Aquatic and human health risk assessment of Humanogenic Emerging Contaminants (HECs), Phthalate Esters from the Indian Rivers.

Phthalate esters (PEs) one of the widely used plasticizers, and are known for their environmental contamination and endocrine disruption. Hence, it is important to study their distribution in a riverine environment. This study was aimed to determine the Spatio-temporal trends of 16 PEs in surface water, sediment and fish from rivers in southern India, and to assess their environmental health risks. Phthalates were quantified in all matrices with the mean concentrations (∑16PEs) in water, sediment and fish as 35.6 µg/L, 1.25 µg/kg and 17.0 µg/kg, respectively. The Kaveri River is highly loaded with PEs compared to the Thamiraparani and Vellar Rivers. PEs such as DBP, DEHP, DCHP and DiBP were most frequently detected in all matrices, and at elevated concentrations in the dry season. The risk quotient (RQ < 1) suggests that the health risk of PEs from river water and fish to humans is negligible. However, DBP and DEHP from the Kaveri River pose some risk to aquatic organisms (HQ > 1). DEHP from the Vellar River may pose risks to algae and crustaceans. Non-priority phthalate (DiBP) may pose risks to Kaveri and Vellar River fish. The bioaccumulation factor of DCHP and DEHP was found to be very high in Sardinella longiceps and in Centropristis striata, and also exceeded the threshold limit of 5000 suggesting that PEs in the riverine environment may pose some health concerns. This is the first study to assess the spatio-temporal distribution, riverine flux and potential ecological effects of 16 PEs from the southern Indian Rivers.

Investigation of distribution, sources and flux of perfluorinated compounds in major southern Indian rivers and their risk assessment.

Perfluorinated compounds (PFCs) are a group of emerging contaminants still less reported in rivers, particularly southern India. Therefore, we investigated the fate of 13 PFCs in three major rivers in southern India during post-monsoon and summer seasons. Twelve PFCs were detected, with an average total PFCs of 1853 ± 1463 pg/l. However, the total PFCs recorded in ppost-monsoon and summer seasons ranged from ND (none detected) to 10,545 pg/l and ND to 4960 pg/l, respectively. Among the individual congeners, perfluoro-n-hexanoic acid (PFHxA) had the highest detection average (929 ± 710 pg/l). The higher detection of short chain PFCs signifies their increasing wide usage as an alternative to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Higher levels of PFCs were observed in summer than post-monsoon season in the river Kaveri, which is mainly attributed to the decrease in river flow. A multidimensional source identification revealed domestic and commercial wastewater as the major source. A correlation analysis showed that most of the detected PFCs share the common source and undergo co-migration into rivers. The flux of PFCs into the Bay of Bengal, loaded by the Kaveri (15 kg/yr) and the Tamiraparani (2.2 kg/yr) rivers, signifies lower per capita emissions than other rivers in India and other countries. Further, the PFC levels found in the rivers can be considered safe for human consumption and aquatic organisms based on international guidelines. Being the first hand report in southern Indian rivers, the results warrant further investigation to understand the exact sources, fate and removal in detail.

Synthetic musks in surface water and fish from the rivers in India: Seasonal distribution and toxicological risk assessment.

Synthetic musks (SMs), a class of organic compounds added to various personal care products (PCPs) to enhance aroma, are increasingly released into the environment and become one emerging contaminants of concern in India. Some SMs like Galaxolide, Tonalide and Musk Ketone (MK) are lipophilic and found ubiquitously in the environment, posing health and ecological risks, especially affecting aquatic organisms. Hence, monitoring the synthetic musks contamination in these rivers become environmentally inevitable. Consequently, three major rivers, the Kaveri (Cauvery), Vellar and Thamirabarani Rivers in Tamil Nadu, India, were investigated to understand the occurrence and fate of SMs. The concentration of Galaxolide, Tonalide and MK in surface water ranged as not detected (ND)-198, ND-77 and ND-62 ng/L, respectively. The levels of SMs in the Kaveri River were comparable with Vellar and Thamirabarani Rivers; however, the detection frequency was low in Thamirabarani river. Fish samples from the Kaveri river had higher concentrations of SMs (galaxolide 36-350 ng/g > MK 2-33 ng/g > Tonalide 1-9 ng/g ww (wet weight)) than in the Vellar River. Based on Hazard Quotient, SMs pose no risks to freshwater systems and the resident organisms in this study. In India, the dry season starts from March to July (35-42 °C) and wet season starts from November to February (25-35 °C). Bioconcentration factor (BCF) values for Galaxolide were found higher during the wet season and lower during the dry season, whereas it is reverse for Tonalide. Among fish Gebilion catla may be a good indicator species for SMs, despite the seasons, it accumulates more. This is the first study of SMs in surface water and fish from the rivers in India.

Occurrence of triclocarban and benzotriazole ultraviolet stabilizers in water, sediment, and fish from Indian rivers.

Triclocarban and benzotriazole ultraviolet stabilizers (BUVSs) are listed as high production volume synthetic chemicals, used extensively in personal care products. Many of these chemicals persist in the aquatic environment as micropollutants. Knowledge on their fate in freshwater ecosystems is still lacking, especially in the Indian Rivers. Our intention is to study the seasonal distribution, hazard quotient, risk assessment, and bioaccumulation of triclocarban and BUVSs (UV-9, UV-P, UV-326, UV-327, UV-328, and UV-329) during wet and dry seasons in water, sediment and fish from the Kaveri, Vellar, and Thamiraparani rivers in Tamil Nadu State, India. Triclocarban and BUVSs were identified in all matrices analysed. Triclocarban was found in water, sediment, and fish up to 1119ng/L, 26.3ng/g (dry wt.), and 692ng/g (wet wt.), respectively. Among BUVSs, UV-329 was found up to 31.3ng/L (water samples), UV-327 up to 7.3ng/g (sediment samples), and UV-9 up to 79.4ng/g (fish samples). The hazard quotient (HQenv.) for triclocarban in surface water was found to be at risk level (HQenv. >1) in the Kaveri, and Thamiraparani rivers during dry season. Bioaccumulation factors indicate that target compounds (triclocarban and BUVSs) could bio-accumulate in organisms.

GC-MS determination of phthalate esters in human urine: A potential biomarker for phthalate bio-monitoring.

Six phthalic acid esters (PAEs) in human urine sampled randomly from three districts (Erode, Thanjavur, and Perambalur) in Tamil Nadu State and a Union Territory (Pondicherry) in India were quantified. We determined gender-wise, age-wise and location-wise distribution of PAEs and measured estrogenic activity of urine by molecular docking. Bis(2­ethylhexyl) phthalate (DEHP) was the predominant phthalic acid ester found and had a recovery of 104.5% (ultrasonic extraction at 15 min). Gender-wise (pregnant women: 185 ng/mL, children: 156 ng/mL, female: 151 ng/mL, and male: 138 ng/mL), age-wise (1-20 y: 157 ng/mL, 21-40 y: 156 ng/mL, and >40 y: 146 ng/mL), location-wise (urban: 154 ng/mL, and rural: 151 ng/mL), and region-wise (Erode district: 185 ng/mL, Thanjavur district: 155 ng/mL, Perambalur district: 117 ng/mL, and Pondicherry: 135 ng/mL) differences with total mean of Σ6 PAEs were found. The molecular docking study showed a high negative binding energy of PAEs with microbial receptors. Based on the results we conclude that urine could be used as an ideal biomarker to understand PAEs exposure in humans.