It has been known that substitution is not a suitable method to address non-detect (ND) data and can result in significant errors. However, reports of reliable statistical methods for handling ND data of polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in fish are rare. This work examines US-EPA's recommended statistical methods and traditional substitution-based methods for handling ND data in PCDD/F and DL-PCB datasets obtained from 240 fish samples. The Kaplan-Meier (KM) method was confirmed as a suitable statistical approach for dealing with our fish datasets. The results of the KM and substitution methods were compared; a significant difference was found in TEQs derived from KM and substitution for PCDD/Fs, suggesting that the handling of ND data is a critical issue for PCDD/Fs. For example, the substitution by ½LOD resulted in 20–25% overestimation of PCDD/F TEQs for fish samples with ND data (60–70%). In conclusion, the use of KM method is preferable for average TEQs, and if the use of KM is not applicable, substitution by zero is preferred. Based on this conclusion, the characteristics of fish contamination by PCDD/Fs and DL-PCBs in Korea were investigated.

In recent years, a trend toward a declining proportion of male births has been noted in several, but not all, industrialized countries. The underlying reason for the drop in the sex ratio is unclear, but one theory states that widespread environmental endocrine disrupting chemicals affecting the male reproductive system in a negative manner could be part of the explanation. The present study was designed to investigate whether the urinary phthalate, pyrethroids and polycyclic aromatic hydrocarbons metabolites concentrations were associated with sperm Y:X ratio.The study population consisted of 194 men aged under 45 years of age who attended infertility clinic in Lodz, Poland for diagnostic purposes with normal semen concentration of 20–300 mln/ml or with slight oligozoospermia (semen concentration of 15–20 mln/ml) (WHO, 1999). The Y:X ratio was assessed by fluorescent in situ hybridization. Urinary concentrations of 1-hydroxypyrene were measured by high performance liquid chromatography, phthalate metabolites were analyzed using a procedure based on the LC-MS/MS methods and metabolites of synthetic pyrethroids were assessed by gas chromatography ion-tap mass spectrometry method.After adjustment for potential confounders (past diseases, age, abstinence, smoking, alcohol consumption, sperm concentration, motility, morphology) 5OH MEHP, CDCCA to TDCCA and 1-OHP was negatively related to Y:X sperm chromosome ratio (p = 0.033, p < 0.001, p = 0.047 respectively).As this is the first study to elucidate the association between the level of metabolites of widespread environmental endocrine disrupting chemicals (phthalates, synthetic pyrethroids, polycyclic aromatic hydrocarbons) on sex chromosome ratio in sperm therefore, these findings require further replication in other populations.

Agricultural soils account for more than 50% of nitrogen leaching (LN) to groundwater in China. When excess levels of nitrogen accumulate in groundwater, it poses a risk of adverse health effects. Despite this recognition, estimation of LN from cropland soils in a broad spatial scale is still quite uncertain in China. The uncertainty of LN primarily stems from the shape of nitrogen leaching response to fertilizer additions (Nrate) and the role of environmental conditions. On the basis of 453 site-years at 51 sites across China, we explored the nonlinearity and variability of the response of LN to Nrate and developed an empirical statistical model to determine how environmental factors regulate the rate of N leaching (LR). The result shows that LN-Nrate relationship is convex for most crop types, and varies by local hydro-climates and soil organic carbon. Variability of air temperature explains a half (∼52%) of the spatial variation of LR. The results of model calibration and validation indicate that incorporating this empirical knowledge into a predictive model could accurately capture the variation in leaching and produce a reasonable upscaling from site to country. The fertilizer-induced LN in 2008 for China's cropland were 0.88 ± 0.23 TgN (1σ), significantly lower than the linear or uniform model, as assumed by Food and Agriculture Organization and MITERRA-EUROPE models. These results also imply that future policy to reduce N leaching from cropland needs to consider environmental variability rather than solely attempt to reduce Nrate.

Stable Pb isotope ratios (Pb-IRs) have been recognized as an efficient tool for identifying sources. This study carried out at Kabwe mining area, Zambia, to elucidate the presence or absence of Pb isotope fractionation in goat and chicken, to evaluate the reliability of identifying Pb pollution sources via analysis of Pb-IRs, and to assess whether a threshold for blood Pb levels (Pb-B) for biological fractionation was present. The variation of Pb-IRs in goat decreased with an increase in Pb-B and were fixed at certain values close to those of the dominant source of Pb exposure at Pb-B > 5 μg/dL. However, chickens did not show a clear relationship for Pb-IRs against Pb-B, or a fractionation threshold. Given these, the biological fractionation of Pb isotopes should not occur in chickens but in goats, and the threshold for triggering biological fractionation is at around 5 μg/dL of Pb-B in goats.

Bisphenol A (BPA), a monomer used in plastic manufacturing, is weakly estrogenic and a potential endocrine disruptor in mammals. Although it degrades quickly, it is pseudo-persistent in the environment because of continual inputs, with reported concentrations in aquatic environments between 0.0005 and 12 μg/L. BPA represents a potential concern for aquatic ecosystems, as shown by its reproductive and developmental effects in aquatic vertebrates.In invertebrates, endocrine-related effects of BPA were observed in different species and experimental conditions, with often conflicting results, indicating that the sensitivity to this compound can vary considerably among related taxa. In the marine mussel Mytilus galloprovincialis BPA was recently shown to affect early development at environmental concentrations. In this work, the possible effects of BPA on mussel embryos were investigated at the molecular level by evaluating transcription of 13 genes, selected on the basis of their biological functions in adult mussels. Gene expression was first evaluated in trocophorae and D-veligers (24 and 48 h post fertilization) grown in physiological conditions, in comparison with unfertilized eggs. Basal expressions showed a general up-regulation during development, with distinct transcript levels in trocophorae and D-veligers. Exposure of fertilized eggs to BPA (10 μg/L) induced a general upregulation at 24 h pf, followed by down regulation at 48 h pf. Mytilus Estrogen Receptors, serotonin receptor and genes involved in biomineralization (Carbonic Anydrase and Extrapallial Protein) were the most affected by BPA exposure. At 48 h pf, changes in gene expression were associated with irregularities in shell formation, as shown by scanning electron microscopy (SEM), indicating that the formation of the first shelled embryo, a key step in mussel development, represents a sensitive target for BPA. Similar results were obtained with the natural estrogen 17β-estradiol. The results demonstrate that BPA and E2 can affect Mytilus early development through dysregulation of gene transcription.

Particulate matter data obtained from the national air quality monitoring network in China has become an essential and critical data source for many current and forthcoming studies as well as the formulation and implementation of air pollution regulatory policies on particulate matter (PM2.5 and PM10). However, the quality control of this data is dubitable and can affect many future studies and policies. This study identifies and elucidates two significant quality control issues with the data. They are PM2.5 levels exceeding concurrent co-located PM10 levels and the registration of same concentrations for consecutive hours at some stations. Future studies utilizing particulate matter data need to acknowledge and address these issues to ensure accurate and reliable results.

Low tech photovoltaic panels (PVPs) installed in the early ’80s are now coming to the end of their life cycle and this raises the problem of their proper disposal. As panels contain potentially toxic elements, unconventional, complex and costly procedures are required to avoid environmental health risks and in countries where environmental awareness and economic resources are limited this may be especially problematic. This work was designed to investigate potential risks from improper disposal of these panels. To accomplish this aim an exhausted panel was broken into pieces and these were placed in water for 30 days. The resulting leached solution was analyzed to determine chemical release or used in toto, to determine its potential toxicity in established tests. The end points were seed germination (on Cucumis sativus and Lens culinaris) and effects on early development in three larval models: two crustaceans, Daphnia magna and Artemia salina, and the sea urchin Paracentrotus lividus. Our results show that the panels release small amounts of electrolytes (Na, Ca and Mg) into solution, along with antimony and manganese, with a concentration under the accepted maximum contaminant level, and nickel at a potentially toxic concentration. Developmental defects are seen in the plant and animal test organisms after experimental exposure to the whole solution leached from the broken panel. The toxic effects revealed in in vitro tests are sufficient to attract attention considering that they are exerted on both plants and aquatic animals and that the number of old PVPs in disposal sites will be very high.

Perfluoroalkyl acids (PFAAs) are highly stable, persistent, and ubiquitous in the environment with significant concerns growing with regards to both human and ecosystem health. Due to the high stability to both biological and chemical attack, the only currently feasible approach for their removal from water is adsorbent technology. The main objective of this study was to assess a covalent triazine-based framework (CTF) adsorbent for removal from aqueous solutions of perfluoro C4, C6, and C8 carboxylates and sulfonates including the two C8s most commonly monitored, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Adsorption affinity and capacity were quantified and compared to three commonly used sorbents: pulverized microporous activated carbon, single-walled carbon nanotubes, and Amberlite IRA-400 anion-exchange resin. CTF adsorbent exhibited pronouncedly higher adsorption affinity and capacity of PFAAs than other test sorbents. The remarkably strong adsorption to CTF can be attributed to the favored electrostatic interaction between the protonated triazine groups on the inner wall of the hydrophobic CTF pore and the negatively charged head groups of the PFAAs intercalated between the CTF layers. The homogeneous, nanosized pores (1.2 nm) of CTF hindered adsorption of a large-sized dissolved humic acid, thus minimizing the suppression of PFAA adsorption. Additionally, regeneration of CTF was easily accomplished by simply raising pH > 11, which inhibited the electrostatic adsorptive interaction of PFAAs.

Sediment samples were collected to a depth of 60 cm along a 350-m sampling belt in a short-term-flooding riparian wetland in the Yellow River Delta of China in three sampling seasons. Contents of heavy metals were determined to investigate their spatial and temporal distributions, sources and ecotoxities. Our results showed that As contents in the top 20 cm sediments increased before decreasing along the sampling belt in summer, whereas they kept stable before increasing in fall and spring. Cd contents increased along the sampling belt in three sampling seasons, whereas Ni and Cr generally exhibited a decreasing tendency. Comparatively, Cu, Pb and Zn consistently increased at the first 50 m distance and then decreased before increasing from the distance of 150 m in summer and fall and increased to the maximum at the distance of 250 m and then showed a decrease in spring. Two “hotspots” of heavy metal accumulation in sediment cores along the belt were observed at the distance from 50 to 100 m in summer and at the distance from 200 to 300 m in spring. Most of sediment samples contained higher heavy metals in excess of threshold effect levels except for Zn and Pb in three sampling seasons and the values of toxic units in more than 30% of sediment samples exceeded 4 in summer. As, Ni and Cr had relatively higher contribution to the values of toxic units compared with other heavy metals in three sampling seasons. Multivariance analysis showed that As and Cd might originate from the same source and Cu, Zn, Cr, Pb and Ni might derive from another similar source. Cd was significantly correlated with salinity (p < 0.01) and pH (p < 0.05). Meanwhile, these heavy metals were also significantly correlated with other properties such as S, Al, TP, SOM and Silt + Clay.

Mercury contamination in the River Beni basin is an important health risk factor, primarily for indigenous communities that live along the river. Among them are the Tacana, living in their original territory with sustainable use of their natural resources, consuming fish, Caiman yacare, and other riverine resources as their main source of protein. To assess mercury exposure to Tacana people, total mercury (THg) was evaluated in the muscle of seven commercial fish, and Caiman yacare (yacare caiman) during 2007 and 2008. THg was extracted by acid digestion and concentrations were determined by atomic absorption spectrometry. Mean mercury concentrations in C. yacare was 0.21 ± 0.22 μg g−1Hg w.w. (wet weight), which is lower than expected given its high trophic level, and its long life-span. It is possible that mercury in C. yacare is accumulated in other organs, not included in this study; but it is also possible that physiological mechanisms are involved that help caimans get rid of ingested mercury, or simply that C. yacare’s diverse diet reduces THg accumulation. Carnivorous fishes (Pygocentrus nattereri, Pseudoplatystoma tigrinum, Zungaro zungaro, Plagioscion squamosissimus, and Leiarius marmoratus) had the highest total mercury concentrations, ranging from 0.35 to 1.27 μg g−1Hg w.w. moreover, most were above the limit recommended by WHO (0.5 μg g−1Hg w.w.); except for Leiarius marmuratus, which presented a mean of 0.353 ± 0.322 μg g−1Hg w.w. The two non-carnivorous fish species (Prochilodus nigricans, and Piaractus brachypomus) present mean concentrations of 0.099 ± 0.027, and 0.041 ± 0.019 μg g−1Hg w.w., respectively. Finally, recommendations on the consumption habits of Tacana communities are discussed.