Near-total darkness and water depths below 200 m define the deep sea, Earth’s largest yet most poorly studied ecosystem. Sowerby’s beaked whales (Mesoplodon bidens), elusive deep-sea foragers, offer a unique opportunity to assess the impacts of anthropogenic pollutants in this remote environment. This study examined a range of legacy and emerging hydrophobic pollutants, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and polychlorinated alkanes (PCAs), across tissues from five stranded whales foraging in Swedish waters. Despite global efforts to reduce pollution, significant pollutant levels in these whales underscore the persistence of legacy contaminants and the widespread use of PCAs. Most pollutants were concentrated in lipid-rich blubber, while PCAs exhibited particularly high levels in whole blood (941-13100 ng/g lipid), indicating tissue-specific accumulation. Blubber pollutant levels were similar to those of harbor porpoises from the same waters, with p,p′-DDE (1020-2280 ng/g lipid) and PCBs (1230-1930 ng/g lipid) exceeding or nearing effect thresholds. Blood concentrations of legacy pollutants were approximately an order of magnitude higher than those in humans from the region, while PCA levels were comparable to those of humans. These findings highlight the urgent need to investigate deep-sea exposure pathways and develop effective management strategies.

Background: Polychlorinated alkanes (PCAs) constitute a large group of individual congeners originating from commercial chlorinated paraffin (CP) products with carbon chain lengths of PCAs-C_10-13, PCAs-C_14-17, and PCAs-C_18-32, occasionally containing PCAs-C_6-9 impurities. The extensive use of CPs has led to global environmental pollution of PCAs. This study aimed to quantify PCAs in paired serum and breast milk of lactating Swedish mothers, exploring their concentration relationship.

Methods: Twenty-five paired samples of mothers’ blood serum and breast milk were analysed and concentrations were determined for PCAs C_6-32 and compared to 4,4′-DDE, the PCB congener 2,2′,4,4′,5,5′-hexachlorobiphenyl (CB-153), and hexachlorobenzene (HCB).

Results: The median concentrations of PCAs-C_6-9, PCAs-C_10-13, PCAs-C_14-17, PCAs-C_18-32 and ΣPCAs in serum were 14, 790, 520, 16 and 1350 ng/g lipid weight (lw), respectively, and in breast milk 0.84, 36, 63, 6.0 and 107 ng/g lw. Levels of 4,4′-DDE, CB-153 and HCB were comparable in the two matrices, serum and breast milk at 17, 12 and 4.9 ng/g lw. The results show significant differences of PCAs-C_10-13 and PCAs-C_14-17 in breast milk with 22– and 6.2-times lower lw-based concentrations than those measured in serum. On wet weight the differences serum/breast milk ratios of PCAs-C_6-9, PCAs-C_10-13, PCAs-C_14-17, PCAs-C_18-32 and ΣPCAs were 1.7, 3.2, 1.0, 0.4 and 1.6, respectively, while the ratio for 4,4′-DDE, CB-153 and HCB were each close to 0.1.

Conclusion: Swedish lactating mothers had high serum concentrations of PCAs-C_10-13 and PCAs-C_14-17, with the ΣPCAs median serum concentration of 1350 ng/g lw. The breast milk concentration, although considerably lower at 107 ng/g lw, still surpassed those of 4,4′-DDE, CB-153 and HCB, suggesting an exposure risk of infants to PCAs. The variation in blood and breast milk accumulation between PCAs and studied legacy POPs, is rarely discussed but warrants further studies on partitioning properties as well as associated toxicological implications.

The large number and diversity of organohalogen compounds(OHCs)occurring in the environment poses a grand challenge to analyticalchemists. Since no single targeted method can identify and quantifyall OHCs, the size of the OHC iceberg may be underestimated.We sought to address this problem in municipal wastewater treatmentplant (WWTP) sludge by quantifying the unidentified fraction of theOHC iceberg using targeted analyses of major OHCs together with measurementsof total and extractable (organo)halogen (TX and EOX, respectively;where X = F, Cl, or Br). In addition to extensive method validationvia spike/recovery and combustion efficiency experiments, TX and/orEOX were determined in reference materials (BCR-461 and NIST SRMs2585 and 2781) for the first time. Application of the method to WWTPsludge revealed that chlorinated paraffins (CPs) accounted for most(similar to 92%) of the EOCl, while brominated flame retardants and per-and polyfluoroalkyl substances (PFAS) accounted for only 54% of theEOBr and 2% of the EOF, respectively. Moreover, unidentified EOF innonpolar CP extracts points to the existence of organofluorine(s)with physical-chemical properties unlike those of target PFAS.This study represents the first multihalogen mass balance in WWTPsludge and offers a novel approach to prioritization of sample extractsfor follow-up investigation. A multihalogenmass balance experiment in WWTP sludge revealedhigh levels of unidentified organofluorine and organobromine. Organochlorinewas characterized mainly by chlorinated paraffins.

Determining the major human exposure pathways is a prerequisite for the development of effective management strategies for environmental pollutants such as chlorinated paraffins (CPs). As a first step, the internal and external exposure to CPs were quantified for a well-defined human cohort. CPs in participants’ plasma and diet samples were analyzed in the present study, and previous results on paired air, dust, and hand wipe samples were used for the total exposure assessment. Both one compartment pharmacokinetic modeling and forensic fingerprinting indicate that dietary intake contributed the most to body burden of CPs in this cohort, contributing a median of 60–88% of the total daily intakes. The contribution from dust ingestion and dermal exposure was greater for the intake of long-chain CPs (LCCPs) than short-chain CPs (SCCPs), while the contribution from inhalation was greater for the intake of SCCPs than medium-chain CPs (MCCPs) and LCCPs. Significantly higher concentrations of SCCPs and MCCPs were observed in diets containing butter and eggs, respectively (p < 0.05). Additionally, other exposure sources were correlated to plasma levels of CPs, including residence construction parameters such as the construction year (p < 0.05). This human exposure to CPs is not a local case. From a global perspective, there are major knowledge gaps in biomonitoring and exposure data for CPs from regions other than China and European countries.

Paddy plants provide staple food for 3 billion people worldwide. This study explores the environmental fate and behavior of a high-volume production emerging contaminants chlorinated paraffins (CPs) in the paddy ecosystem. Very-short-, short-, medium-, and long-chain CPs (vSCCPs, SCCPs, MCCPs, and LCCPs, respectively) were analyzed in specific tissue of paddy plants at four main growth stages and soils from the Yangtze River Delta, China throughout a full rice growing season. The total CP concentrations in the paddy roots, stalks, leaves, panicles, hulls, rice, and soils ranged from 181 to 1.74 × 10³, 21.7–383, 19.6–585, 108–332, 245–470, 59.6–130, and 99.6–400 ng/g dry weight, respectively. The distribution profile indicated the translocation of SCCPs and MCCPs from soils to paddy tissue, highlighting their elevated bioaccumulative potential. The evolution of CP level/mass/pattern during the whole growth cycle suggested atmospheric CPs deposition on leaves and hulls, as well as stalk-rice transfer. CSOIL plant uptake model well predicted the level, distribution pattern, and bioconcentration factors (BCFs) of SCCPs and MCCPs in paddy shoot and recognized the soil-air-shoot pathway as the major contributor. Moreover, risk evaluation indicated that MCCPs intake and subsequent risks dominated the total exposure to CPs via rice ingestion. This is the first report on the occurrence, fate and risk assessment of all CPs classes in paddy ecosystems, and the results underline the potential health effects caused by the in-use MCCPs via rice ingestion.

The Stockholm Convention is key to addressing the global threats of persistent organic pollutants (POPs) to humanity and the environment. It has been successful in identifying new POPs, but its national implementation remains challenging, particularly by low- and middle-income Parties. Concerted action is needed to assist Parties in implementing the Convention’s obligations. This analysis aims to identify and recommend research and scientific support needed for timely implementation of the Convention. We aim this analysis at scientists and experts from a variety of natural and social sciences and from all sectors (academia, civil society, industry, and government institutions), as well as research funding agencies. Further, we provide practical guidance to scientists and experts to promote the visibility and accessibility of their work for the Convention’s implementation, followed by recommendations for sustaining scientific support to the Convention. This study is the first of a series on analyzing policy needs for scientific evidence under global governance on chemicals and waste. 

Germany is one of several major European producers of chlorinated paraffins (CPs). This study showed that not only the legacy short-chain products (SCCPs, C10-13), but also the current-use medium- and long-chain products (MCCPs, C14-17; LCCPs, C 17) as well as the very-short-chain impurities (vSCCPs, C<10) are ubiquitous in the 72 samples collected from the coastal, terrestrial, and freshwater ecosystems across the country. The concentrations of LCCPs surpassed those of the other CPs in 40% of the biota samples. Archived bream samples collected downstream of a CP-manufacturing factory showed decreasing temporal trends of (v)SCCPs and relatively constant levels of MCCPs from 1995 to 2019; however, the overall levels of LCCPs have increased by 290%, reflecting the impact of chemical regulation policies on changes in CP production. A visualization algorithm was developed for integrating CP results from various matrices to illustrate spatial tendencies of CP pollution. Higher levels of (v)SCCPs were indicated in the former West Germany region, while MCCP and LCCP concentrations did not seem to differ between former East and West Germany, suggesting relatively equal production and use of these chemicals after the German Reunification. The results provide an early warning signal of environmental concerns from LCCPs on the eve of their booming global production and use.

Previous studies have found relatively high chlorinated paraffin (CP) concentrations in moose (Alces alces) compared with other wildlife from Scandinavia. To explore CP accumulation behaviors in this long-lived terrestrial mammal, temporal trends of muscle concentrations of CPs were first measured in samples collected over the past 40 years from moose calves from Grimsö, Sweden. The four CP classes, i.e., very-short-chain, short-chain, medium-chain, and long-chain (LCCPs) classes, showed similar temporal trends, with increasing concentrations from 1982 to the 1990s, relatively high levels in two time periods around 1993 and 2008, and decreasing concentrations after 2012. A concentration plateau period was identified, and moose samples of both sexes and different ages from the median year (1993) of the concentration plateau period were selected for further analysis. CP levels increased exponentially with age in the male moose, while CP levels were found to exponentially decrease with age in females. LCCPs showed the slowest decreasing tendency with age in females compared with the other three classes, resulting in a general increase of the LCCP proportions with age. The sex-biased accumulation of CPs indicates additional stresses from these POP-like chemicals toward males of the largest and one of the most widespread terrestrial mammals in northern hemisphere forests. 

Cationic surfactants have a strong affinity to sorb to phospholipid membranes and thus possess an inherent potential to bioaccumulate, but there are few measurements of bioconcentration in fish. We measured the bioconcentration of 10 alkylamines plus two quaternary ammonium compounds in juvenile rainbow trout at pH 7.6, and repeated the measurements at pH 6.2 for 6 of these surfactants. The BCF of the amines with chain lengths <= C-14 was positively correlated with chain length, increasing similar to 0.5 log units per carbon. Their BCF was also pH dependent and approximately proportional to the neutral fraction of the amine in the water. The BCFs of the quaternary ammonium compounds showed no pH dependence and were >2 orders of magnitude less than for amines of the same chain length at pH 7.6. This indicates that systemic uptake of permanently charged cationic surfactants is limited. The behavior of the quaternary ammonium compounds and the two C-16 amines studied was consistent with previous observations that these surfactants accumulate primarily to the gills and external surfaces of the fish. At pH 7.6 the BCF exceeded 2000 L kg(-1) for 4 amines with chains >= C-13, showing that bioconcentration can be considerable for some longer chained cationic surfactants.