In JoVE (1)

Other Publications (11)

Articles by Rakesh Kanda in JoVE

Other articles by Rakesh Kanda on PubMed

Steroid Estrogens Profiles Along River Stretches Arising from Sewage Treatment Works Discharges

Environmental Science & Technology. May, 2003  |  Pubmed ID: 12775044

Concentrations of estradiol, estrone, and ethinylestradiol were measured in the water column (daily for 28 or 14 days) and in the bed sediment (weekly over the same period) of the River Nene and the River Lea, U.K., upstream and downstream of sewage treatment works (STW). The concentrations of the three steroids in the STW effluents were also measured. Estrone was detected at the highest concentration and in almost all samples from the three STW effluents, concentrations ranging from <0.4 to 12.2 ng/L. Estradiol was also detected frequently (<0.4-4.3 ng/L), but ethinylestradiol was detected infrequently (<0.4-3.4 ng/L). Positive detections were only found for estrone in the sediment, and these seemed to be unrelated to the water column concentrations. Levels of estrone were clearly raised above background levels in the rivers as a result of the STW discharges. Levels of estradiol and ethinylestradiol were too close to their detection limits to assess the STW impact. River water estrone concentration declined downstream at a rate that was in excess of that due to dilution. The most likely cause of this decline is a combination of sorption and biodegradation equivalent to a first-order decay half-life of 2.5 days for the River Nene and 0.5 days for the River Lea.

Pharmaceutical and Personal Care Products in Sewage Treatment Works

Journal of Environmental Monitoring : JEM. Oct, 2003  |  Pubmed ID: 14587856

In this study a number of analytical procedures are described to determine pharmaceuticals and personal care products (PPCPs) and their metabolites during sewage treatment. The work shows that PPCPs occur in sewage influent and are removed by various wastewater treatment processes. PPCPs include a wide range of chemicals such as prescription drugs as well as diagnostic agents, fragrances, sun-screen agents, and various other compounds commonly present in household items (e.g. detergents, cleaners, toothpastes etc.). During this study a number of PPCPs including painkillers (aspirin, ibuprofen), cholesterol control medication (clofibric acid), antibacterial agents (triclosan), musks (including galaxolide and tonalide), X-ray contrast media (diatrizoate), cancer treatment drugs (cyclophosphamide) and anti-depressant drugs (fluvoxamine) were investigated. Analysis was carried out using a number of techniques. Samples were extracted using solid phase extraction or liquid-liquid extraction and the extracts analysed using capillary gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring or liquid chromatography mass spectrometry (LC-MS) or LC-MS-MS. The results obtained show that aspirin, clolibric acid, diatrozate, fluvoxamine and cyclophosphamide were not detected in any of the crude sewage or sewage effluent samples above the limit of detection of the applied methods. Ibuprofen was detected in all crude sewage samples as well as in all effluent samples with one exception. Removal of ibuprofen by the different STWs was generally between 80-100%, with the exception of one STW where removal was poor (14.4 to 44%). Triclosan was also detected in all crude sewage samples and in all sewage effluent samples. The highest concentration of triclosan detected was 3100 ng l(-1). A high removal efficiency was observed in effluent samples taken on two occasions (average removal 95.6%). The concentrations of musks detected in the crude sewage were generally low except for galaxolide and tonalide. The results from STW effluent samples showed significant removal of galaxolide (70-83% removal) except at one STW (STW 1) where removal was low (57% and 39%). Similar removal efficiencies for tonalide were achieved at these STWs (73-96%) except at STW 1 where removal was poor (53%).

What Difference Might Sewage Treatment Performance Make to Endocrine Disruption in Rivers?

Environmental Pollution (Barking, Essex : 1987). May, 2007  |  Pubmed ID: 17030080

An assessment of the steroid estrogen removing performance of 23 different sewage treatment plants (STPs) was performed. The assessment relied on a model to estimate influent concentrations, and completed questionnaires on the STP treatment details from the relevant water companies. This information was compared with observed effluent 17beta-estradiol (E2) and estrone (E1) concentrations. The 10 biological filter plants (BFP) in the study performed poorly with only 30% (SD 31) removal on average for E1. This reduced E1 removal performance of the BFPs compared to all the other STP types in the survey was statistically significant (p<0.001). Scenarios of all the STPs as activated sludge types, and one as all BFP types were modelled using the GREAT-ER model set up for the Aire/Calder catchment in the UK. This difference was shown to have an important effect on predicted river E1 concentrations and consequent risk classifications.

Determination of Decamethylcyclopentasiloxane in River Water and Final Effluent by Headspace Gas Chromatography/mass Spectrometry

Journal of Chromatography. A. Nov, 2008  |  Pubmed ID: 18962646

A method is described for the analysis of decamethylcyclopentasiloxane (D(5)) in river water and treated waste water using headspace gas chromatography/mass spectrometry. Internal standard addition to samples and field blanks was carried out in the field to provide both a measure of recovery and to prevent any exposure of samples to laboratory air, which contained background levels of D(5). Measured levels of D(5) were typically in the range <10-29ngL(-1) in the River Great Ouse (UK) with slightly higher levels in the River Nene (UK). The measured concentration of D(5) in treated waste water varied between 31 and 400ngL(-1), depending on the type of treatment process employed.

Comparing Predicted Against Measured Steroid Estrogen Concentrations and the Associated Risk in Two United Kingdom River Catchments

Environmental Toxicology and Chemistry / SETAC. Apr, 2012  |  Pubmed ID: 22278704

Predicted concentrations of estrone, 17β-estradiol, and 17α-ethinylestradiol generated from a geographical information systems-based model (LF2000-WQX) have previously been used to assess the risk of causing intersex in male fish in the rivers of England and Wales, United Kingdom. Few measured data of sufficient quality and spatial extent have been available to verify this risk assessment. New measured data have been collected from sewage treatment plant effluents and the receiving waters upstream and downstream of these discharges from the Erewash River and the Avon River systems in England. The model results for these rivers were in good agreement with the measured values in terms of estradiol equivalents. Critically, the risk assessment based on the measured data gave a risk assessment nearly identical to that derived from the modeled results. For individual estrogens, 17α-ethinylestradiol was modeled best and estrone worst. Poor simulations reflected poor estimates of the effluent concentrations, which were more variable from day to day and between works of nominally similar type than is assumed in the model. In support of this, model results for the Erewash River, calculated using observed effluent concentrations, were in excellent agreement with the measured data. The model has proved to be adequate in predicting overall estrogenic potency, and therefore risk, along these rivers; however, improvements are possible, particularly in predicting STP removal efficiency and therefore effluent concentrations.

Additional Treatment of Wastewater Reduces Endocrine Disruption in Wild Fish--a Comparative Study of Tertiary and Advanced Treatments

Environmental Science & Technology. May, 2012  |  Pubmed ID: 22500691

Steroid estrogens are thought to be the major cause of feminization (intersex) in wild fish. Widely used wastewater treatment technologies are not effective at removing these contaminants to concentrations thought to be required to protect aquatic wildlife. A number of advanced treatment processes have been proposed to reduce the concentrations of estrogens entering the environment. Before investment is made in such processes, it is imperative that we compare their efficacy in terms of removal of steroid estrogens and their feminizing effects with other treatment options. This study assessed both steroid removal and intersex induction in adult and early life stage fish (roach, Rutilus rutilus). Roach were exposed directly to either secondary (activated sludge process (ASP)), tertiary (sand filtrated (SF)), or advanced (chlorine dioxide (ClO(2)), granular activated charcoal (GAC)) treated effluents for six months. Surprisingly, both the advanced GAC and tertiary SF treatments (but not the ClO(2) treatment) significantly removed the intersex induction associated with the ASP effluent; this was not predicted by the steroid estrogen measurements, which were higher in the tertiary SF than either the GAC or the ClO(2). Therefore our study highlights the importance of using both biological and chemical analysis when assessing new treatment technologies.

Modeling of Steroid Estrogen Contamination in UK and South Australian Rivers Predicts Modest Increases in Concentrations in the Future

Environmental Science & Technology. Jul, 2013  |  Pubmed ID: 23631391

The prediction of risks posed by pharmaceuticals and personal care products in the aquatic environment now and in the future is one of the top 20 research questions regarding these contaminants following growing concern for their biological effects on fish and other animals. To this end it is important that areas experiencing the greatest risk are identified, particularly in countries experiencing water stress, where dilution of pollutants entering river networks is more limited. This study is the first to use hydrological models to estimate concentrations of pharmaceutical and natural steroid estrogens in a water stressed catchment in South Australia alongside a UK catchment and to forecast their concentrations in 2050 based on demographic and climate change predictions. The results show that despite their differing climates and demographics, modeled concentrations of steroid estrogens in effluents from Australian sewage treatment works and a receiving river were predicted (simulated) to be similar to those observed in the UK and Europe, exceeding the combined estradiol equivalent's predicted no effect concentration for feminization in wild fish. Furthermore, by 2050 a moderate increase in estrogenic contamination and the potential risk to wildlife was predicted with up to a 2-fold rise in concentrations.

Environmental Concentrations of Anti-androgenic Pharmaceuticals Do Not Impact Sexual Disruption in Fish Alone or in Combination with Steroid Oestrogens

Aquatic Toxicology (Amsterdam, Netherlands). Mar, 2015  |  Pubmed ID: 25630045

Sexual disruption in wild fish has been linked to the contamination of river systems with steroid oestrogens, including the pharmaceutical 17α-ethinylestradiol, originating from domestic wastewaters. As analytical chemistry has advanced, more compounds derived from the human use of pharmaceuticals have been identified in the environment and questions have arisen as to whether these additional pharmaceuticals may also impact sexual disruption in fish. Indeed, pharmaceutical anti-androgens have been shown to induce such effects under laboratory conditions. These are of particular interest since anti-androgenic biological activity has been identified in the aquatic environment and is potentially implicated in sexual disruption alone and in combination with steroid oestrogens. Consequently, predictive modelling was employed to determine the concentrations of two anti-androgenic human pharmaceuticals, bicalutamide and cyproterone acetate, in UK sewage effluents and river catchments and their combined impacts on sexual disruption were then assessed in two fish models. Crucially, fish were also exposed to the anti-androgens in combination with steroid oestrogens to determine whether they had any additional impact on oestrogen induced feminisation. Modelling predicted that the anti-androgenic pharmaceuticals were likely to be widespread in UK river catchments. However, their concentrations were not sufficient to induce significant responses in plasma vitellogenin concentrations, secondary sexual characteristics or gross indices in male fathead minnow or intersex in Japanese medaka alone or in combination with steroid oestrogens. However, environmentally relevant mixtures of oestrone, 17β-oestradiol and 17α-ethinylestradiol did induce vitellogenin and intersex, supporting their role in sexual disruption in wild fish populations. Unexpectedly, a male dominated sex ratio (100% in controls) was induced in medaka and the potential cause and implications are briefly discussed, highlighting the potential of non-chemical modes of action on this endpoint.

Removal of Ecotoxicity of 17α-ethinylestradiol Using TAML/peroxide Water Treatment

Scientific Reports. 2015  |  Pubmed ID: 26068117

17α-ethinylestradiol (EE2), a synthetic oestrogen in oral contraceptives, is one of many pharmaceuticals found in inland waterways worldwide as a result of human consumption and excretion into wastewater treatment systems. At low parts per trillion (ppt), EE2 induces feminisation of male fish, diminishing reproductive success and causing fish population collapse. Intended water quality standards for EE2 set a much needed global precedent. Ozone and activated carbon provide effective wastewater treatments, but their energy intensities and capital/operating costs are formidable barriers to adoption. Here we describe the technical and environmental performance of a fast- developing contender for mitigation of EE2 contamination of wastewater based upon small- molecule, full-functional peroxidase enzyme replicas called "TAML activators". From neutral to basic pH, TAML activators with H2O2 efficiently degrade EE2 in pure lab water, municipal effluents and EE2-spiked synthetic urine. TAML/H2O2 treatment curtails estrogenicity in vitro and substantially diminishes fish feminization in vivo. Our results provide a starting point for a future process in which tens of thousands of tonnes of wastewater could be treated per kilogram of catalyst. We suggest TAML/H2O2 is a worthy candidate for exploration as an environmentally compatible, versatile, method for removing EE2 and other pharmaceuticals from municipal wastewaters.

Nitrogenous Disinfection Byproducts in English Drinking Water Supply Systems: Occurrence, Bromine Substitution and Correlation Analysis

Water Research. Nov, 2015  |  Pubmed ID: 26302218

Despite the recent focus on nitrogenous disinfection byproducts in drinking water, there is limited occurrence data available for many species. This paper analyses the occurrence of seven haloacetonitriles, three haloacetamides, eight halonitromethanes and cyanogen chloride in 20 English drinking water supply systems. It is the first survey of its type to compare bromine substitution factors (BSFs) between the haloacetamides and haloacetonitriles. Concentrations of the dihalogenated haloacetonitriles and haloacetamides were well correlated. Although median concentrations of these two groups were lower in chloraminated than chlorinated surface waters, median BSFs for both in chloraminated samples were approximately double those in chlorinated samples, which is significant because of the higher reported toxicity of the brominated species. Furthermore, median BSFs were moderately higher for the dihalogenated haloacetamides than for the haloacetonitriles. This indicates that, while the dihalogenated haloacetamides were primarily generated from hydrolysis of the corresponding haloacetonitriles, secondary formation pathways also contributed. Median halonitromethane concentrations were remarkably unchanging for the different types of disinfectants and source waters: 0.1 μg · mgTOC(-1) in all cases. Cyanogen chloride only occurred in a limited number of samples, yet when present its concentrations were higher than the other N-DBPs. Concentrations of cyanogen chloride and the sum of the halonitromethanes were not correlated with any other DBPs.

TAML/H2O2 Oxidative Degradation of Metaldehyde: Pursuing Better Water Treatment for the Most Persistent Pollutants

Environmental Science & Technology. May, 2016  |  Pubmed ID: 27088657

The extremely persistent molluscicide, metaldehyde, widely used on farms and gardens, is often detected in drinking water sources of various countries at concentrations of regulatory concern. Metaldehyde contamination restricts treatment options. Conventional technologies for remediating dilute organics in drinking water, activated carbon, and ozone, are insufficiently effective against metaldehyde. Some treatment plants have resorted to effective, but more costly UV/H2O2. Here we have examined if TAML/H2O2 can decompose metaldehyde under laboratory conditions to guide development of a better real world option. TAML/H2O2 slowly degrades metaldehyde to acetaldehyde and acetic acid. Nuclear magnetic resonance spectroscopy ((1)H NMR) was used to monitor the degradation-the technique requires a high metaldehyde concentration (60 ppm). Within the pH range of 6.5-9, the reaction rate is greatest at pH 7. Under optimum conditions, one aliquot of TAML 1a (400 nM) catalyzed 5% degradation over 10 h with a turnover number of 40. Five sequential TAML aliquots (2 μM overall) effected a 31% removal over 60 h. TAML/H2O2 degraded metaldehyde steadily over many hours, highlighting an important long-service property. The observation of metaldehyde decomposition under mild conditions provides a further indication that TAML catalysis holds promise for advancing water treatment. These results have turned our attention to more aggressive TAML activators in development, which we expect will advance the observed technical performance.

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