Assessment of petroleum hydrocarbon in a tropical brackish water lagoon: Chilika, India

Abstract

Assessment of petroleum hydrocarbon (PHC) in the Chilika Lagoon, India, revealed a significant spatio-temporal variation in surface water (analysis of variance: n = 120, p < .01), whereas insignificant variation in sediment samples. The lagoon exhibited the highest PHC concentration during summer, attributed to higher boat activity and mixing of PHC from bottom sediment. For PHC in both the water of the lagoon and regions adjacent to jetties, the northern sector exhibited highest concentrations, followed by the southern, outer channels and central sectors, in order. The highest PHC level was due to the highest density of fishing boat operations and maintenance activities, as well as the resuspension of lake sediments across the shallowest region of the lagoon. The PHC found in the water and sediment in the jetty regions were relatively high in comparison to the rest of the lagoon, again attributed to the maintenance and operational activities of the motorised boats in the jetties. The sediment PHC concentration was ∼1000 times higher than the respective value for water, which could result from long-term deposition. The overall PHC concentration in the lagoon and jetties was found to be under the threshold limit and hence there is no risk to the existing biodiversity of the Chilika Lagoon. ARTICLE HISTORY

Sources and Variability of Petroleum Hydrocarbon Residues in Sediments of Chilika Lagoon, East Coast of India

“…Globally, many studies have been conducted on the distribution of PHC in water columns, sediments, and aquatic organisms (Chouksey et al 2004;Li et al 2010;Venkatachalapathy et al 2010). When directly released into water through spills or leaks, certain PHC fractions evaporate, but some fractions float and may form thin films over the surface of the water (Mohanty et al 2016). Heavier fractions accumulate in sediment, which may affect bottom-feeding fish and organisms .…”

“…The lagoon hosts a capture fishery, estimated to provide approximately 10,000 metric tons per annum (Mohapatara et al 2007). Thus, it is estimated that fishery production from Chilika underpins 200,000 local livelihoods, resulting in approximately 6640 fishing boats active within the lagoon, of which 2342 are motorized and 3398 are non-motorized (Mohanty et al 2016). The tourism sector is the major alternative livelihood activity; subsequently an additional 900 motorized boats are active in the tourism sector (Mohanty et al 2016).…”

“…Thus, it is estimated that fishery production from Chilika underpins 200,000 local livelihoods, resulting in approximately 6640 fishing boats active within the lagoon, of which 2342 are motorized and 3398 are non-motorized (Mohanty et al 2016). The tourism sector is the major alternative livelihood activity; subsequently an additional 900 motorized boats are active in the tourism sector (Mohanty et al 2016). During maintenance or operational activities of these boats, there might be chance of oil leakage or seepage from the boat engines.…”

Influence of seasonality, salinity and temperature on catch trend of Penaeus indicus H. Milne-Edwards, 1837 in a coastal lagoon, India

“…Although the species tolerates a wide range of salinity ranging from 5 to 50 ppt (Branford, 1981;Macia, 2004), particularly in the juvenile stage, it prefers habitat salinity of around 10-15 ppt (FAO, 1980). The mean salinity of Chilika Lagoon reaches around 15-18 ppt during summer (Mohapatra et al, 2007;Mohanty et al, 2016), which turns the estuarine water a preferable destination for juveniles. As a result, a large quantity of P. indicus juveniles ingresses into Chilika and stay there for at least 4-5 months until the salinity of Chilika water drops.…”

Imprints of COVID-19 lockdowns on total petroleum hydrocarbon levels in Asia's largest brackish water lagoon

“…Coastal lagoons are also vulnerable to TPHC and derivatives as they could be sourced from natural or anthropogenic activities that include point discharges and urban runoff, with a significant contribution from boat activities for fishery and tourism. Assessment of the status of the TPHC with respect to the controlling factors is vital in such ecosystems as the local population depends on them for their livelihood ( Chouksey et al, 2004 ; Li et al, 2010 ; Mohanty et al, 2016 ; Hemalatha et al, 2020 ). Expanded literature on the impacts and dynamics of TPHC in natural waters is provided in the Supplementary section and tables (S.1; S. T1 and S. T2).…”