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This research paper examines the exposure to particulate matter (PM) and its deposition on the human respiratory tract (HRT) in 12 critical urban zones — institutional zone, commercial zone, construction zone, hospital zone, landfill zone, industrial zone, residential zone, high-traffic zone, main roads, medium-traffic zone secondary roads, low-traffic zone, coastal zone, and environmentally sensitive zone. This study measured the size-segregated PM concentrations using a Grimm aerosol spectrometer. The multiple-path particle dosimetry model assesses particles' total and regional deposition mass rates for different urban zones. A stochastic model of the 60th percentile is used to illustrate the deposition of PM in the human lung. The deposition rate of PM in the HRT is examined for the different urban zones from different emission sources. The analysis shows that the PM concentration in zone V (dumpsite zone) is at an elevated level (i.e., PM10 = 570.4 µg/m3, PM2.5 = 128.3 µg/m3, and PM1 = 28.1 µg/m3) and lowest at zone XII (eco-sensitive zone) (i.e., PM10 = 25.1 µg/m3, PM2.5 = 1 6.9 µg/m3, and PM1 = 14.8 µg/m3). Further, dumpsite, commercial, and eco-sensitive zones are identified to be critical zones that influence higher deposition in the tracheobronchial and pulmonary regions. The investigation concludes that local turbulence and emission source significantly impacts air quality and deposition of PM at HRT. In addition, as the PM diameter decreases, the acidity of PM increases, and it can penetrate deep into the lower airways. Since this can have profound consequences, it is imperative to better understand the deposition of PM across various urban zones. [ABSTRACT FROM AUTHOR]

The term “meiobenthos” refers to a diverse community of organisms inhabiting the interstitial spaces between sand grains retained on sieve sizes ranging between 38 to 500 μm. This study investigates the diversity and density of meiobenthic communities across five locations along the Chennai coast. We examined the dominant meiobenthic groups, with nematodes exhibiting high dominance at Napier station (288.6 ± 91.07 ind.10cm²) and harpacticoids dominating at Marina station (449.88 ± 264.3 ind.10cm²). To establish the relationship between meiobenthic organisms and environmental parameters, we analyzed seven physicochemical factors throughout the study period. The results indicate a negative correlation between ammonia, nitrate, and phosphate levels in the water and a few meiobenthic groups, notably harpacticoids and ostracods. However, no significant relationship was observed between physicochemical parameters and dominant groups of this study, such as nematodes and polychaetes. These findings highlight substantial fluctuations in the diversity and density of meiobenthos and physicochemical parameters throughout the study period, emphasizing the dynamic nature of these coastal ecosystems. Moreover, the results of this study contribute to our understanding of meiobenthic dynamics and their interactions with the environment. [ABSTRACT FROM AUTHOR]

This paper discusses about the results of a short term monitoring study of sea coast contaminated with oil spill. Collision of two oil-cargo ships, namely BW Maple and MT Dawn Kanchipuram near the Ennore Port, Chennai had released an approximately 200 tonnes of heavy fuel oil. We analyzed four different oil spill samples collected from Chennai beaches for different time intervals (1st, 3rd, 6th, 10th day of oil spill) from 1 km away from the source of the off shore spill location. The physicochemical characteristics of spilled oil sludge, concentration of total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs) present in the spilled oil were investigated. The variations in pH, moisture content and volatile hydrocarbon content, viscosity and density of the spilled oil were in the range of 7 ± 0.2, 255–575 g/kg, 118 to 850 PaS and 1.04 to 0.98 g/cm3 respectively. Elemental analysis showed that C, H, N and S were in the range of 9.9–13.3 (%), 0.63 to 1.76 (%), 1.88 to 1.02 (%) and 0.29 to 0.27 (%) respectively. Analysis of oil spill samples using gas chromatography and mass spectrometry (GCMS) shows the presence of recalcitrant and hazardous PAHs such as fluoranthene and pyrene. Ocean sediments were collected at different locations along the coast line from Ennore to Cooum after 60 days of oil spill and analyzed for TPH in GCMS. The results showed that the residual concentrations of TPH varied from 0.19 to 3.43 mg/g. The presence of heavy PAHs, which are highly toxic and recalcitrant, could pose a severe threat to the marine environment and ecology.The long term effects of these compounds were unexplored on marine environment. This environmental monitoring study gives an overview about the post oil spill activities and steps taken to remediate the sludge along the coastline. Image 1 • This study highlights the immediate fate and characteristics of the Chennai oil spill over a short period. • Total petroleum hydrocarbon concentration increased from third day to sixth day and then stabilized. • Viscosity of the spilled oil increased eight times from day1 to day 10 after the oil spill. • Priority pollutants such as Fluoranthene and pyrene were identified in beach sediments using GC-MS. [ABSTRACT FROM AUTHOR]

Abstract: The newly constructed port in 2001 at Ennore, on the southeast coast of India near Chennai, with breakwaters on either side (north and south) has been causing large-scale changes in nearshore morphology. Beach profiles and shoreline positions along 25 km coastline of Ennore were measured at regular intervals during 2001–06 to understand the sediment transport patterns in the region. At the same time the results of wave hind-casting and wave transformation modeling were incorporated in LITDRIFT model to compute the sediment transport rates along Ennore coast. The model results are compared with the sediment transport values obtained from beach profile measurements. The performance of the model at different locations within the study area with variable wave conditions has been examined. The annual net sediment loss (−) versus accumulation (+) were estimated for two smaller study areas (cells) containing ten regularly spaced beach profiles numbered from north to south, BP1-5 in cell I and BP6-10 in cell II. For the cell I region, which is protected by the Ennore shoals and where human interference is minimum, the annual net sediment supply is +0.02×106 m3 as obtained from beach profile measurements while the model gave a value of +0.014×106 m3. For the cell II region where there is large human intervention by way of Ennore port development and breakwater construction, the annual net sediment movement as obtained by the beach measurements is −0.14×106 m3 while the model gave a value of −0.154×106 m3. It is found that the performance of the model is satisfactory and the model may be used successfully to study sediment dynamics along any coastline provided one has detailed understanding of the coastline orientation, nearshore topography, cross-shore bathymetry and prevailing annual wave climate. Based on the sediment transport data and beach profile measurements the beach and shoreline changes for transect locations BP-1 to BP-10 are also critically examined in this paper. [Copyright &y& Elsevier]