Chromium (IV) transfer to Amusium pleuronectes by LDPE microplastics: An experimental study.

An experiment was carried out to investigate the potential of virgin LDPE microplastics to transfer heavy metals. Desired shapes (fibres, fragments, and films) and sizes (< 5 mm) of virgin LDPE microplastics were immersed in a known concentration (30 µg/l) of chromium (IV). These Cr-coated microplastics were introduced into a culture tank containing edible scallops (Amusium pleuronectes). After the completion of the experiment (5 days), the sediments in the culture tank and edible tissues of A. pleuronectes were tested for the presence of Cr. In the sediments, a maximum concentration of 1.934 µg/g of Cr was accumulated at a rate of R2 = 0.979, while in the tissues, the maximum accumulation concentration was 0.733 µg/g of Cr at a rate of R2 = 0.807. Energy Dispersive X-ray Spectroscopy analysis also confirmed the presence of Cr (2.61 ± 0.44 mass % and 1.80 ± 0.30 atom%) in the tissues of A. pleuronectes, which was absent in the control tissues. The study showed that when exposed to contaminants such as heavy metals, LDPE microplastics can adhere and transfer them to biotic tissues. LDPE showed the potential to transfer adhered contaminants; however, the effects caused by these transferred contaminants on biota must be studied further. Risk assessment study showed that potential ecological risk of Cr is < 40 indicating low risk however, the combined effect of Cr and LDPE can compound its toxicity which needs to be studied further.

Eco-friendly preparation and characterization of bioplastic films made from marine fish-scale wastes.

Synthetic plastics are becoming hazardous wastes, posing a threat to environmental sustainable health; hence, they must be replaced with alternatives. This study aimed to prepare corn starch-based bioplastics using fish scale through film casting technique as an alternative to synthetic plastics. In this work, four types of bioplastic films (CSF, CSFSF1, CSFSF2, FSF) containing different percentages of fish-scale powder and corn starch were prepared. Physical and chemical properties such as texture, color, solubility in hot water, tensile strength, functional groups, and morphology of all the four types of the prepared bioplastics were analyzed. The mixture of fish-scale powder and corn starch powder in the ratio of 1:3 (CSFSF1) yielded the best results. Its average thickness is 0.0420 ± 0.001 mm, water absorption range is 55-60%, tensile strength is 6.06 ± 0.05 MPa, and thermal stability is 278.741 °C. In the biodegradability test, degradation was noticed after 7 days of treatment with organic waste. The degradation was confirmed by surface changes in the morphology and the development of Aspergillus sp. Corn starch film (CSF) exhibited the highest degradation (60%), while the fish-scales film (FSF) underwent the least degradation (28%). The produced bioplastics were prepared from eco-friendly, inexpensive, and natural materials. Thus, the present research has provided a viable alternative to synthetic plastics.

Synthesis and characterization of nano-hydroxyapatite from Sardinella longiceps fish bone and its effects on human osteoblast bone cells.

Organic debris in the form of fish bone wastes account to several thousand tons annually. In recent years, researchers have turned attention towards the bioconversion of organic debris into materials with biomedical applications. Accordingly, the present study synthesized nano-Hydroxyapatite (n-HAP) from bones of discarded Sardinella longiceps by the alkaline hydrolysis method. The synthesized n-HAP was characterized by using the scanning electron microscope (SEM), X-ray diffraction (XRD), atomic force microscope (AFM), and Fourier transform infrared spectroscopy (FTIR). Crushed fish bone demonstrated an agglomerate of fine and rod-like crystals as observed in SEM, whereas n-HAP exhibited a structure of dense thick particles. FTIR spectral data confirmed the functional groups such as alkanes, esters, saturated aliphatic, and aromatic groups. XRD analysis exhibited strong diffraction peaks of HAP confirming its presence in synthesized n-HAP. AFM analysis affirmed that the synthesized particles had an average size of 19.65 nm. Cell viability was tested at different concentrations (10, 50, 100, 250 µg/mL) against human osteoblast bone cells (MG-63).The maximum cell viability (141.3 ± 3.1%) was observed at 100 µg/mL (24 h). Mineralization was evaluated using Alizarin red staining of osteoblast MG-63 cells treated with n-HAP at the concentration of 50 and 100 µg/mL (0.54 ± 0.03 and 0.99 ± 0.05%) which exhibited red color indicating good results. The size, morphology, functional groups, viability and mineralization of the synthesized n-HAP are favorable for its use in bone tissue engineering and other potential osteo and dental applications.