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Phthalate esters are well known for their environmental contamination and toxicological effects as "endocrine disruptors." In this study, environmental levels of phthalate esters and ecotoxicological risk assessments were performed in one of the major rivers in India, the Kaveri. Water and sediment samples were collected during 2010-2012 representing the major stretch of the river and extracted by solid-phase and ultrasonic methods, respectively, and analyzed for six major phthalates by using a gas chromatograph-mass spectrometer. The analytical recovery for phthalates in water and sediment ranged from 79 to 121%. Results indicated that diethyl phthalate (DEP) and dimethyl phthalate were found in every sample, whereas butylbenzyl phthalate and diethylhexyl phthalate (DEHP) were detected in 92% of the water samples. Likewise, in sediment samples, DEP was found most often (94%). The total phthalates in water samples ranged from 313 to 1,640 ng/l, whereas in sediments it was 2 to 1,438 ng/g dw (dry weight) with DEHP having the highest concentration. Human health risk assessment based on drinking water consumption showed no potential risk for phthalates and also DEHP levels were safe with respect to USEPA guideline (6,000 ng/l). Further, DEHP and di-n-octyl phthalate levels in water were expected to pose little threat to sensitive organisms in the riverine ecosystem as per ECOSAR chronic values. In case of sediment, the DEHP concentration was well above the USEPA sediment guideline value. To our knowledge, this is the first study to describe the levels and ecotoxicological risks of phthalates in Kaveri River, India.

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.

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.

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