Abandonment of fibreglass reinforced plastic fishing boats in Kerala, India, and chemical emissions arising from their burning.

Little information exists on the fate and impacts of boats constructed of fibreglass reinforced plastic (FRP) once they reach their end-of-life. In this study, the number of abandoned fishing boats constructed of FRP or constructed of plywood-wood and sheathed by FRP has been determined along the coast of Kerala, India, and chemical emissions have been estimated when boats are burned as a means of disposal. A total of 292 abandoned boats were observed across eight coastal transects constructed around selected landing centres, with abandonment ranging from 13 to 48 per km (average = 29 km-1). This results in the generation of 1420 kg of FRP debris (glass mat and epoxy resin) per km of coastline. A controlled combustion experiment, simulating open burning, revealed that 63% of original boat mass is emitted to the atmosphere, with the remainder forming a burnt residue. Total concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans emitted and remaining were found to be 2.6 ng Nm-3 and 249.6 µg kg-1, respectively, with respective calculated toxicity equivalence (TEQ) levels of 437.6 pg TEQ Nm-3 in air emissions and 26.6 µg TEQ kg-1 in the residue. These figures are equivalent to the total emission from FRP boat burning of about 17,000 µg TEQ t-1. Burning also generates significant quantities of potentially toxic metals, with resulting concentrations of Co, Cr and Cu close to or exceeding soil guideline values. The study calls for a greater awareness of the impacts arising from boat abandonment and burning amongst fishermen, and guidelines or regulatory protocols regarding safe and sustainable boat disposal or recycling.

Occurrence and characteristics of fibreglass-reinforced plastics and microplastics on a beach impacted by abandoned fishing boats: A case study from Chellanam, India.

Plastics and microplastics have been quantified and characterised at disposal sites of abandoned fishing boats and along the high-water line (HWL) of a fish landing centre in Chellanam, India. Fibreglass-reinforced plastic (FRP) made a greater contribution to the plastic pool at the disposal sites (~ 4.5 n m-2 and 18 g m-2) than the HWL (~ 0.25 n m-2 and < 1 g m-2) and was an abundant component of the microplastic pool at the former. Infrared analysis of micro-sized FRPs revealed various resins (e.g., alkyd, polyester, epoxy), while X-ray fluorescence analysis of the painted surfaces of meso-sized FRPs returned variable concentrations of copper and lead. Concentrations of Pb were high enough to contaminate sand up to ~400 mg kg-1. The relatively high density of FRP and its association with glass fibres and metal-bearing paints results in particles with potentially very different fates and toxicities to more "conventional" (non-composite) thermoplastics.

Microplastics in the edible tissues of shellfishes sold for human consumption.

Microplastics in seafood are an emerging area of seafood safety concern. In this study, we investigated the presence of microplastics (100 µm - 5 mm) in the edible tissues of four species of shellfishes - two species of shrimp, Metapenaeus dobsoni and Fenneropenaeus indicus; one species of crab, Portunus pelagicus; and one species of squid Uroteuthis (Photololigo) duvaucelii -all bought from fishing harbours of Kerala, India. An average of 2.7 ± 12 microplastic particles kg-1 of edible tissue (wet weight) and 0.07 ± 0.3 microplastic particles/individual were obtained from the sampled shellfishes. No microplastics were found in the edible tissues of shrimps examined, while U. (P) duvaucelii had the highest microplastic content with an average of 7.7 ± 20 microplastic particles kg-1 of edible tissue, followed by P. pelagicus with an average of 3.2 ± 10 microplastic particles kg-1 of edible tissue. There was significant species variation in the microplastic contamination of shellfish soft tissues (p < 0.05). The study is the first of its kind to report the detection of microplastics in edible tissues of a squid species. Results suggested an annual dietary intake of about 13 ± 58 microplastic particles per year by shellfish consumers, which can vary based on the species, quantity, and extent of gut removal of seafood consumed.

Microplastics in the edible and inedible tissues of pelagic fishes sold for human consumption in Kerala, India.

Microplastics in commercially important seafood species is an emerging area of food safety concern. While there have been reports of plastic particles in the gastrointestinal tract of several species, presence of microplastics in edible fish tissues has not yet been reported from India. This study examined the presence of microplastics in the edible (muscle and skin) and inedible (gill and viscera) tissues of nine commercially important pelagic fish species from Kerala, India. A total of 163 particles consisting mainly of fragments (58%) were isolated. Out of 270 fishes analysed (n = 30 per species), 41.1% of the fishes had microplastics in their inedible tissues while only 7% of fishes had microplastics in their edible tissues. The quantity of microplastics in inedible tissue was significantly larger in filter feeders than, that in visual predators (p < 0.05). The average abundance of microplastics in edible tissues was 0.07 ± 0.26 items/fish (i.e., 0.005 ± 0.02 items/g) and was 0.53 ± 0.77 items/fish (i.e., 0.054 ± 0.098 items/g) in inedible tissues. The results suggest the possibility of human intake of microplastics by the consumption of pelagic fishes from this region, albeit in small quantities.

Abundance, characteristics and seasonal variation of microplastics in Indian white shrimps (Fenneropenaeus indicus) from coastal waters off Cochin, Kerala, India.

The microplastic contamination of seafood species is increasingly becoming a global concern due to its potential influence on food safety and human health. This study investigated the presence and seasonal variation of microplastics in a commercially important marine shrimp species, Fenneropenaeus indicus, from the coastal waters of Cochin, India. The soft tissues of 330 shrimps were examined over a period of 12 months, from March 2018 to February 2019. A total of 128 microplastics were detected, of which 83% were fibres. An average (mean ± SD) of 0.39 ± 0.6 microplastics/shrimp (0.04 ± 0.07 microplastics/g wet weight) was obtained from the shrimps sampled. Microplastic contamination was significantly higher in July-August (Monsoon season) compared with other months. This study reports microplastic contamination in F. indicus for the first time. Results also suggest that consumption of peeled but undeveined or whole dried white shrimps can be one of the ways of the human uptake of microplastics, especially during the monsoon season.

Protein hydrolysate from yellowfin tuna red meat as fortifying and stabilizing agent in mayonnaise.

Present study addresses the fortification of mayonnaise with fish protein hydrolysate by partial replacement of egg yolk in the product. Red meat of yellowfin tuna (Thunnus albacares), a by-product from tuna canning industry was used as the source of protein hydrolysate (TPH). Substitution of egg yolk with hydrolysate imparted noticeable fish flavor to the product only at higher levels of replacement (50% and above). Emulsion stability of mayonnaise samples was not significantly affected at the given range of substitution. The preliminary product acceptability parameters indicated higher desirability with a sensory score of 7.6 ± 0.7 for a replacement ratio of 1:2::TPH:egg yolk. Hence, the same combination was further subjected to morphological, rheological characterization, and opted for storage stability studies. Fortified mayonnaise exhibited lower particle size, indicative of higher emulsion quality which was also evident in the rheological properties of the sample. Results indicated better oxidative and physicochemical stability for fortified samples compared to control under chilled conditions, suggesting the applicability of fish protein hydrolysate as fortifying and stabilizing agent in mayonnaise preparations.

Biofouling Control Using Nano Silicon Dioxide Reinforced Mixed-Charged Zwitterionic Hydrogel in Aquaculture Cage Nets.

Biofouling in aquaculture cages negatively affects the farm productivity, and it requires huge sums of money and labor for its management. A superhydrophilic pseudozwitterionic hydrogel, N-isopropylacrylamide (NIPA) + [2-(methacryloyloxy)ethyl]trimethylammonium (TMA) + 3-sulfopropyl methacrylate (SA) copolymer, is considered as a potential antifouling agent. The present study aimed to synthesize a nano silicon oxide reinforced NIPA-TMA-SA mixed-charged zwitterionic hydrogel over polyaniline-coated polyethylene aquaculture cage nets through the in situ microwave reaction and to test its biofouling resistance. The study highlighted the formation of stable coating over polyethylene, four different treatments, and their effective inhibition of fouling compared with the untreated one. Six month's immersions of treated nettings in the estuarine environments demonstrated that the biofouling inhibition by nano silicon oxide reinforced zwitterionic hydrogel-coated polyethylene was unable to satisfy the industrial standards but made the samples free from hard-shelled fouling organisms compared with untreated controls. More research is needed to improve the quality of the coatings. The mixed-charged zwitterionic hydrogel with nano silicon oxide showed medium hydrophilic nature. Fourier transform infrared, scanning electron microscopy, and spectroscopic evaluation showed the successful formation of hydrogel over the aquaculture cage net. Nano silicon oxide reinforced in the matrix through hydrogen and coordination bonding between NH2 and carbonyl of the polymeric chain, respectively.

Polylactic acid/chitosan films for packaging of Indian white prawn (Fenneropenaeus indicus).

Composite films were developed by embedding nanochitosan (0.5%, 1% and 2%) in a polylactic acid (PLA) matrix using polyethylene glycol as a cross linking agent and polyvinyl alcohol as plasticizer. The mixture was casted into films via solvent casting. The interaction between the polylactic acid/nanochitosan (PLA/NCS) and polyethylene glycol had a significant effect on the tensile strength and the heat sealing properties. Antimicrobial properties of PLA/NCS films have been confirmed against aerobic microorganisms. PLA/NCS solvent casted films were used to pack prawn meat (Fenneropeneaus indicus) which was further stored in chilled condition for 18 days. The study proved that microbial and biochemical quality indices of prawn samples packed in different PLA/NCS film were retained and concluded that PLA/NCS composite films can be used for packing of fresh prawn to increase its shelf life.