A two dimensional numerical model has been developed to study the dispersion of a primary pollutant emitted from an urban area source in the presence of mesoscale wind. The model takes into account the transformation and removal mechanisms through chemical reaction, dry deposition and gravitational settling processes. The numerical model is solved using the Crank–Nicolson finite difference scheme under the stability dependent meteorological parameters involved in wind velocities and eddy diffusivity profiles. The urban heat island effect generates its own mesoscale winds and consequently prevents the dispersal of pollutants which will result in an increase in the concentration of pollution in the atmosphere. The analysis shows that the mesoscale wind reduces the concentration of a primary pollutant in the upwind side of centre of heat island and increases the concentration in the downwind side of centre of heat island.

Marine debris is a ubiquitous problem that poses a serious threat to the global oceans; it has motivated public participation in clean-up campaigns, as well as governmental involvement in developing mitigation strategies. While it is known that the problem of marine litter may be affected by waste management practices on land, beach survey results have seldom been compared with them. In this study, marine litter surveys on four beaches of Cijin Island were conducted to explore the effects of waste management and policy implications. Indirect evidence shows that chances for land-based litter, such as plastic bags and bottles, entering the marine environment can be greatly decreased if they can be properly reduced, reused and recycled. We suggest that mitigation measures should focus on source reduction, waste recycling and management, utilizing effective economic instruments, and pursuing a long-term public education campaign to raise the public awareness of this problem.

The need for quantitative molecular methods is growing in environmental, food, and medical fields but is hindered by low and variable DNA extraction and by co-extraction of PCR inhibitors. DNA extracts from Enterococcus faecium, seawater, and seawater spiked with E. faecium and Vibrio parahaemolyticus were tested by qPCR for target recovery and inhibition. Conventional and novel methods were tested, including Synchronous Coefficient of Drag Alteration (SCODA) and lysis and purification systems used on an automated genetic sensor (the Environmental Sample Processor, ESP). Variable qPCR target recovery and inhibition were measured, significantly affecting target quantification. An aggressive lysis method that utilized chemical, enzymatic, and mechanical disruption enhanced target recovery compared to commercial kit protocols. SCODA purification did not show marked improvement over commercial spin columns. Overall, data suggested a general need to improve sample preparation and to accurately assess and account for DNA recovery and inhibition in qPCR applications.

Knowledge of dispersal and establishment during the early stages of invasion is essential for allocating monitoring effort, detecting nascent populations and predicting spread. The scarcity of these data, however, provides little guidance for monitoring programs. Here we present data on the adult distribution and the subsequent pattern of larval recruitment from a nascent population of the invasive tunicate Ciona intestinalis in Prince Edward Island, Canada. Existing niche models indicate the entire study site is suitable for recruitment, suggesting an equal probability of detection throughout the site. In contrast, we found a heterogeneous pattern of larval recruitment, including areas of zero recruitment. By fitting a dispersal kernel, we show Ciona is not capable of naturally dispersing between bays, restricting further spread, and provide guidance for future monitoring. Our results also highlight how large-scale models, although important, lack the small-scale patterns essential for monitoring and early detection of invasive species.

Hedges are ubiquitous green elements in many European cities. The selection of hedge types characterized by different traits can be suggested for urban greening projects to decrease pollution levels. At this end, carbon dioxide (CO2) sequestration and noise attenuation capability were analyzed in the following hedge types: Laurus nobilis, Nerium oleander, Pittosporum tobira and Pyracantha coccinea, largely used as green infrastructure in Rome (Italy). Representative hedges for each species were selected from high level traffic streets in the city centre (P sites). Traffic density (TD) was monitored simultaneously with CO2 concentration and noise level (N) in each of the considered P sites. The monthly CO2 sequestration capability (MSC) was calculated multiplying the total photosynthesis per hedge by the total photosynthetic activity time (in hours) per month. The multiple regression analysis predicted noise attenuation (ΔN) by a linear combination of total leaf area (TLA), total leaf density (TLD) and leaf mass area (LMA) of the considered hedge types. All the considered species, being evergreens, were active all year long, including winter, when CO2 emissions from road transport peaked. Nevertheless, among the considered hedge types, P. tobira and L. nobilis were the most efficient species in both MSC (31.6±2.8 and 25.4±2.4 kg CO2 month–1, respectively) and ΔN (15±1%, mean value). The results give insight on the use of hedges to mitigate pollution effects. Moreover, this method can be used to monitor hedge contribution to air quality, in relation to various elements in the city (i.e. traffic density, new cars produced, application of management projects, local laws). These results might be available for projects based on the use of vegetation in order to improve environmental quality in urban areas.

A multi-nested prediction system for the Yellow Sea using drifter trajectory simulations was developed to predict the movements of an oil spill after the MV Hebei Spirit accident. The speeds of the oil spill trajectories predicted by the model without tidal forcing were substantially faster than the observations; however, predictions taking into account the tides, including both tidal cycle and subtidal periods, were satisfactorily improved. Subtidal flow in the simulation without tides was stronger than in that with tides because of reduced frictional effects. Friction induced by tidal stress decelerated the southward subtidal flows driven by northwesterly winter winds along the Korean coast of the Yellow Sea. These results strongly suggest that in order to produce accurate predictions of oil spill trajectories, simulations must include tidal effects, such as variations within a tidal cycle and advections over longer time scales in tide-dominated areas.

Four successive oil discharges were observed during the last 2years following the recording of the earthquake events. Oil slicks were clearly observed in the thermal band of the Enhanced Thematic Mapper images acquired during the discharge events. Lineaments were extracted from the ETM+ image data and SRTM (DEM). The seismic activity is conformable in time and spatially related to active major faults and structural lineaments. The concerned site was subjected to a numerous earthquakes with magnitudes ranging from 3 to 5.4Mb. Aeromagnetic field data analyses indicated the existence of deep major faults crossing the Gebel El-Zeit and the Mellaha basins (oil reservoirs). The magnetic field survey showed major distinctive fault striking NE–SW at 7000m depth. Occurrence of these faults at great depth enables the crude oil to migrate upward and appear at the surfaces as oil seeps onshore and as offshore slicks in the Gemsa–Hurghada coastal zone.

This paper quantifies the mixing and dispersion from an outboard motor by field experiments in a small subtropical waterway. Organic dye was used as a surrogate for exhaust emissions and was mixed with uncontaminated creek water before being dispersed into the creek. Dye concentrations were measured with an array of concentration probes stationed in the creek. The data were then processed and fitted with a power law function. The corresponding dispersion constants agreed well with the literature. However, the amplitude was lower than the IMO equation but higher than the correlation from laboratory tests. Results for dye concentration intermittency (presence of dye) are presented for the first time from such field measurements and show significant mixing in-homogeneity.

There has been a widespread world-wide use of flathead mullet, Mugilcephalus, in fish biomonitor studies within the coastal zone. This review summarises this research field, focusing on heavy metals, and considers the implications of the accumulated data. Differences in sampling methodology, tissues analysed and units of reported data provide challenges in assessing and benchmarking these biomonitor studies. The benthic feeding strategy of M.cephalus invariably increases exposure risk relative to middle or upper water column feeders, nevertheless contaminant accumulation via direct and indirect pathways was regulated sufficiently such that toxicants were below food guidelines in most coastal regions (32 of the 49 examined). Human health issues can arise if fish are consumed from heavily industrialised regions. Recommendations are provided for future biomonitoring studies, based on the results for M. cephalus but relevant for fish species more broadly, to provide more comparable data so that managers can benchmark against local conditions.

The fluorescence EEM technique, PARAFAC modeling, and hydrocarbon composition were used to characterize oil components and to examine the chemical evolution and degradation pathways of Macondo crude oil under controlled laboratory conditions. Three major fluorescent oil components were identified, with Ex/Em maxima at 226/328, 262/315, and 244/366nm, respectively. An average degradation half-life of ∼20d was determined for the oil components based on fluorescence EEM and hydrocarbon composition measurements, showing a dynamic chemical evolution and transformation of the oil during degradation. Dispersants appeared to change the chemical characteristics of oil, to shift the fluorescence EEM spectra, and to enhance the degradation of low-molecular-weight hydrocarbons. Photochemical degradation played a dominant role in the transformation of oil components, likely an effective degradation pathway of oil in the water column. Results from laboratory experiments should facilitate the interpretation of field-data and provide insights for understanding the fate and transport of oil components in the Gulf of Mexico.