Adsorptive removal of metformin on specially designed algae-lignocellulosic biochar mix and techno-economic feasibility assessment.

Batch sorption of metformin hydrochloride (MET) onto a specially designed biochar mix consisting of both macro (MAC) and micro (MIC) algae, rice husk and pine sawdust was conducted. Pyrolysis of both MAC and MIC algae mixture was done followed by chemical activation with hydrogen-peroxide. Additionally, sorption of MET under the influence of pH was separately investigated. Batch studies of isotherms were well described by Freundlich model with high non-linearity and Freundlich exponent values ranged anywhere from 0.12 to 1.54. Heterogeneity of MET adsorption to the bonding sites was attributed to the surface functional groups of the modified biochar. Amongst the four biochars, the activated macroalgae biochar (MACAC) and microalgae biochar (MICAC) depicted favourable adsorption of MET with maximum adsorption at pH 7. Up to 76% of MET removal from the environment was obatained using the MACAC biochar. Scanning electron micrographs coupled with energy dispersive X-ray, as well as elemental analyses confirmed formation of oxygen containing surface functional groups due to activation strengthening chemisorption as the main sorption mechanism. Further, Fourier transform infra-red spectroscopy and other surface functional group analyses along with Zeta potential measurements reinforced our proposed sorption mechanism. Lowest zeta potential observed at pH 7 enhanced the electrostatic force of attraction for both the biochars. Negative zeta potential value of the biochars under different pH indicated potential of the biochars to adsorb other positively charged contaminants. From a techno-economic perspective, capital expenditure cost is not readily available, however, it is envisaged that production of pyrolyzed biochar from algal biomass could make the process economically attractive especially when the biochar could be utilised for high-end applications.

Modelling degradation kinetics of metformin and guanylurea in soil microcosms to derive degradation end-points.

The degradation of metformin (MET) and guanylurea (GUA) fortified separately in freshly collected two top soils (0-10 cm) from New Zealand's pastoral region was studied under controlled laboratory conditions. Incubation studies were carried at 30 °C under aerobic conditions at 60% of maximum water holding capacity and at two (0.5 mg/kg and 5 mg/kg) nominal soil concentrations. Degradation profiles revealed a bi-phasic pattern of both the compounds with an initial rapid degradation followed by slow dissipation rate, resulting in poor fits by simple first order kinetics. However, the use of three non-linear mathematical models sufficiently described the measured data and well supported by an array of statistical indices to judge model's ability to fit the measured datasets. Further evaluation using box-whisker plots showed that double first-order in parallel (DFOP) and first-order two-compartment (FOTC) models best fitted the data points followed by the Bi-exponential (BEXP) model. Mechanistic assumptions from DFOP and FOTC suggest that degradation of MET and GUA proceeds at two different rates, possibly in two compartments. The calculated DT50 using both models were in the range of 2.7-15.5 days and 0.9-4 days, while 90% dissipation time (DT90) varied between 91 and 123 days and 44 and 137 days for MET and GUA, respectively. Degradation of both compounds were dependent on soil types and properties, incubation conditions and initial substrate concentration. Formation of GUA with decrease in MET concentration over time confirmed that GUA is a transformation product concomitantly formed from aerobic degradation of MET in soil.

Sorption and mobility of metformin and guanylurea in soils as affected by biosolid amendment: Batch and column tests.

Recent classification of metformin as an emerging contaminant warrants assessment of its fate and behaviour in the natural environment especially with land-based application of potentially contaminated wastewaters and biosolids. The present study provided further insight into the sorption mechanisms of metformin and its transformation product guanylurea in soil and upon biosolid fortification. Decreased metformin sorption (12.4%) as measured by the effective distribution coefficient (Kdeff) was observed with biosolids amendment while significant increase (2500%) in guanylurea sorption was calculated. Analysis of co-solute effects confirmed their contrasting sorption mechanisms with the absence of competitive effects in unamended soil. Results of the column tests were in good agreement with the batch sorption studies as the fitted values of retardation factors decreased and increased for metformin and guanylurea, respectively, upon addition of biosolids. The shapes of the breakthrough curves suggest slower desorption rates for both compounds in unamended soil resulting to non-equilibrium conditions and back-end tailings. However, in biosolid-amended soil columns, these tailings were less pronounced resembling equilibrium transport. Results also demonstrated enhanced mobility of both compounds upon biosolids fortification. The non-equilibrium chemical transport model fitted the measured data well (0.975 > r2 > 0.988) especially for unamended soils which suggests the existence of non-equilibrium conditions and rate-limited sorption sites.

Insight into the sorption mechanism of metformin and its transformation product guanylurea in pastoral soils and model sorbents.

Single solute sorption mechanisms of metformin (MET) and guanylurea (GUA) were investigated in six soils and three model sorbents (kaolinite, bentonite and humic acid) at varying initial pH and background electrolyte (Ca2+) concentrations. Electrostatic interaction and cation exchange were proposed as mechanisms of MET sorption. At initial solution pH between pKa1 and pKa2, electrostatic interaction is the dominating mechanism of MET sorption. However, as pH approaches pKa1, cation exchange becomes a significant mechanism of sorption as evidenced by the increased distribution coefficient (Kd) values in Matawhero (130-fold) and Nelson (2000-fold) soils with high cation exchange capacities (CEC) and permanently negative charged sites and when equilibrium pH < pKa1 where the divalent cationic form dominates in the solution. Furthermore, results showed higher sorption of MET on bentonite with effective distribution coefficient (Kdeff) value of 14.92 L/kg with high permanent negative charges than on kaolinite (Kdeff = 6.70 L/kg), a variable charge clay. Increased MET sorption at low equilibrium pH on kaolinite (Kdeff = 2.3 × 107 L/kg) and humic acid (Kdeff = 20.86 L/kg) further suggest cation exchange is also possible at pH < pKa1. On the other hand, two lines of evidence suggest cation exchange as an important mechanism of GUA sorption: (a) the positive correlation between cation exchange capacity and Kdeff values and (b) decreased Kdeff values as the Ca2+ concentration in solution was increased in all soils. Biosolids amendment of three soils resulted in contrasting effects on sorption affinities with a decrease for MET and increase for GUA, further confirming sorption mechanisms and significance of solution pH and CEC on the sorption of MET and GUA, respectively.

Biodegradation of metformin and guanylurea by aerobic cultures enriched from sludge.

Sewage sludge from a municipal wastewater treatment facility employing activated sludge process was pre-incubated with varying substrates and mixtures of substrates including metformin (MET), guanylurea (GUA) and glucose. The biomass from enriched cultures separately utilising MET and glucose/GUA was then used to investigate the kinetics of aerobic biodegradation of MET and GUA, respectively, as individual substrates in batch reactors. The results showed that GUA can be completely degraded as a nitrogen source when glucose is provided as a carbon and energy source. On the contrary, MET can be biodegraded as a sole carbon and energy source. However, formation of by-product GUA in solution, which acts as a nitrogen source, rapidly increased the degradation rate of MET resembling autocatalytic behaviour. At low starting concentration of 5 mg/L, the specific substrate utilisation rates of MET and GUA were 0.0033 day-1 and 0.0013 day-1, respectively, which is reported first time in this study. Out of the five biodegradation kinetic models used to describe substrate utilisation, the Quiroga-Sales-Romero (QSR) model was found to predict the measured MET and GUA degradation profile well supported by the goodness of fit parameters. Furthermore, the QSR model was able to describe the autocatalytic degradation of MET and the incomplete biodegradation of GUA in solution.

Detailed sorption characteristics of the anti-diabetic drug metformin and its transformation product guanylurea in agricultural soils.

Detection of metformin, an antidiabetic drug and its transformation product guanylurea in various environmental matrices such as surface water and groundwater, coupled with their effects on aquatic organisms warrant an understanding of the compounds fate and behaviour in the environment. Batch studies were conducted with the aim of evaluating the sorption of these two emerging contaminants in six New Zealand agricultural soils of contrasting physico-chemical properties. Kinetic studies revealed that metformin and guanylurea sorption in Te Kowhai soil was very rapid initially achieving 90% sorption within the first 4 and 13h, respectively. Fit of several isotherm models to the measured batch sorption data showed that the hybrid models Langmuir-Freundlich and Redlich-Peterson best described the isotherms. Freundlich isotherm showed higher linearity for guanylurea (nF=0.58-0.93) in all soils compared to metformin (nF=0.25-0.71). A linear isotherm was fitted at environmentally relevant low concentrations (< 3mg/L) of target compounds and calculated values of sorption distribution coefficient (Kd) were in the range of 8.97 to 53.49L/kg for metformin and between 10.6 and 37.51L/kg for guanylurea. Sorption of both metformin and guanylurea was dependent on the soil characteristics, however, no generalisation could be made as to which had higher affinity to soils studied. Pearson's correlation and multiple regression analyses indicate that Si/Al (p=0.042) and clay (p=0.015) significantly influenced metformin Kd values, whereas the soil's cation exchange capacity (p=0.024) is the single most significant factor determining guanylurea sorption in soils. It is likely that the type of minerals present in soils and its ion-exchange capacity could play an important role in metformin and guanylurea sorption, respectively.

A global perspective on the use, occurrence, fate and effects of anti-diabetic drug metformin in natural and engineered ecosystems.

Metformin is the most commonly used anti-diabetic drug in the world. When consumed, this unmetabolised pharmaceutical compound is excreted by the body and eventually enters the environment through a variety of pathways. Based on its high consumption and excretion rates, high concentrations of metformin have been detected in influents of wastewater treatment plants. Metformin and its transformation product, guanylurea, are also expected to be present in other aquatic environments based on their physico-chemical properties. Not surprisingly, guanylurea has also been detected in surface water, groundwater, and drinking water. Available information on ecotoxicological effects of metformin suggests that metformin is a potential endocrine disruptor and thus further emphasising the threat this drug could pose to our environment. This review provides a comprehensive overview of metformin and critically discusses available literature data with respect to its global use/demand, occurrence, fate and ecotoxicity in treatment facilities equipped with conventional and advanced treatment technologies, and its degradation/removal mechanisms. Final section highlights the existing knowledge gaps regarding its ultimate fate under the natural and engineered ecosystems and identifies some important research areas requiring urgent attention from regulatory makers and scientific community.

Piloting Health Text Messages for Rural Low-Income Mothers: Effects of Source Similarity and Simple Action Steps.

Approximately 85% of people living in rural settings own a cell phone, and of those, 76% send or receive text messages. Thus, text messaging may be an effective way to reach rural low-income mothers with important information and resources that will improve their health and well-being. This exploratory study examined the utility of using text messaging for disseminating health information to rural low-income mothers. Researchers tested messages that were personalized and sent from a source similar to participants, a mom named Ms. Peg. Ms. Peg sent text messages about physical activity, oral health, nutrition, and health insurance-facts and tips that addressed barriers and lifestyles in rural low-income contexts-over a 4-week period. Participants completed a prequestionnaire assessing healthy behaviors, text message use and preference, and demographic information. Participants then received two text messages for 4 weeks. Findings indicated that participants were satisfied receiving information through text messages, with half finding it "easy" and "convenient." The majority reported being highly motivated by the messages, and for 41% the messages were associated with self-efficacy and intention to act. Close to half of the participants found the use of personalization effective and perceived the messages as "relatable."

Empowerment in the process of health messaging for rural low-income mothers: an exploratory message design project.

Rural, low-income mothers face challenges to their health equal to or greater than those of low-income mothers from urban areas. This study put health message design into the hands of low-income rural mothers. The current study filled a research gap by analyzing a participatory process used to design health messages tailored to the everyday lives of rural low-income mothers. A total of forty-three mothers participated in nine focus groups, which were held from 2012 to 2013, in eight states. The mothers were from different racial and ethnic backgrounds. Participants discussed food security, physical activity, and oral health information. They created messages by considering several elements: visuals, length of message, voice/perspective, self-efficacy and personal control, emotional appeals, positive and negative reinforcements, and steps to health behavior change. This study was innovative in its focus on empowerment as a key process to health message design.

Harnessing the Web: How E-Health and E-Health Literacy Impact Young Adults' Perceptions of Online Health Information.

BACKGROUND: The rise of technology has changed how people take control of their health, enabling individuals to choose to live healthier lives and make better treatment decisions. With this said, the Internet has emerged as the channel used by individuals for actively seeking or passively receiving health information. OBJECTIVE: To explore how young adults assess the quality of health information, and how they construct meaning of online health information in general. Through 50 in-depth interviews, this study aims to examine how and why young adults turn to the Web for health information, and what strategies they employ to ensure that they are getting credible information. METHODS: A total of 50 in-depth interviews were conducted with young adults to explore how they make meaning of online health information. Depending on the geographic area of the participant, the interview took place face-to-face at a location convenient for them, over Skype, or over the telephone and lasted on average 40 minutes. The interviews were transcribed verbatim, fully retaining the speech style of the moderator and the participants. Data were analyzed using techniques from the grounded theory approach, using a constant comparative method to allow for themes to emerge from the transcripts. RESULTS: The participants shared several benefits to this mode of health information seeking, claiming that it made for more productive visits with doctors and made health information more readily accessible through a variety of different formats. Additionally, the participants demonstrated their e-health literacy levels by discussing how they assessed online health information, engaging in a series of strategies that encompassed different aspects of e-health literacy. Social media channels were brought up by the participants as relatively new tools that can be used to assist in the seeking, understanding, and sharing of health information. However, participants also cautioned about the use of social media in regards to its informal nature, warning users to evaluate sources accordingly and to use these channels as supplementary outlets of information for more traditional channels. CONCLUSIONS: The use of the Internet and technology for health purposes is a growing area for both scholarship and practice that has strong implications for health consumers, medical professionals, and communicators alike. The findings that emerged from this research demonstrated that the online space is an acceptable channel through which young adults can find and share information. However, in spite of the rising usage of social media by this particular group, the findings showed that they were hesitant and wary of the channel, not seeing it as a resource for health information but more of a channel for networking and entertainment. In spite of this, this study shows that the online health information seeking behaviors is an area that warrants further exploration.

Parental cancer beliefs and trust in health information from medical authorities as predictors of HPV vaccine acceptability.

This research examines parental cancer beliefs and trust in health information from medical authorities as predictors of HPV vaccine acceptability. Specifically, the authors investigated how parents' perceived susceptibility to and severity of cancer, fatalistic beliefs about cancer prevention, and trust in health information from doctors/health professionals and government health agencies are related to willingness to vaccinate their daughters ages 11-12 years against HPV. The authors analyzed data from the 2007 Health Information National Trends Survey. The authors found that parents were more likely to accept the vaccine if they perceived a higher risk of getting cancer themselves and if they had a higher level of trust in health information from medical authorities. Perceived severity of cancer and fatalistic beliefs about cancer prevention did not predict vaccine acceptance.

A current appraisal of health- and nutrition-related claims in magazine food advertisements.

This article reports a content analysis of health- and nutrition-related claims used in food advertisements in popular women's and men's magazines. The authors analyzed 734 food ads and 100 magazine issues. Their research shows that nutrient content claims (i.e., ones that focus on a specific nutrient component such as "low in fat") are the most predominantly used, followed by general nutrition claims, structure/function claims, and healthy claims. The least used category is health claims, in which the advertised food is linked to reduced risk of a disease or health problem. The use of health- and nutrition-related claims differs across different food groups and types of magazines.

Kinetics of acetaminophen degradation by Fenton oxidation in a fluidized-bed reactor.

Acetaminophen (ACT), an analgesic and antipyretic substance, is one of the most commonly detected pharmaceutical compound in surface waters and wastewaters. In this study, fluidized-bed Fenton (FB-Fenton) was used to decompose ACT into its final degradation products. The 1.45-L cylindrical glass reactor had inlet, outlet and recirculating sections. SiO(2) carrier particles were supported by glass beads with 2-4 mm in diameter. ACT concentration was determined by high performance liquid chromatography (HPLC). During the first 40 min of reaction, a fast initial ACT removal was observed and the "two-stage" ACT degradation conformed to a pseudo reaction kinetics. The effects of ferrous ion dosage and [Fe(2+)]/[H(2)O(2)] (FH ratio) were integrated into the derived pseudo second-order kinetic model. A reaction pathway was proposed based on the intermediates detected through SPME/GC-MS. The aromatic intermediates identified were hydroquinone, benzaldehydes and benzoic acids while the non-aromatic substances include alcohols, ketones, aldehydes and carboxylic acids. Rapid initial ACT degradation rate can be accomplished by high initial ferrous ion concentration and/or low FH ratio.

When vaccines go viral: an analysis of HPV vaccine coverage on YouTube.

This article reports a content analysis of YouTube videos related to the human papillomavirus (HPV) vaccine. In total, 172 YouTube videos were examined with respect to video sources, tones, and viewer responses. Additionally, coverage of specific content was analyzed through the lens of the Health Belief Model (Rosenstock, 1974) and in terms of two content themes (i.e., conspiracy theory and civil liberties). The relations among these aspects of the videos were assessed as well. We found that most of these videos were news clips or consumer-generated content. The majority of the videos were negative in tone, disapproving of the HPV vaccine. In addition, negative videos were liked more by the viewers than positive or ambiguous ones. Accusations of conspiracy theory and infringement of civil liberties were manifested in these videos. The videos also presented mixed information related to the key determinants of health behavior as stipulated in the Health Belief Model. Implications for the findings are discussed.

Sorting through search results: a content analysis of HPV vaccine information online.

INTRODUCTION: Surveys have shown that many people now turn to the Internet for health information when making health-related decisions. This study systematically analyzed the HPV vaccine information returned by online search engines. HPV is the most common sexually transmitted disease and is the leading cause of cervical cancers. METHODS: We conducted a content analysis of 89 top search results from Google, Yahoo, Bing, and Ask.com. The websites were analyzed with respect to source, tone, information related to specific content analyzed through the lens of the Health Belief Model, and in terms of two content themes (i.e., conspiracy theories and civil liberties). The relations among these aspects of the websites were also explored. RESULTS: Most websites were published by nonprofit or academic sources (34.8%) and governmental agencies (27.4%) and were neutral in tone (57.3%), neither promoting nor opposing the HPV vaccine. Overall, the websites presented suboptimal or inaccurate information related to the five behavioral predictors stipulated in the Health Belief Model. Questions related to civil liberties were present on some websites. CONCLUSION: Health professionals designing online communication with the intent of increasing HPV vaccine uptake should take care to include information about the risks of HPV, including susceptibility and severity. Additionally, websites should include information about the benefits of the vaccine (i.e., effective against HPV), low side effects as a barrier that can be overcome, and ways in which to receive the vaccine to raise individual self-efficacy.