Small-scale pollution events involve the release of potentially harmful substances into the marine environment. These events can affect all levels of the ecosystem, with damage to both fauna and flora. Numerous reporting structures are currently available to document spills, however there is a lack of information on small-scale events due to their magnitude and patchy distribution. To this end, volunteers may provide a useful tool in filling this data gap, especially for coastal environments with a high usage by members of the public. The potential for citizen scientists to record small-scale pollution events is explored using the UK as an example, with a focus on highlighting methods and issues associated with using this data source. An integrated monitoring system is proposed which combines citizen science and traditional reporting approaches.

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.

This study assessed the microplastic contamination of 3 most abundant sessile and intertidal invertebrates (Rock Oyster: Saccostrea forskalii, Striped Barnacle: Balanus amphitrite, Periwinkle: Littoraria sp.) in 3 beaches of the eastern coasts of Thailand. The results showed a significant accumulation of microplastics in the invertebrates at rates of 0.2–0.6 counts/g indicating higher pollution levels along the coastline. Filter feeding organisms showed comparatively higher accumulation rates of microplastics. Thus, contaminated bivalves pose potential health risks for seafood consumers. The plastic pollutant prevalence in sessile and intertidal communities was corresponded with pollution characteristics of contaminated beach habitats where they live. Thus, bivalves, gastropods and barnacles can be used as indicators for contamination of microplastics in the areas. This study also demonstrated the need for controlling plastic pollution in Thai coastal areas.

Estuary sediment is a major pollutant enrichment medium and is an important biological habitat. This sediment has attracted the attention of the marine environmental scientists because it is a more stable and effective medium than water for monitoring regional environmental quality conditions and trends. Based on a large amount of measurement data, we analyzed the concentrations, distribution, and sources of seven heavy metals (As, Cd, Cr, Cu, Hg, Pb, and Zn) in the surface sediment of typical estuaries that empty into the sea in eastern China: the Liaohe River Estuary, Yellow River Estuary, Yangtze River Estuary, Minjiang River Estuary, and Pearl River Estuary. The heavy metal concentrations in the sediments vary considerably from one estuary to the next. The Liaohe River Estuary sediment contains elevated levels of Cd, Hg, and Zn. The Yellow River Estuary sediment contains elevated levels of As. The sediments in the Yangtze River and Minjiang River estuaries contain elevated levels of Cd and Cu and of Pb and Zn, respectively. The sediment in the Pearl River Estuary contains elevated levels of all seven heavy metals. We used the Nemerow index method to assess the environment quality. The heavy metal pollution in the Liaohe River and Pearl River estuaries is more severe than that in the other estuaries. Additional work indicates that the heavy metal pollution in the Liaohe River and Pearl River estuaries is caused mainly by human activity.

Sources of heavy metals pollution in the Burullus Lagoon include phosphate fertilizers, sewage and oil spills from fishing boats.The benthic species identified in this lagoon are Adelosina carinata striata (Wiesner), Quinqueloculina bosciana (d'Orbigny), Quinqueloculina seminulum (Linnaeus), Ammonia tepida (Cushman), Elphidium excavatum (Terquem). A. tepida is the most dominant species in the lagoon. It constitutes more than 97% of the total benthic foraminiferal assemblages reflecting tolerance to the very low salinity in the Burullus Lagoon.The intensity of deformation was severe exhibiting a peculiar change in the coiling direction in A. tepida with increase in cadmium concentration. A. tepida exhibited a great morphological variability and the recorded morphological abnormalities show high spire giving the spiroconvex test, additional chamber, aberrant chamber shape and size, twisted tests with elongated axes of rotation and complex deformities, whereas E. excavatum showed additional calcite secretion (tumors).

This study focuses on chromium detected in 13 harbor sediments dredged across the English Channel. The total concentrations of Cr range from 5 to 61mgkg−1, which reveal no or low enrichment for 12 of the 13 samples, according the enrichment factor (EF) calculations. Sequential extraction procedure was applied to determine the mineralogical speciation of Cr, in order to assess its potential (re)mobilization to the aquatic environment. Cr is mainly associated to the residual fraction, then distributed in the oxydizable and reducible fractions. The possible relationships between the enrichment, mobility and possible biological effects (according calculation of Adverse Effect Index (AEI)) suggests possible toxicity incidence even for moderate enrichment. A link is observed with the oxydizable fraction (r=0.8 and r=0.5 respectively for EF and AEI).

Sediment was sampled in the vicinity of a long-term source of Polycyclic Aromatic Hydrocarbons (PAHs) to evaluate whether tolerance can be induced in situ. Total PAH concentrations as well as the bioavailable PAHs were measured, and for nine PAHs the pore water concentration could be calculated. An induced tolerance in the ammonium oxidizing community was detected at the site with highest PAH concentration and tolerance was strongest, although not significantly, correlated to bioavailable alkylated PAHs. In addition, the tolerant microbial community showed a significant lower baseline capability for nitrification with an on average 35% reduction compared to the other sites. Meiofaunal community structure differed between all sites, and the difference was significantly correlated to bioavailable alkylated PAHs and PAH31 concentrations. The results suggest that in order to judge magnitude of long-term effects, the bioavailable fraction is to be preferred, and when possible as estimation of the freely dissolved concentration.

Industrial areas on estuarine systems are commonly affected by heavy metals, affecting all local biota. Random Amplified Polymorphic DNA (RAPD) was used to evaluate genetic diversity of Ucides cordatus at mangroves in southeastern Brazil (Juréia, J; São Vicente, SV; and Cubatão, C), with distinct pollution levels by metals. The genetic diversity of this species was compared with concentrations of metals (Cd, Pb, Cu, Cr and Hg) in the environment. A pollution gradient was confirmed (SV>C>J), with low levels detected in water, except for mercury in SV. All metals in the sediment samples were below Threshold Effect Level (TEL), without an apparent biological risk to the biota. Genetic distance was very similar between J and C, with SV occurring as an out-group. RAPD was a powerful tool to investigate the effect of metal pollution on genetic diversity of this mangrove crab, and to evaluate the conservation status of the mangrove ecosystem.

Metal concentrations (Al, Cr, Ni, Cu, Zn, and Pb), grain size, and total organic carbon content in 29 surface sediment samples from the nearshore area off Calicut were analyzed to determine their distribution and pollution status. Surface sediments were dominantly silts with low percentage of clay and sand at nearshore and offshore areas. The mean metal concentrations were in the following order: Cr>Ni>Zn>Pb>Cu. The enrichment factor and geo-accumulation index of metals suggest that the surface sediments were not polluted by Zn and moderately polluted by Cu and Ni. By contrast, Cr and Pb showed significant enrichment levels. Results from a multivariate statistical analysis suggested that the spatial enrichment of these heavy metals was related to sediment type. Thus, the sediment distribution and their metal enrichment were mainly controlled by local hydrodynamic conditions that caused the winnowing of fine-grained sediments.

The Arctic is considered a pristine environment, where pollution mainly originates from global sources. The present study examines particle number concentrations (PNCs) and the main sources of airborne ultrafine particles (UFPs, d < 100 nm) in the town Sisimiut and two nearby settlements, Sarfannguit and Itilleq, in West Greenland. Measurements were carried out during three weeks in April and May 2016. Air temperatures during the measurements ranged from −4.4 to +8.7 °C. A portable condensation particle counter (P-Trak) was used for the measurements. Results showed that the lowest concentrations were found during days with high wind speeds, with the lowest PNC average of 72 ± 11 cm−3 (n = 9) (12 m/s). Background concentrations were usually low compared to more densely populated countries, with a couple of exceptions, where there was no clear cause for elevated PNCs in a background area East of Sisimiut. Measured PNCs in the flue gas in the waste incineration plant in Sisimiut showed up to 334,976 cm−3 and are expected to be higher in the gas after it is released through the chimney. Average PNCs up to 77,009 ± 43,880 cm−3 (n = 26) were measured by a road located by the harbor in Sisimiut, while subsequent measurements at the same location showed much lower PNCs. The presence of heavy machinery elevated PNCs highly during two measurement events, giving PNCs up to 270,993 cm−3 but dropping to 1180 cm−3 10 min later, after the vehicle had passed by. A measurement event in Sisimiut Airport while an aircraft landed and departed showed an average PNC of 44,741 ± 85,094 cm−3 (n = 21). Two 24-h measurements resulted in average PNCs of 2960 ± 5704 cm−3 and 3935 ± 10,016 cm−3 respectively.