Edmond Sanganyado

Chiral pharmaceuticals: A review on their environmental occurrence and fate processes

More than 50% of pharmaceuticals in current use are chiral compounds. Enantiomers of the same pharmaceutical have identical physicochemical properties, but may exhibit differences in pharmacokinetics, pharmacodynamics and toxicity. The advancement in separation and detection methods has made it possible to analyze trace amounts of chiral compounds in environmental media. As a result, interest on chiral analysis and evaluation of stereoselectivity in environmental occurrence, phase distribution and degradation of chiral pharmaceuticals has grown substantially in recent years. Here we review recent studies on the analysis, occurrence, and fate of chiral pharmaceuticals in engineered and natural environments. Monitoring studies have shown ubiquitous presence of chiral pharmaceuticals in wastewater, surface waters, sediments, and sludge, particularly β-receptor antagonists, analgesics, antifungals, and antidepressants. Selective sorption and microbial degradation have been demonstrated to result in enrichment of one enantiomer over the other. The changes in enantiomer composition may also be caused by biologically catalyzed chiral inversion. However, accurate evaluation of chiral pharmaceuticals as trace environmental pollutants is often hampered by the lack of identification of the stereoconfiguration of enantiomers. Furthermore, a systematic approach including occurrence, fate and transport in various environmental matrices is needed to minimize uncertainties in risk assessment of chiral pharmaceuticals as emerging environmental contaminants.

Sources, behaviour, and environmental and human health risks of high-technology rare earth elements as emerging contaminants

Recent studies show that high-technology rare earth elements (REEs) of anthropogenic origin occur in the environment including in aquatic systems, suggesting REEs are contaminants of emerging concern. However, compared to organic contaminants, there is a lack of comprehensive reviews on the anthropogenic sources, environmental behaviour, and public and ecological health risks of REEs. The current review aims to: (1) identify anthropogenic sources, transfer mechanisms, and environmental behaviour of REEs; (2) highlight the human and ecological health risks of REEs and propose mitigation measures; and (3) identify knowledge gaps and future research directions. Out of the 17 REEs, La, Gd, Ce and Eu are the most studied. The main sources of anthropogenic REE include; medical facilities, petroleum refining, mining and technology industries, fertilizers, livestock feeds, and electronic wastes and recycling plants. REEs are mobilized and transported in the environment by hydrological and wind-driven processes. Ecotoxicological effects include reduced plant growth, function and nutritional quality, genotoxicity and neurotoxicity in animals, trophic bioaccumulation, chronic and acute toxicities in soil organisms. Human exposure to REEs occurs via ingestion of contaminated water and food, inhalation, and direct intake during medical administration. REEs have been detected in human hair, nails, and biofluids. In humans, REEs cause nephrogenic systemic fibrosis and severe damage to nephrological systems associated with Gd-based contrast agents, dysfunctional neurological disorder, fibrotic tissue injury, oxidative stress, pneumoconiosis, cytotoxicity, anti-testicular effects, and male sterility. Barring REEs in medical devices, epidemiological evidence directly linking REEs in the environment to human health conditions remains weak. To minimize health risks, a conceptual framework and possible mitigation measures are highlighted. Future research is needed to better understand sources, environmental behaviour, ecotoxicology, and human epidemiology. Moreover, research on REEs in developing regions, including Africa, is needed given prevailing conditions predisposing humans to health risks (e.g., untreated drinking water).

Bioaccumulation of organic pollutants in Indo-Pacific humpback dolphin: A review on current knowledge and future prospects

Indo-Pacific humpback dolphin (Sousa chinensis) are chronically exposed to organic pollutants since they inhabit shallow coastal waters that are often impacted by anthropogenic activities. The aim of this review was to evaluate existing knowledge on the occurrence of organic pollutants in Indo-Pacific humpback dolphins, identify knowledge gaps, and offer recommendations for future research directions. We discussed the trends in the bioaccumulation of organic pollutants in Indo-Pacific humpback dolphins focusing on sources, physicochemical properties, and usage patterns. Furthermore, we examined factors that influence bioaccumulation such as gender, age, dietary intake and tissue-specific distribution. Studies on bioaccumulation in Indo-Pacific humpback dolphin remain scarce, despite high concentrations above 13,000u202fng/g lw we previously detected for PFOS, ∑PBDE and chlorinated paraffins. The maximum concentration of organochlorines detected was 157,000u202fng/g wt. Furthermore, variations in bioaccumulation were shown to be caused by factors such as usage patterns and physicochemical properties of the pollutant. However, restrictions in sampling inhibit investigations on exposure pathway and toxicity of organic pollutants in Indo-Pacific humpback dolphin. We proposed the use of biopsy sampling, predictive bioaccumulation and toxicity modeling, and monitoring other emerging contaminants such as microplastics and pharmaceuticals for future health risk assessment on this critically endangered marine mammal species.

Broad interests reap benefits for science

We asked young scientists this question: How do broad interests benefit your science? Scientists with a variety of hobbies responded that their extracurricular activities have enhanced a wide range of skills, from creativity to communication to resilience. Many also mentioned the value of clearing

Establishment and characterization of pygmy killer whale (Feresa attenuata) dermal fibroblast cell line

The pygmy killer whale (Feresa attenuata) (PKW) is a tropical and subtropical marine mammal commonly found in the Atlantic, Indian and Pacific oceans. Since the PKWs live in offshore protected territories, they are rarely seen onshore. Hence, PKW are one of the most poorly understood oceanic species of odontocetes. The dermal tissue comes primarily from stranding events that occur along the coast of the Shantou, Guangdong, China. The sampled tissues were immediately processed and attached on collagen-coated 6-well tissue culture plate. The complete medium (DMEM and Ham’s F12, fetal bovine serum, antibiotic and essential amino acids) was added to the culture plates. The primary culture (PKW-LWH) cells were verified as fibroblast by vimentin and karyotype analyses, which revealed 42 autosomes and two sex chromosomes X and Y. Following transfection of PKW-LWH cells with a plasmid encoding, the SV40 large T-antigens and the transfected cells were isolated and expanded. Using RT-PCR, western blot, immunofluorescence analysis and SV40 large T-antigen stability was confirmed. The cell proliferation rate of the fibroblast cells, PKW-LWHT was faster than the primary cells PKW-LWH with the doubling time 68.9h and 14.4h, respectively. In this study, we established PKW dermal fibroblast cell line for the first time, providing a unique opportunity for in vitro studies on the effects of environmental pollutants and pathogens that could be determined in PKW and/or Cetaceans.

Impact of African traditional worldviews on climate change adaptation

Recent studies show cultural worldviews are a key determinant of environmental risk perceptions; thus, they could influence climate change adaptation strategies. African traditional worldviews encourage harmony between humans and the environment through a complex metaphysical belief system transmitted through folklore, taboos, and traditional knowledge. However, African traditional worldviews hold a belief in traditional gods that was shown to have a low connectedness to nature and a low willingness to change. In Makueni District, Kenya, 45% of agropastoralists surveyed believed drought was gods plan and could not be changed. In contrast, traditional knowledge, which is shaped by African traditional worldviews, is often used to frame adaptive strategies such as migration, changing modes of production, and planting different crop varieties. Furthermore, traditional knowledge has been used as a complement to science in areas where meteorological data was unavailable. However, the role of African traditional worldviews on climate change adaption remains understudied. Hence, there is a need to systematically establish the influence of African traditional worldviews on climate change risk perception, development of adaptive strategies, and policy formulation and implementation. In this commentary, we discuss the potential impacts of African traditional worldviews on climate change adaptation. Integr Environ Assess Manag 2018;14:189-193.

My path to contentment

I leapt into the air, screaming at the top of my lungs with tears rolling down my cheeks as the news sank in. I had lost both of my parents when I was 16 years old, and I had often been sent home from school for unpaid tuition as I worked my way to a bachelors degree in my home country of Zimbabwe

Adsorption of sugarcane vinasse effluent on bagasse fly ash: A parametric and kinetic study

Sugarcane and bioethanol production produces large amounts of bagasse fly ash and vinasse, which are solid and viscous liquid wastes, respectively. However, these wastes are often disposed into the environment without treatment, thus posing an environmental and public health risk. This study investigated the treatment of vinasse effluent in terms of reduction of chemical oxygen demand (COD) and acidity removal using sugarcane bagasse fly ash. A maximum COD removal efficiency of 72% was obtained using an effluent volume of 100u202fmL, contact time of 180u202fmin, and shaking speed of 240u202frpm. The adsorbent dose and particle sizes were 4.5u202fg and 90-125u202fμm, respectively. Furthermore, the potential application of bagasse fly ash as an adsorbent in a sand filtration bed was assessed using a column test. A maximum recovery of 68% was obtained at the 25-min interval. The adsorption data was found to fit the Freundlich model best (Kfu202f=u202f2.16u202fmgu202fg-1; R2u202f=u202f0.96), and the kinetics fit the pseudo-second order model (R2u202f=u202f0.98).

Mechanistic Insights into Stereospecific Bioactivity and Dissipation of Chiral Fungicide Triticonazole in Agricultural Management

Research interest in chiral pesticides has increased probably because enantiomers often exhibit different environmental fate and toxicity. An investigation into the enantiomer-specific bioactivity of chiral triticonazole enantiomers in agricultural systems revealed intriguing experimental and theoretical evidence. For nine of the phytopathogens studied ( Rhizoctonia solani, Fusarium verticillioide, Botrytis cinerea (strawberry and tomato), Rhizoctonia cereali, Alternaria solani, Gibberella zeae, Sclerotinia sclerotiorum, and Pyricularia grisea), the fungicidal activity data showed ( R)-triticonazole was 3.11-82.89 times more potent than the ( S) enantiomer. Furthermore, ( R)-triticonazole inhibited ergosterol biosynthesis and cell membrane synthesis 1.80-7.34 times higher than its antipode. Homology modeling and molecular docking studies suggested the distinct bioactivities of the enantiomers of triticonazole were probably due to their different binding modes and affinities to CYP51b. However, field studies demonstrated that ( S)-triticonazole was more persistent than ( R)-triticonazole in fruits and vegetables. The results showed that application of pure ( R)-triticonazole, with its high bioactivity and relatively low resistance risk, instead of the racemate in agricultural management would reduce the application dosage required to eliminate carcinogenic mycotoxins and any environmental risks associated with this fungicide, yielding benefits in food safety and environmental protection.

Integrated assessment of heavy metal pollution using transplanted mussels in eastern Guangdong, China

Heavy metal contamination has been widely studied in coastal areas around the world. However, integrative studies of heavy metals pollution by monitoring and characterizing sediments, organisms, and biomarkers as well as their holistic interactions are rare. Here, we selected a developed coastal area in eastern Guangdong, China as the study field. Heavy metal analysis (both in sediment and mussel) and biomarker tests, including neutral red retention time test (NRRT) and micronuclei (MN) test, were employed in the current research. Anthropogenic activities influenced the heavy metal levels in sediments. Significant relationships (pu202f<u202f0.05) were observed in the concentrations of Cd, Cu, and Zn between sediments and transplanted mussel, and significant relationships (pu202f<u202f0.05) were also observed in between the concentrations of Cd, Cu, and Zn in sediments and the NRRT of mussel. The potential ecological risk index (RI) of sediments significantly correlated with NRRT (Ru202f=u202f-0.991, pu202f<u202f0.05). In Hao River, where the highest RI of sediments was found, the highest MN frequency and the lowest NRRT in mussels were detected simultaneously. The results indicated that the heavy metal pollution might cause subcellular toxic and genotoxic effects on mussels, especially for those from polluted areas (i.e., Hao River). The present study suggests that the transplanted green-lipped mussels are suitable for assessing heavy metal pollution, especially for Cd, Cu, and Zn.