Microplastic contamination in Indian rural and urban lacustrine ecosystems.

This study investigates the microplastics (MPs) pollution of the lacustrine ecosystems of Tamil Nadu, South India. It examines the seasonal distribution, characteristics and morphology of MPs and assesses the risk posed by MPs pollution. MPs abundance in the 39 rural and urban lakes studied varies from 16 ± 2.69 to 118.17 ± 22.17 items/L (water) and 19.50 ± 4.75 to 156.23 ± 36.41 items/kg (sediment). The water and sediment of urban lakes show average MPs abundances of 88.06 items/L and 115.24 items/kg respectively, while the rural lakes exhibit average MPs abundances of 42.98 items/L and 53.29 items/kg. The results demonstrate that study areas with more residential and urban centers with higher population density and larger discharge of sewage have greater MP abundance. Urban zones have greater MP diversity integrated index (MPDII = 0.73) than rural zones (MPDII = 0.59). Fibres are the dominant group and polyethylene and polypropylene are the most commonly found polymers, possibly gaining entry through land-based plastic litter and urban activities in this region. The weathering index values, 50 % of MPs exhibit high degree of oxidation (WI >0.31) with an age of >10 years. SEM-EDAX results reveal that the weathered MPs from urban lakes have a wider variety of metal elements (Al, Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Hg, Pb and Cd) than those from rural lakes (Na, Cl, Si, Mg, Al, Cu). Though PLI shows low risk (<10) in terms of abundance, PHI reflects pollution status III (10-100) and IV (100-1000) in rural areas and IV and V (>1000) in urban areas based on the toxicity score of the polymer. Ecological risk assessment shows minor risks (<150) at present. The assessment indicates the risk posed by the MPs to the lakes studied and emphasizes the necessity for best MP management practices in future.

Comparative study on the status of microplastics in different functional areas of Tuticorin, Southeast coast of India.

Microplastics (MPs) and the pollutants associated with them pose a significant risk to the aquatic ecosystems. This study analysed the spatial and seasonal differences in MPs in terms of diversity, inventory and associated heavy metals, and assessed the risk carried by MPs in different functional areas of Tuticorin, southeast coast of India. The mean MPs abundance varies from 5.67 ± 3.1 to 94.66 ± 6.5 items/L in water and 6 ± 1.73 to 147 ± 18.6 items/kg in sediment. More MPs are found in monsoon water and post-monsoon sediment. Fibre-shaped polyethylene (PE) and polypropylene (PP) MPs have a dominant presence in all seasons. They might derive from synthetic clothing, derelict fishing gear and improper dumping of plastic waste in this region. The carbonyl index (CI) of PE varies from 0.01 to 1.2 and that of PP from 0.03 to 0.98. The high surface oxidation rate (with CI ≥ 0.31) indicates the weathering level of MPs. The high microplastics diversity index (MPDII) of the Fishing Harbour points to the diverse pollution sources. The inventory of MPs is expressed in terms of their weight-based accumulation. Higher inventory of MPs is detected in the water (0.018 ton/km2) and sediment (2.03 ton/km2) of Fishing Harbour. The scanning electron microscope (SEM) images of MPs reveal various surface morphologic features like cracks, protrusion, void space, and adsorbed microorganisms. Energy dispersive X-ray spectroscopy (EDAX) shows the presence of metals (Mn, Cu, Zn, Ni, K, Ca, Cr, Mg, Ti, Cd, As, Se, Fe, Al, and Si) on the MPs surfaces. The polymer hazard index (PHI) indicates a III to IV chemical risk level. All the information obtained from the analysis presents a clear image of the nature and distribution of MPs in this region.

Seasonal and spatial variations in the distribution pattern, sources and impacts of microplastics along different coastal zones of Tamil Nadu, India.

We investigated spatiotemporal variations of microplastics (MPs) in Coromandel Coast, Palk Bay, Gulf of Mannar, and West Coast of Tamil Nadu, India. MPs abundance varies from 37 ± 1.52 to 189 ± 9.02 items/kg in sediment and 23 ± 15.25 to 155.25 ± 4.16 items/L in water. Highest abundance in monsoon by riverine inflow transports plastic waste to the ocean. MPs sizes 0.5-1 mm are dominant in summer with 16 polymers, while 3-4 mm dominates the monsoon with 23 polymers. Carbonyl Index shows high MP oxidation (>0.31), unrelated to spatiotemporal changes. SEM-EDAX shows weathered MPs carrying hazardous metals. High MP diversity (MPDII = 0.77) of Coromandel Coast points to many sources of pollution and the need for immediate control measures. Pollution load values indicate low degree of MP pollution (<10), polymer hazard index shows level III (10-100) and IV (100-1000), and ecological risk assessment shows minor risks (<150) at present.

Preliminary Study on the Role of Mangroves in Entrapping Microplastics in Tuticorin Coast of Gulf of Mannar, Southeast Coast of India.

Mangroves constitute a unique and important type of coastal wetlands in tropical and subtropical zones worldwide. The abundance of microplastics (MPs) in the mangrove sediments is poorly understood. This study aimed to quantify the role of mangrove root systems in effectively entrapping MPs in the mangrove areas of Tuticorin and Punnakayal Estuary. It investigated the abundance, characteristics, and weathering patterns of MPs in different mangrove sediments. Sediment samples were collected from ten mangrove sites and two control sites without mangroves. Microplastics were extracted from mangrove sediments by density separation method, and then counted and categorized according to their shape, size, and colour. Microplastics were identified in all ten sampling sites. Punnakayal Estuary has a greater MPs concentration (27 ± 2.65 items/kg dw) than Tuticorin (9.33 ± 2.52 items/kg dw). Also, microplastic concentrations are higher in the mangrove sites than in the control sites. Most MPs are fibres with size ranges of 1-2 mm and 2-3 mm dominating. Blue and transparent are the predominant colours. Four polymers were identified, namely polyethylene (PE), polypropylene (PP), polymethyl methaacrylate (PMMA), and polyurethane (PUR). The degree of weathering was confirmed by carbonyl index and the values vary between 0.28 and 1.25 for PE and 0.6 and 1.05 for PP.

Microplastic pollution and its implicated risks in the estuarine environment of Tamil Nadu, India.

Estuaries are transition zones between freshwater and seawater. There are only few studies on microplastic (MPs) pollution in estuaries. In this study, investigating the spatiotemporal variations of MPs in water, sediment and biota samples of 19 estuaries in Tamil Nadu, India, we assessed the chemical and human exposure risks of MPs. MPs extracted by digestion and density separation and characterized them using microscope, Fourier transform infrared spectroscopy and scanning electron microscopy with energy dispersive analysis of X-rays. MP abundancesin summer and monsoon range from 31.7 ± 3.8 to 154.7 ± 4.2 items/L in water and 51.7 ± 3.6 to 171.4 ± 9.1 items/kg in sediment. Highest MPs abundance is found in water and sediment of the urbanized Adayar estuary. MP levels are higher in monsoon than in summer (P < 0.05) due to the discharge of wastewater via storm water outlets. More small-size MPs are found in summer (<0.5-1 mm) while monsoon has a greater diversity of MP polymers (MPDII: 0.81). MP abundance in fish varies from 0.01 ± 0.003 to 0.15 ± 0.03 items/g, and in shellfish from 0.75 ± 0.12 to 9.7 ± 0.28 items/g. In fish, more MPs are found in intestine than in gill or muscle. Shell fishes contain more MPs than fishes. In all the matrices, fibers of different sizes, and polymers of polyethylene and polypropylene are commonly found. An average local person is likely to ingest 781 items of MPs via fish and 2809 items via shellfish annually. Polymer hazard index shows hazard levels of IV to V indicating the serious MP pollution trend, which poses a risk to the biota. In conclusion, MPs observed in this study show that estuaries are a major pathway for land-derived plastics to reach the ocean. The results will help implement remedial/clean-up measures for the estuary for better ecosystem conservation.

Microplastic in the coral reef environments of the Gulf of Mannar, India - Characteristics, distributions, sources and ecological risks.

Microplastics (MPs; particles <5 mm) are widely distributed in various habitats from the land to the oceans. They have even reached the remotest of places, including the deep seas and Polar Regions. Although research on MPs pollution in the marine environment has received widespread attention in recent years, the distribution, sources and ecological risks of MPs in coastal areas remain unclear. This study assessed the abundance, characteristics, sources and ecological risk of MPs in surface waters and sediment of the mainland coast and four island groups comprising the coral reef environment of the Gulf of Mannar (GoM), southeast India. Mean MPs abundance across all 95 sampling sites ranged from 28.4 to 126.6 items L-1 in water and from 31.4 to 137.6 items kg-1 in sediment. MP fibers <2 mm dominated the water, while fragments >3 mm were predominant in sediments. Polyethylene (PE) and polypropylene (PP) were the most common polymers in both matrices. The major proportion of MPs in the GoM derived from land-based sources, with distance to the mainland, coastal population density and improper handling of solid waste being the main factors influencing the abundance of MPs. Polymer Hazard Index (PHI), Pollution Load Index (PLI) and Potential Ecological Risk Index (PERI) were used to assess current levels of MPs. While the GoM has high PHI values (>1000) resulting from MPs with high hazard scores (e.g. polyamide, polystyrene, polyvinyl chloride), the PLI values (1.46 and 1.51) indicate low MPs pollution levels in GoM waters and sediments, and the PERI values (31.7 and 24.4) indicate that this represents a minor ecological risk. The results from the current study enhance our understanding of the characteristics, sources, and associated environmental risks of MPs to marine ecosystems. This data may provide a baseline for future monitoring and the formulation of environmental policy.

Spatial and vertical distribution of microplastics and their ecological risk in an Indian freshwater lake ecosystem.

This study investigated the spatial and vertical distribution of microplastics (MPs) in the water and sediment samples collected from different locations in Kodaikanal Lake, a very popular tourist location. The lake provides water to placesdownstream. MPs are found in the surface water, surface sediment and core sediment, with their respective values of abundance being 24.42 ± 3.22 items/ l, 28.31 ± 5.29 items/ kg, and 25.91 ± 7.11 items/ kg. Spatially, abundance, colour, type and size of MPs vary in the samples of surface water and sediment. The highest levels of MPs are found in the lakes' outlet region. MPs detected are primarily fibres and fragments 3-5 mm in size with PE and PP being the predominant polymers. Seven sampling points were selected to investigate the vertical distribution of MPs. In the core sediment, the abundance and size of MPs decrease with depth. This probably indicates the presence of more MPs in the recent sediment. The core sediment is dominated by sand silt clay fractions, which facilitates potential downward infiltration of fine MPs. SEM images of MPs reveal that the degree of weathering increases with depth, and EDAX shows that smooth MP surface displays a lesser adhesion ability than the rough surface. Plastic wastes generated by tourism are the important source of MPs in the lake. The lake has high PHI values (>1000) due to MPs with high hazard score polymers (PS and PEU), whereas the PLI values (1.33) indicate low level of MP pollution representing a minor ecological risk. The MP level in Kodaikanal Lake is influenced by the lake's hydrology and the sources of pollution. Although the impacts of MP pollution on the health and functioning of the environment is uncertain, observing, understanding and halting of further MP contamination in the Kodaikanal Lakes is important.

Microplastic contamination in Indian edible mussels (Perna perna and Perna viridis) and their environs.

This study investigated the microplastic (MPs) contamination of the mussels, P. viridis and P. perna of different sizes, and their environment viz. water and sediment. MPs were recovered from the soft tissues of both species. The mean abundance of MPs ranges from 0.87 ± 0.55 to 10.02 ± 4.15 items/individual; 0.1 ± 0.03 to 2.05 ± 0.33 items/g; 31.57 ± 7.63 to 59.25 ± 14.32 items/l in water, and 79.54 ± 18.66 to 108 ± 40.36 items/kg in sediment. Smaller mussels (3-6 cm) are capable of ingesting higher quantities of MPs per gram of tissue weight, and the rate of MP uptake decreases when the mussels grow in size. These might be due to the faster filtration rate in smaller mussels. MPs of fiber type and blue color in the size range of 500 µm to 1 mm are predominant in mussels. Eleven different polymeric groups were identified, of which PE is the most common, followed by PP. The distribution patterns of MP abundance, shape, size, color, and polymer in mussels more closely resemble those in water. There is no significant difference in MP quantities between P. perna and P. viridis (p > 0.05). FTIR-ATR spectroscopy and SEM analysis show that most of the MPs have been strongly weathered. EDAX analysis detects heavy metals like As, Ni, Fe, Zn, and Cd associated with MPs. This study shows that the MPs contents of both the mussel species are transferred from seawater to their edible meat. This study again proved that mussels can act as bio indicator of MPs pollution.

COVID-19 lockdown improved the health of coastal environment and enhanced the population of reef-fish.

Reduction in the impact of human-induced factors is capable of enhancing the environmental health. In view of COVID-19 pandemic, lockdowns were imposed in India. Travel, fishing, tourism and religious activities were halted, while domestic and industrial activities were restricted. Comparison of the pre- and post-lockdown data shows that water parameters such as turbidity, nutrient concentration and microbial levels have come down from pre- to post-lockdown period, and parameters such as dissolved oxygen levels, phytoplankton and fish densities have improved. The concentration of macroplastics has also dropped from the range of 138 ± 4.12 and 616 ± 12.48 items/100 m2 to 63 ± 3.92 and 347 ± 8.06 items/100 m2. Fish density in the reef areas has increased from 406 no. 250 m-2 to 510 no. 250 m-2. The study allows an insight into the benefits of effective enforcement of various eco-protection regulations and proper management of the marine ecosystems to revive their health for biodiversity conservation and sustainable utilization.

Occurrence and characteristics of microplastics in the coral reef, sea grass and near shore habitats of Rameswaram Island, India.

This study compares the occurrence and characteristics of microplastics (MPs) and heavy metal contaminants in the water and sediment of three habitats (corals, seagrass-beds and near-shores) of Rameswaram Island, India. The overall mean concentration of MPs varies from 24 ± 9 to 96 ± 57 items/L in water, and from 55 ± 21 to 259 ± 88 items/kg in sediment. The value of abundance is the greatest in the coral reef site CR-1 (96 ± 51 items/L; 259 ± 88 items/kg) followed by the seagrass site SG-2 (94 ± 55 items/L; 203 ± 75 items/kg) and the near-shore site St-15 (95 ± 63 items/L; 193 ± 75 items/kg). PE fiber (<1000 µm) is predominant in water, whereas PP fiber and fragment (between 2000 and 5000 µm) dominate the sediment. The SEM images of MPs reveal features which are characteristic of degradation like surface roughness, cracks, protrusions, and chalking, along with surface precipitates of both chemical and biological origin. EDAX images show the presence of Cr, Fe, Hg, Pb, Cu, As and Cd associated with MP surfaces.

Microplastic and heavy metal distributions in an Indian coral reef ecosystem.

The current study focuses on the occurrence and characteristics of microplastics (MPs) and spatial distribution and pollution status of heavy metals in the water and sediments of the coral reef ecosystems associated with the Tuticorin and Vembar groups of islands in the Gulf of Mannar, southeast India. Mean abundance of MPs varies from 60 ± 54 to 126.6 ± 97 items/L in water and from 50 ± 29 to 103.8 ± 87 items/kg in sediment. Water and sediment samples from the Tuticorin islands contain higher MP concentrations than the Vembar islands. The highest MP were observed in the mainland samples, while MP distributions in the shoreward direction i.e. towards the islands closely reflect those of the mainland (p < 0.05). Polyethylene is the most common polymer, with fibers (1-3 mm) being the most abundant form in water and fragments (3-5 mm) being the most abundant in sediment. Pollution indices such as enrichment and contamination factors indicate moderate contamination of sediments by Zn, Hg, Cd, Pb and Ni. Heavy metal associated with MPs are greater than those in sediments, and this indicates that MP may be a source of metal pollution or that metals from the sediment preferentially partition to MPs. SEM analysis highlights the presence of cracks, protrusions and depositions on the surface of many MPs, indicating partial degradation. EDAX frequently showed the presence of Zn, Cd, Pb, Ni and Fe associated with MP surfaces. This study offers an insight into the level of MPs and associated elements that filter feeding corals in the region are exposed to current.

Monitoring of microplastics in the clam Donax cuneatus and its habitat in Tuticorin coast of Gulf of Mannar (GoM), India.

Microplastics (MPs) in the marine environment are ubiquitous. The ingestion of these pollutants by marine organisms has drawn global attention. This work studies the distribution pattern and characteristics of MPs found in the body of the clam Donax cuneatus and its environment in order to understand the possible relationship between the MP concentration in the environment (water and sediment) and that in the clam's body. Samples of D. cuneatus were collected from the coast between Vembar and Periyathazhai in Tuticorin district along GoM. MP concentrations range from 0.6 to 1.3 items/g (wet weight) in clams, 10-30 items/l in water, and 24-235 items/kg in sediment. Small-sized clams contain the highest concentration of MPs. Hence it is hypothesised that allometric relationship exists between body size and MP concentration, depending on the surface-area to volume ratio. MP abundance in clam body has a clear, positive, significant correlation with MP abundance in sediment but not with abundance of MP in water. Microplastics of fiber type with size 100-250 µm have a predominant presence in clams. The study identified ten types of polymers, of which polyethylene is the most common polymer in all sample types. FTIR-ATR spectra and surface morphology indicate that most of the microplastics have been strongly weathered. Energy dispersive X-ray spectroscopy analysis detected heavy metals associated with MPs like Cd, Pb, Cu, Zn, Ni and Fe. Filter-feeding clams like Donax sp. can provide valuable information on the spatial patterns of MP distribution, and so can act as bio-indicators in monitoring MP pollution in coastal areas.

Microplastics in Salt of Tuticorin, Southeast Coast of India.

Microplastics (< 5 mm) are considered to be global environmental pollutants. This study investigates the occurrence, physical properties, polymer composition and surface morphology, and element composition of MPs present in food-grade salts produced from seawater and bore-well water in Tuticorin, Tamil Nadu, Southeast coast of India. Fourteen different brands of sea salts and bore-well salts were collected from the salt manufacturing units. The mean abundance of microplastics was 35 ± 15 to 72 ± 40 items/kg in sea salt and 2 ± 1 to 29 ± 11 items/kg in bore-well salt. Four types of polymers viz. polyethylene (51.6%), polypropylene (25%), polyester (21.8%), and polyamide (1.6%) were found in salt. Polyethylene fibers of size ranging from 100 to 500 µm were observed commonly. Being manufactured from seawater, sea salt had the highest quantities of different microplastic particles. The study reveals that people consume approximately 216 particles of MPs per year via sea salt and 48 items per year via bore-well salt if the average person has a daily salt intake of 5 g. The surface morphology of MPs as exhibited in the SEM-EDAX images obtained in the study revealed the different weathering features of MPs, such as pits, cracks, and particles adhering to the surface. The presence of the elements Fe, As, and Ni on the surfaces as identified by energy-dispersive x-ray spectroscopy indicates that these elements exist in the environment as contaminants and have become associated with the MPs. The trace metals adsorbed onto MPs increase the risks of human exposure and may cause some adverse effects in humans.

Occurrence of microplastics in epipelagic and mesopelagic fishes from Tuticorin, Southeast coast of India.

This study investigated the microplastic (MP) contamination of seawater and fishes from different habitats so as to understand the level of human exposure to microplastics. Samples of Harpodon nehereus, Chirocentrus dorab, Sardinella albella, Rastrelliger kanagurta, Katsuwonus pelamis and Istiophorus platypterus were collected from Tuticorin, southeast coast of India. The MPs in seawater and the gastrointestinal tracts of fish were identified using Stereomicroscope and characterized by FTIR and SEM-EDAX analysis. The abundance of MPs varied from 3.1 ± 2.3 to 23.7 ± 4.2 items L-1 in water, from 0.11 ± 0.06 to 3.64 ± 1.7 items/individual, and from 0.0002 ± 0.0001 to 0.2 ± 0.03 items/g gut weight. The epipelagic fishes had higher levels of MP contamination than the mesopelagic ones. Most of the MPs identified were of blue color, of fiber type and with their size <500 µm. Polyethylene was the most commonly detected MP, followed by polyester and polyamide, and this fact could be attributed to the inflow of domestic sewage and to the intensive fisheries activities in the area. SEM-EDAX spectra revealed the weathered MP surfaces which could adsorb/leach inorganic elements (colorants and fillers) from/to the environment. We may conclude that the concentration of MPs in fishes is a function of the concentration of MPs in their environment.

Macro-, meso- and microplastic debris in the beaches of Tuticorin district, Southeast coast of India.

This study investigates the mean concentration and characteristics of macroplastics (>2.5 cm), mesoplastics (5 mm - 2.5 cm) and microplastics (<5 mm) on eight sandy beaches along the shoreline of Tuticorin, Tamil Nadu. Prevalence of plastic litters varies among the study sites depending on the intensity of fishing and other human activities. Mean concentrations of macroplastics (1.38 ± 78 to 6.16 ± 94 items/m2), mesoplastics (2 ± 0.8 to 17 ± 0.11 items/m2) and microplastics (25 ± 1.58 to 83 ± 49 items/m2) were estimated in respect of the polymers composing them namely PE, PP, PET, NY, PS and PVC, of which PE is the most predominant polymer. At Sites 1, 2, 3, 5 and 8 there is correlation between the intensity of fishing activity and the concentrations of macro- (p = 0.02) and microplastics (p = 0.03). Sites 4, 6 and 7 there is correlation established between the degree of recreational activity and the concentrations of meso- (p = 0.02) and microplastics (p = 0.01).

Profiling microplastics in the Indian edible oyster, Magallana bilineata collected from the Tuticorin coast, Gulf of Mannar, Southeastern India.

The objective of this study is to quantify the extent of microplastic (MP) contamination in the Indian edible oyster (Magallana bilineata) and to understand how this relates to the MP contamination in its surrounding marine environment. Samples of water, sediment and oysters of different sizes were collected from three sites along Tuticorin coast in Gulf of Mannar in Southeast India. The mean abundance of MP in oysters was found to be 6.9 ±â€¯3.84 items/individual and the mean concentration to be 0.81 ±â€¯0.45 items/g of tissue. Polyethylene (PE) and polypropylene (PP) fibers were the dominant MP types in oysters (92% and 4%, respectively) and in seawater (75% and 25%, respectively), with PE fibers, ranging from 0.25 to 0.5 mm, being the most common. Both PE and PP are low-density polymers which are slow to sediment to the seafloor. This increases the potential of their availability in the environment and ingestion by the oysters. The largest oysters (14-16 cm) contained the highest abundance and concentrations of MP, suggesting a greater proportion of MP in the water column is ingested with increasing size. The calculated microplastic index (0.02 to 0.99) also indicates that MP bioavailability increases with increasing size of oysters. The distribution patterns of MP abundance, shape and size in oysters more closely resemble those in water than in sediment. The surface morphology of the MPs reveals the characteristic pits and cracks which result from partial degradation through the weathering processes. Energy-dispersive X-ray spectroscopy analysis shows the presence of Ni and Fe in association with MP, and this probably indicates the fly-ash pollution and the petroleum-related activities in the surrounding area. Being sessile animals the oysters are good candidates for use as sentinel organisms for monitoring MP in specific marine environments.

Abundance, characteristics and surface degradation features of microplastics in beach sediments of five coastal areas in Tamil Nadu, India.

This study undertook to investigate the occurrence of microplastics (MPs) in the high and low-tide sediments of five coastal areas in Tamil Nadu, India. The abundance of microplastics vary from 439 ±â€¯172 to 119 ±â€¯72 (HTL) and 179 ±â€¯68 to 33 ±â€¯30 (LTL) items kg-1 of sediments. The MP polymers found in the study sites are Polyethylene (73.2%), polypropylene (13.8%), nylon (8.2%), polystyrene (2.8%) and polyester (2%). The weathered surfaces might act as high-capacity carriers and this was confirmed by SEM-EDAX. The results of an analysis of the textures of the sediments do not ascribe any influence on microplastic abundance. The recreation, religious and fishing activities are the major contributors to plastic pollution in these beaches, which is borne out by the high abundance of MPs in the study sites. A regular and permanent waste management system should be put in place for the protection of beaches.

Effect of radiation on the nutritional and microbial qualities of salted and sun-dried Sharpfin barracuda (Sphyraena acutipinnis).

PURPOSE: To evaluate the effect of low-dose gamma irradiation (5 kGy) on the nutritional and microbial qualities of sun dried fin fish, Sharpfin barracuda (Sphyraena acutipinnis). MATERIALS AND METHODS: Salted and sun-dried S. acutipinnis with 25.8% moisture content were exposed to total body irradiation with a dose of 5 kGy. Control groups were non-irradiated and both the control and irradiated samples were stored under ambient temperature. One week after irradiation, the control and irradiated samples were analyzed for nutritional, microbial and organoleptic properties. The data were statistically analyzed. RESULTS: The proximate composition and quality parameters like free fatty acid (FFA), Trimethyl amine nitrogen (TMA-N) and total volatile base nitrogen (TVB-N) were significantly different (p < 0.05). The organoleptic qualities of the irradiated fish products were good. Total bacterial count was reduced, whereas Salmonella, Vibrio and fungi were totally eliminated after irradiation. CONCLUSIONS: The irradiation helps to improve the quality and safety of sun-dried fishes. The process would not only reduce the risk resulting from pathogens but also would destroy many of the spoilage agents like bacteria, insects, parasites, moulds and yeasts which are known to be the main cause of food losses in developing countries.

Isolation of a novel antibacterial phenyl thioketone from the seagrass, Cymodocea serrulata.

A total of 40 extract types of varying polarities from commonly occurring seagrasses were tested for their antibacterial efficiency against 14 clinically isolated human pathogens using agar well diffusion technique. The extracts from acetone of Cymodocea serrulata expressed moderate broad span of activity against a range of gram-positive and gram-negative isolates that were at least resistant to five of the commercially available antibiotics at a minimal concentration of 10 µg. The active extracts of C. serrulata that showed maximal inhibitions were purified using column chromatography that afforded six compounds (a-f). Compound f elicited pronounced inhibitions against Escherichia coli with minimal inhibitory concentration values of 1-3 µg concentration using micro-dilution method. The active compound was identified as phenyl thioketone using various spectral analyses. This is the first investigation that reveals thioketone functionality from this seagrass species possessing antibacterial actions. This study indicates that there are thiocarbonyl groups from marine floral sources too, which could be possibly used for therapeutic purposes.