that the aquatic environment in Asia–Pacific regions is still being contaminated by some OCs. To our knowledge, this is a first report on the detection of butyltin compounds in green mussels (Perna viridis) from Thailand, Philippines and India.

Contamination by trace elements at e-waste recycling sites in Bangalore, India.

The recycling and disposal of electronic waste (e-waste) in developing countries is causing an increasing concern due to its effects on the environment and associated human health risks. To understand the contamination status, we measured trace elements (TEs) in soil, air dust, and human hair collected from e-waste recycling sites (a recycling facility and backyard recycling units) and the reference sites in Bangalore and Chennai in India. Concentrations of Cu, Zn, Ag, Cd, In, Sn, Sb, Hg, Pb, and Bi were higher in soil from e-waste recycling sites compared to reference sites. For Cu, Sb, Hg, and Pb in some soils from e-waste sites, the levels exceeded screening values proposed by US Environmental Protection Agency (EPA). Concentrations of Cr, Mn, Co, Cu, In, Sn, Sb, Tl, Pb and Bi in air from the e-waste recycling facility were relatively higher than the levels in Chennai city. High levels of Cu, Mo, Ag, Cd, In, Sb, Tl, and Pb were observed in hair of male workers from e-waste recycling sites. Our results suggest that e-waste recycling and its disposal may lead to the environmental and human contamination by some TEs. To our knowledge, this is the first study on TE contamination at e-waste recycling sites in Bangalore, India.

Accumulation of Organochlorine Pesticides and Polychlorinated Biphenyls in Sediments, Aquatic Organisms, Birds, Bird Eggs and Bat Collected from South India

Concentrations of polychlorinated biphenyls (PCBs), DDT and its metabolites (DDTs), HCH isomers (HCHs), chlordane compounds (CHLs) and hexachlorobenzene (HCB) were determined in sediment, soil, whole body homogenates of resident and migratory birds and their prey items (including fish, green mussel, snail, earthworm, crabs, prawn, lizard and frogs), bird eggs and bats collected from southern India during 1995 and 1998. Accumulation pattern of organochlorines (OCs) in biota was, in general, in the order, HCHs > DDTs > PCBs > CHLs=HCB. Magnitude of OC concentrations increased in the order of sediments < green mussel < earthworm < frog < lizard < fish < bird egg < bats < birds tissues. Biomagnification features of OCs were examined in resident and migrant birds to evaluate the exposure levels of these chemicals in wintering grounds of migrant birds. Accumulation of DDTs in migratory birds during wintering in India may be of concern due to the great biomagnification potential of DDTs. Eggs of some resident species contained noticeable concentrations of OCs. Concentrations of OCs in three species of bats analyzed in this study were lower than that found in passerine birds. In addition to OCs, butyltin compounds were also detected at low concentrations in bats.

Distribution and behaviour of persistent organochlorine insecticides in paddy soil and sediments in the tropical environment: a case study in South India.

Paddy soil and sediment samples collected from the Vellar River watershed, Tamil Nadu state, South India from December, 1987 to January, 1989 were analysed to understand the comprehensive behaviour of organochlorine insecticides (HCH and DDT) in the tropical environment. HCH (BHC) showed higher levels in soil during wet season, reflecting the application of technical HCH largely during the flowering season of rice. On the other hand, DDT residues were low and did not show a significant seasonal trend in soil or sediment, indicating small quantities of DDT utilized at present for agricultural purposes in India. When compared to soil, the residue levels in sediments are low and the seasonal variation is less pronounced. This indicates that in tropical watersheds, the relative flux of residues into the aquatic environment is smaller than the amount volatilized to the atmosphere.

Persistent organochlorines in human breast milk from major metropolitan cities in India

The present study was carried out to understand the current contamination status of organochlorine compounds (OCs) in human breast milk from three metropolitan cities in India (New Delhi, Mumbai and Kolkata). Among the OCs analyzed, DDTs were predominant followed by HCHs and PCBs. CHLs and HCB levels were much lower. Contamination patterns were different in human milk found in our previous study in Chennai, a metropolitan city in southern India, indicating region specific exposure routes and variable sources. In comparison with previous data, levels of DDTs and HCHs generally declined with time, implying the effect of various bans and restrictions on their usage. No association between concentrations of OCs and demographic characteristics such as parity and age of mothers was observed which might be due to narrow range of mothers age. Estimated daily intake shows that some infants are exposed to OCs to a greater extent, particularly HCHs than the guideline standard.

Accumulation features of persistent organochlorines in resident and migratory birds from Asia.

Concentrations of organochlorine contaminants including polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) were determined in the resident and migratory birds, which were collected from India, Japan, Philippines, Russia (Lake Baikal) and Vietnam. Accumulation patterns of organochlorine concentrations in resident birds suggested that the predominant contaminants of each country were as follows: Japan--PCBs Philippines--PCBs and CHLs, India--HCHs and DDTs, Vietnam--DDTs, and Lake Baikal--PCBs and DDTs. The migratory birds from Philippines and Vietnam retained mostly the highest concentrations of DDTs among the organochlorines analyzed, indicating the presence of stopover and breeding grounds of those birds in China and Russia. On the other hand, migratory birds from India and Lake Baikal showed different patterns of organochlorine residues, reflecting that each species has inherent migratory routes and thus has exposure to different contaminants. Species which have breeding grounds around the Red Sea and Persian Gulf showed high levels of PCBs, indicating the presence of areas heavily polluted by PCBs in the Middle East.

Persistent organochlorine residues in dolphins from the Bay of Bengal, South India

Abstract Blubber samples of 12 accidentally netted dolphins from the coastal waters of Porto Novo, southeast coast of India were monitored to assess the persistent organochlorine (HCHs, DDTs, PCBs, and HCB) contamination in these animals. ΣDDT concentrations ranked first, followed by PCBs, ΣHCH, and HCB. HCHs were detected for the first time in dolphins from the tropical waters. The variations in residue levels could be attributed to the physicochemical and biochemical properties of the above compounds. International comparison of residue levels in cetaceans in the recent decade revealed that DDT concentrations in Indian dolphins were comparable to those from other localities whereas PCB levels were low. The continuing contamination by these persistent organochlorines and their toxic effects in tropical cetacean species is predicted in the future.

Characteristic trend of persistent organochlorine contamination in wildlife from a tropical agricultural watershed, south India.

The residue levels of persistent organochlorines, such as HCH (BHC: 1,2,3,4,5,6-hexachlorocyclohexane) isomers, DDT [1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane] compounds, PCBs (polychlorobiphenyls) and HCB (hexachlorobenzene), were measured in wildlife. The wildlife were sampled from terrestrial and aquatic habitats in and around the agricultural watershed of Parangipettai, South India. On the basis of overall concentrations ∑HCH ranked first followed by ∑DDT, ∑PCB and HCB, reflecting the increasing usage of HCH in recent years in India. The residue levels of organochlorines in birds varied according to their feeding habits and showed the following pattern: inland piscivores and scavengers > coastal piscivores > insectivores > omnivores > granivores. High levels of HCH and DDT residues were recorded in Pond heron and Cattle egret which feed in the agricultural fields. Comparison of HCH concentrations in fish and birds in the study area to other locations was made to further understand the dynamics of contaminant accumulation in tropical wildlife. Regarding birds, a wide variation in residue levels could be seen among various countries, with tropical regions registering high levels. In contrast, the variation is not prominent in the case of fish. The residue levels in fish measured in the present study were generally comparable to values reported from other locations. This suggests that the bioavailability of contaminants to the aquatic fauna is less due to the smaller flux and shorter residence time of these chemicals in the tropics.

Organohalogen compounds in human breast milk from mothers living in Payatas and Malate, the Philippines: Levels, accumulation kinetics and infant health risk

Human breast milk samples (n=33) from primipara and multipara mothers from Payatas a waste dump site, and Malate a reference site in the Phillipines were collected in 2004 and analyzed for eight organohalogen compounds, viz., PCBs, DDTs, CHLs, HCHs, HCB, TCPMe, PBDEs and HBCDs. DDTs and PCBs were predominant in all the samples. Overall mean concentrations of PBDEs found in our study were higher (7.5 ng/g lipid wt.) than those reported for Japan and many other Asian countries. Primipara mothers had significantly higher levels of DDTs, CHLs and HCHs than multipara mothers, but not PBDEs and HBCDs. A few individuals accumulated CHLs close to or even higher than the tolerable daily intake guidelines proposed by Health Canada.

Fate of the insecticide HCH in the tropical coastal area of South India

Abstract The residue levels of the insecticide HCH in Vellar estuary, Tamil Nadu, South India were surveyed along with the physical structure of estuary and its hydrokinetic parameters to assess the transport of contaminants in tropical coastal areas. From the flux model it was estimated that most of the HCH applied to the catchment area of Vellar river is removed to the air and only a small part of it was drained to the sea. Compared to the present situation, the flux of HCH to the sea seems to be much larger in the past when the river structure was different from the present. This implies that at present the localized contamination of HCH in the sea is reducing: instead more rapid contamination is advancing on global terms due to the ‘long-range atmospheric transport’ of residues from the ‘point-source’ areas.