Synthesis of fluorinated polybrominated diphenyl ethers (F-PBDEs) as internal standards for environmental analysis

Polybrominated diphenyl ethers (PBDEs) have become widely distributed as environmental contaminants due to their wide-spread use as flame retardants. Their structural similarity to other halogenated organic pollutants, for example polychlorinated biphenyls (PCBs), has led to speculation that they may have similar toxicological properties and effects. Recent focus on PBDEs as possible priority pollutants has also led to an increasing need for reference standards of PBDEs for toxicological studies and for environmental analysis. In this work we synthesized a series of fluorinated PBDEs (F-PBDEs) which can be used as possible internal standards, as an alternative to high-cost alternatives, such as the (13)C-labelled analogues. F-PBDEs have been synthesized by using different coupling reactions and by bromination of fluorinated starting materials.     

A Biomimetic Approach to the Detection and Identification of Estrogen Receptor Agonists in Surface Waters Using Semipermeable Membrane Devices (SPMDs) and Bioassay-Directed Chemical Analysis (12 pp)

Goal, Scope and Background Some anthropogenic pollutants posses the capacity to disrupt endogenous control of developmental and reproductive processes in aquatic biota by activating estrogen receptors. Many anthropogenic estrogen receptor agonists (ERAs) are hydrophobic and will therefore readily partition into the abiotic organic carbon phases present in natural waters. This partitioning process effectively reduces the proportion of ERAs readily available for bioconcentration by aquatic biota. Results from some studies have suggested that for many aquatic species, bioconcentration of the freely-dissolved fraction may be the principal route of uptake for hydrophobic pollutants with logarithm n-octanol/water partition coefficient (log Kow) values less than approximately 6.0, which includes the majority of known anthropogenic ERAs. The detection and identification of freely-dissolved readily bioconcentratable ERAs is therefore an important aspect of exposure and risk assessment. However, most studies use conventional techniques to sample total ERA concentrations and in doing so frequently fail to account for bioconcentration of the freely-dissolved fraction. The aim of the current study was to couple the biomimetic sampling properties of semipermeable membrane devices (SPMDs) to a bioassay-directed chemical analysis (BDCA) scheme for the detection and identification of readily bioconcentratable ERAs in surface waters. Methods SPMDs were constructed and deployed at a number of sites in Germany and the UK. Following the dialytic recovery of target compounds and size exclusion chromatographic clean-up, SPMD samples were fractionated using a reverse-phase HPLC method calibrated to provide an estimation of target analyte log Kow. A portion of each HPLC fraction was then subjected to the yeast estrogen screen (YES) to determine estrogenic potential. Results were plotted in the form of 'estrograms' which displayed profiles of estrogenic potential as a function of HPLC retention time (i.e. hydrophobicity) for each of the samples. Where significant activity was elicited in the YES, the remaining portion of the respective active fraction was subjected to GC-MS analysis in an attempt to identify the ERAs present. Results and Discussion Estrograms from each of the field samples showed that readily bioconcentratable ERAs were present at each of the sampling sites. Estimated log Kow values for the various active fractions ranged from 1.92 to 8.63. For some samples, estrogenic potential was associated with a relatively narrow range of log Kow values whilst in others estrogenic potential was more widely distributed across the respective estrograms. ERAs identified in active fractions included some benzophenones, various nonylphenol isomers, benzyl butyl phthalate, dehydroabietic acid, sitosterol, 3-(4-methylbenzylidine)camphor (4-MBC) and 6-acetyl-1,1,2,4,4,7-hexamethyltetralin (AHTN). Other tentatively identified compounds which may have contributed to the observed YES activity included various polycyclic aromatic hydrocarbons (PAHs) and their alkylated derivatives, methylated benzylphenols, various alkylphenols and dialkylphenols. However, potential ERAs present in some active fractions remain unidentified. Conclusions and Outlook Our results show that SPMD-YES-based BDCA can be used to detect and identify readily bioconcentratable ERAs in surface waters. As such, this biomimetic approach can be employed as an alternative to conventional methodologies to provide investigators with a more environmentally relevant insight into the distribution and identity of ERAs in surface waters. The use of alternative bioassays also has the potential to expand SPMD-based BDCA to include a wide range of toxicological endpoints. Improvements to the analytical methodology used to identify ERAs or other target compounds in active fractions in the current study could greatly enhance the applicability of the methodology to risk assessment and monitoring programmes.     

The valuation of forest carbon services by Mexican citizens: the case of Guadalajara city and La Primavera biosphere reserve

Adequate demand for, and recognition of, forest carbon services is critical to success of market mechanisms for forestry-based conservation and climate change mitigation. National and voluntary carbon-offsetting schemes are emerging as alternatives to international compliance markets. We developed a choice experiment to explore determinants of local forest carbon-offset valuation. A total of 963 citizens from Guadalajara in Mexico were asked to consider a purchase of voluntary offsets from the neighbouring Biosphere Reserve of La Primavera and from two alternative more distant locations: La Michilía in the state of Durango and El Cielo in Tamaulipas. Surveys were applied in market stall sessions and online using two different sampling methods: the snowball technique and via a market research company. The local La Primavera site attracted higher participation and valuation than the more distant sites. However, groups particularly interested in climate change mitigation or cost may accept cost-efficient options in the distant sites. Mean implicit carbon prices obtained ranged from $6.79 to $15.67/tCO_2eq depending on the surveying methodology and profile of respondents. Survey application mode can significantly affect outcome of the experiment. Values from the market stall sessions were higher than those from the snowball and market research samples obtained online; this may be linked to greater cooperation associated with personal interaction and collective action. In agreement with the literature, we found that valuation of forest carbon offsets is associated with cognitive, ethical, behavioural, geographical and economic factors.     

Illicit crops and armed conflict as constraints on biodiversity conservation in the Andes region

Coca, once grown for local consumption in the Andes, is now produced for external markets, often in areas with armed conflict. Internationally financed eradication campaigns force traffickers and growers to constantly relocate, making drug-related activities a principal cause of forest loss. The impact on biodiversity is known only in general terms, and this article presents the first regional analysis to identify areas of special concern, using bird data as proxy. The aim of conserving all species may be significantly constrained in the Santa Marta and Perijá mountains, Darién, some parts of the Central Andes in Colombia, and between the middle Mara?ón and middle Huallaga valleys in Peru. Solutions to the problem must address the root causes: international drug markets, long-lasting armed conflict, and lack of alternative income for the rural poor.     

HPLC-PFD determination of priority pollutant PAHs in water,sediment, and semipermeable membrane devices

High performance liquid chromatography coupled with programmable fluorescence detection was employed for the determination of 15 priority pollutant polycyclic aromatic hydrocarbons (PPPAHs) in water, sediment, and semipermeable membrane devices (SPMDs). Chromatographic separation using this analytical method facilitates selectivity, sensitivity (ppt levels), and can serve as a non-destructive technique for subsequent analysis by other chromatographic and spectroscopic techniques. Extraction and sample cleanup procedures were also developed for water, sediment, and SPMDs using various chromatographic and wet chemical methods. The focus of this publication is to examine the enrichment techniques and the analytical methodologies used in the isolation, characterization, and quantitation of 15 PPPAHs in different sample matrices.     

Antenatal ultrasonic diagnosis of dyssegmental dysplasia: A case report

Sonographic prenatal diagnosis and management of a pregnancy complicated by dys-segmental dysplasia of the Silverman-Handmaker type are presented. This is a documented case of this type of short-limbed dwarfism presenting in a family of Hispanic-American ancestry.     

Prenatal ultrasound diagnosis of amelia

Amelia is a very rare form of limb reduction defect. The incidence of isolated amelia with or without other limb reductions is 0.4 per 100 000 births. We report a cluster of three cases diagnosed prenatally. One was isolated tri-amelia and two were isolated tetra-amelia.