Available data were reviewed to assess the status of contamination by persistent organic pollutants (POPs), including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), ...polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), in drinking water sources and coastal waters of China. The levels of POPs in China's waters were generally at the high end of the global range. A comparison of China's regulatory limits indicated that PCBs in rivers and coastal water may pose potential human health risk. Occurrence of DDTs in some rivers of China may also pose health risk to humans using the regulatory limits of DDTs recommended by the European Union. Future monitoring of POPs in China's waters should be directed towards analytes of concern (e.g. PCBs and PCDD/Fs) and to fill data gaps for analytes (e.g. PBDEs, PCDD/Fs, and chlordane) and in watersheds/regions (e.g. West China) where data are scarce.
► Levels of POPs in China's aquatic systems were generally at the high end of the global range. ► New inputs of DDTs, likely related to the use of dicofol and anti-fouling paints, were found. ► Occurrence of PCBs and DDTs in some water bodies pay pose potential human health risk. ► Long-term monitoring of POPs in China's waters is needed to fill data gaps.
Occurrence, potential sources and ecological and human health risk of persistent organic pollutants in China's waters are reviewed.
Although low density polyethylene (PE) passive samplers show promise for the measurement of aqueous phase hydrophobic organic chemicals (HOCs), the lack of a practical and unsophisticated approach to ...account for non-equilibrium exposure conditions has impeded widespread acceptance and thus application in situ. The goal of this study was to develop a streamlined approach based on an exponential model and a convection mass transfer principle for correcting aqueous concentrations for HOCs deduced by PE samplers under non-equilibrium conditions. First, uptake rate constants (k1), elimination rate constants (k2), and seawater-PE equilibrium partition coefficients (KPEWs) were determined in laboratory experiments for a diverse suite of HOCs with logKow range of 3.4–8.3. Linear relationships between log k2 and logKow, and between log KPEW and logKow were established. Second, PE samplers pre-loaded with 13C-labeled performance reference compounds (PRCs) were deployed in the ocean to determine their k2in situ. By applying boundary layer and convection mass transfer theories, ratio (C) of k2 values in field and laboratory exposures was estimated. This C value was demonstrated a constant that was only determined by water velocities and widths of PE strips. A generic equation with C and logKow as parameters was eventually established for extrapolation of non-equilibrium correction factors for the water boundary layer-controlled HOCs. Characterizing the hydrodynamic conditions indicated the sampler configuration and mooring mode should aim at sustaining laminar flow on the PE surface for optimal mass transfer. The PE estimates corrected using this novel approach possessed high accuracy and acceptable precision, and can be suited for a broad spectrum of HOCs. The presented method should facilitate routine utilization of the PE samplers.
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•A new exponential model of non-equilibrium correction for HOCs.•Linkage of two exposure scenarios based on convection mass transfer principle.•Established relationships between rate constants or log KPEW and log Kow.•Incorporating hydrodynamics for optimization of PE sampler configuration.•The proposed method was validated showing close agreement with alternative method.
•Contaminants of emerging concern were measured in mussels along the California coast.•Sixty-eight total stations. Sixty-seven of the 167 analytes had at least one detect.•The influence of ...urbanization, agriculture, and ocean discharge was investigated.•Alkylphenols, lomefloxacin, and PBDE were the most abundant contaminants.•Perfluorinated compound and HBCD detection frequencies were greater than 25%.
Contaminants of emerging concern were measured in mussels collected along the California coast in 2009–2010. The seven classes were alkylphenols, pharmaceuticals and personal care products, polybrominated diphenyl ethers (PBDE), other flame retardants, current use pesticides, perfluorinated compounds (PFC), and single walled carbon nanotubes. At least one contaminant was detected at 67 of the 68 stations (98%), and 67 of the 167 analytes had at least one detect (40%). Alkylphenol, PBDE, and PFC concentrations increased with urbanization and proximity to storm water discharge; pesticides had higher concentrations at agricultural stations. These results suggest that certain compounds; for example, alkylphenols, lomefloxacin and PBDE, are appropriate for inclusion in future coastal bivalve monitoring efforts based on maximum concentrations >50ng/g dry weight and detection frequencies >50%. Other compounds, for example PFC and hexabromocyclododecane (HBCD), may also be suggested for inclusion due to their >25% detection frequency and potential for biomagnification.
Despite decades-long bans on the production and use of certain chemicals, many halogenated organic compounds (HOCs) are persistent and can bioaccumulate in the marine environment with the potential ...to cause physiological harm to marine fauna. Highly lipid-rich tissue (e.g., marine mammal blubber) functions as a reservoir for HOCs, and selecting ideal indicator species is a priority for retrospective and proactive screening efforts. We selected five marine mammal species as possible indicators for the Southern California Bight (SCB) and applied a non-targeted analytical method paired with an automated data reduction strategy to catalog a broad range of known, known but unexpected, and unknown compounds in their blubber. A total of 194 HOCs were detected across the study species (n = 25 individuals), 81% of which are not routinely monitored, including 30 halogenated natural products and 45 compounds of unknown structure and origin. The cetacean species (long-beaked common dolphin, short-beaked common dolphin, and Risso's dolphin) averaged 128 HOCs, whereas pinnipeds (California sea lion and Pacific harbor seal) averaged 47 HOCs. We suspect this disparity can be attributed to differences in life history, foraging strategies, and/or enzyme-mediated metabolism. Our results support proposing (1) the long- and short-beaked common dolphin as apex marine predator sentinels for future and retrospective biomonitoring of the SCB ecosystem and (2) the use of non-targeted contaminant analyses to identify and prioritize emerging contaminants. The use of a sentinel marine species together with the non-targeted analytical approach will enable a proactive approach to environmental contaminant monitoring.
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•Organic contaminants were identified in Southern California marine mammal blubber.•Cetaceans accumulated more contaminants than pinnipeds.•Common dolphins are proposed as sentinels for emerging contaminants in this region.
Targeted environmental monitoring reveals contamination by known chemicals, but may exclude potentially pervasive but unknown compounds. Marine mammals are sentinels of persistent and bioaccumulative ...contaminants due to their longevity and high trophic position. Using nontargeted analysis, we constructed a mass spectral library of 327 persistent and bioaccumulative compounds identified in blubber from two ecotypes of common bottlenose dolphins (Tursiops truncatus) sampled in the Southern California Bight. This library of halogenated organic compounds (HOCs) consisted of 180 anthropogenic contaminants, 41 natural products, 4 with mixed sources, 8 with unknown sources, and 94 with partial structural characterization and unknown sources. The abundance of compounds whose structures could not be fully elucidated highlights the prevalence of undiscovered HOCs accumulating in marine food webs. Eighty-six percent of the identified compounds are not currently monitored, including 133 known anthropogenic chemicals. Compounds related to dichlorodiphenyltrichloroethane (DDT) were the most abundant. Natural products were, in some cases, detected at abundances similar to anthropogenic compounds. The profile of naturally occurring HOCs differed between ecotypes, suggesting more abundant offshore sources of these compounds. This nontargeted analytical framework provided a comprehensive list of HOCs that may be characteristic of the region, and its application within monitoring surveys may suggest new chemicals for evaluation.
Analytical methods for contaminant monitoring are generally targeted; i.e., they measure defined lists of compounds. Routine monitoring projects using targeted methods are not usually designed to ...screen for unrecognized or novel contaminants and therefore miss compounds within the region or population of study that cause, or have the potential to cause, adverse biological impacts. We describe a nontargeted analytical method utilizing direct sample introduction coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry. To test the capabilities of this instrumental method within the context of marine contaminant surveys, we characterized a broad array of nonpolar, persistent, and bioaccumulative contaminants in Atlantic common dolphin ( Delphinus delphis ) blubber, including compounds that are not typically monitored. Compound identifications were made by searching a standard reference database, by contemporaneously analyzing mass spectra from reference standards, and by de novo interpretation. We identified a total of 271 compounds belonging to 24 classes; all compounds but 1 were halogenated. Anthropogenic contaminants and halogenated natural products were concurrently detected. A total of 86 compounds were anthropogenic contaminants that are not routinely targeted in environmental surveys, and 54 compounds were halogenated natural products. A total of 112 spectra were identified de novo, demonstrating that exclusive reliance on commercially available reference standards and mass spectral libraries may miss a significant fraction of identifiable compounds. We also cataloged 27 halogenated mass spectra that were not able to be identified. Due to the volume and complexity of the identification data, we developed custom software to organize and provide shared access to the identified mass spectra and related information. The nontargeted analytical method and data reporting system, in combination with the analysis of a high-trophic-level sentinel species, demonstrates a framework for creating an inventory of persistent and bioaccumulative contaminants in marine environments, with the future goal of suggesting new compounds for further investigation by targeted monitoring and risk assessment.
To catalog the diversity and abundance of halogenated organic compounds (HOCs) accumulating in high trophic marine species from the southwestern Atlantic Ocean, tissue from bottlenose dolphins ...(Tursiops truncatus) stranded or incidentally captured along the coast of Rio de Janeiro, Brazil, were analyzed by a nontargeted approach based on GC×GC/TOF-MS. A total of 158 individual HOCs from 32 different structural classes were detected in the blubber of 4 adult male T. truncatus. Nearly 90% of the detected compounds are not routinely monitored in the environment. DDT-related and mirex/dechlorane-related compounds were the most abundant classes of anthropogenic origin. Methoxy-brominated diphenyl ethers (MeO-BDEs) and chlorinated methyl- and dimethyl bipyrroles (MBPs and DMBPs) were the most abundant natural products. Reported for the first time in southwestern Atlantic cetaceans and in contrast to North American marine mammals, chlorinated MBPs and DMBPs were more abundant than their brominated and/or mixed halogenated counterparts. HOC profiles in coastal T. truncatus from Brazil and California revealed a distinct difference, with a higher abundance of MeO-BDEs, mirex/dechloranes and chlorinated bipyrroles in the Brazilian dolphins. Thirty-six percent of the detected HOCs had an unknown structure. These results suggest broad geographical differences in the patterns of bioaccumulative chemicals found in the marine environment and indicate the need to develop more complete catalogs of HOCs from various marine environments.
Nontargeted GC×GC-TOF/MS analysis of blubber from 8 common bottlenose dolphins (Tursiops truncatus) inhabiting the Southern California Bight was performed to identify novel, bioaccumulative ...DDT-related compounds and to determine their abundance relative to the commonly studied DDT-related compounds. We identified 45 bioaccumulative DDT-related compounds of which the majority (80%) is not typically monitored in environmental media. Identified compounds include transformation products, technical mixture impurities such as tris(chlorophenyl)methane (TCPM), the presumed TCPM metabolite tris(chlorophenyl)methanol (TCPMOH), and structurally related compounds with unknown sources, such as hexa- to octachlorinated diphenylethene. To investigate impurities in pesticide mixtures as possible sources of these compounds, we analyzed technical DDT, the primary source of historical contamination in the region, and technical Dicofol, a current use pesticide that contains DDT-related compounds. The technical mixtures contained only 33% of the compounds identified in the blubber, suggesting that transformation products contribute to the majority of the load of DDT-related contaminants in these sentinels of ocean health. Quantitative analysis revealed that TCPM was the second most abundant compound class detected in the blubber, following DDE, and TCPMOH loads were greater than DDT. QSPR estimates verified 4,4',4″-TCPM and 4,4'4,″-TCPMOH are persistent and bioaccumulative.
Passive samplers for moderately hydrophobic organic compounds (MHOCs) (i.e., log K
ranging from 2 to 5) are under-developed compared to those that target polar or strongly hydrophobic compounds. The ...goal of this study was to identify a suitable polymer and develop a robust and sensitive film-based passive sampler for MHOCs in aquatic systems. Poly(methyl methacrylate) (PMMA) exhibited the highest affinity for fipronil and its three metabolites (i.e., fipronils) (log K
2.4-4.8) as model MHOCs compared with polyethylene and nylon films. In addition, a 30-60 min treatment of PMMA in ethyl ether was found to increase its sorption capacity by a factor of 10. Fipronils and 108 additional compounds (log K
2.4-8.5) reached equilibrium on solvent-treated PMMA within 120 h under mixing conditions and their uptake closely followed first-order kinetics. PMMA-water partition coefficients and K
revealed an inverse parabolic relationship, with vertex at log K
of 4.21 ± 0.19, suggesting that PMMA was ideal for MHOCs. The PMMA sampler was tested in an urban surface stream, and in spiked sediment. The results demonstrated that PMMA film, after a simple solvent swelling treatment, may be used as an effective passive sampler for determining C
of MHOCs in aquatic environments.
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