Being the most reactive of all chemical elements and the lightest member of halogen group, fluorine is found in the environment as fluoride. Both natural and anthropogenic activities are responsible for fluoride contamination in groundwater. Fluoride has dual effect on human health. While lower concentration (<0.5 mg/L) is responsible for dental fluorosis, higher concentration (>1.5 mg/L) leads to skeletal fluorosis and even death. The present review paper is aimed at providing detailed occurrence of fluoride pollution around the globe and in India. Among the different defluoridation techniques to remove excess fluoride from contaminated drinking water at both community and domestic levels, adsorption is found to be very effective due to its technical feasibility, simple characteristics and comparative low-cost nature. Various adsorbents have been tested for their ability to treat fluoride contaminated water, viz., activated carbon, activated alumina, soil, clay and a variety of waste materials. Since fluoride pollution of drinking water is a major concern of poor people as they cannot afford to spend on purification of water, usage of low-cost natural mineral (natural mineral) as adsorbent for fluoride removal is one of the most essential issues in modern era. The present review bestows a detailed discussion on natural mineral as adsorbent used in defluoridation process with special emphasis on soil and low-cost clay minerals.

This study focused on whistles produced by Guiana dolphin under different noise conditions in Guanabara Bay, southeastern Brazil. Recording sessions were performed with a fully calibrated recording system. Whistles and underwater noise levels registered during two behavioral states were compared separately between two areas. Noise levels differed between the two areas across all frequencies. Whistle duration differed between areas and was negatively correlated with noise levels. Whistling rate was positively correlated with noise levels, showing that whistling rate was higher in noisier conditions. Results demonstrated that underwater noise influenced Guiana dolphin acoustic behavior.

Many people practice open defecation in south Asia. As a result, lot of human waste containing nutrients such as nitrogen (N) and phosphorus (P) enter rivers. Rivers transport these nutrients to coastal waters, resulting in marine pollution. This source of nutrient pollution is, however, ignored in many nutrient models. We quantify nutrient export by large rivers to coastal seas of Bangladesh, India and Pakistan, and the associated eutrophication potential in 2000 and 2050. Our new estimates for N and P inputs from human waste are one to two orders of magnitude higher than earlier model calculations. This leads to higher river export of nutrients to coastal seas, increasing the risk of coastal eutrophication potential (ICEP). The newly calculated future ICEP, for instance, Godavori river is 3 times higher than according to earlier studies. Our modeling approach is simple and transparent and can easily be applied to other data-poor basins.

Marine pollution by metals has been a major challenge for ecological systems; however, water quality criteria (WQC) for metals in saltwater is still lacking. Especially from a regulatory perspective, chronic effects of metals on marine organisms should receive more attention. A quantitative ion characteristic–activity relationships–species sensitivity distributions (QICAR-SSD) model, based on chronic toxicities for eight marine organisms, was established to predict the criteria continuous concentrations (CCCs) of 21 metals. The results showed that the chronic toxicities of various metals had good relationships with their physicochemical properties. Predicted CCCs of six metals (Hg2+, Cu2+, Pb2+, Cd2+, Ni2+ and Zn2+) were in accordance with the values recommended by the U.S. EPA, with prediction errors being less than an order of magnitude. The QICAR-SSD approach provides an alternative tool to empirical methods and can be useful for deriving scientifically defensible WQC for metals for marine organisms and conducting ecological risk assessments.

We examined prey selection and foraging behaviors of the crab Charybdis japonica exposed to four combinations of pH (7.3 and 8.1) and temperature (18°C and 25°C). The order of prey selection by C. japonica was Potamocorbula laevis, Ruditapes philippinarum, Tegillarca granosa and Mactra veneriformis. Under high pCO2, times for searching, breaking, eating and handling were all significantly longer than those at the normal pCO2, and the prey profitability and predation rate under high pCO2 were significantly lower than normal pCO2. Moreover, temperature significantly influenced the foraging behaviors, but its effects were not as strong as those of pH; times for searching, eating and handling under high temperature were significantly lower than the low temperature, and the prey predation rates under high temperature was significantly higher than low temperature. In conclusion, high pCO2 negatively affected the foraging behavior, but high temperature actively stimulated the foraging behaviors of crabs.

The levels and sources of VOCs in the atmosphere of Bursa have been investigated by measuring C2–C12 VOCs which include alkanes, alkenes, alkines, aromatics and halogenated hydrocarbons in two different campaigns. The first campaign was carried out between September 14 and November 6, 2005, and the second one between March 17 and May 10, 2006. The concentrations of 112 VOCs were detected in the collected samples. The median total concentrations of VOCs were 115 and 86 μg m−3 for the first and second campaigns, respectively. Alkanes (x− = 51.50 μg m−3) are the most abundant group in the Bursa airshed, which is followed by aromatics (x− = 49.38 μg m−3), alkenes (x− = 36.86 m-3) and halogenated compounds (x− = 13.07 μg m−3). In the present study, the VOCs showed well defined diurnal, weekday/weekend and seasonal variations. Diurnal variation of most of the measured organic compounds followed traffic rush-hours. On the other hand, some VOCs such as 1-octene, 1-nonene, 1-undecene, n-nonane, n-decane, 1,2,3-trimethylbenzene, undecane and dodecane have displayed unusual profiles that do not follow the traffic pattern during the first campaign due to asphalting operations. Moreover, the average T/B ratio obtained in the first campaign was found to be significantly higher than the second one. This relatively high difference between T/B ratios is an indication of the availability of different sources rather than the traffic. Therefore, it can be suggested that there were additional VOC sources than traffic in Bursa city center.

March 2017 marks the 50th anniversary of the SS Torrey Canyon oil spill and cleanup, off the Cornwall coast in the English Channel. It was the world's first major supertanker disaster. It was a signature event in the marine pollution field, especially related to oil spill response and the initiation of scientific studies of monitoring and researching the fate and effects of oil in the sea. This paper recalls this event, notes our growing understanding of marine pollution and global efforts for cleaner seas, and encourages further work on both oil and the many emerging environmental issues affecting the marine environment.

Exotic species invasions are serious ecological problems. Leaf construction cost (CC) and growth traits of two Sonneratia (Sonneratia caseolaris and S. apetala) and four native species (Bruguiera gymnorrhiza, Kandelia obovata, Aegiceras corniculatum and Avicennia marina) in Hainan and Shenzhen mangrove wetlands were compared to evaluate invasive potentials of Sonneratia after introduced to Shenzhen, their new habitat. There were no significant differences in CC and growth traits between two wetlands, suggesting Sonneratia did not lose any advantage in the new habitat and were competitive in both wetlands. CC per unit mass (CCM), CC per unit area (CCA) and caloric values of Sonneratia were significantly lower than those of native mangrove species while specific leaf area (SLA) was just the opposite. CCM of S. caseolaris and S. apetala were 6.1% and 11.9% lower than those of natives, respectively. These findings indicated the invasive potential of Sonneratia in Shenzhen after their introduction.

Seabirds can interact with marine litter, mainly by entanglement or ingestion. The ingestion of plastics can lead to starvation or physical damage to the digestive tract. For chicks, it could additionally lead to reduced growth, affecting survival and fledging. This study quantified the ingestion of plastics by seabird chicks via an opportunistic sampling strategy. When ringing is carried out at colonies, birds may spontaneously regurgitate their stomach contents due to the stress or as a defence mechanism. Regurgitates were collected from nestlings of three different species: Black-legged Kittiwake (Rissa tridactyla, n=38), Northern Fulmar (Fulmarus glacialis, n=14) and Great Cormorant (Phalacrocorax carbo, n=28). Plastic was present in all species, with the highest frequency of occurrence (FO) in Northern Fulmar chicks (28.6%), followed by Black-legged Kittiwakes (7.9%) and Great Cormorants (7.1%). The observed load of plastics on chicks, which have not yet left the nest, highlights the pervasive nature of plastic pollution.

This study explores how plasticity in biochemical attributes, used as indicators of health and condition, enables the coral Acropora tenuis to respond to differing water quality regimes in inshore regions of the Great Barrier Reef. Health attributes were monitored along a strong and weak water quality gradient, each with three reefs at increasing distances from a major river source. Attributes differed significantly only along the strong gradient; corals grew fastest, had the least dense skeletons, highest symbiont densities and highest lipid concentrations closest to the river mouth, where water quality was poorest. High nutrient and particulate loads were only detrimental to skeletal density, which decreased as linear extension increased, highlighting a trade-off. Our study underscores the importance of assessing multiple health attributes in coral reef monitoring. For example, autotrophic indices are poor indicators of coral health and condition, but improve when combined with attributes like lipid content and biomass.