Reconstructing the history of metal deposition in Singapore lake sediments contributes to understanding the anthropogenic and natural metal deposition in the data-sparse Southeast Asia. To this end, we present a sedimentary record of Pb, Pb isotopes and eleven other metals (Ag, As, Ba, Cd, Co, Cr, Cu, Ni, Tl, U and Zn) from a well-dated sediment core collected near the depocenter of MacRitchie Reservoir in central Singapore. Before the 1900s, the sedimentary Pb concentration was less than 2 mg/kg for both soil and sediment, with a corresponding 206Pb/207Pb of ∼1.20. The Pb concentration increased to 55 mg/kg in the 1990s, and correspondingly the 206Pb/207Pb decreased to less than 1.14. The 206Pb/207Pb in the core top sediment is concordant with the 206Pb/207Pb signal of aerosols in Singapore and other Southeast Asian cities, suggesting that Pb in the reservoir sediment was mainly from atmospheric deposition. Using the Pb concentration in the topmost layer of sediment, the estimated atmospheric Pb flux in Singapore today is ∼1.6 × 10−2 g/m2 yr. The concentrations of eleven other metals preserved in the sediment were also determined. A principal component analysis showed that most of the metals exhibit an increasing trend towards 1990s with a local concentration peak in the mid-20th century.

The distribution, inventory, and potential risk of organochlorine pesticides (OCPs), including Hexachlorocyclohexanes (HCHs) and Dichlorodiphenyltrichloroethanes (DDTs), and their correlation with soil properties and anthropogenic factors were investigated in soils of the Campanian Plain. The total concentrations of HCHs and DDTs ranged from 0.03 to 17.3 ng/g (geometric mean: GM = 0.05 ng/g), and 0.08–1231 ng/g (GM = 14.4 ng/g), respectively. In general, the concentration of OCPs in farmland and orchards was higher than on land used for non-agricultural purposes. There are significant differences in the concentration of OCPs in the soils across the region, more specifically, the Acerra-Marigliano conurbation (AMC) and Sarno River Basin (SRB) are recognized as severely OCP-contaminated areas. The recent application of technical HCHs and DDTs in large quantities appears unlikely in light of the ratio of α-HCH/β-HCH and p,p′-DDT/p,p′-DDE, and the prohibition of the use of these chemicals in Italy nearly forty years ago. The clear correlation between the concentration of DDTs and organic carbon suggests a typical secondary distribution pattern. The mass inventory of OCPs in soils of the Campanian Plain is estimated to have a GM of 17.3 metric tons. There is no clear evidence linking the impact of geographical distribution of OCPs on the incidence of cancer, and the 95% confidence interval of total incremental lifetime cancer risk (TILCR) data falls below the internationally accepted benchmark value of 1 × 10−5.

Air samples were collected during the cold and the warm period of the year 2012 and 2013 at three sites in the major Thessaloniki area, northern Greece (urban-industrial, urban-traffic and urban-background) in order to evaluate the occurrence, profiles, seasonal variation and gas/particle partitioning of polybrominated diphenyl ethers (PBDEs). The mean total concentrations of particle phase ∑12PBDE in the cold season were 28.7, 19.5 and 3.87 pg m−3 at the industrial, urban-traffic and urban-background site, respectively, dropping slightly in the warm season (23.7, 17.5 and 3.14 pg m−3), respectively. The corresponding levels of gas-phase ∑12PBDE were 14.4, 7.15 and 4.73 pg m−3 in the cold season and 21.2, 11.1 and 6.27 pg m−3 in the warm season, respectively. In all samples, BDE-47 and BDE-99 were the dominant congeners. Absorption of PBDEs in the organic matter of particles appeared to drive their gas/particle partitioning, particularly in the cold season. The estimated average outdoor workday inhalation exposure to ∑12PBDE in the cold and the warm period followed the order: industrial site (288 and 299 pg day−1) > urban-traffic site (178 and 191 pg day−1) > urban-background site (58 and 63 pg day−1). The exposures to BDE-47, BDE-99, BDE-153 and ∑3PBDE via inhalation, for children outdoor worker and seniors were several orders of magnitude lower than their corresponding oral RfD values.

Uptake of Cry toxins by insect natural enemies has rarely been considered and bioaccumulation has not yet been demonstrated. Uptake can be demonstrated by the continued presence of Cry toxin after exposure has stopped and gut contents eliminated. Bioaccumulation can be demonstrated by showing uptake and that the concentration of Cry toxin in the natural enemy exceeds that in its food. We exposed larvae of the aphidophagous predator, Harmonia axyridis, to Cry1Ac and Cry1F through uniform and constant tritrophic exposure via an aphid, Myzus persicae, and looked for toxin presence in the pupae. We repeated the experiment using only Cry1F and tested newly emerged adults. Both Cry toxins were detected in pupae, and Cry1F was detected in recently emerged, unfed adults. Cry1Ac was present 2.05 times and Cry1F 3.09 times higher in predator pupae than in the aphid prey. Uptake and bioaccumulation in the third trophic level might increase the persistence of Cry toxins in the food web and mediate new exposure routes to natural enemies.

Air pollution by particulate matter is a serious problem in Beijing. Strict pollution control measures have been carried out in Beijing prior to and during the 2015 China Victory Day Parade in order to improve air quality. This distinct event provides an excellent opportunity for investigating the impact of such measures on the chemical properties of particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5). The water-soluble ions as well as sulfur and oxygen isotopes of sulfate in PM2.5 collected between August 19 and September 18, 2015 (n = 31) were analyzed in order to trace the sources and formation processes of PM2.5 in Beijing. The results exhibit a decrease in concentration of water-soluble ions in PM2.5 including aerosol sulfate. In contrast, the mean values of δ34Ssulfate (4.7 ± 0.8‰ vs. 5.0 ± 2.0‰) and δ18Osulfate (18.3 ± 2.3‰ vs. 17.2 ± 6.0) in PM2.5 during the air pollution control period and the non-source control period exhibit no significant differences, which suggests that despite a reduction in concentration, the sulfate source remains identical for the two periods. It is inferred that the decrease in concentration of sulfate in PM2.5 mainly results from variations in air mass transport. Notably, the air mass during the pollution control period originated mainly from north and northeast and changed to southerly directions thereafter. The sulfur and oxygen isotopes of the sulfate point to coal combustion as the major source of sulfate in PM2.5 from the Beijing area.

Trace organic contaminants such as pharmaceuticals, personal care products and industrial chemicals are frequently detected in the urban water cycle, including wastewater, surface water and groundwater, as well as drinking water. These also include human metabolites (HMs), which are formed in the human body and then excreted via urine or feces, as well as transformation products (TPs) formed in engineered treatment systems and the aquatic environment. In the current study, the occurrence of HMs as well as their TPs of the anticonvulsants carbamazepine (CBZ) and oxcarbazepine (OXC) were investigated using LC tandem MS in effluents of wastewater treatment plants (WWTPs), surface water and groundwater. Highest concentrations were observed in raw wastewater for 10,11-dihydro-10,11-dihydroxycarbamazepine (DiOHCBZ), 10,11-dihydro-10-hydroxy-cabamazepine (10OHCBZ) and CBZ with concentrations ranging up to 2.7 ± 0.4, 1.7 ± 0.2 and 1.07 ± 0.06 μg L−1, respectively. Predictions of different toxicity endpoints using a Distributed Structure-Searchable Toxicity (DSSTox) expert system query indicated that several HMs and TPs, in particular 9-carboxy-acridine (9-CA-ADIN) and acridone (ADON), may exhibit an increased genotoxicity compared to the parent compound CBZ. As 9-CA-ADIN was also detected in groundwater, a detailed investigation of the genotoxicity of 9-CA-ADIN is warranted. Investigations of an advanced wastewater treatment plant further revealed that the discharge of the investigated compounds into the aquatic environment could be substantially reduced by ozonation followed by granular activated carbon (GAC) filtration.

Seabirds are ideal model organisms to track mercury (Hg) through marine food webs as they are long-lived, broadly distributed, and are susceptible to biomagnification due to foraging at relatively high trophic levels. However, using these species as biomonitors requires a solid understanding of the degree of species, sexual and age-specific variation in foraging behaviors which act to mediate their dietary exposure to Hg. We combined stomach content analysis along with Hg and stable isotope analyses of blood, feathers and common prey items to help explain inter and intra-specific patterns of dietary Hg exposure across three sympatric Pygoscelis penguin species commonly used as biomonitors of Hg availability in the Antarctic marine ecosystem. We found that penguin tissue Hg concentrations differed across species, between adults and juveniles, but not between sexes. While all three penguins species diets were dominated by Antarctic krill (Euphausia superba) and to a lesser extent fish, stable isotope based proxies of relative trophic level and krill consumption could not by itself sufficiently explain the observed patterns of inter and intra-specific variation in Hg. However, integrating isotopic approaches with stomach content analysis allowed us to identify the relatively higher risk of Hg exposure for penguins foraging on mesopelagic prey relative to congeners targeting epipelagic or benthic prey species. When possible, future seabird biomonitoring studies should seek to combine isotopic approaches with other, independent measures of foraging behavior to better account for the confounding effects of inter and intra-specific variation on dietary Hg exposure.

The roles of protein and lipid in the accumulation and distribution of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in seven species of plants from biosolids-amended soils were investigated. The PFOS and PFOA root concentration factors (Croot/Csoil) ranged from 1.37 to 4.68 and 1.69 to 10.3 (ng/groot)/(ng/gsoil), respectively, while the translocation factors (Cshoot/Croot) ranged from 0.055 to 0.16 and 0.093 to 1.8 (ng/gshoot)/(ng/groot), respectively. The PFOS and PFOA accumulations in roots correlated positively with root protein contents (P < 0.05), while negatively with root lipid contents (P < 0.05). These suggested the promotion effects of protein and inhibition effects of lipid on root uptake. The translocation factors correlated positively with the ratios between protein contents in shoots to those in roots (P < 0.05), showing the importance of protein on PFOS and PFOA translocation. This study is the first to reveal the different roles of protein and lipid in the accumulation and distribution of PFOS and PFOA in plants.

Copper (Cu) is an essential yet potentially toxic metal, thus delicate homeostatic controls are developed in the fish. In this study, a physiologically based pharmacokinetic (PBPK) model was developed to simulate the homeostatic regulation of Cu in a marine fish (Terapon jarbua) under dietary and waterborne exposures. In this model, fish were schematized as a six-compartment model, with the intestine being divided into two sub-compartments (chyme and gut wall). The blood was assumed to be the “carrier” distributing Cu into different compartments. The transfer rates between different compartments were determined in fish during Cu exposure (20 d) and depuration (20 d). The differences in Cu transfer from chyme to gut wall between dietary and waterborne treatments suggested that the intestine regulated the dietary uptake and re-absorption of Cu from the chyme. The extremely low uptake rate constant (0.0013 d−1) for gills under waterborne exposure indicated that gills strongly restricted Cu uptake from the ambient water. For both treatments, the liver had considerable input rate through the enterohepatic circulation and comparably high exchange rate with the blood, suggesting that the liver can efficiently accumulate newly absorbed Cu. The differences in Cu output from the liver between dietary and waterborne treatments suggested that it can effectively regulate the redistribution of Cu. All of these observations demonstrated that the liver played the central role in Cu homeostasis by serving as the main depository and distributing center. Modeling results also indicated that renal and branchial excretion was of minor importance, whereas biliary excretion combined with defecation played the most important role in whole-body Cu elimination in marine fish. The effective regulation by the “Blood-Liver-Intestine” cycle could be the main reason for the relatively low levels of Cu in fish.

Scale generated from the maintenance of equipment contaminated by naturally occurring radioactive materials may contain also chemical components that cause hazardous pollution to human health and the environment. This study spotlights the characterisation of chemical pollutants in scales in relation to home-made comparison samples as no reference material for such waste exists. Analysis by energy dispersive x-ray fluorescence, with accuracy and precision better than 90%, revealed that barium was the most abundant element in scale samples, ranging from 1.4 to 38.2%. The concentrations of the toxic elements such as lead and chromium were as high as 2.5 and 1.2% respectively. Statistically, high correlation was observed between the concentration of Ba and Sr, sample density, radionuclide contents (210Pb and 226Ra) and self-attenuation factor used for the radio-measurements. However, iron showed a reverse correlation. Interpretation of data with regards to the mineralogical components indicated that 226Ra and 210Pb co-precipitated with the insoluble salt Ba0.75Sr0.25SO4. Since both Ba and Sr have high Z, samples of high density (ρ) were accompanied with high values of self-attenuation correction factors (Cf) for the emitted radiation; correlation matrix of Pearson reached 0.935 between ρ and Cf. An attempt to eliminate the effect of the elemental composition and improve gamma measurements of 210Pb activity concentration in scale samples was made, which showed no correction for self-attenuation was needed when sample densities were in the range 1.0–1.4 g cm−3. For denser samples, a mathematical model was developed. Accurate determinations of radionuclide and chemical contents of scale would facilitate future Environmental Impact Assessment for the petroleum industry.