Cadmium and lead soil contamination is a widespread environmental problem that requires profound and sustainable solutions. These toxic elements can be naturally occurring on the Earth’s crust or from man-made origins. Cadmium and lead could accumulate and translocate in soil over the long term. Thus, their risk of entering the food chain is extremely elevated and their effects on the living organisms in the food web are of great concern. The main purpose of this review study is to emphasize the risk to human health of cadmium and lead as an environmental contaminant in soil and plants. Human exposure to cadmium and lead can cause severe illness; for instance, long-term exposure to cadmium can alter kidney health and cause dysfunction. Additionally, lead threatens the nervous system and causes countless diseases. Hence, the remediation of cadmium and lead from soil before they enter the food chain remains essential, and regular monitoring of their principal sources is crucially needed for a sustainable soil ecosystem.

Titanium dioxide (TiO₂) nanoparticles were synthesized via a novel eco-friendly green chemistry approach using marine natural extracts of two red algae (Bostrychia tenella and Laurencia obtusa), a green alga (Halimeda tuna), and a brown alga (Sargassum filipendula) along with a marine sponge sample identified as Carteriospongia foliascens. X-ray diffraction (XRD), scanning electron microscope (SEM), UV–Vis, X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR) were employed to characterize the crystal structure, surface morphology, and optical properties of the synthesized nanoparticles. Each of the as-synthesized marine extract based TiO₂ nanoparticles was individually incorporated as an antifouling agent to form a newly fabricated marine paint formulation. The newly prepared formulations were applied on unprimed steel panels. A comparative study with a commercial antifouling paint (Sipes Transocean Coatings Optima) was carried out. After 108 days of the coated steel panels’ immersion in the Eastern Harbour seawater of Alexandria-Egypt, the prepared paints using B. tenella and C. foliascens extracts demonstrated an excellent antifouling performance toward fouling organisms by inhibiting their settlement and controlling their adhesion onto the immersed panels. In contrast, heavy fouling with barnacles was observed on the surface of the coated panel with the commercial paint. The physicochemical parameters of the seawater surrounding the immersed coated panels were estimated to investigate the influence of the fabricated paint formulations. Interestingly, no effects of the immersed coated panels on the physicochemical characteristics of the surrounding seawater were observed. Based on the obtained results and a comparison with commercially available antifouling products, the marine extract based TiO₂ nanoparticle preparations of B. tenella and C. foliascens are promising candidates for eco-friendly antifouling agents. Based on the obtained results and a comparison with commercially available antifouling products, the marine extract based TiO₂ nanoparticle preparations of B. tenella and C. foliascens are promising candidates for eco-friendly antifouling agents, which could be attributed to the small crystallite sizes of 22.86 and 8.3 nm, respectively, in addition to the incorporation of carbon in the crystal structure of the nanoparticles.

Recently, the contribution of earthworms to plastic degradation and their capability to swallow smaller plastic fragments, known as microplastics, has been emphasized. The worm physically changes the size of microplastics and enhances microbial activities to increase the possibility of degradation. However, no research has shown that earthworms can chemically degrade microplastics to an element form, CO₂ or H₂O. In this review, previous research has been thoroughly explored to analyse the role that earthworms could play in plastic degradation in the soil. Earthworms can significantly affect the physical characteristics of plastics. However, earthworms’ abilities to chemically degrade or change the chemical structure of plastics and microplastics have not been observed. Additionally, earthworms exhibit selective feeding behaviour, avoiding areas containing a high plastics concentration and rejecting plastics. Consequently, earthworms’ abilities to adapt to the microplastics in soil in the environment can cause a problem. Based on this review, the challenges faced in earthworm application for plastic degradation are mostly expected to be associated with the toxicity and complexity of the plastic material and environmental factors, such as the moisture content of the soil and its temperature, microbial population, and feeding method.

Nature has always inspired innovative minds for development of new designs. Animals and plants provide various structures with lower density, more strength and high energy sorption abilities that can incite the development of new designs with significant properties. By observing the important functions of biological structures found in nature, scientists have fabricated structures by bio-inspiration that have been proved to exhibit a significant improvement over traditional structures for their applications in the environmental and energy sector. Bio-fabricated materials have shown many advantages due to their easy synthesis, flexible nature, high performance and multiple functions as these can be used in light harvesting systems, batteries, biofuels, catalysis, purification of water, air and environmental monitoring. However, there is an urgent need for sensitive fabrication instruments that can synthesize bio-inspired structures and convert laboratory scale synthesis into large scale production. The present review highlights recent advances in synthesis of bio-inspired materials and use of hierarchical nanomaterials generated through biomolecular self-assembly for their use in removal of environmental contaminants and sustainable development.

Polycyclic aromatic hydrocarbons are compounds with 2 or more benzene rings, and 16 of them have been classified as priority pollutants. Among them, pyrene has been found in higher concentrations than recommended, posing a threat to the ecosystem. Many bacterial strains have been identified as pyrene degraders. Most of them belong to Gram-positive strains such as Mycobacterium sp. and Rhodococcus sp. These strains were enriched and isolated from several sites contaminated with petroleum products, such as fuel stations. The bioremediation of pyrene via Mycobacterium strains is the main objective of this review. The scattered data on the degradation efficiency, formation of pyrene metabolites, bio-toxicity of pyrene and its metabolites, and proposed degradation pathways were collected in this work. The study revealed that most of the Mycobacterium strains were capable of degrading pyrene efficiently. The main metabolites of pyrene were 4,5-dihydroxy pyrene, phenanthrene-4,5-dicarboxylate, phthalic acid, and pyrene-4,5-dihydrodiol. Some metabolites showed positive results for the Ames mutagenicity prediction test, such as 1,2-phenanthrenedicarboxylic acid, 1-hydroxypyrene, 4,5-dihydropyrene, 4-phenanthrene-carboxylic acid, 3,4-dihydroxyphenanthrene, monohydroxy pyrene, and 9,10-phenanthrenequinone. However, 4-phenanthrol showed positive results for experimental and prediction tests. This study may contribute to enhancing the bioremediation of pyrene in a different matrix.

Nowadays, the logarithmic production of existing well-known food materials is unable to keep up with the demand caused by the exponential growth of the human population in terms of the equality of access to food materials. Famous local food materials with treasury properties such as mangrove fruits are an excellent source to be listed as emerging food candidates with ethnomedicinal properties. Thus, this study reviews the nutrition content of several edible mangrove fruits and the innovation to improve the fruit into a highly economic food product. Within the mangrove fruit, the levels of primary metabolites such as carbohydrates, protein, and fat are acceptable for daily intake. The mangrove fruits, seeds, and endophytic fungi are rich in phenolic compounds, limonoids, and their derivatives as the compounds present a multitude of bioactivities such as antimicrobial, anticancer, and antioxidant. In the intermediary process, the flour of mangrove fruit stands as a supplementation for the existing flour with antidiabetic or antioxidant properties. The mangrove fruit is successfully transformed into many processed food products. However, limited fruits from species such as Bruguiera gymnorrhiza, Rhizophora mucronata, Sonneratia caseolaris, and Avicennia marina are commonly upgraded into traditional food, though many more species demonstrate ethnomedicinal properties. In the Middle East, A. marina is the dominant species, and the study of the phytochemicals and fruit development is limited. Therefore, studies on the development of mangrove fruits to functional for other mangrove species are demanding. The locally accepted mangrove fruit is coveted as an alternate food material to support the sustainable development goal of eliminating world hunger in sustainable ways.