Little is known about the bioaccumulation behavior of polybrominated diphenyl ethers (PBDEs) and other halogenated flame retardants (HFRs) in plants and in herbivores. In the present study, PBDEs and several alternative HFRs (AHFRs) were examined in a small herbivorous food chain (paddy soils–rice plant–apple snails) from an electronic waste recycling site in South China. Mean concentrations of total PBDEs were 40.5, 1.81, and 5.54 ng/g dry weight in the soils, rice plant, and apple snails, respectively. Levels of total AHFRs in the samples were comparable to or even higher than those of PBDEs. The calculated plant to soil concentration ratios for most AHFRs (0.05–3.40) were higher than those for PBDEs (0.02–0.23), indicating the greater bioavailability of the AHFRs in the rice plant. All PBDE congeners and Dechlorane Plus (DP) isomers were biomagnified from the rice plant to apple snails, with mean biomagnification factors (BMFs) of 1.1–5.0.

We measured Dechlorane Plus (DP) and its dechlorinated analogs in the blood and milk from women living in e-waste recycling sites in Wenling of Taizhou region, China (n = 49). Both syn-DP and anti-DP were detected in all samples. Another compound, Cl11-DP, was detected in 45% and 84% of milk and serum samples, respectively. DP levels in blood and milk from residents living in the local environment >20 yrs (R20 group) were significantly higher than those living in Taizhou <3 yrs (R3 group) (p < 0.05). The milk/serum partition coefficient from the same women was approximately 0.43 and 0.47 for syn-DP and anti-DP, respectively. A similar value in milk compared with anti-DP/∑DPs (fanti) in serum suggested that stereoselective DP bio-accumulation did not occur during the DP transport from blood to milk. This result indicate that DP can bio-accumulate in blood and milk with the low milk/serum partition coefficient and similar blood and milk stereoselective bio-accumulation profiles.

A distributed adaptation of i-Tree Eco was used to simulate dry deposition in an urban area. This investigation focused on the effects of varying temperature, LAI, and NO2 concentration inputs on estimated NO2 dry deposition to trees in Baltimore, MD. A coupled modeling system is described, wherein WRF provided temperature and LAI fields, and CMAQ provided NO2 concentrations. A base case simulation was conducted using built-in distributed i-Tree Eco tools, and simulations using different inputs were compared against this base case. Differences in land cover classification and tree cover between the distributed i-Tree Eco and WRF resulted in changes in estimated LAI, which in turn resulted in variations in simulated NO2 dry deposition. Estimated NO2 removal decreased when CMAQ-derived concentration was applied to the distributed i-Tree Eco simulation. Discrepancies in temperature inputs did little to affect estimates of NO2 removal by dry deposition to trees in Baltimore.

Accumulation of selenium (Se) by lesser and greater scaup (Aythya affinis, A. marila) at staging and wintering areas could have contributed to the decline in their continental population. We exposed lesser scaup to background (0.8 μg/g), moderate (8.1 μg/g) and high (20.7 μg/g) levels of dietary Se in captivity and measured survival rates and indices of health in relation to hepatic Se concentrations. There was 100% survival in scaup exposed to Se for 10-weeks (average staging duration at Great Lakes), but ducks in the high treatment group had less lipids. There was 93% survival after 23-weeks (average wintering duration at Great Lakes), but no differences among treatment groups in body composition. There were no effects of Se on oxidative stress and cell-mediated immunity; rather we recorded immuno-stimulatory effects on antibody production. Results from our captive study suggest Se alone did not cause the continental decline in scaup populations.

This study focuses on gender-specific accumulation features of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in common (great) cormorants (Phalacrocorax carbo) collected from Lake Biwa, Japan. Male cormorants showed a tendency to have higher levels of PCDD/DFs and DL-PCBs than did females. For PCDDs, the male-to-female concentration ratio (M/F ratio) for each congener significantly decreased with the liver-to-muscle concentration ratio (Li/Mu ratio). For PCDFs, there also was a weak negative relationship between Li/Mu ratio and M/F ratio. In contrast, for DL-PCBs, M/F ratios showed no correlation with Li/Mu ratios, but increased with an increase in lipophilicity. These results, together with observations from prior studies, suggest that congener-specific hepatic sequestration may be a factor limiting the maternal transfer of PCDDs and, to a lesser extent, PCDFs. Maternal transfer of DL-PCBs seems to favor more lipophilic congeners in the cormorants.

Polychlorinated biphenyl (PCB) congeners (PCB 52, 77, and 153) singly and in mixture were spiked and aged in soil microcosms and subsequently planted with switchgrass (Panicum virgatum) or poplar (Populus deltoids x nigra DN34). The planted reactors showed significantly greater reductions in PCB parent compounds when compared to unplanted systems after 32 weeks. There was evidence of reductive dechlorination in both planted and unplanted systems, but the planted microcosms with fully developed roots and rhizospheres showed greater biotransformation than the unplanted reactors. These dechlorination products accounted for approximately all of the molar mass of parent compound lost. Based on the transformation products, reductive dechlorination pathways are proposed for rhizospheric biotransformation of PCB 52, 77, and 153. This is the first report of rhizosphere biotransformation pathways for reductive dechlorination in marginally aerobic, intermittently flooded soil as evidenced by a mass balance on transformation products.

Quantum dots (QDs) have strong adsorption capacity; therefore, their potential toxicity of the facilitated transport of other trace toxic pollutants when they co-exist to aquatic organisms has become a hot research topic. The lab study was performed to determine the developmental toxicities to the zebrafish after exposed to the combined pollution of Cadmium-telluride (CdTe) QDs and copper ion (Cu2+) compared to the single exposure. Our findings for the first time revealed that: 1) CdTe QDs facilitated the accumulation of Cu2+ in zebrafish, 2) the higher mortality, lower hatch rate, and more malformations can be clearly observed, 3) the diverse vascular hyperplasia, turbulence, and bifurcation of the exposed FLI-1 transgenic zebrafish larvae appeared together, 4) the synergistic effects played more important role during joint exposure. These observations provide a basic understanding of CdTe QDs and Cu2+ joint toxicity to aquatic organisms.

Polychlorinated naphthalenes (PCNs) belong to a group of dioxin-like pollutants; however little information is available on PCNs in North China. In this study, gridded field observations by passive air sampling at 90 sites were undertaken to determine the levels, spatial distributions, and sources of PCNs in the atmosphere of North China. A median concentration of 48 pg m−3 (range: 10–2460 pg m−3) for ∑29PCNs indicated heavy PCN pollution. The compositional profile indicated that nearly 90% of PCNs observed were from thermal processes rather than from commercial mixtures. Regarding the source type, a quantitative apportionment suggested that local non-point emissions contributed two-thirds of the total PCNs observed in the study, whereas a point source of electronic-waste recycling site contributed a quarter of total PCNs. The estimated toxic equivalent quantity for dioxin-like PCNs ranged from 0.97 to 687 fg TEQ m−3, with the electronic-waste recycling site with the highest risk.

It is a common method to analyse physiological mechanisms of organisms – commonly referred to as biomarkers – to indicate the presence of environmental pollutants. However, as biomarkers respond to a wide range of stressors we want to direct the attention on natural stressors, i.e. on parasites. After two years maintenance under controlled conditions, roach (Rutilus rutilus) revealed no influence on levels of metallothionein by the parasite Ligula intestinalis. The same was found for Gammarus fossarum infected with Polymorphus minutus. However, the heat shock protein (HSP70) response was affected in both host-parasite systems. While the infection of roach resulted in reduced levels of HSP70 compared to uninfected roach, the infection in G. fossarum led to higher levels of HSP70. We also analysed the effect of a 14 days Cd exposure (4 μg/L) on the uninfected and infected gammarids. The exposure resulted in induced levels for both, metallothionein and HSP70 whereas the combination of stressors, parasite and exposure, revealed a decrease for levels of HSP70 in comparison to the metal exposure only. Accordingly, parasites as natural parts of aquatic ecosystems have to be considered in ecotoxicological research.

Silver nanoparticles (AgNPS) are an important model system for studying potential environmental risks posed by the use of nanomaterials. So far there is no consensus as to whether toxicity is due to AgNPs themselves or Ag+ ions leaching from their surfaces. In sea urchin Paracentrotus lividus, AgNPs cause dose dependent developmental defects such as delayed development, bodily asymmetry and shortened or irregular arms, as well as behavioural changes, particularly in swimming patterns, at concentration ∼0.3 mg/L AgNPs. It has been observed that AgNPs are more toxic than their equivalent Ag+ ion dose.