Plastic pollution is a new, pressing, environmental topic. Microplastics are considered contaminants of emerging concern and, consequently, microplastic research has grown exponentially in the last decade. Here, current knowledge regarding the impacts of micro- and nanoplastics on terrestrial plants and aquatic macrophytes is discussed, with a special focus on adsorption, uptake and toxicological effects. Our review reveals that a range of plants and macrophytes can adsorb or internalise plastic particles. Both processes depend on particle characteristics such as size and charge, as well as plant features including a sticky or hydrophobic surface layer. This finding is of concern given that plants and aquatic macrophytes are at the bottom of food webs and are a crucial component of the human diet. Therefore, there is a critical need for improved understanding of adsorption, uptake and impacts of micro- and nanoplastics, and the consequences thereof for trophic transfer, food safety and security. Also, a range of stress responses have been observed for many plant and macrophyte species after both short and long-term exposures to plastic particles. Given that some plastic particles can affect plant productivity, we surmise that plastic particles may potentially impact ecosystem productivity and function. Here we present a synthesis and a critical evaluation of the state of knowledge of micro- and nanoplastics and plants and macrophytes, identifying key questions for future research.

Shellfish constitute an important component of human diet, especially for those living in coastal regions. Shellfish have attracted extensive attention due to high enrichment of heavy metals. The aims of this study were to investigate the levels of trace elements in shellfish from coastal waters of Shenzhen, China and to assess human intake risks. Nine elements, including chromium (Cr), copper (Cu), iron (Fe), zinc (Zn), manganese (Mn), selenium (Se), cadmium (Cd), arsenic (As) and lead (Pb) were measured in 216 shellfish samples from eight species. Their concentrations (based on wet weight) were: Cr (0.28–21.4 mg kg⁻¹), Cu (1.40–158 mg kg⁻¹), Fe (16.5–5387 mg kg⁻¹), Zn (11.1–847 mg kg⁻¹), Mn (1.33–422 mg kg⁻¹), Se (0.15–11.8 mg kg⁻¹), Cd (0.02–18.4 mg kg⁻¹), Pb (<LOQ-10.9 mg kg⁻¹) and As (2.24–95.5 mg kg⁻¹), relatively greater than those reported in shellfish from other locations of China. Crassostrea ariakensis and Babylonia areolata were found to enrich As and Cd, respectively. The target hazard quotient (THQ) values of Cd and As were more than 1, suggesting considerable health risks from the consumption of shellfish of this zone. To our knowledge, this is the first study to assess the human risk exposure to trace elements via shellfish consumption in South China.

The growing use of lithium (Li) in industrial and energetic applications and the inability to completely recycle the alkali metal will most likely increase anthropogenic emissions and environmental concentrations in the future. Although non-essential to plants, Li+ is an important ultra-trace element in the animal and human diet and is also used in the treatment of e.g. mental disorders. Most of the lithium is consumed with the drinking water and vegetables, but concentrations in foodstuffs vary with the geochemistry of the element. In order to identify potential risks and to avoid an overmedication due to consumption of Li rich or Li contaminated foods it is advisable to identify background levels and to derive recommended Daily Allowances (RDAs) for the element. Although Germany does not possess large amounts of primary or secondary resources of lithium, geochemical investigations (mineral and ground waters and soils) in this country confirm a wide variation of environmental concentrations with generally higher levels in the southwest. Despite the large number of soil and water data, only very few data exist on lithium concentrations in plants and its phytotoxicity. Within the scope of present study common grassland plant species were sampled in regions of SW-Germany with reportedly high geogenic levels of Li. The data are discussed with regard to literature surveys and existing reference values. Since lithium has phytotoxic effects a greenhouse experiment was performed with different Li salts (LiCl and Li2CO3) and plant species (maize, bean and buckwheat) to derive dose-response relationships for the endpoint shoot growth. While corn growth was not reduced significantly by soil concentrations of 118 ppm, EC50 values in buckwheat were 47 and 16 ppm for lithium derived from LiCl and Li2CO3, respectively.

The effects of ozone exposure during the cropping season on rice grain quality were investigated in chamber experiments employing four ozone treatments (charcoal filtered air, ambient, 2× ambient, and 2.5× ambient concentration) and six genotypes. The concentrations of protein and lipids in brown rice increased significantly in response to ozone, while starch concentration and thousand kernel mass decreased. Other parameters, including the concentrations of iron, zinc, phenolics, stickiness and geometrical traits did not exhibit significant treatment effects. Total brown rice yield, protein yield, and iron yield were negatively affected by ozone. Numerous genotypic differences occurred in the response to ozone, indicating the possibility of optimizing the grain quality in high ozone environments by breeding. It is concluded that although the concentrations of two important macronutrients, proteins and lipids, increased in ozone treated grains, the implications for human nutrition are negative due to losses in total grain, protein and iron yield.

This study aimed to determine the presence of MPs in the gut and muscle tissue of riverine fish collected from the Qarasu River, Kermanshah, Iran. The results highlighted that MPs were found in the gut and muscle of all fish species at an average abundance of 8.12 ± 4.26 P/individual and 0.85 ± 0.38 P/g muscles, respectively. High amounts of MPs were found in the range of 1-25 μm in terms of size distribution. The properties of MPs extracted indicated that PE, PP, PS, and PA in the monotype of fiber and fragment were the most abundant plastic types and shapes found. Additionally, EAI was calculated for MPs found in the muscle. So, 174.43 and 127.19 P/kg/bw/year (1.28 and 0.93 g/kg/bw/year), were intake by two groups of adults and children, respectively. These findings highlight the contamination of fish as a common source of marine food in home consumption and the probability of entrance into the human diet.

Arsenic is the most toxic element for humans. Presenting naturally in aquatic ecosystems and due to anthropogenic action, this semi-metal transfers to shellfish through the food chain. This systematic review aims to explain the dynamic of arsenic in the marine aquatic system, investigating factors that affect its bioaccumulation. A total of 64 articles were considered from three databases. The key abiotic factor influencing the presence of arsenic in shellfish is anthropogenic contamination, followed by geographic location. The crucial biotic factor is the genetics of each species of shellfish, including their diet habits, habitat close to the sediment, metabolic abilities, physiological activities of organisms, and metal levels in their habitats and food. Finally, arsenic presents an affinity for specific tissues in shellfish. Despite containing mostly less toxic organic arsenic, shellfish are a relevant source of arsenic in the human diet.

Nanoparticles interact with plants to induce a positive, negative, or neutral effect on their growth and development. In this study, we document the positive influence of magnesium oxide (MgO) nanoparticles (NPs) on the morpho-biochemical parameters of Macrotyloma uniflorum (horse gram). Horse gram is a protein and polyphenol-rich legume crop. It is an important part of the human diet and nutrition. When exposed to MgO-NPs, a significant increment in the shoot–root length, fresh biomass, and chlorophyll content of horse gram was evident. Furthermore, there was a 4–20 and 18–127% increase in the accumulation of carbohydrate and protein content on MgO-NP exposure. The antioxidant potential was enhanced by 5–19% on NP treatment as a result of the increase in the accumulation of total polyphenolics. Total phenols and flavonoids were enhanced by 7–20 and 50–84% in the presence of MgO-NPs. The enzyme activity of SOD, CAT, and APX was also enhanced in MgO-NP-exposed horse gram. The observed alterations were also justified by the Pearson correlation. Overall, the MgO-NP-induced morpho-biochemical alterations in horse gram indicated their probable role as a nano-fertilizer. However, it further warrants the need to extensively investigate the responses of various other plant types to MgO-NPs before industry scale application.

The radioactive isotope, ⁴⁰K, of naturally occurring potassium (0.012%) is present in the Earth’s crust in a low percentage of all potassium, leading to its presence in almost all foodstuffs. The impact of ⁴⁰K activity concentrations was assessed in wild and cultivated edible mushrooms and in growing substrates. Samples were analysed by gamma spectroscopy. In the wild mushroom species, the average activity concentration of ⁴⁰K was 1291 Bq kg⁻¹ dry weight (dw), approximately 140 Bq kg⁻¹ fresh weight (fw), with a range of average values per species from 748 in Lactarius deliciosus to 1848 Bq kg⁻¹ dw in Tricholoma portentosum. The cultivated species presented an average value of 1086 Bq kg⁻¹ dw; and the soils, compost of cultivation and wood of substrate are 876, 510 and 59.4 Bq kg⁻¹ dw, respectively. The total K content reached a maximum of 59,935 mg kg⁻¹ dw in T. portentosum. The transfer factors (TF > 1) suggested that mushrooms preferentially bioconcentrated ⁴⁰K. Cantharellus cibarius, Craterellus tubaeformis, Hydnum repandum and T. portentosum by most TF could be considered as bioindicators of ⁴⁰K. Taking into account that the annual radiation dose of ⁴⁰K due to the average consumption of mushrooms analysed (0.15 μSv/year) is very low, it can be concluded that the consumption of these mushrooms does not represent a toxicological risk for human health. Finally, according to the total K content, from the nutritional point of view, these mushrooms could be considered as a potential source of potassium for the human diet.

Zinc deficiency is widespread in cultivated soils, limiting the grain crop production and the adequate human nutrition. Several wastes from metallurgical activity can be used as Zn source, but these materials generally also have other potentially toxic elements, such as Pb, that can be highly toxic for plants and humans. This study aimed to evaluate the efficiency of five chemical extractors (water, citric acid, DTPA, Mehlich 1, and USEPA 3051A) in better correlating with the bioavailable contents of Zn and Pb in soils treated with steel mill wastes (metallurgic press residue (MPR), filter press mud (FPM), and phosphate mud (PM)). Rice plants were cultivated in pots with 4 kg of a Haplic Eutrophic Gleisol and steel mill wastes were applied in soil at increasing doses (0, 0.5, 1, 2, 4, 8, and 16 t ha⁻¹). The availability of the potentially toxic elements Zn and Pb was assessed as total contents in rice shoots, grains, husks, and roots. The results showed that the USEPA 3051A method extracted greater contents of Zn and Pb from soil compared with other extractants. Due to their greater natural Pb and Zn contents, MPR and PM promoted higher contents of these elements in soils, respectively. Doses of PM influenced Zn contents in grains. After adding 16 t ha⁻¹ of PM, Zn content in rice grains was 0.1 mg kg⁻¹. However, at doses 0.5, 1, 2, and 4 t ha⁻¹, the average concentration of Zn in the grains was 40 mg kg⁻¹. The wastes MPR and FPM at 16 t ha⁻¹ promoted Zn concentration in grains of 42 and 45 mg kg⁻¹, respectively. The greatest contents of Pb in grains were found after addition of FPM at doses 0.5, 1, and 2 t ha⁻¹: 6.67, 4.96, and 0.45 mg kg⁻¹, respectively, and above 4 t ha⁻¹ (4, 8, and 16 t ha⁻¹); Pb content in grains was less than 0.3 mg kg⁻¹. The content of Pb in roots at 16 t ha⁻¹ of PM, MPR, and FPM was 18, 25, and 155 mg kg⁻¹, respectively, and for Zn, under the same conditions, 100, 255, and 813 mg kg⁻¹ for MPR, FPM, and PM, respectively. USEPA 3051A can be used to assess Pb and Zn available contents, and positive correlations with bioavailable contents of these elements in roots prove its feasibility. Further studies are necessary to state the safety of using steel mill application, including the use of other crop species, but PM is a promising waste for soil Zn fertilization.