Dichlorodiphenyltrichloroethane (DDT) was heavily used in the past in many regions of the world. The occurrence of DDTs in island populations may be elevated if the island is adjacent to major DDT consumption estuaries, such as the Yangtze River Delta. In this study, colostrum samples were collected from maternal-neonate pairs (n = 106) from the Shengsi Island, located directly downstream from the Yangtze River outlet. DDT isomers and enantiomer compositions were analyzed by gas chromatography equipped with mass spectrometer (GC/MS) and GC/MS-MS. The average levels of p,p’-DDE, o,p’-DDD, p,p’-DDD, o,p’-DDT, p,p’-DDT and total DDTs were 1.32, 0.03, 0.09, 0.08, 0.48, and 1.93 μg g⁻¹ lipid weight, respectively. Maternal age and pregnancy body mass index (BMI) were positively associated with levels of DDTs (p < 0.05). High (DDE+DDD)/DDT and p,p′-DDE/p,p′-DDT ratios suggested that current DDT residues originated primarily from historical use of DDT products, but new sources may also contribute partially to some high o,p′-DDT/p,p′-DDT ratios. Enantiomeric enrichment was found for the (−)-enantiomer of o,p’-DDD and the (+)-enantiomer of o,p’-DDT, suggesting stereoselective attenuation. Based on breast milk consumption, the average daily intake of DDTs by neonates was 8.33 ± 7.34 μg kg⁻¹bw per day, which exceeded the WHO's tolerable daily intake guideline of 0.01 mg kg⁻¹ bw per day by 25%, implying some neonates in the Yangtze River region are potentially at high risk from exposure to DDTs.

Chlorothalonil is a broad spectrum fungicide with high annual production and environmental contamination. Despite its high consumption, studies regarding the potential ecological risks of chlorothalonil, especially its metabolites, to aquatic organisms are still limited. In this study, we selected the zebrafish (Danio rerio) as the in vivo model and first identified the metabolite (4-hydroxychlorothalonil) of chlorothalonil in zebrafish by tandem quadrupole/orthogonal-acceleration time-of-flight (Q-TOF). Then, the in vivo and in vitro models were applied to comprehensively estimate the embryo toxicity and potential endocrine effect of chlorothalonil and 4-hydroxychlorothalonil. The data from zebrafish embryo toxicity showed that the lowest observed effect concentrations of both chlorothalonil and 4-hydroxychlorothalonil were 50 μg/L after 96 h of exposure. The mortality rate of the 4-hydroxychlorothalonil was 2.6-fold higher than that of the parent compound at the concentration of 50 μg/L. Dual-luciferase reporter gene assays indicated that both chlorothalonil and 4-hydroxychlorothalonil exerted estrogen receptor α (ERα) agonist activity with REC20 values of 2.4 × 10−8 M and 3.6 × 10−8 M, respectively. However, only 4-hydroxychlorothalonil exhibited both thyroid receptor β (TRβ) agonistic and antagonistic activities. Lastly, we employed molecular docking to predict the binding affinity of chlorothalonil and 4-hydroxychlorothalonil with ERα or TRβ. The results revealed that the potential endocrine effect of chlorothalonil and 4-hydroxychlorothaloni might be attributed to the different binding affinities with the receptors. In conclusion, our studies revealed that 4-hydroxychlorothalonil exhibited potent endocrine-disrupting effects compared to its parent compound, chlorothalonil. The results provided here remind us that the assessment of the potential ecological and health risks of the metabolites of fungicides in addition to their parent compounds should arouse great concerns.

Yellow perch (Perca flavescens) collected from 11 lakes in the Canadian mining regions of Sudbury (Ontario) and Rouyn-Noranda (Quebec) display wide ranges in the concentrations of cadmium (Cd), nickel (Ni), selenium (Se), and thallium (Tl) in their livers. To determine if these trace elements, as well as copper (Cu) and zinc (Zn), are causing oxidative stress in these fish, we measured three biochemical indicators (glutathione (GSH), glutathione disulfide (GSSG) and thiobarbituric acid-reactive substances (TBARS)) in their livers. We observed that 44% of the yellow perch that we collected were at risk of cellular oxidative stress and lipid peroxidation. Considering all fish from all lakes, higher liver Se concentrations were coincident with both lower proportions of GSSG compared to GSH and lower concentrations of TBARS, suggesting that the essential trace-element Se acts as an antioxidant. Furthermore, fish suffering oxidative stress had higher proportions of Cd, Cu and Zn in potentially sensitive subcellular fractions (organelles and heat-denatured proteins) than did fish not suffering from stress. This result suggests that reactive oxygen species may oxidize metal-binding proteins and thereby reduce the capacity of fish to safely bind trace metals. High Cd concentrations in metal-sensitive subcellular fractions likely further exacerbate the negative effects of lower Se exposure.

The effect of fireworks on the aerosol number characteristics of atmosphere was studied for an urban mega city. Measurements were made at 50 m height to assess the local changes around the festival days. Apart from the increase in total number concentration and characteristic accumulation mode, short-term increase of ultrafine particle concentration was noted. Total number concentration varies an order of magnitude during the measurement period in which peak occurs at a frequency of approximately one per day. On integral scale, it seems not possible to distinguish an episodic (e.g. firework bursting induced aerosol emission) and a normal (ambient atmospheric changes) event. However these events could be differentiated on the basis of size evolution analysis around number concentration peaks. The results are discussed relative to past studies and inferences are drawn towards aerosol signatures of firework bursting. The short-term burst in ultrafine particle concentration can pose an inhalation hazard.

The effects of mariculture on mercury (Hg) contamination and speciation in water, sediment and cultured fish in a typical mariculture zone located in Xiangshan bay, Zhejiang province, east China, were studied. Water, sediment and fish samples were collected from mariculture sites (MS) and from corresponding reference sites (RS) 2500 m away from the MS. The THg concentration in overlying water in Xiangshan bay reached as high as 16.6 ± 19.5 ng L−1, indicating that anthropogenic sources in this bay may contribution on Hg contamination in overlying water. Mariculture activities resulted in an increase in THg concentration in water from surface and bottom layers, which may be attributed to the discharge of domestic sewage and the accumulation of unconsumed fish feed and fish excreta in the benthic environment. Methylmercury (MeHg) concentrations in the bottom layer of overlying water and top surface layer of porewater underneath MS were higher than at RS, implying that mariculture activities promote Hg methylation in the interface between sediments and water. In addition, the concentrations of MeHg in sediment and porewater were significantly higher in summer than winter. It was observed that THg and MeHg contents in the muscle of blackhead seabream (Acanthopagrus schlegelii) (fed by the trash fish) were significantly higher (p < 0.001) than those in red snapper (Lutjanus campechanus) or perch (Perca fluviatilis) (fed by pellet fish feed). The THg and MeHg concentrations in the fish meat were closely related to the feeding mode, which indicate that fish feed rather than environmental media is the major pathway for Hg accumulation in fish muscle.

Several pollutants, which include metals, are present in the Antarctic atmosphere, snow, marine and terrestrial organisms. This work reports the elements incorporated by Usnea sp thalli in Potter Peninsula, 25 de Mayo (King George) Island, South Shetlands, Antarctica. Geological origin was analyzed as possible sources of elements. For this purpose, correlations were done using a geochemical tracer, principal component analysis and enrichment factors were computed. Lithophile elements from particulate matter were present in most of the sampling sites. Bromine, Se and Hg showed the highest enrichment factors suggesting other sources than the particulate matter. Mercury values found in Usnea sp were in the same range as those reported for Deception Island (South Shetlands) and remote areas from the Patagonia Andes.

Urbanizations have increased the loadings of reactive nitrogen in urban riverine environments. However, limited information about dissimilatory nitrate reduction processes and associated contributions to nitrogen removal is available for urban riverine environments. In this study, sediment slurry experiments were conducted with nitrogen isotope-tracing technique to investigate the potential rates of denitrification, anaerobic ammonium oxidation (anammox) and dissimilatory nitrate reduction to ammonium (DNRA) and their contributions to nitrate reduction in sediments of urban river networks, Shanghai. The potential rates of denitrification, anammox and DNRA measured in the study area ranged from 0.193 to 98.7 nmol N g−1 h−1 dry weight (dw), 0.0387–23.7 nmol N g−1 h−1 dw and 0–10.3 nmol N g−1 h−1 dw, respectively. Denitrification and DNRA rates were higher in summer than in winter, while anammox rates were greater in winter than in summer for most sites. Dissolved oxygen, total organic carbon, nitrate, ammonium, sulfide, Fe(II) and Fe(III) were found to have significant influence on these nitrate reduction processes. Denitrification contributed 11.5–99.5%% to total nitrate reduction, as compared to 0.343–81.6% for anammox and 0–52.3% for DNRA. It is estimated that nitrogen loss of approximately 1.33 × 105 t N year−1 was linked to both denitrification and anammox processes, which accounted for about 20.1% of total inorganic nitrogen transported annually into the urban river networks of Shanghai. Overall, these results show the potential importance of denitrification and anammox in nitrogen removal and provide new insight into the mechanisms of nitrogen cycles in urban riverine environments.

The aim of this study was to assess the genotoxic effects of starvation and dimethoate (organophosphate insecticide) in female and male wolf spiders Xerolycosa nemoralis (Lycosidae) exposed to the stressors under laboratory conditions. DNA damage was measured in haemocytes and midgut gland cells using the comet assay. In response to the two stressing factors, both cell types showed %TDNA, tail length (TL) and OTM values higher in males than in females. Level of DNA damage in haemocytes was greater than in midgut gland cells. In both sexes, the strongest genotoxicity was recorded at single application of dimethoate. After five-time exposure to the pesticide, genotoxic effects of a single dose were sustained in males and reduced to the control level in females. Starvation stress was well tolerated by the females, in which neither cell type was affected by DNA damage. However, in male haemocytes food deprivation induced severe DNA damage, what suggests suppression of the defence potential at prolonged starvation periods.

Production of bisphenol A (BPA) analogues such as bisphenol F (BPF) and bisphenol AF (BPAF) has recently increased, due to clear evidence of adverse effects of BPA on humans and wildlife. Bisphenols (BPs) have already been released into aquatic environment without previous available information about potential adverse effects of BPs and their potential risk to aquatic ecosystems. In this study, lethal and sublethal effects of BPF and BPAF to bacteria, algae, crustacea and fish embryos were investigated and the results were compared to the adverse effects obtained for BPA. We found that BPAF was the most toxic compound to Daphnia magna, Danio rerio and Desmodesmus subspicatus; the lowest 72 h EC50 (median effective concentration) and 21 d NOEC (no observed effect concentration) values were determined at 2.2 mg/L regarding zebrafish hatching success and 0.23 mg/L of BPAF obtained for growth and reproduction of water fleas, respectively. In most cases, BPA was more toxic to D. magna, D. rerio and D. subspicatus in comparison to BPF, but pigmentation of zebrafish embryos after 48 h of exposure and reproduction of water fleas after 21-day D. magna reproductive test exposure to BPF were much more impaired. Risk quotients (measured environmental concentration/21 d NOEC) showed that BPA, BPF and BPAF are recently not chronically hazardous to the survival, reproduction and growth of water fleas in surface waters. On the other hand, we importantly show that currently present BPAF concentrations in surface waters could cause a potential ecological risk to aquatic organisms. In the near future, higher concentrations of BPF and BPAF in surface waters are anticipated and for this reason further testing using test systems with various aquatic species and endpoints are needed to provide additional information about toxic impacts of BPF and BPAF on aquatic biota.

Both occupational and environmental exposure to asbestos-mineral fibres can be associated with lung diseases. The pathogenic effects are related to the dimension, biopersistence and chemical composition of the fibres. In addition to the major mineral elements, mineral fibres contain trace elements and their content may play a role in fibre toxicity. To shed light on the role of trace elements in asbestos carcinogenesis, knowledge on their concentration in asbestos-mineral fibres is mandatory. It is possible that trace elements play a synergetic factor in the pathogenesis of diseases caused by the inhalation of mineral fibres. In this paper, the concentration levels of trace elements from three chrysotile samples, four amphibole asbestos samples (UICC amosite, UICC anthophyllite, UICC crocidolite and tremolite) and fibrous erionite from Jersey, Nevada (USA) were determined using inductively coupled plasma mass spectrometry (ICP-MS). For all samples, the following trace elements were measured: Li, Be, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Sb, Cs, Ba, La, Pb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, U. Their distribution in the various mineral species is thoroughly discussed.The obtained results indicate that the amount of trace metals such as Mn, Cr, Co, Ni, Cu and Zn is higher in anthophyllite and chrysotile samples, whereas the amount of rare earth elements (REE) is higher in erionite and tremolite samples. The results of this work can be useful to the pathologists and biochemists who use asbestos minerals and fibrous erionite in-vitro studies as positive cyto- and geno-toxic standard references.