Affiner votre recherche
Résultats 1701-1710 de 5,149
Insights of the Removal Mechanisms of Pharmaceutical and Personal Care Products in Constructed Wetlands Texte intégral
2018
Vo, Hoang-Nhat-Phong | Bui, Xuan-Thanh | Nguyen, Thi-Minh-Hong | Koottatep, T. | Bandyopadhyay, Amitava
PURPOSE OF REVIEW: Pharmaceutical and personal care products (PPCPs) are chemicals employed in human healthcare, veterinary, medical diagnosis, and cosmetics, which have increasingly polluted water sources. Extensive research has demonstrated constructed wetlands (CWs) technology as a low-cost but efficient approach for PPCPs removal. There has been a growing interest to better understand the degradation mechanisms of PPCPs in wetland cells. Data corroborated in this review show that these degradation mechanisms include photolytic degradation, adsorption, phytodegradation, and microbial degradation. Each of these degradation mechanisms performs differently in wetland cells. This review also highlights the lack of research works to quantify the contribution of these degradation mechanisms to the overall efficiency of CWs to remove PPCPs as a major bottleneck for further application of this technology. The ultimate goal is to apply and prioritize a suitable degradation mechanism for successfully eliminating corresponding PPCPs. This review, therefore, provides further insights to (i) elucidate the importance of these removal mechanisms, and (ii) quantify their contribution in overall PPCPs removal processes. This review aims to understand the importance and contribution of degradation mechanisms of PPCPs removal in constructed wetlands. RECENT FINDINGS: The degradation mechanisms of PPCPs in constructed wetlands depended on various conditions; yet, which factors are preferred? Furthermore, the number of research works, related to quantifying the contribution of degradation mechanisms, is limited. The hydrophobic/hydrophilic character, reflecting as log Kₒw (or log Dₒw), is the most commonly used. The photolytic degradation is appropriate with low and moderate hydrophobic values (log Dₒw from − 2.3 to 3). The role of adsorption is moderate, while it is more efficient with the higher hydrophobic compounds. The media is important for plant growth and micro-organism community development. The plant uptake is better for PPCPs with higher hydrophobicity (log Kₒw from 1 to 4). However, it is difficult to quantify their contribution and the number of related studies is limited.
Afficher plus [+] Moins [-]Release of PAHs and heavy metals in coastal environments linked to leisure boats Texte intégral
2018
Egardt, Jenny | Mørk Larsen, Martin | Lassen, Pia | Dahllöf, Ingela
Release of PAHs and heavy metals in coastal environments linked to leisure boats Texte intégral
2018
Egardt, Jenny | Mørk Larsen, Martin | Lassen, Pia | Dahllöf, Ingela
Leisure boats are responsible for elevated levels of heavy metals and PAHs in sediments in- and near marinas and natural harbours. As these compounds are released directly into the water column they also pose a threat to organisms in the pelagic environment.Passive samplers were deployed during peak and post tourist season in the water column of natural harbours, leisure boat waterways and small marinas to measure the dissolved fraction of PAHs and metal ions.Differences between seasons indicative of leisure boat activities were found as PAH composition differed between peak and post season for natural harbours and waterways, where heavier PAHs increased during peak season. During peak season, metal samplers were covered by biofouling, which likely affected the uptake. Post season metal concentrations differ between locations, with concentrations exceeding quality standards at near mainland locations where boats are maintained, compared to the sites in the archipelago.
Afficher plus [+] Moins [-]Impacts of recreational boating in coastal seascapes and implications for management Texte intégral
2018
Egardt, Jenny
Kosterhavet National Park, a marine protected area on the Swedish west coast, is a popular destination for tourists and attracts over half a million visitors annually. Many of the tourists arrive by boat, and the natural harbours are frequently visited. Boat presence may affect bottom substrates through anchoring, and pollution could also occur in the form of leaching antifouling paints, fuel residue (PAHs) and litter. This thesis set out to investigate if there are any lingering impacts resulting from boat tourism in Kosterhavet and suggests management efforts in those cases there are. Through studies using a video sled, data from two consecutive years revealed visible anchor traces on soft unvegetated bottoms, and number of traces were also linked to number of bottom anchoring boats. Furthermore, it was found that visitors engage in bottom anchoring at locations where sensitive habitats like eelgrass and oyster beds are located, which may result in harm to both habitat types. Sediment samples taken in both natural harbours and small marinas unexpectedly showed presence of long since banned antifouling products like TBT, but also more recently prohibited biocides like irgarol and diuron. This suggests that they are still in use. Moreover, water samples from the area show that the currently used antifouling compound copper, is likely to exceed threshold values set by the Swedish Agency for Marine and Water Management (SwAM) during peak boat season. Concentrations of PAHs were found to be below threshold values for water, but they are also known to have low water solubility and are more likely to be bound to particles. From the video data, occurrence of seafloor litter was also obtained, and data on beach litter from reference sites on the Swedish west coast was downloaded from the OSPAR beach litter database. Seafloor litter, in contradiction to beach litter, was at a much higher degree found to have an origin related to recreational activities. This suggest that beach litter stem from other activities in the park, or are brought to the area by currents. A threat analysis based on the leisure boat related threats; anchoring, antifouling, PAHs and litter were performed. Threats were analysed with respect to their potential impact to the soft bottom values; eelgrass, oysters and blue mussels. The sum of these threats showed that eelgrass was highly impacted by anchoring, but oysters were more severely affected when all threats were considered. This type of threat analysis can be of great value to park managers, as they need to make prioritizations regarding how to use their often limited resources. Based on these finding, it is, among others, suggested that bottom anchoring should not be allowed at locations where eelgrass and oyster beds occur, and that bottom friendly mooring solutions should be made available to avoid negative impact on these habitats.
Afficher plus [+] Moins [-]Statistical models of fecal coliform levels in Pacific Northwest estuaries for improved shellfish harvest area closure decision making Texte intégral
2018
Zimmer-Faust, Amity G. | Brown, Cheryl A. | Manderson, Alex
There is a substantial need for tools that effectively predict spatial and temporal fecal pollution patterns in estuarine waters. In this study, statistical models of exceedances of shellfish fecal coliform (FC) water quality criteria were developed using a 10-year dataset of FC levels and environmental data. Performance (sensitivity, specificity, and predictive capacity) of five different types of models was tested (MLR regression, Tobit (censored) regression, Firth's binary logistic regression (BLR), classification trees, and mixed-effects regression) for each of three conditionally managed shellfish-harvesting areas in Tillamook Bay, Oregon (USA). The most influential variables were related to precipitation and river stage height in the wet season and wind and tidal-stage in the dry season. Classification tree and Firth's BLR approaches better explained exceedances of shellfish water quality standards than the current closure thresholds. Findings demonstrate the utility of statistical modeling approaches for improved management of shellfish harvesting waters.
Afficher plus [+] Moins [-]Occurrence and virulence of Vibrio parahaemolyticus isolated from seawater and bivalve shellfish of the Gyeongnam coast, Korea, in 2004–2016 Texte intégral
2018
Park, Kunbawui | Mok, Jong Soo | Ryu, A Ra | Kwon, Ji Young | Ham, In Tae | Shim, Kil Bo
We determined the abundance and virulence of Vibrio parahaemolyticus in seawater and bivalves from the Gyeongnam coast in Korea, a major area for the seafood industry, during 2004–2016. V. parahaemolyticus is one of the most common pathogen causing seafood-borne illnesses in Korea, and increases during the summer. Its occurrence in seawater and bivalve samples was seasonally dependent, with high levels during the summer to early autumn. There were more strains in the area of sea continually exposed to inland wastewater. Only 5.1% and 3.5% of V. parahaemolyticus isolates from seawater and bivalves, respectively, had the trh gene, and only the bivalve isolates produced the tdh gene at levels below 2%. Continuous monitoring is clearly needed to reduce seafood-borne outbreaks of disease caused by V. parahaemolyticus, and to reveal the occurrence patterns and the presence of toxic genes of the strains in different marine environments.
Afficher plus [+] Moins [-]Impact of anthropogenic activities on mussel (Mytella guyanensis) in the Gulf of Paria, Trinidad Texte intégral
2018
Balgobin, Aaron | Ramroop Singh, Natasha
This body of work demonstrated the levels of selected contaminants (as well as their potential sources), in mussels (Mytella guyanensis) - a known bio-indicator of pollution, along the west coast (Gulf-of-Paria) of Trinidad. The findings demonstrated that polyaromatic hydrocarbons levels in the mussels investigated were moderate to high (201.80–1200.08 μg/kg). Notably, benzo(a)pyrene levels (1.15–9.32 μg/kg) exceeded the European Union guidelines at various sites. The distribution of PAHs and trace elements in the Gulf of Paria are impacted by tidal currents and local source discharge. Significant risks were identified from toxic carcinogenic equivalent levels (3.01 to 22.37 μg/kg) and mutagenic equivalent levels (3.98 to 38.61 μg/kg). The concentration of trace elements, Zn (46.05–56.36 mg/kg) and Cd (0.46–1.17 mg/kg), exceeded both local and international guidelines at certain sites investigated. The analysis revealed a high bioavailability of the identified pollutants in the Gulf of Paria from industrial, urban and marine activities.
Afficher plus [+] Moins [-]Synthetic lipids as a biocide candidate for disinfection of ballast water Texte intégral
2018
Batista, William R. | Fernandes, Flavio C. | Neves, Maria H.C.B. | Nascimento, Thiana S. | Lopes, Rosangela S.C. | Lopes, Claudio C. | Ziegler, Gregory P. | Soler-Figueroa, Brenda M. | Sparks, Darrick | Fontaine, Diana N. | Carney, Katharine J. | Quiñones-Oquendo, Luz E. | Ruiz, Gregory M.
The objective of this study is to propose the use of specific synthetic lipid as an active substance (biocide) in the control of harmful aquatic microorganisms, such as pathogens and non-indigenous species, transported in ships' ballast water. The biocide candidate, without metal or halogen components, was produced from a sub-product of the edible oil industry, the lecithin. Laboratory assays were conducted with phytoplankton, zooplankton, and marine bacteria to evaluate the efficiency of the biocide. The study also considers specific biocide's characteristics related to environmental risks, such as chemical composition, persistence, bioaccumulation, and toxicity. Results showed that, in the first 24 h of treatment, the biocide effectively reduced the concentration of the planktonic micro-organisms to very low levels. Additionally, a preliminary risk evaluation pointed that biocide candidate has a low residual toxicity, also a low potential for persistence and bioaccumulation in the environment.
Afficher plus [+] Moins [-]Changes to polychlorinated biphenyl (PCB) signatures and enantiomer fractions across different tissue types in Guillemots Texte intégral
2018
Megson, David | Brown, Thomas A. | O'Sullivan, Gwen | Robson, Matthew | Ortiz, Xavier | Worsfold, Paul J. | Comber, Sean | Lohan, Maeve C. | Reiner, Eric J.
Two Guillemot carcases were dissected, each providing 12 discrete tissue samples and 3 samples of partially digested food. One hundred and five PCBs from the 209 PCBs determined by GCxGC-ToFMS were detected. The relative proportions of individual PCBs did not vary greatly within tissue types, although the PCB profile from undigested food could be distinguished. Enantiomer fractions (EFs) were determined for CB-95, CB-136 and CB-149 by GC-HRqToFMS. EFs in the partially digested food were near racemic, with high levels of enrichment for E1 CB-95 in the kidneys and liver (EF of 0.80 and 0.84 respectively). This provides some of the clearest evidence to date that fractionation takes place in the organs where metabolic biotransformation and elimination of PCBs occurs. Our findings also confirm the ability of non-lethal sampling techniques, such as collection of small (<1 g) blood samples, to provide PCB signatures that are representative of an individual organism.
Afficher plus [+] Moins [-]Evaluating the impact of sewage discharges on the marine environment with a lightweight AUV Texte intégral
2018
Bonin-Font, Francisco | Lalucat, Jordi | Oliver-Codina, Gabriel | Massot-Campos, Miquel | Font, Eric Guerrero | Carrasco, Pep Lluis Negre
Environmental studies that use small Autonomous Underwater Vehicles (AUVs) can survey wider and deeper areas, compared to traditional methods, at a reasonable cost. Thanks to the precise vehicle navigation systems, the data collected can be accurately geolocalized. Besides, lightweight vehicles can be deployed from the shore or from small boats and programmed by means of user-friendly graphical interfaces, thus reducing and simplifying the need of human resources and infrastructures. Based on such a technology, this paper presents a framework to assess the environmental impact of a marine sewage outfall set in the Bay of Palma (Mallorca, Spain). We report the results of the analysis of the images recorded in the course of six missions conducted with an AUV. The plan was designed after a microbiological analysis detected the presence of cyanobacteria in a sample of sand and water collected by scuba divers close to the sewer pipe mouth.
Afficher plus [+] Moins [-]Degradation of Deepwater Horizon oil buried in a Florida beach influenced by tidal pumping Texte intégral
2018
Huettel, Markus | Overholt, Will A. | Kostka, Joel E. | Hagan, Christopher | Kaba, John | Wells, Wm Brian | Dudley, Stacia
After Deepwater Horizon oil reached the Florida coast, oil was buried in Pensacola Beach (PB) sands to ~70cm depth, resulting in Total Petroleum Hydrocarbon (TPH) concentrations up to ~2kg per meter of beach. This study followed the decomposition of the buried oil and the factors influencing its degradation. The abundance of bacteria in oiled sand increased by 2 orders of magnitude within one week after oil burial, while diversity decreased by ~50%. Half-lives of aliphatic and aromatic hydrocarbons reached 25 and 22days, respectively. Aerobic microbial oil decomposition, promoted by tidal pumping, and human cleaning activities effectively removed oil from the beach. After one year, concentrations of GC-amenable hydrocarbons at PB were similar to those in the uncontaminated reference beach at St. George Island/FL, and microbial populations that disappeared after the oil contamination had reestablished. Yet, oxihydrocarbons can be found at PB to the present day.
Afficher plus [+] Moins [-]Inorganic arsenic causes apoptosis cell death and immunotoxicity on European sea bass (Dicentrarchus labrax) Texte intégral
2018
Cordero, Hector | Morcillo, Patricia | Martínez, Salvadora | Meseguer, José | Pérez-Sirvent, Carmen | Chaves-Pozo, Elena | Martínez Sánchez, María José | Cuesta Arranz, Alberto | Ángeles Esteban, M.
Inorganic arsenic causes apoptosis cell death and immunotoxicity on European sea bass (Dicentrarchus labrax) Texte intégral
2018
Cordero, Hector | Morcillo, Patricia | Martínez, Salvadora | Meseguer, José | Pérez-Sirvent, Carmen | Chaves-Pozo, Elena | Martínez Sánchez, María José | Cuesta Arranz, Alberto | Ángeles Esteban, M.
Inorganic arsenic (As) is one of the most toxic pollutants in the water. We have studied their effects on the marine teleost European sea bass (Dicentrarchus labrax) at 2 and 10 days of 5 μM of As2O3 (sub-lethal doses) waterborne exposure. Arsenic accumulates in liver and gill tissues. The expression profile of five genes (bax, blc2, casp3, casp8 and casp9) involved in apoptosis cell death confirmed apoptotic effects in liver, slight changes in gill and no effects in skin according with the histopathology findings. Total IgM level and peroxidase activities were increased at 2 and 10 days, respectively. The bactericidal activity was decreased at 2 days after As exposure. A general decrease of cellular immune activities with significant differences in the case of respiratory burst activity was observed after 2 and 10 days of exposure. This work describes for the first time the effects of As exposure on European sea bass.
Afficher plus [+] Moins [-]Inorganic arsenic causes apoptosis cell death and immunotoxicity on European sea bass (Dicentrarchus labrax) Texte intégral
2018
Cordero, Héctor | Morcillo, Patricia | Martínez, Salvadora | Meseguer, José | Pérez-Sirvent, Carmen | Chaves-Pozo, Elena | Martínez-Sánchez, María José | Cuesta, Alberto | Esteban, María Ángeles
Inorganic arsenic (As) is one of the most toxic pollutants in the water. We have studied their effects on the marine teleost European sea bass (Dicentrarchus labrax) at 2 and 10 days of 5 μMofAs2O3 (sub-lethal doses) waterborne exposure. Arsenic accumulates in liver and gill tissues. The expression profile of five genes (bax, blc2, casp3, casp8 and casp9) involved in apoptosis cell death confirmed apoptotic effects in liver, slight changes in gill and no effects in skin according with the histopathology findings. Total IgM level and peroxidase activities were increased at 2 and 10 days, respectively. The bactericidal activity was decreased at 2 days after As exposure. A general decrease of cellular immune activities with significant differences in the case of respiratory burst activity was observed after 2 and 10 days of exposure. This work describes for the first time the effects of As exposure on European sea bass. | SI
Afficher plus [+] Moins [-]