RESUMEN
Research on the occurrence of microplastics in invertebrates of the Thoothukudi region is limited. Capitellids are non-selective suspension feeders and are usually used as bioindicator of water pollution. Hence, an investigation was carried out to identify the microplastic occurrence in the capitellids (Capitella capitata) (Fabricius, 1780) collected from the Vellapatti and Spic Nagar sites of the Thoothukudi region. Result from this investigation showed the occurrence of 0.21 ± 0.17 items/indiv and a mean abundance of 13.33% in Thoothukudi coast. The mean microplastic abundance in the capitellids was significantly higher in the Spic Nagar (0.26 ± 0.19 MPs/indiv), probably due to the dumping of plastic waste, fishing and recreational activities. However, no significant difference was observed between seasons. Only fragments (Vellapatti 66.66% and Spic Nagar 33.33%) and fibre-shaped microplastics (Vellapatti 50% and Spic Nagar 50%) were identified. The size and colour of the microplastics dominant in both sites were 1-2 mm (Vellapatti 77.77% and Spic Nagar 75%) and blue (Vellapatti 88.88% and Spic Nagar 87.5%), respectively. The results of Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) analysis revealed the presence of polyethylene (PE) and polypropylene (PP) polymers in the capitellids. PE polymer is one of the most common sources of microplastics contamination globally and it is also frequently found in the coastal waters of Thoothukudi. This accounted for the high occurrence of PE polymers in the capitellids with the occurrence rate of 77% in Vellapatti and 58.52% in Spic Nagar. The present study provides baseline data on the occurrence, characterization (shapes, sizes and colours) and qualitative analysis of the microplastics in the capitellids, and their presence was influenced by their non-selective feeding habits. Further, future studies have to be conducted to identify the levels of microplastics in different polychaetes and other invertebrates to better understand the effects of microplastic pollution in invertebrate communities.
Asunto(s)
Monitoreo del Ambiente , Microplásticos , Poliquetos , Contaminantes Químicos del Agua , Animales , Microplásticos/análisis , Contaminantes Químicos del Agua/análisis , Plásticos/análisisRESUMEN
Accurate drought information is essential for preventing agricultural and societal losses. The indicators of how severe a drought is the deficiency in precipitation, soil moisture, and vegetation stress. The indicators were evaluated using the Precipitation Condition Index (PCI), Vegetation Condition Index (VCI), and Temperature Condition Index (TCI).The indices were combined using Principal Component Analysis to create the Synthetic Drought Index (SDI) for the evaluation of drought severity. The indices were estimated using multi-source remote sensing data from the Tropical Rainfall Measuring Mission (TRMM) and Operational Land Imager (OLI) of various years. Temporal analysis showed that the district is drought-prone and deficiency of 65% of precipitation in northeast monsoon of 2016 and below average non-monsoon rainfall in 2017, caused drought and affected 223.5 Km2 in 2017. Below average precipitation in northeast monsoon of 2018 and below average non-monsoon rainfall in 2019, caused drought and affected 423 Km2 in 2019. The northeast coastal regions of Ottapidaram, Thoothukudi, and Vilathikulam taluks of the district were more severely prone to drought. Failure of monsoon is the root cause of water deficit in water bodies. The semi-arid coastal climate accelerates the evaporation of water in water bodies and causes soil moisture deficit that leads to drought in the coastal district. A sequential evaluation of this index can be used to identify the onset of drought and mitigate the effect of drought.
Asunto(s)
Sequías , Tecnología de Sensores Remotos , Estaciones del Año , Suelo , Agua , Monitoreo del AmbienteRESUMEN
Microplastics pollute the marine environment and pose a greater risk to marine organisms. The microplastics were observed in the guts of the 12 species, which varied from 0.00 to 1.80 ± 1.19 particles /individual. Most of the microplastics were fibre shaped, 0.5-1 mm sized, blue-coloured, and polyethylene polymers. The abundance of the microplastics was higher for benthic species (0.66 ± 0.13 particles/ individual) than the pelagic species (0.53 ± 0.11 particles/individual), with no significant difference (p > 0.05). According to their feeding habits and trophic level, significantly the microplastics were abundant in the herbivores (1.23 ± 0.61 particles/individual) and quaternary consumers (0.76 ± 0.16 particles/individual), respectively. The present study suggests that microplastic ingestion in commercially important species was influenced by their feeding habits irrespective of their habitat and length and weight. In addition to this, biomagnification of the microplastics (Trophic Magnification Factor, TMF = 1.02) was also observed in the commercially important species with increasing trophic level. This further indicates that the trophic level can serve as the pathway for the transfer of microplastics from lower trophic level organisms to higher trophic level organisms. The present study concludes that the occurrence of biomagnification of microplastics and the pollutants absorbed by them might harm the commercially important species from the Thoothukudi region.
Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Plásticos , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente , India , Ingestión de AlimentosRESUMEN
Microplastics contamination poses a serious threat to marine biota, so the current study was carried out to assess the incidence of microplastics in the gastrointestinal tracts of pelagic and benthic species collected from the six sampling sites along Thoothukudi region from January 2021 to December 2021. In the present study, benthic species (0.67 ± 0.14 MPs/indiv) showed a higher abundance of microplastics than pelagic species (0.53 ± 0.11 MPs/indiv). The dominance of microplastic shapes, sizes, colours and polymers found were comparable among both pelagic and benthic species, this being fibre (27.56% and 48.33%), 0.5-1mm (39.78% and 42.94%), blue (50% and 40.85%), and PE (46.24% and 48.18%), respectively. The present study showed that microplastics are ubiquitous in both habitats, which raises serious concerns for public health. Hence, measures focusing on reducing local emissions and plastic waste disposal should be implemented to control microplastic pollution in the marine environment.
Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Plásticos , India , Contaminantes Químicos del Agua/análisis , Monitoreo del AmbienteRESUMEN
The groundwater is very precious in the world. Rapid urbanization and industrialization create tremendous stress on groundwater quality and quantity. Unscientific groundwater extraction and waste disposal methods impact the groundwater aquifer's susceptibility in the coastal area. This research examines how industrial waste, seawater intrusion, and solid waste dumping affect the Thoothukudi District, located on the southwest coast of Tamil Nadu, India. The groundwater vulnerability potential is determined using the DRASTIC and analytical hierarchy process (AHP)-based DRASTIC model. DRASTIC-AHP method's weights and ranks are determined using multi-criteria decision analysis (MCDA)-based pairwise comparison method. Remote sensing (RS) and geographical information system (GIS) are implemented to prepare the input layers for DRASTIC and DRASTIC-AHP. The findings reveal a very high category of vulnerability along the coastline that is covered in sand and loose sediments from an aquifer. Similar conditions exist on the southeast side, which is covered with gravel, sand, and sandstone with shale and has relatively low-slope topography. This enables higher contaminant percolation into the groundwater and raises the possibility for pollution. The DRASTIC-AHP method's results reveal that the southeast side has a significant possibility of contamination. The water table, net recharge, vadose zone, and conductivity greatly impacted the DRASTIC vulnerability assessment due to their stronger weight than theoretical weight. It may be stated that the DRASTIC technique is more cost-effective and time-efficient in analyzing a wide range of regional groundwater risks while avoiding sloppy, uncontrolled land development and other unwanted activities.
Asunto(s)
Sistemas de Información Geográfica , Agua Subterránea , Contaminación del Agua/análisis , India , Arena , Proceso de Jerarquía Analítica , Monitoreo del Ambiente/métodos , Modelos Teóricos , Agua Subterránea/análisisRESUMEN
Microplastics are a widespread environmental contaminant that raises serious concern for aquatic organisms. Hence, the present study was conducted to investigate the spatial and seasonal variation of microplastics, their characteristics, polymer types and the risk assessment caused by the microplastics in six sampling sites along the Thoothukudi region. The average microplastic abundance ranged from 32 ± 26 to 232 ± 229 items/kg and 54 ± 41 to 619 ± 377 items/l in sediment and surface water, respectively, and they exhibited a significant spatial difference among the sampling sites. The microplastic abundance also showed a significant difference among the seasons with the monsoon significantly recording the highest mean microplastic abundance in sediment (160 ± 130 items/kg) and surface water (454 ± 374 items/l). In sediment and surface water, fragment (sediment: 52.72%, surface water: 40.89%), 0.5-1 mm (sediment: 43.96%, surface water: 31.11%) and blue-coloured (sediment: 52.33%, surface water: 41.85%) microplastics were dominant with no significant difference both spatially and seasonally. Polyethylene, the dominant polymer, was observed in both the sediment and surface water, accounting for about 47.58% and 49.83%, respectively, and it showed no significant difference among the selected sites. This signifies that they are homogenously distributed along the coast and further suggests that these particles persisted in the sediment and surface water for a longer period of time. The results of the polymer hazard index show that the sediment (PHI = 1181.63) and surface water (PHI = 1018.66) were severely contaminated (hazard level V) with microplastic polymers such as PE, PP, PS, PET and PA. It was also found that the degree of the microplastic contamination in sediment (PLI = 3.57) and surface water (PLI = 3.84) was lower (hazard level I). The overall risk index (RI) for sediment (253.48) and surface water (444.74) falls under the higher risk category. From the correlation analysis, a significantly positive relationship was observed between microplastics in sediment and surface water based on each classification (abundance, shape, size, colour and polymer). This suggests that microplastics rejoin the water column from the sediment through resuspension, which occurs due to the circulation, tides and sedimentation rate. This might be the reason for the higher microplastic abundance in the surface water than in the sediment. As a result, proper management measures to reduce plastic waste disposal in the marine environment should be implemented to lessen the effects of microplastics on marine biota and on public health.
Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Sedimentos Geológicos , India , Plásticos/análisis , Polietileno/análisis , Medición de Riesgo , Estaciones del Año , Agua/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Microplastics accumulation on beaches raises a serious concern worldwide. Hence, the present study was conducted with the focus of investigating the abundance, characteristics, risk assessment, surface morphology and elemental composition of microplastics (MPs) in the beach sediments of the Thoothukudi region, situated on the south-east coast of India, Gulf of Mannar region. The MPs abundance ranged between 19 ± 18.62 and 78.55 ± 95.17 items/kg with a mean abundance of 33.82 ± 26.11 items/kg and the spatial distribution of MPs showed insignificant variation. Fragments (59.48%), 0.5-1 mm (43.66%) and blue-coloured MPs (45.61%) were highly predominant in the sediments. Attenuated total reflection - Fourier transform infrared (ATR-FTIR) spectroscopy showed the dominance of polyethylene polymers in sediments (52.26%) and their sources could be attributed to the direct inflow of sewage, recreational and fishing activities and accidental loss. The current study revealed that microplastics (< 5 mm) are ubiquitous along the Thoothukudi coast, posing a serious threat to the marine environment and marine organisms. The ecological risk assessment of MPs in sediments was calculated by adopting 3 models: the polymer hazard index (PHI), pollution load index (PLI) and potential ecological risk assessment (RI). The overall PHIsediments = 698.96 exhibited a hazard level of IV, which was mainly due to the varying abundance of polymer composition in sediments. The value of PLIsediments is 2.51, which mainly depends on the MPs abundance in sediments and yields the hazard level of I. The ecological risk posed by MPs in beach sediments along the Thoothukudi coast (RIsediments = 241.06) falls into the medium category, indicating that steps must be taken to reduce the flow of plastics through management measures such as proper wastewater treatment practices, recycling of plastic waste and proper waste disposal. Field emission scanning electron microscopy (FESEM) images revealed that MPs surfaces were strongly weathered and energy dispersive X-ray (EDX) spectroscopy spectra showed that the presence of inorganic elements associated with the surface MPs might be derived from the surrounding environment or additives in plastics. Hence, further research has to be conducted in view of studying the combined effects of MPs pollution and organic pollutants, which will provide further understanding of the contamination of MPs in the marine environment.
Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Sedimentos Geológicos , Plásticos , Polietileno/análisis , Polímeros , Medición de Riesgo , Aguas del Alcantarillado , Contaminantes Químicos del Agua/análisisRESUMEN
Planktivorous fish are easily susceptible to passive microplastic ingestion during their feeding behaviour and may be transferred along with the marine food web. Hence, the present study was conducted to assess the microplastics prevalence in the planktivorous fish (677 individuals) collected from 2 landing centres in the Thoothukudi, Gulf of Mannar region, South Tamil Nadu, India. The prevalence of microplastics was detected in 118 out of 677 individuals, with a mean abundance and percent occurrence of 1.22 ± 0.47 items/individual and 17%, respectively. The ingestion of microplastics in planktivorous fish was primarily due to their feeding habitat, in which they were prone to the accidental or passive intake of microplastics regardless of the fish's length and body weight. The microplastics abundance was significantly higher in Sardinella gibbosa (1.34 ± 0.56 items/individual), which might be due to their pelagic and planktivorous feeding habitat, highest filtration capacity, presence of closed gill rakers, and also due to the passive ingestion of microplastics as food items. Fibres, blue, and 1 to 2mmsized microplastics were predominant in the guts of Sardinella gibbosa, accounting for 95.74, 47.87, and 46.80%, respectively, whereas in Leiognathus lineolatus, fragments, black, and 1 to 2mmsized microplastics were highly prevalent with 62.96, 72.22, and 79.62%, respectively. The predominance of various shapes (fragments, fibres), sizes (1-2 mm), and colours (blue and black) of microplastics in the guts of fish was influenced by their passive ingestion, ingestion of contaminated planktonic prey, lack of selectivity of prey particles and their resemblance to plankton species. Polypropylene polymers predominated (96.77% and 95.23%) in both fish, followed by polystyrene (3.22% and 4.76%). Furthermore, this study provides baseline data and insists that there is a need for continuous monitoring of the distribution of microplastics.
Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Animales , Monitoreo del Ambiente , Peces , Tracto Gastrointestinal/química , India , Plásticos , Contaminantes Químicos del Agua/análisisRESUMEN
Ascidians belonging to the sub-phylum Uro-chordata are used as potential model organisms in various parts of the world for biosorption of metals. The sedentary nature, filter feeding habits, presence of vanadocytes and the absence of kidneys cause them to accumulate metals. The present study was aimed to compare biosorption of metals such as cadmium, copper, lead, mercury and vanadium in test and mantle body of solitary ascidian Phallusia nigra between two ecologically significant stations such as Thoothukudi (Station 1) and Vizhinjam (Station 2) ports of India. Monthly samplings of water and P. nigra were done for a period of one year from September 2010 to August 2011 and subjected to analysis of metal accumulation. The average metal concentrations except mercury in the Thoothukudi water were found to be higher of comparable magnitudes than the Vizhinjam water. One-way ANOVA showed significant differences between the stations. A comparison of average metal concentrations in the test and mantle body of P. nigra between two stations showed that the enrichment of V, Cd, Pb, Cu and Hg in the Thoothukudi samples may be due to high bioaccumulation factors of these elements as compared to other species of ascidians. The bioaccumulation factors were in the order of V>Pb>Cd>Cu> Hg for the test and mantle body in stations 1 and 2. Application of one-way ANOVA for the concentration of these metals between test and mantle body showed significant differences in both stations. Similarly, ANOVA for biosorption of these trace metals by P. nigra showed significant difference between stations. Metal concentrations recorded in this ascidian could effectively be used as good reference material for monitoring metal contamination in Indian sea waters.