We quantified the amount of plastic found in food loads delivered to nestlings in Cassin's Auklet (Ptychoramphus aleuticus), a small, zooplanktivorous seabird, on Triangle Island, British Columbia, in 1996–2016. The density of plastic in surrounding waters is moderately high, yet few food loads contained any plastic (3 of 850), and none more than two pieces. That result accords well with previous observations on the other four North Pacific auklets (Aethia spp.), leading us to conclude that true auklets rarely transfer plastic to nestlings. However, many hatch-year Cassin's Auklets found dead in coastal British Columbia, Washington and Oregon during the mass mortality event of fall and winter 2014–15 had plastic in their ventriculi. We suggest that these plastic particles would have been obtained at sea after fledging, perhaps while the birds transited south through a region of high plastic density off the west coast of Vancouver Island, Washington and Oregon.

Heavy metals are a hazard to marine fauna and human health. In this study we assess stable isotopes and metal content in Prionace glauca and Isurus oxyrinchus and analyse these results within and among other species and across regions and geographical areas. Also, we evaluate their suitability, together with Raja clavata and Galeorhinus galeus, as Mid-Atlantic bioindicators. Prionace glauca and I. oxyrinchus shared the same trophic level in a pelagic food web and did not present significant differences between genders or metals, except for As. Arsenic and Hg accumulated while Cd and Pb were not detected. One I. oxyrinchus presented Hg values above regulatory limits. A high Hg exposure was associated with I. oxyrinchus since its maximum weekly intake was exceeded. Elasmobranchs can be used as metal sentinels, each presenting different key features which defines a good marine bioindicator, allowing long-term monitoring at different temporal and spatial scales.

The 2010 Deepwater Horizon (DWH) oil spill in the northern Gulf of Mexico (NGOM) resulted in over 780million liters of crude oil spilling into Gulf waters. In an effort to disperse the oil, nearly 7.6million liters of dispersant was applied. Many commercially and recreationally important species reside in or near the area of the spill. The blue crab, Callinectes sapidus, is common in the NGOM and is both economically and ecologically important in this region. In this study, after exposing juvenile blue crabs to oil or a mixture of oil and dispersant we tested for relative expression of heat shock protein 90 (hsp90) and vitellogenin (vtg) by measuring their corresponding mRNA expression. We also monitored crabs over two molts to test for effects on growth. Expression of hsp90 was significantly downregulated, and we did not detect any effects of exposure to oil or oil/dispersant mixture on growth or vtg expression.

The study aimed at investigating factors influencing the recovery of the canopy seaweed Cystoseira brachycarpa. A manipulative experiment was done to test if in barren patches the recovery of Cystoseira I) is enhanced by the removal of the urchins, II) is prevented by eutrophication, III) depends on the time of patch clearance and IV) decreases with the distance from Cystoseira bed edge within the barren patch. The effects of the same factors on the structure of the macroalgal assemblage were also tested. Cystoseira recovered abundantly only in clearings where nutrients were not added and urchins were removed. Furthermore, Cystoseira recovered irrespectively of the time the patches were cleared and the distance from the canopy edge. This study showed that the lack of sea urchins at oligotrophic conditions was essential for Cystoseira brachycarpa recruitment, providing evidence that interacting constraints are involved in the recovery of Cystoseira beds.

To characterize the spatiotemporal distribution and potential ecological risk for trihalomethanes (THMs) in the surface water of a river estuary, surface water samples were collected over five consecutive months (from March to July 2016) from four sites in the Haihe River estuary of Bohai Bay. The potential ecological risks of THMs were evaluated quantitatively based on a species sensitivity distribution (SSD) model. The results demonstrate that trichloromethane (TCM) was the predominant THM in surface water of the Haihe River estuary (2.93±1.98μg/L) followed by tribromomethane (TBM) (0.42±0.33μg/L), bromodichloromethane (BDCM) (0.14±0.06μg/L) and dibromochloromethane (DBCM) (0.09±0.10μg/L). The concentration of TCM was higher in summer than that in spring, while TBM displayed the opposite trend. The TCM concentration decreased from the estuary to the adjacent sea. However, the levels of TBM and DBCM in the adjacent sea were higher than those in the estuary. The ecological risks of THMs in surface water of Haihe River were notably low, and the ecological risks of THMs in freshwater were generally higher than those in seawater. Compared with other contaminants in water and surface sediment from rivers and coastal areas, the ecological risk levels of THMs in surface water can be considered low. This study is a contribution to the progress of ecological risk assessment of THMs.

We reveal a dose–response relationship for bioaccumulation of Zn, Cu and Cr in shrimp Litopenaeus schmitti from Sepetiba Bay, Rio de Janeiro, Brazil. Our model estimates the current risk (AD50 was 70% of the legal limit) and the daily metal uptake rate for each metal. It can also evaluate the relative reliability of predictions for tissue concentrations reaching the legal limits for human consumption (approximately 1year) and predictions related to asymptotic length, arising from (i) direct regression of the metal concentration (MeC) versus total length (TL) and age (duration of exposure), and (ii) correlation of the incorporation rate (IR=MeC/TL) with age. Metal incorporation rates (IR), i.e. a kinetic proxy for absorption during growth up to attainment of asymptotic length, decrease with age, reflecting a slow-down in metal absorption. This pattern mitigates the high initial concentrations observed for juveniles.

Surface sediments (n=17) were collected from 6 sites located in the coasts of the Bushehr Peninsula. ∑16PAH concentrations were in the range of 285.9–1288ngg−1 dw and the sediments were moderately polluted. Py, Ph, B(a)A and Flu showed >70% of the detected values in order of the mentioned rank. 4-ring PAHs were the dominant compounds and the molecular ratios presented the dominant pyrolytic source. The toxicity of PAHs for sediment dwelling life was averagely equivalent to occurrence of 0.08ngg−1 of Dioxin in dw of the examined sediments. The evaluated narcotic potential (confidence level of 99%) was 0.027–3.04 and upper part of the Bushehr Peninsula, where the human population is more concentrated, showed more narcotic potential. ∑n-alkane concentrations (n-C15−n-C32) were in the range of 3.10–35.6μgg−1 dw. The dominant distribution of even carbon number n-alkanes was traced back to a possibly autochthonous source.

This paper uses ARIMA models for daily temporal analysis of the effect of land surface coverage (LSC) on PM10 concentrations in a high-altitude megacity. Bogota, the capital of Colombia, is the urban center with the greatest population density and third-highest air pollution levels in Latin America. Six automatic monitoring stations were used; they were equipped with measurement instruments for PM10, temperature and solar radiation as well as wind speed and wind direction. The duration of the sampling period was 6 years. The hourly PM10 sampling system included continuous-monitoring equipment that used beta ray attenuation. We analyzed atmospheric stability and the spatial distribution of LSC (vegetated, non-vegetated, impervious and water bodies) before applying the iterative process of Box-Jenkins for ARIMA models. ARIMA analysis indicates greater persistence in PM10 pollution in the presence of increased vegetated LSC (trees and grasslands); persistence decreased in the presence of more impervious LSC (roofs, pavements and footpaths). PM10 persistence is found to be 2 days (48 h). The best distance to demonstrate these findings is between 50 and 100 m, with respect to the monitoring stations' physical location. Urban areas with a predominance of vegetated LSC register lower PM10 concentrations than urban areas with a predominance of impervious LSC (average daily difference = 42.7%). This study's findings serve as a reference point for the development of differentiated strategies for air pollution control in line with urban LSC.