Recently, several researchers have attempted to address Deepwater Horizon incident environmental fate and effects issues using laboratory testing and extrapolation procedures that are not fully reliable measures for environmental assessments. The 2013 Rico-Martínez et al. publication utilized laboratory testing approaches that severely limit our ability to reliably extrapolate such results to meaningful real-world assessments.The authors did not adopt key methodological elements of oil and dispersed oil toxicity standards. Further, they drew real-world conclusions from static exposure tests without reporting actual exposure concentrations. Without this information, it is not possible to compare their results to other research or real spill events that measured and reported exposure concentrations.The 1990s' Chemical Response to Oil Spills: Ecological Effects Research Forum program was established to standardize and conduct exposure characterization in oil and dispersed oil aquatic toxicity testing (Aurand and Coelho, 2005). This commentary raises awareness regarding the necessity of standardized test protocols.

Experiments were conducted to analyze processes impacting arsenic transport in irrigation water flowing over bare rice-field soils in Bangladesh. Dissolved concentrations of As, Fe, P, and Si varied over space and time, according to whether irrigation water was flowing or static. Initially, under flowing conditions, arsenic concentrations in irrigation water were below well-water levels and showed little spatial variability across fields. As flowing-water levels rose, arsenic concentrations were elevated at field inlets and decreased with distance across fields, but under subsequent static conditions, concentrations dropped and were less variable. Laboratory experiments revealed that over half of the initial well-water arsenic was removed from solution by oxidative interaction with other water-column components. Introduction of small quantities of soil further decreased arsenic concentrations in solution. At higher soil-solution ratios, however, soil contributed arsenic to solution via abiotic and biotic desorption. Collectively, these results suggest careful design is required for land-based arsenic-removal schemes.

This study investigates the suitability of multivariate techniques, including principal component analysis and discriminant function analysis, for analysing polycyclic aromatic hydrocarbon and heavy metal-contaminated aquatic sediment data. We show that multivariate “fingerprint” analysis of relative abundances of contaminants can characterize a contamination source and distinguish contaminated sediments of interest from background contamination. Thereafter, analysis of the unstandardized concentrations among samples contaminated from the same source can identify migration pathways within a study area that is hydraulically complex and has a long contamination history, without reliance on complex hydrodynamic data and modelling techniques. Together, these methods provide an effective tool for drinking water source monitoring and protection.

The roles that ozone and nitric oxide (NO), the chief O3 precursor, play in the antioxidative balance and inducible volatile emissions of lima bean were assessed. Exposure to O3 inhibited APX, CAT, and GR, decreased GSH content and induced emissions of (E)-β-ocimene, limonene, 1,8-cineole, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene (E)-DMNT, 2-butanone and nonanal. O3 did not induce emissions of (E)-β-caryophyllene and appeared to reduce the antioxidative capacity of plants to a greater extent than NO and NO followed by O3 (NO/O3) treatments. There were significant differences in emissions of (E)-β-ocimene and linalool between NO/O3 treated plants and controls, but no differences in antioxidant concentrations. A model to explain the relationships between the ascorbate–glutathione cycle and O3 and NO inducible volatiles was proposed. Our findings suggest that prior exposure to NO modulates the oxidative effect of ozone by the process of cross-tolerance, which might regulate the antioxidative system and induction of volatile organic compounds.

Rock varnish is a manganese–iron rich coating that forms on rocks, most often in arid climates. To assess its utility as an environmental monitor of mercury contamination, cold vapor atomic absorption spectrometry (CVAAS) was used for analysis. Samples were collected in the fallout patterns of two coal-fired power plants in southern Nevada: the defunct Mohave Power Plant (MPP) and the operating Reid Gardner Power Plant (RGPP). The resultant Hg concentrations in rock varnishes were plotted as a function of the distance from each power plant. The highest concentrations of Hg occurred at locations that suggest the power plants are the main source of pollutants. In addition, past tracer plume studies carried out at MPP show that the highest tracer concentrations coincide with the highest rock varnish Hg concentrations. However, additional samples are required to further demonstrate that power plants are indeed the sources of mercury in varnishes.

Pyrethroids are widely used insecticides that may seriously harm aquatic organisms. Being strongly hydrophobic, pyrethroids in solution occur only in short pulses but may be retained in sediments for longer periods. Consequently, most studies consider the chronic exposure of sediment dwelling organisms. We collected data from 16 studies to determine effect thresholds for stream macroinvertebrates exposed to short pyrethroid pulses evaluating lethal and sublethal ecologically relevant endpoints. Dose–response models showed EC50 for lethality, functional and behavioural endpoints down to 1/100, 1/100 and 1/1000 of the 48 h LC50 for Daphnia magna, respectively. The results indicate that the overall sensitivity of stream macroinvertebrates to pyrethroids may be higher than previously believed. This review shows the relevance of incorporating data on sublethal endpoints and appropriate post-exposure observation periods in future studies. The current risk assessment procedures and the higher tier approach are discussed in the light of our results.

Electronic waste recycling produces Polycyclic Aromatic Hydrocarbons (PAHs) and Polybrominated Diphenyl Ethers (PBDEs) which may affect fetal growth and development by altering the insulin-like-growth factor (IGF) system. Questionnaires were administered to pregnant women (Guiyu, an e-waste site, n = 101; control, n = 53), and umbilical cord blood (UCB) and placentas were collected upon delivery. PBDEs and PAHs in UCB and placental IGF-1 and IGFBP-3 mRNA levels were analyzed using GC–MS and real-time PCR, respectively. Infant birth length and Apgar scores were lower in Guiyu. All PAHs (except Fl, Chr, IP, BbF and BP), total 16-PAHs, total/individual PBDEs, placental IGF-1 (median 0.23 vs 0.19; P < 0.05) and IGFBP-3 (median 1.91 vs 0.68; P < 0.001) levels were significantly higher in Guiyu. Spearman correlation showed that BDE-154, BDE-209 and ∑5ring-PAHs positively correlate with IGF-1 while PBDEs, 4 rings and total PAHs correlate with IGFBP-3 expression. Increased placental IGF-1 level might indirectly affect fetal growth and development.

This study presents the occurrence and risk of PBDEs, new brominated and organophosphorus flame retardants along a river affected by urban and industrial pressures (River Aire, UK). Tris(2-choroethyl) phosphate (TCEP), tris(2-chloro-1-methylethyl) phosphate (TCPP), tris[2-chloro-1-(chloromethyl)ethyl] phosphate (TDCP) and triphenyl phosphate (TPhP) were detected in all samples, with TCPP present at the highest concentrations, ranging from 113 to 26 050 ng L-1. BDE-209 was detected in most of the sampled sites, ranging from 17 to 295 ng L−1, while hexabromobenzene (HBB) and pentabromoethyl benzene (PBEB) were seldom detected. A risk quotients based on predicted no effect concentrations (PNEC) and flame retardants water concentration proved significant risk for adverse effects for algae, Daphnia and fish in sites close to industrial and urban sewage discharges. This study provides a protocol for the risk estimation of priority and new generation flame retardants based on river concentrations and toxicological values.

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) were determined in water, sediments, sediment cores, and three fish species from a river running through a highly industrialized area in South China. TBBPA concentrations exceeded those of HBCDs in the sediment and the dissolved phase of water and its levels in fish were at the high end of worldwide figures. 26% of HBCDs and 99% of TBBPA were found in dissolved phase of water. Plecostomus occupying high trophic level exhibited higher HBCD levels and higher abundance of α-HBCD than mud carp and nile tilapia which occupy low trophic level. An enrichment of (+)-α-HBCD in three fish species but (−)-α-HBCD in sediment was observed. As for γ-HBCD, most of sediment exhibited racemic while a species-dependence in fish sample was found. No clear trend was found for vertical distribution of enantiomeric profile for γ-HBCD, suggesting that the enantioselectivity of degradation of γ-HBCD is limited.

Passive air samplers were deployed to collect both gas and particulate phase polycyclic aromatic hydrocarbons in Taiyuan between 2009 and 2010. Annual average concentrations of BaP equivalent concentration (B[a]Peq) in background, rural and urban areas were 2.90 ± 0.29, 23.2 ± 30.8 and 27.4 ± 28.1 ng/m3, respectively, with higher concentration in the winter than in other seasons. The median B[a]Peq concentrations of annual inhalation exposure were estimated to be in the range of 103–347 ng/d for all population groups in rural as well as in urban areas. The median values of incremental lifetime cancer risk (ILCR) induced by whole year inhalation exposure for all groups were basically larger than 10−6, with higher values in winter than in other seasons and in urban than in rural area. In the same season and area, the ILCR of adults was larger than other age groups and that of females was a little higher than males.