This study uses Taiwan's WEF nexus as a case study to demonstrate how the resource flow and associated environmental impact of the WEF nexus can be assessed as basis for evaluating strategies for promoting the sustainable use of natural resources. In this study, material flow analysis (MFA) and life-cycle assessment (LCA), were combined. The MFA was used to examine the interdependence of the three natural resources, and the LCA was used to evaluate the environmental impacts of the WEF system. The WEF nexus analysis shows that tap water supply, oil refining, the cogeneration of steam and electricity, thermoelectric power plants, irrigation, animal husbandry, and aquaculture are the main interwoven nodes and have the most prominent impact on the three natural resources. When the unit products from the WEF system were determined, LCA was implemented for these products to identify 15 types of environmental impacts. The environmental impacts for the WEF system were then calculated based on the use of unit products. The results of LCA showed that the most prominent impacts are the impact of public electricity on climate change; oil products on ozone depletion and ionizing radiation; tap water on metal depletion; and animal husbandry on terrestrial ecotoxicity. Based on the assessment of the alternative resource management strategies, if both water and energy policies are modified simultaneously, the impact of the overall WEF system on most environmental impact categories could be reduced.

Nanomaterials of various shapes and dimensions are widely used in the medical, chemical, and electronic industries. Multiple studies have reported the ecotoxicological effects of nanaoparticles when released in aquatic and terrestrial ecosystems; however, information on the toxicity of silver nanowires (AgNWs) to freshwater organisms and their transfer through the food webs is limited. In the present study, we aimed to evaluate the toxicity of 10- and 20-μm-long AgNWs to the alga Chlamydomonas reinhardtii, the water flea Daphnia magna, and the zebrafish and study their movement through this three-species food chain using a variety of qualitative and quantitative methods as well as optical techniques. We found that AgNWs directly inhibited the growth of algae and destroyed the digestive organs of water fleas. The results showed that longer AgNWs (20μm) were more toxic than shorter ones (10μm) to both algae and water fleas, but shorter AgNWs were accumulated more than longer ones in the body of the fish. Overall, this study suggests that AgNWs are transferred through food chains, and that they affect organisms at higher trophic levels, potentially including humans. Therefore, further studies that take into account environmental factors, food web complexity, and differences between nanomaterials are required to gain better understanding of the impact of nanomaterials on natural communities and human health.

The Milky stork is listed as an endangered species endemic to the Southeast Asia region. In Malaysia, the population is currently being reintroduced back into the wild. However, the increase of anthropogenic activity throughout the coastal area might expose the population to hazardous chemicals such as heavy metals. This study highlights the contamination of cadmium (Cd) and lead (Pb) in the Milky stork’s diet. Additionally, this is the first time an integrated exposure model being used to assess heavy metal exposure risk to the population. Lead level (5.5–7.98mgkg⁻¹) in particular was relatively high compared to Cd (0.08–0.33mgkg⁻¹). This was probably related to the different niches occupied by the species in the aquatic environment. The results further show that the predicted exposure doses (through intake of both food and water) for all metals are much lower than the Tolerable Daily Intake (TDI) values. The total exposure dose for Cd was 0.11mgkg⁻¹d⁻¹ with TDI value of 0.54mgkg⁻¹d⁻¹ while Pb total exposure dose was 0.31mgkg⁻¹d⁻¹ with TDI value of 0.64mgkg⁻¹d⁻¹. Several possible factors that could lead to the observed pattern were discussed. In conclusion, there is an urgent need to improve the current habitat quality to protect the endangered species. The authors also emphasized on the protection of remaining Milky stork’s habitats i.e. mudflats and mangroves and the creation of buffer zone to mitigate the negative impacts that may arise from pollution activity.

Titanium dioxide nanoparticles seem to have a low toxicity to terrestrial organisms, though few studies are published in this area. TiO₂ used in sunscreens are nanocomposites where TiO₂ has been coated with magnesium, silica or alumina, as well as amphiphilic organics like polydimethyl siloxane (PDMS), and these coatings are modified by ageing. We assessed the ecotoxicity and propensity for bioaccumulation of an aged TiO₂ nanocomposite used in sunscreen cosmetics, and its potential effect on the frequency of apoptosis in different earthworm tissues. The earthworm Lumbricus terrestris was exposed to the TiO₂ nanocomposite for 7days in water or 2–8weeks in soil with the nanocomposite mixed either into food or soil at concentrations ranging from 0 to 100mgkg⁻¹. Apoptosis was then measured by immunohistochemistry and Ti localized by XRF microscopy. Results showed no mortality, but an enhanced apoptotic frequency which was higher in the cuticule, intestinal epithelium and chloragogenous tissue than in the longitudinal and circular musculature. TiO₂ nanoparticles did not seem to cross the intestinal epithelium/chloragogenous matrix barrier to enter the coelomic liquid, or the cuticule barrier to reach the muscular layers. No bioaccumulation of TiO₂ nanocomposites could thus be observed.