Evaluating spatial distribution and seasonal variation of phthalates using passive air sampling in southern India.

Usage of phthalates as plasticizers has resulted in worldwide occurrence and is becoming a serious concern to human health and environment. However, studies on phthalates in Indian atmosphere are lacking. Therefore, we studied the spatio-temporal trends of six major phthalates in Tamil Nadu, southern India, using passive air samplers. Phthalates were ubiquitously detected in all the samples and the average total phthalates found in decreasing order is pre-monsoon (61 ng m-3) > summer (52 ng m-3) > monsoon (17 ng m-3). Largely used phthalates, dibutylphthalate (DBP) and diethylhexlphthalate (DEHP) were predominantly found in all the seasons with contribution of 11-31% and 59-68%, respectively. The highest total phthalates was observed in summer at an urban location (836 ng m-3). Furthermore, through principal component analysis, potential sources were identified as emissions from additives of plasticizers in the polymer industry and the productions of adhesives, building materials and vinyl flooring. Although inhalation exposure of infants was higher than other population segments (toddlers, children and adults), exposure levels were found to be safe for people belonging to all ages based on reference dose (RfD) and tolerable daily intake (TDI) values. This study first attempted to report seasonal trend based on atmospheric monitoring using passive air sampling technique and exposure risk together.

GC-MS determination of bisphenol A and alkylphenol ethoxylates in river water from India and their ecotoxicological risk assessment.

Water samples from three rivers in southern India were analyzed for octylphenol (OP), nonylphenol (NP), and bisphenol A (BPA) residues by gas chromatography and mass spectrometry. The concentrations of OP, NP and BPA ranged from ND (not detected) to 16.3 ng/L, ND to 2200 ng/L, and 2.8 to 136 ng/L with detection frequencies of 96%, 66% and 100%, respectively. All three rivers showed a similar distribution pattern of NP>>BPA>OP, however, the Kaveri river had elevated levels. The phenolic compounds in rivers are expected to cause potential toxicity to aquatic organism including crustaceans, molluscs, insects and fish. In respect to aquatic risk assessment, NP showed a greater hazard quotient (HQ) than did OP and BPA, and the highest HQ (62) was observed for fish in the Kaveri river. The backwater and estuarine NP levels may pose a risk to larvae of oysters and barnacles. Based on tolerable daily intake and reference dose, BPA and NP levels are considered safe for humans. However, NP levels in some water samples were greater than the drinking water safety limit (0.5 µg/L). This is the first report on phenolic compounds and their associated aquatic risks in Indian rivers.

Non-steroidal anti-inflammatory drugs in Indian rivers.

Pharmaceutical concentration data for Indian surface waters are currently scarce. Sewage often enters Indian rivers without prior treatment, and so previously reported environmental concentrations from regions with routinely implemented sewage treatment cannot simply be used to predict concentrations in Indian surface water. Improved knowledge of pharmaceutical concentrations in Indian waters would enable determination of potential risks posed to aquatic wildlife and human health in this region. The concentrations of five common non-steroidal anti-inflammatory drugs (NSAIDs; diclofenac, ketoprofen, naproxen, ibuprofen, and acetylsalicylic acid) were determined in surface waters from 27 locations of the Kaveri, Vellar, and Tamiraparani Rivers in southern India. The samples were extracted by solid-phase extraction and analyzed by GC-MS. The measured concentrations of four of the five drugs in this reconnaissance were relatively similar to those reported elsewhere (ND-200 ng/l); however, acetylsalicylic acid, the most readily degradable of the investigated drugs, was found at all sites and at considerably higher concentrations (up to 660 ng/l) than reported in European surface waters. This is the first report on the occurrence of NSAIDs in Indian rivers. The finding of elevated concentrations of acetylsalicylic acid is most likely a result of direct discharges of untreated sewage. Therefore, readily degradable pharmaceuticals may present larger concern in regions without consistent sewage treatment. Based on measured environmental concentrations, the risks of direct toxicity to aquatic wildlife and of humans consuming the water are discussed.

Paraben resistance in bacteria from sewage treatment plant effluents in India.

Parabens, the antimicrobial preservatives used in cosmetics, food and pharmaceuticals, are often detected in the aquatic environment. Generally, sewage treatment plants (STPs) receive community sewage containing parabens, which are ultimately released into streams/rivers. In this study, bacteria in STP effluents were evaluated for their resistance to parabens. The susceptibility was in the order of Staphylococcus aureus > Bacillus sp. >Escherichia coli > Pseudomonas aeruginosa. Gram-negative bacteria showed less susceptibility than their control and Gram-positive bacteria. Further, the bacteria were more sensitive towards butyl and ethyl parabens. Interestingly, the strains showed resistance to ≥5 mg of parabens, which is equivalent to or higher than reported environmental concentrations. The increase in paraben chain length did not enhance the susceptibility in all cases and it was understood that the activity may differ for each bacterium in the environment. This is the first profile on paraben resistance in common pathogens of Indian STPs. Paraben resistance may be developed due to continuous exposure even at sub-inhibitory and/or chronic levels in the environment and this resistance may be transferred to other pathogenic bacteria in receiving waters. Thus the study demonstrates the effectiveness of the disc diffusion method in environmental bacterial resistance assessment and addresses the risk involved in the use of parabens.

GC-MS analysis and ecotoxicological risk assessment of triclosan, carbamazepine and parabens in Indian rivers.

Pharmaceutical and personal care products are used extensively worldwide and their residues are frequently reported in aquatic environments. In this study, antiepileptic, antimicrobial and preservative compounds were analyzed in surface water and sediment from the Kaveri, Vellar and Tamiraparani rivers, and in the Pichavaram mangrove in India by gas chromatography-mass spectrometry (GC-MS). The mean concentration of carbamazepine recorded in the Kaveri River water (28.3 ng/L) was higher than in the other rivers and the mangrove. Because carbamazepine is used only in human drugs, this may reflect the relative contributions of human excretions/sewage in these rivers. The mean triclosan level in the Tamiraparani River (944 ng/L) was an order of magnitude greater than in the other water systems, and the concentrations at two of the sites reported here (3800-5160 ng/L) are, to our best knowledge, among the highest detected in surface waters. Sediment levels were, however, comparable with other sites. We conclude that industrial releases are likely major contributors of triclosan into this river system. Among parabens, ethyl paraben was predominantly observed. Hazard Quotients suggest greater environmental risks for triclosan than for carbamazepine and parabens. This is the first study on antiepileptic, antimicrobial and preservatives in rivers and mangroves from India.