Studies have been devoted to the transport and accumulation of persistent organic pollutants (POPs) in mountain environments. The Himalayas have the widest altitude gradient of any mountain range, but few studies examining the environmental behavior of POPs have been performed in the Himalayas. In this study, air, soil, and leaf samples were collected along a transect on the southern slope of the Himalayas, Nepal (altitude: 135–5100 m). Local emission occurred in the lowlands, and POPs were transported by uplift along the slope. During the atmospheric transport, the HCB proportion increased from the lowlands (20%) to high elevation (>50%), whereas the proportions of DDTs decreased. The largest residue of soil POPs appeared at an altitude of approximately 2500 m, and may be related to absorption by vegetation and precipitation. The net deposition tendencies at the air–soil surface indicated that the Himalayas may be a ‘sink’ for DDTs and PCBs.

In this study, we demonstrate that partial least-squares regression analysis with full cross-validation of spectral reflectance data estimates the amount of polycyclic aromatic hydrocarbons in petroleum-contaminated tropical rainforest soils. We applied the approach to 137 field-moist intact soil samples collected from three oil spill sites in Ogoniland in the Niger Delta province (5.317°N, 6.467°E), Nigeria. We used sequential ultrasonic solvent extraction–gas chromatography as the reference chemical method. We took soil diffuse reflectance spectra with a mobile fibre-optic visible and near-infrared spectrophotometer (350–2500 nm). Independent validation of combined data from studied sites showed reasonable prediction precision (root-mean-square error of prediction = 1.16–1.95 mg kg−1, ratio of prediction deviation = 1.86–3.12, and validation r2 = 0.77–0.89). This suggests that the methodology may be useful for rapid assessment of the spatial variability of polycyclic aromatic hydrocarbons in petroleum-contaminated soils in the Niger Delta to inform risk assessment and remediation.

Concentrations of polychlorinated biphenyls, polyaromatic hydrocarbons, hexachlorobenzene, and DDE were determined by passive sampling (semipermeable membrane devices) with exposure times of 1–1.5 years at 0.1–5 km depth in the Irminger Sea, the Canary Basin (both North Atlantic Ocean), and the Mozambique Channel (Indian Ocean). The dissipation of performance reference compounds revealed a pronounced effect of hydrostatic pressure on the sampler-water partition coefficients. Concentrations in the Irminger Sea were uniform over the entire water column (0.1–3 km). At the Canary Basin site, concentrations were 2–25 times lower near the bottom (5 km) than at 1.4 km. Concentrations in the Mozambique Channel (0.6–2.5 km) were lower than at the other two locations, and showed a near-bottom maximum. The data suggest that advection of surface waters down to a depth of about 1 km is an important mechanism of contaminant transport into the deep ocean.

Field measurements were conducted to measure emission factors of particulate matter (EFPM), organic carbon (EFOC), elemental carbon (EFEC), 28 parent polycyclic aromatic hydrocarbons (EF28pPAHs), and 4 oxygenated PAHs (EF4oPAHs) for four types of crop straws burned in two stoves with similar structure but different ages. The average EFPM, EFOC, EFEC, EF28pPAHs, and EF4oPAHs were 9.1 ± 5.7 (1.8–22 as range), 2.6 ± 2.9 (0.30–12), 1.1 ± 1.2 (0.086–5.5), 0.26 ± 0.19 (0.076–0.96), 0.011 ± 0.14 (1.3 × 10−4 – 0.063) g/kg, respectively. Much high EF28pPAHs was observed in field compared with the laboratory derived EFs and significant difference in EF28pPAHs was identified among different crop residues, indicating considerable underestimation when laboratory derived EFs were used in the inventory. The field measured EFPM, EFOC, and EFEC were significantly affected by stove age and the EFs of carbonaceous particles for the 15-year old stove were approximately 2.5 times of those for the 1-year old stove.

We observed that the sorption kinetics of nitrobenzene and 2,4-dinitrotoluene (two model polar compounds) was significantly slower than that of 1,4-dichlorobenzene and phenanthrene (two model apolar compounds). The difference was attributable to the strong non-hydrophobic interactions between the polar molecules and soil. Interestingly, sorption kinetics of the polar sorbates to the soil organic matter-free soil, humic/fulvic acid-free soil, and extracted humic acids was very fast, indicating that different soil components played a synergetic role in the observed slow kinetics. We propose that slow sorption kinetics of highly polar sorbates stems mainly from the strong specific interactions (H-bonding, electron donor–acceptor interactions, etc.) with humic/fulvic acids; such specific interactions occur when sorbate molecules diffuse through humic/fulvic acids coiled, in relatively compressed confirmations, within the complex, tortuous, and porous soil matrices formed by mineral grains/particles and soil organic matter.

Contamination of organohalogen pollutants (OHPs), including dichlorodiphenyl trichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenylethane (DBDPE), hexabromocyclododecanes (HBCDs), and dechlorane plus (DP) in three metropolises of China, Beijing, Wuhan, and Guangzhou, and a reference rural site were determined using terrestrial residential passerine species as bioindicator. DDTs dominated in Wuhan whereas flame retardants dominated in Guangzhou and Beijing. No geographical variation was found for PCB levels but it exhibited different homologue profiles among different sites which could be attributed to different dietary sources of birds. Industry characteristics of the sampling location contributed to the geographical differences in the occurrence and contamination profile of OHPs. The transformation of traditional agriculture characterized contamination profiles to industry characterized profiles in Beijing and Guangzhou implicates significantly environmental concern on the flame retardants contamination in non-hot-spot regions of China.

Potential effects of natural emissions of hydrocarbons in the marine environment have been poorly investigated. In this study, a multidisciplinary weight of evidence (WOE) study was carried out on a shallow seepage, integrating sediment chemistry with bioavailability and onset of subcellular responses (biomarkers) in caged eels and mussels. Results from different lines of evidence (LOEs) were elaborated within a quantitative WOE model which, based on logical flowcharts, provide synthetic indices of hazard for each LOE, before their integration in a quantitative risk assessment.Evaluations of different LOEs were not always in accordance and their overall elaboration summarized as Moderate the risk in the seepage area. This study provided first evidence of biological effects in organisms exposed to natural hydrocarbon emissions, confirming the limit of chemical characterization as stand-alone criteria for environmental quality assessment and the utility of multidisciplinary investigations to determine the good environmental status as required by Environmental Directives.

A significant challenge in ecotoxicology and risk assessment lies in placing observed contaminant effects in a meaningful ecological context. Polychlorinated biphenyls (PCBs) have been shown to affect juvenile snapping turtle survival and growth but the ecological significance of these effects is difficult to discern without a formal, population-level assessment. We used a demographic matrix model to explore the potential population-level effects of PCBs on turtles. Our model showed that effects of PCBs on juvenile survival, growth and size at hatching could translate to negative effects at the population level despite the fact that these life cycle components do not typically contribute strongly to population level processes. This research points to the utility of using integrative demographic modeling approaches to better understand contaminant effects in wildlife. The results indicate that population-level effects are only evident after several years, suggesting that for long-lived species, detecting adverse contaminant effects could prove challenging.

Studying the physiologic effects of components of fine particulate mass (PM2.5) could contribute to a better understanding of the nature of toxicity of air pollution.We examined the relation between acute changes in cardiovascular and respiratory function, and PM2.5-associated-metals.Using generalized linear mixed models, daily changes in ambient PM2.5-associated metals were compared to daily changes in physiologic measures in 59 healthy subjects who spent 5-days near a steel plant and 5-days on a college campus.Interquartile increases in calcium, cadmium, lead, strontium, tin, vanadium and zinc were associated with statistically significant increases in heart rate of 1–3 beats per minute, increases of 1–3 mmHg in blood pressure and/or lung function decreases of up to 4% for total lung capacity.Metals contained in PM2.5 were found to be associated with acute changes in cardiovascular and respiratory physiology.

This pilot study compared penalized spline regression (PSR) and random forest (RF) regression using visible and near-infrared diffuse reflectance spectroscopy (VisNIR DRS) derived spectra of 164 petroleum contaminated soils after two different spectral pretreatments [first derivative (FD) and standard normal variate (SNV) followed by detrending] for rapid quantification of soil petroleum contamination. Additionally, a new analytical approach was proposed for the recovery of the pure spectral and concentration profiles of n-hexane present in the unresolved mixture of petroleum contaminated soils using multivariate curve resolution alternating least squares (MCR-ALS). The PSR model using FD spectra (r2 = 0.87, RMSE = 0.580 log10 mg kg−1, and residual prediction deviation = 2.78) outperformed all other models tested. Quantitative results obtained by MCR-ALS for n-hexane in presence of interferences (r2 = 0.65 and RMSE 0.261 log10 mg kg−1) were comparable to those obtained using FD (PSR) model. Furthermore, MCR ALS was able to recover pure spectra of n-hexane.