Comparison of two screening level risk assessment approaches for six disinfectants and pharmaceuticals

A critical review on environmental presence of pharmaceutical drugs tested for the covid-19 treatment

On March 11, 2020, the World Health Organization (WHO) declared COVID-19 a pandemic. The outbreak caused a worldwide impact, becoming a health threat to the general population and its professionals. To date, there are no specific antiviral treatments or vaccines for the COVID-19 infection, however, some drugs are being clinically tested. The use of these drugs on large scale raises great concern about their imminent environmental risk, since the elimination of these compounds by feces and urine associated with the inefficiency of sewage treatment plants in their removal can result in their persistence in the environment, putting in risk the health of humans and of other species. Thus, the goal of this work was to conduct a review of other studies that evaluated the presence of the drugs chloroquine, hydroxychloroquine, azithromycin, ivermectin, dexamethasone, remdesivir, favipiravir and some HIV antivirals in the environment. The research indicated the presence of these drugs in the environment in different regions, with concentration data that could serve as a basis for further comparative studies following the pandemic.

Concentration and environmental fate of ivermectin in floodplain wetlands: An ecosystem approach

Ivermectin (IVM) is commonly used for broad control of endo- and ecto- parasites in cattle. In wetlands of the Parana Medio River, cattle has been treated repeatedly with IVM for years and concerns have been raised on possible presence of the drug in these ecosystems. A field study was conducted to assess concentration of IVM in two wetlands subjected to different cattle use and frequency of IVM injection. Concentration of IVM in roots of macrophytes, Chironomus sp., Coelotanypus sp., Brachymesia furcata (larvae), Dero sp., Hyalella sp., Hirudinea, Planorbidae, Boana pulchella (larvae), Aphyocharax anisitsi and Serrapinnus calliurus were shown for the first time. Total concentration of IVM in the wetlands, and concentration in cattle manure, sediment, water and macrophytes increased with the number of treated cattle and frequency of IVM injections. Accumulation of IVM in aquatic assemblages is alarming because these organisms fulfill a key role in food webs, constituting a serious risk to human health. Management strategies should be implemented by farmers to keep recently treated animals away from watercourses to reduce the introduction of IVM into aquatic systems.

A critical review on organic micropollutants contamination in wastewater and removal through carbon nanotubes

The prevalence of organic micropollutants (OMPs) in various environmental compartments is posing a serious health risks to all kinds of lives on the planet. The levels of OMPs such as polyaromatic hydrocarbons, antibiotics, pesticides, contraceptive medicines, and personal care products in water bodies are increasing with each passing day. It is an urgent need of time to limit the release of OMPs into the environment, and to remove the prevailing OMPs for sustainable environmental management. The majority of the conventional means of water decontamination are either inefficient or expensive. However, due to nanosize, high surface area, and hollow and layered structure, carbon nanotubes (CNTs) serve as excellent sorbents for the removal of a diverse range of OMPs. The occurrence of emerging OMPs and their detrimental effects on human and animal health are collected and discussed in this review. The characteristics and efficacy of various CNTs (pristine and modified) for the efficient removal of different OMPs, and the removal mechanisms have been reviewed and discussed. The literature demonstrated that adsorption of OMPs onto CNTs is very complicated and rely on multiple factors including the properties of adsorbent and the adsorbate as well as solution chemistry. It was found that H-bonding, electrostatic interactions, van der Waals forces, hydrophobic interactions, H-π bongs, and π-π interactions were the major mechanisms responsible for the adsorption of OMPs onto various kinds of CNTs. Despite of higher affinities for OMPs, hydrophobicity and higher costs restrain the practical application of CNTs for wastewater treatment on large scale. However, continuous production may lead to the development of cost-effective, efficient and eco-friendly CTNs technology for wastewater treatments in future.

Greywater irrigation as a source of organic micro-pollutants to shallow groundwater and nearby surface water

Increased water demands due to population growth and increased urbanisation have driven adoption of various water reuse practices. The irrigation of greywater (water from all household uses, except toilets) has been proposed as one potential sustainable practice. Research has clearly identified environmental harm from the presence of micro-pollutants in soils, groundwater and surface water. Greywater contains a range of micro pollutants yet very little is known about their potential environmental fate when greywater is irrigated to soil. Therefore, this study assessed whether organic micro-pollutants in irrigated greywater were transferred to shallow groundwater and an adjacent surface waterway. A total of 22 organic micro-pollutants were detected in greywater. Six of these (acesulfame, caffeine, DEET, paracetamol, salicylic acid and triclosan) were selected as potential tracers of greywater contamination. Three of these chemicals (acesulfame, caffeine, DEET) were detected in the groundwater, while salicylic acid was also detected in adjacent surface water. Caffeine and DEET in surface water were directly attributable to greywater irrigation. Thus the practice of greywater irrigation can act as a source of organic micro-pollutants to shallow groundwater and nearby surface water. The full list of micro-pollutants that could be introduced via greywater and the risk they pose to aquatic ecosystems is not yet known.

Chemical monitoring of Swedish coastal waters indicates common exceedances of environmental thresholds, both for individual substances as well as their mixtures

Chemical pollution was monitored and assessed along the Swedish west coast. 62 of 172 analyzed organic chemicals were detected in the water phase of at least one of five monitored sites. A Concentration Addition based screening-level risk assessment indicates that all sites are put at risk from chemical contamination, with total risk quotients between 2 and 9. Only at one site did none of the individual chemicals exceeded its corresponding environmental threshold (PNEC, EQS). The monitoring data thus demonstrate a widespread blanket of diffuse pollution, with no clear trends among sites. Further issues critical for the environmental chemical risk assessment include the challenges to achieve sufficiently low levels of detection, especially for hormones and cypermethrin (a pyrethroid insecticide), the appropriate consideration of non-detects and the limited availability of reliable PNECs and EQS values.

Pharmaceutical Residues in Sewage Treatment Works and their Fate in the Receiving Environment

Pharmaceuticals are increasingly used in large amounts in human (and veterinary) medicine around the world. They reach the aquatic environment mainly through sewage treatment systems and can reach μg l−1 levels. The continual input of pharmaceuticals to the aquatic environment, via sewage, can also impart a persistent quality to compounds that otherwise possess no inherent environmental stability. While the literature contains increasing numbers of studies detailing fate, effects and behaviour in the environment, the subject is still not fully understood for all the different therapeutic classes. The toxicological significance for non-target (especially aquatic) organisms is poorly understood. The use/release of antibiotics and natural/synthetic steroids to the environment has generated most of the concern to date, but a plethora of other drugs are increasingly attracting attention, as their biological activity alone may support ecotoxicity assessments of those compounds with high production volumes (or toxicity), especially in view of the increasing importance of freshwater resources. Pharmaceuticals display a variety of removal efficiencies during wastewater treatment and their fate and behaviour are not determined by their physicochemical properties alone. Despite the fact that many drugs have high sorption potentials, partitioning to the solid phase was determined to be an unlikely removal pathway for the majority of compounds. The partitioning behaviour of these compounds both in sewage treatment and the aquatic environment is likely to be dictated by a number of physicochemical parameters. Findings also indicate that the costs of using tertiary treatment options (mainly based on drinking water treatment) to remove drugs from wastewater effluent are likely to be prohibitively expensive, and potentially undesirable, due sustainability implications. While adjusting existing treatment parameters may increase the removal efficiencies of pharmaceuticals, any changes to sewage treatment parameters would need to be offset against the economic and environmental costs. Likewise, any regulations on drug use must be balanced against health benefits. If receiving waters are used for potable supplies, the presence of these compounds may (although it is unlikely) represent a potential hazard to human health, especially in areas without advanced water treatment. The focus for future research should therefore be on proper and sufficient science for establishing the occurrence, exposure and effects of pharmaceuticals in the environment, so that sound decisions can be made regarding human and ecological health.

Imprinted silica nanoparticles coated with N-propylsilylmorpholine-4-carboxamide for the determination of m-cresol in synthetic and real samples

m-Cresol-imprinted silica nanoparticles coated with N-propylsilylmorpholine-4-carboxamide have been developed that contain specific pockets for the selective uptake of m-cresol. Silica nanoparticles were synthesized by a sol-gel process followed by functionalization of their surface with N-propylsilylmorpholine-4-carboxamide. The formation of m-cresol-imprinted silica nanoparticles was confirmed by UV-Vis spectrophotometry, infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. Electron microscopic studies revealed the formation of monodispersed imprinted silica nanoparticles with spherical shape and an average size of 83 nm. The developed nanoparticles were filled in a syringe and used for the extraction of m-cresol from aqueous samples followed by quantification using high-performance liquid chromatography with diode array detection. Various adsorption experiments showed that developed m-cresol-imprinted silica nanoparticles exhibited a high adsorption capacity and selectivity and offered a fast kinetics for rebinding m-cresol. The chromatographic quantification was achieved using mobile phase consisting of acetonitrile/water (70:30 v/v) at an isocratic flow rate of 1.0 mL/min using a reversed-phase C18 column and detection at λmax = 275 nm. The limits of detection and quantification were 1.86 and 22.32 ng/mL, respectively, for the developed method. The percent recoveries ranged from 96.66-103.33% in the spiked samples. This combination of this nanotechnique with molecular imprinting was proved as a reliable, sensitive and selective method for determining the target from synthetic and real samples.

Health risk assessment of organic micropollutants in greywater for potable reuse

In light of the increasing interest in development of sustainable potable reuse systems, additional research is needed to elucidate the risks of producing drinking water from new raw water sources. This article investigates the presence and potential health risks of organic micropollutants in greywater, a potential new source for potable water production introduced in this work. An extensive literature survey reveals that almost 280 organic micropollutants have been detected in greywater. A three-tiered approach is applied for the preliminary health risk assessment of these chemicals. Benchmark values are derived from established drinking water standards for compounds grouped in Tier 1, from literature toxicological data for compounds in Tier 2, and from a Threshold of Toxicological Concern approach for compounds in Tier 3. A risk quotient is estimated by comparing the maximum concentration levels reported in greywater to the benchmark values. The results show that for the majority of compounds, risk quotient values were below 0.2, which suggests they would not pose appreciable concern to human health over a lifetime exposure to potable water. Fourteen compounds were identified with risk quotients above 0.2 which may warrant further investigation if greywater is used as a source for potable reuse. The present findings are helpful in prioritizing upcoming greywater quality monitoring and defining the goals of multiple barriers treatment in future water reclamation plants for potable water production.

Systematic screening of common wastewater-marking pharmaceuticals in urban aquatic environments: implications for environmental risk control

In this report, we refer to pharmaceuticals that are widespread in the urban aquatic environment and that mainly originate from wastewater treatment plants or non-point source sewage as "wastewater-marking pharmaceuticals" (WWMPs). To some extent, they reflect the condition or trend of water contamination and also contribute to aquatic environmental risk assessment. The method reported here for screening typical WWMPs was proposed based on academic concerns about them and their concentrations present in the urban aquatic environment, as well as their properties of accumulation, persistence, eco-toxicity and related environmental risks caused by them. The screening system consisted of an initial screening system and a further screening system. In the former, pharmaceuticals were categorised into different evaluation levels, and in the latter, each pharmaceutical was given a normalised final evaluation score, which was the sum of every score for its properties of accumulation, persistence, eco-toxicity and environmental risk in the aquatic environment. The system was applied to 126 pharmaceuticals frequently detected in the aquatic environment. In the initial screening procedure, five pharmaceuticals were classified into the "high" category, 16 pharmaceuticals into the "medium" category, 15 pharmaceuticals into the "low" category and 90 pharmaceuticals into the "very low" category. Subsequently, further screening were conducted on 36 pharmaceuticals considered as being of "high", "medium" and "low" categories in the former system. We identified 7 pharmaceuticals with final evaluation scores of 1-10, 10 pharmaceuticals with scores of 11-15, 15 pharmaceuticals with scores from 16 to 20 and 4 pharmaceuticals with scores above 21. The results showed that this screening system could contribute to the effective selection of target WWMPs, which would be important for spatial-temporal dynamics, transference and pollution control of pharmaceuticals in the urban aquatic environment. However, there remains a number of pharmaceutical parameters with measured data gaps, such as organic carbon adsorption coefficients and bioconcentration factors, which, if filled, would improve the accuracy of the screening system.

Prioritizing chemicals and data requirements for screening-level exposure and risk assessment

BACKGROUND

Scientists and regulatory agencies strive to identify chemicals that may cause harmful effects to humans and the environment; however, prioritization is challenging because of the large number of chemicals requiring evaluation and limited data and resources.

OBJECTIVES

We aimed to prioritize chemicals for exposure and exposure potential and obtain a quantitative perspective on research needs to better address uncertainty in screening assessments.

METHODS

We used a multimedia mass balance model to prioritize > 12,000 organic chemicals using four far-field human exposure metrics. The propagation of variance (uncertainty) in key chemical information used as model input for calculating exposure metrics was quantified.

RESULTS

Modeled human concentrations and intake rates span approximately 17 and 15 orders of magnitude, respectively. Estimates of exposure potential using human concentrations and a unit emission rate span approximately 13 orders of magnitude, and intake fractions span 7 orders of magnitude. The actual chemical emission rate contributes the greatest variance (uncertainty) in exposure estimates. The human biotransformation half-life is the second greatest source of uncertainty in estimated concentrations. In general, biotransformation and biodegradation half-lives are greater sources of uncertainty in modeled exposure and exposure potential than chemical partition coefficients.

CONCLUSIONS

Mechanistic exposure modeling is suitable for screening and prioritizing large numbers of chemicals. By including uncertainty analysis and uncertainty in chemical information in the exposure estimates, these methods can help identify and address the important sources of uncertainty in human exposure and risk assessment in a systematic manner.

Prioritising chemicals used in personal care products in China for environmental risk assessment: application of the RAIDAR model

China represents a significant market for the sale of personal care products (PCPs). Given the continuous emission of hundreds of chemicals used in PCPs to waste water and the aquatic environment after regular use, methods for prioritising the environmental risk assessment for China are needed. In an effort to assess the prioritisation of chemicals used in PCPs in China, we have identified the chemical ingredients used in 2500 PCPs released to the Chinese market in 2009, and estimated the annual emission of these chemicals. The physical-chemical property data for these substances have been estimated and used as model inputs in the RAIDAR model. In general, the RAIDAR model provides an overall assessment of the multimedia fate of chemicals, and provides a holistic approach for prioritising chemical ingredients. The prioritisation exercise conducted in this study is shown to be strongly influenced by loss processes, such as the removal efficiencies of WWT plants and biotransformation.

Potential Ecological and Human Health Risks Associated With the Presence of Pharmaceutically Active Compounds in the Aquatic Environment

Recently, considerable interest has developed regarding the presence of pharmaceuticals in the environment, but as yet the potential ecological effects associated with the presence of these compounds have been largely ignored. In this review, laboratory-based acute and chronic toxicity data, as well as studies concerned with the effects of pharmaceuticals on a variety of different organisms, are examined, along with the reported environmental concentrations of pharmaceuticals in aquatic systems. The possible sources and pathways of these compounds to the environment and the effects of a variety of medicines on a range of organisms are also highlighted, and recommendations are made for further research.

Comparison of predicted and measured concentrations of selected pharmaceuticals, fragrances and hormones in Spanish sewage

A review of consumption and excretion rates of 17 pharmaceuticals, two musk fragrances and two hormones by the Spanish population in 2003 was performed. For that purpose, three different models were used: (i) extrapolation of the per capita use in Europe to the number of inhabitants of Spain for musk fragrances; (ii) annual prescription items multiplied by the average daily dose for pharmaceuticals and; (iii) excretion rates of different groups of population for hormones. This information enabled the prediction of the expected concentrations (PEC) entering sewage treatment plants (STPs), which were subsequently compared with the measured environmental concentrations (MEC) in raw sewage. Annual drugs consumption in Spain ranges from few kilograms (Oxazepam and 17alpha-ethinylestradiol) to several hundred of tons (Ibuprofen). The quantities of musks used accounts for 110-450 kg d(-1) and the total amount of hormones excreted daily reaches almost 1 kg d(-1). 12 out of 21 selected substances were predicted to be present in raw sewage influent at concentrations greater than 100 ng l(-1) and these predicted concentrations fitted with the measured values for half of them (Carbamazepine, Diazepam, Ibuprofen, Naproxen, Diclofenac, Sulfamethoxazole, Roxithromycin, Erythromycin and 17alpha-ethinylestradiol).

Effects of the parasiticide ivermectin on the cladoceran Daphnia magna and the green alga Pseudokirchneriella subcapitata

Although widely used for the treatment of endo- and ectoparasites in livestock and pets, very few data on chronic effects on aquatic organisms are available for the parasiticide ivermectin. In the present study, toxicity of ivermectin to two freshwater organisms, the cladoceran Daphnia magna and the green alga Pseudokirchneriella subcapitata was investigated. For D. magna, a mean LC(50) 48 h of 5.7 ngl(-1) was derived from 10 acute tests. Chronic toxicity of ivermectin to D. magna was extremely high: with 0.001 and 0.0003 ngl(-1), respectively, nominal LOEC and NOEC based on growth and reproduction were far below the analytical limit of detection for this compound. P. subcapitata was considerably less sensitive to ivermectin than D. magna. For both growth rate and yield, EC(50) was >4,000 microgl(-1), LOEC was 1,250 microgl(-1) and NOEC 391microgl(-1). In view of the high toxicity to D. magna, the use of ivermectin might pose a risk to local aquatic ecosystems. Further studies should be carried out to investigate the effects of ivermectin and its degradation products on pelagic and benthic freshwater invertebrates.

Veterinary pharmacovigilance. Part 2. Veterinary pharmacovigilance in practice -- the operation of a spontaneous reporting scheme in a European Union country -- the UK, and schemes in other countries

Veterinary pharmacovigilance, as it operates in the European Union (EU), covers a very broad remit, including adverse effects in treated animals, exposed humans and the environment, and in addition, it extends to cover the violation of maximum residue limits. The mainstay of veterinary pharmacovigilance is the spontaneous reporting scheme working along side other systems such as those reporting on residues surveillance. One of the most well established schemes in the EU is that operating in the UK and this paper examines the evolution of that scheme and some of its findings, data from other countries, and information available from the literature. It also tentatively examines the ways that pharmacovigilance can be used for regulatory purposes, and the contribution from pharmacoepidemiology.

Modelling of pharmaceutical residues in Australian sewage by quantities of use and fugacity calculations

A conceptual model is presented for determining which currently prescribed pharmaceutical compounds are most likely to be found in sewage, and for estimating their concentrations, both in raw sewage and after successive stages of secondary sewage treatment. A ranking of the "top-50" pharmaceutical compounds (by total mass dispensed) in Australia over the 1998 calendar year was prepared. Information on the excretion ratios and some metabolites of the pharmaceuticals enabled prediction of the overall rates of excretion into Australian sewage. Mass-balance and fugacity modelling, applied to sewage generation and to a sewage treatment plant, allowed calculation of predicted concentrations of the compounds in raw, primary and secondary treated sewage effluents. Twenty nine of the modelled pharmaceutical residuals were predicted to be present in raw sewage influent at concentrations of 1 microgl(-1) or greater. Twenty of the compounds were predicted to remain in secondary effluent at concentrations of 1 microgl(-1) or greater.