Alternative energy policies targeting the adoption of hydrogen fuel cell vehicles (HFCVs) could have significant positive impacts on Malaysia’s ability to meet both its carbon reduction goal and its energy security needs. The transport sector generally contributes heavily to carbon emissions, and is also difficult to decarbonize because of the costs associated with many greener options. This study explores the possibility of decarbonizing the Malaysian transport sector by promoting the use of hydrogen vehicles, and analyzes the adoption challenges and economic obstacles (especially public acceptance) associated with introducing HFCVs. This study contends that the adoption challenges of this new technology can be overcome through the use of development strategies outlined. This study also addresses the regulatory framework that Malaysia (and other countries) might use to overcome common policy adoption challenges of HFCVs.

The bioavailability of metals can be influenced not only by soil properties but also by other species living at polluted sites. However, in laboratory experiments, usually only one test species is used to estimate bioavailability. In this study, a two-species approach was applied to assess the impact of the earthworm Lumbricus rubellus on the bioavailability of cadmium and lead to the springtail Folsomia candida using natural soils from a gradient of metal pollution. Earthworms were kept in half of the soil replicates for 4 weeks. Subsequently, the uptake and elimination kinetics of cadmium and lead in F. candida exposed for 21 days to the soils was determined. Earthworm activity affected soil properties but did not significantly affect metal uptake rate constants in springtails. The slightly higher uptake due to the presence of earthworms, which was consistent in all tested soils and for both metals, suggests that further research is needed on the role of species interactions in affecting metal bioavailability in soil.

Groundwater particularly drinking water contamination with metals has created an environmental disaster in Bangladesh. Manganese (Mn), an essential trace element, plays a key role in the development and function of the brain. Excess Mn exposure is reported to be associated with complex neurological disorders. Here, we have found a notably large extent of Mn above the permissive limit in the tube-well water of Rajshahi and Naogaon districts in Bangladesh. Higher levels of Mn in hair and nail samples, and a decreasing level of butyrylcholinesterase (BChE) activity were detected in plasma samples of the human subjects recruited from Naogaon district. Mn concentrations in water, hair, and nails were negatively correlated with the plasma BChE levels in Mn-exposed populations. To compare and validate these human studies, an animal model was used to determine the in vivo effects of Mn on neurobehavioral changes and blood BChE levels. In elevated plus maze, the time spent was significantly reduced in open arms and increased in closed arms of Mn-exposed mice compared to control group. The mean latency time to find the platform was declined significantly in control mice compared to Mn-treated group during 7 days in Morris water maze test, and Mn-exposed group also spent significantly less time in the desired quadrant as compared to the control group in probe trial. BChE activity was significantly reduced in Mn-exposed mice compared to control mice. Taken together, these results suggest that plasma BChE levels may serve as reliable biomarker of Mn-induced neurotoxicity related to behavioral changes.

Phosphorus (P) characteristics in eutrophic lakes change during algal growth. Furthermore, algae have a significant relationship with the microbial communities of lake sediments. This study addressed the influence of algal growth and soluble reactive phosphorus (SRP) concentrations on P characteristics within the sediment-water-algal (SWA) system. Results indicated that the SWA system simulating a high algal bloom level (SWA-HAB) had a correspondingly high SRP concentration (258.9 μg L⁻¹), and that algal growth promoted a high SRP concentration in the overlying water. The high SRP concentration in overlying water could support algal growth, resulting in a high chlorophyll a (Chl-a) concentration (285.23 mg L⁻¹). During algal growth, the P release flux was high in sediments from the high-SRP SWA system, with the highest P release flux measured at 0.982 mg m⁻² day⁻¹. Furthermore, microbial community abundance had a significant relationship with Chl-a concentrations in overlying water (p < 0.05) and increases with algae growth.

The sequential extraction method was used to determine the fraction of arsenic (As) in different-sized particulate matters (PMs) (i.e., PM₂.₅, PM₁₀, and total suspended particles (TSP)). Samples were collected from Baoding, a typical medium-sized city with the serious haze pollution in China. The bioavailabilities of As in the samples were estimated based on the fraction results. A large percentage of fine particles were detected in TSP, with the average PM₂.₅/PM₁₀ and PM₁₀/TSP ratios all above 0.69. The total concentrations of As in PM₂.₅, PM₁₀, and TSP samples were in the range of 4.5–296.4, 14.1–708.0, and 32.8–798.0 ng m⁻³, respectively. The mass percentages of As in PM₂.₅, PM₂.₅–₁₀, and PM₁₀–₁₀₀ were calculated; the results indicated that As tended to concentrate in fine particles. PM-bound As mainly presented in the nonspecifically sorbed fraction (F1) during all of the sampling periods. The percentages of F1-As and bioavailability of As were higher in PM₂.₅, followed by PM₁₀ and TSP. By contrast, the residual fraction (F5-As) contents declined in the order of TSP > PM₁₀ > PM₂.₅. Significant differences in the speciation and bioavailability of As in different-sized PMs were found, and the influence of particle size on the speciation and bioavailability of As in PMs was verified. Fine particles adsorbed more As with higher bioavailability, and potentially led to more serious adverse effects on human health than the larger ones.

Heavily chromium-polluted areas, where people are prohibited from entering, are paradises for stray dogs. In this study, stray dogs were used to study the effects of chromium exposure on the heart of dogs in severely Cr(VI)-contaminated rural areas of China. The dogs were given water (control), low dose (L, 0.92 mg/kg), medium dose (M, 1.15 mg/kg), and high dose (H, 1.38 mg/kg) of Cr(VI). The changes of electrocardiogram (ECG), myocardial enzyme parameters, inflammatory factors, oxidative kinase, and ATPase were measured to determine the toxicity of chromium on the heart of dogs. Results showed that the ST segment of ECG increased significantly, and the amplitude of T wave increased in the experimental group. The myocardial enzyme (CK-MB, AST, CK, and LDH) content in groups M and H increased significantly over time. The values of CAT, T-SOD, IL-10, and ATPase (K⁺-Na⁺-ATPase and Ca²⁺-Mg²⁺-ATPase) decreased with the increase of Cr(VI) dose, and the content of MDA, IL-1β, IL-8, and TNF-α increased with the increase of Cr(VI) dose. Our study suggested that the heart of Chinese rural dog was damaged by Cr(VI), and Cr(VI) could cause oxidative damage and alteration of ATPase content in dogs.

To estimate the impact of mercury discharged from artisanal and small-scale gold mining (ASGM) activity, variations in the concentrations of elemental mercury (Hg0), mercury ion (Hg2+), particulate mercury (P-Hg), and total mercury in filtered river water (FT-Hg) were investigated from sampling locations extending from 10 km upstream to 30 km downstream of ASGM operations in West Java, Indonesia. The average of the annual concentrations at the ASGM site from 2013 to 2017 were 0.14–0.85 μg L⁻¹, 0.27–12.9 μg L⁻¹, 4.3–49.5 μg L⁻¹, and 1.2–12.5 μg L⁻¹ for Hg0, Hg²⁺, P-Hg, and FT-Hg, respectively. The concentration of mercury species decreased as the distance from the ASGM site increased, while the ratio of P-Hg increased towards the lower reaches of the river system, with the percentage of P-Hg estimated at 90% of Hg at the sample location furthest downstream. A high mercury concentration of 600 mg kg⁻¹ was observed for suspended particulate matter (SPM) at the ASGM site. The SPM maintained a high concentration of mercury, even in the downstream area. In the annual variations of the mercury species from 2013 to 2017, FT-Hg and P-Hg concentrations tended to decrease from 2016, which suggested a decline of ASGM activity in this area. However, SPM and river sediment showed no apparent changes in their mercury concentrations over this period, indicating that the contamination in the river system is persistent and does not recover quickly.

Different microalgae species produce varying quantity and quality of the lipids. Fatty acid methyl ester composition, which comprises both saturated and unsaturated contents, critically affects biodiesel properties. Current study compares six locally isolated microalgae strains belonging to three classes (Trebouxiophyceae, Chlorophyceae, and Cyanophyceae) on the basis of lipid content and biodiesel properties. All the six species are grown in similar condition up to the late stationary phase, and their lipid content and fatty acid methyl ester composition are measured experimentally. Multi-criteria decision analysis (MCDA) tool has ranked Calothrix species (class Cyanophyceae) on the top, owing to better cetane number, density and oxidation stability; whereas Chlorococcum species (class Chlorophyceae) is ranked second because of its higher lipid content, better cold flow property, and low viscosity. Property analysis of these two species is extended in the enlarge temperature range for five properties, vapor pressure, latent heat of vaporization, liquid density, liquid viscosity and vapor diffusivity, which are important in spray and combustion modeling. It is found through detailed property estimation that Chlorococcum sp. is a more suitable species in comparison with Calothrix sp. as it is having better properties and its lipid content is much higher than that of Calothrix sp. Although the properties of microalgae biodiesel are poorer in comparison with conventional diesel fuel, a greater number of such studies will help in understanding the requisite changes as required for microalgae biodiesel–based engine and their properties as compared with conventional diesel.

The present study was designed to investigate the protective role of dietary supplementation of Spirulina platensis (SP) against cytotoxic and genotoxic effects of lead nitrate in Clarias gariepinus. Four groups of fishes were used: first group as control which fed on basal diet, second group fed on basal diet and exposed to (1 mg/L of lead nitrate), third group fed on diet containing 0.25% SP and exposed to (1 mg/L of lead nitrate), and fourth group fed on diet containing 0.5%SP and exposed to (1 mg/L of lead nitrate). Fish samples were taken at 2nd and 4th week of exposure. The hematological indices of lead nitrate–exposed group were decreased significantly compared to the control group at 2nd and 4th week of exposure. Lead nitrate caused a significant increase in the percentage of poikilocytosis, micronuclei, and apoptotic cells as well as comet tail length and olive tail moment compared with the control group at 2nd and 4th week of exposure. The highest level of damage was found on 4th week of exposure with all parameters. Dietary inclusion of SP ameliorated these cytotoxic and genetic changes, as well as this amelioration was concentration and time dependent. Consequently, the present study proposed that the addition of SP to the fish diet can be used as a promising protective agent to oppose cytotoxic and genotoxic effects of lead nitrate in aquaculture. Graphical abstract

To comprehend city-level driving mechanisms of carbon emissions, this paper utilizes spectral cluster and two-layer LMDI (logarithmic mean divisia index) method to systematically assess the contribution values of correlative factors from each cluster to Henan’s carbon emissions increments, and accordingly comes up with more strategies about how to reduce carbon emissions for each cluster on the basis of driving forces of carbon emissions. The results of clustering and the decomposition are as follows: (1) the 18 prefecture-level cities in Henan were divided into five categories by spectral clustering, and there are similar development patterns within each category, so they can learn from each other to improve their own defects of development; (2) this paper utilizes the two-layer LMDI method to divide the factors affecting each cluster of carbon emissions into four types, which includes energy structure, energy intensity, per capita GDP, and population, and calculates the contribution value of each factor. It was concluded that the contribution value of per capita GDP dominantly drove up carbon emissions, while energy intensity played a significant role in offsetting them. Therefore, it is important for Henan’s low-carbon development to control the expansion of economic activity and improve energy efficiency in the future.