Spatial assessment of triazole organic compounds in surface water from the coastal estuaries to the East China sea

Species-specific and habitat-dependent bioaccumulation of halogenated flame retardants in marine organisms from estuary to coastal seas

Halogenated flame retardants (HFRs) have attracted global attention owing to their adverse effects on ecosystems and humans. The Shandong Peninsula is the largest manufacturing base for HFRs in East Asia, yet its impacts on marine ecosystems are unclear. Seventeen HFRs were analyzed in organisms captured from the Xiaoqing River estuary, Bohai Sea (BS), Yellow Sea and Northern East China Sea to investigate the distribution and bioaccumulation of HFRs on a broad scale. The results showed a downward trend in ΣHFR concentrations from the estuary (37.7 ng/g lw on average) to Laizhou Bay (192 ng/g lw) and to coastal seas (3.13 ng/g lw). The concentrations of ΣHFRs were significantly higher in demersal fish (0.71-198 ng/g lw) and benthic invertebrates (0.81-3340 ng/g lw) than in pelagic fish (0.30-27.6 ng/g lw), reflecting a habitat dependence. The concentrations of higher-brominated homologs were greater in benthic invertebrates, whereas a greater level of lower-brominated PBDE congeners was observed in fish, suggesting different profiles between species. Furthermore, the analogue composition of HFRs in fish was similar to that in the dissolved phase of seawater, whereas the HFR pattern in benthic invertebrates was consistent with the profile in sediment. The concentrations of HFRs in organisms vary widely depending on emissions from anthropogenic activities, whereas bioaccumulation patterns are strongly influenced by species and habitat.

Aquatic and sediment ecotoxicity data of difenoconazole and its potential environmental risks in ponds bordering rice paddies

Difenoconazole has a widespread agricultural use to control fungal diseases in crops, including rice. In edge-of-field surface waters the residues of this lipophilic fungicide may be toxic to both pelagic and benthic organisms. To allow an effect assessment we mined the regulatory and open literature for aquatic toxicity data. Since published sediment toxicity data were scarce we conducted 28 d sediment-spiked toxicity test with 8 species of benthic macroinvertebrates. Ecotoxicological threshold levels for effects were assessed by applying the species sensitivity distribution approach. Based on short-term L(E)C50's for aquatic organisms from water-only tests an acute Hazardous Concentration to 5% of the species (HC5) of 100 µg difenoconazole/L was obtained, while the HC5 based on chronic NOEC values was a factor of 104 lower (0.96 µg difenoconazole/L). For benthic macroinvertebrates the chronic HC5, based on 28d-L(E)C10 values, was 0.82 mg difenoconazole/kg dry weight sediment. To allow a risk assessment for water- and sediment-dwelling organisms, exposure concentrations were predicted for the water and sediment compartment of an edge-of-field pond bordering rice paddies treated with difenoconazole using the Chinese Top-Rice modelling approach, the Chinese Nanchang exposure scenario and the Equilibrium Partitioning theory. It appeared that in the vast majority of the 20 climate years simulated, potential risks to aquatic and sediment organisms cannot be excluded. Although the HC5 values based on laboratory toxicity data provide one line of evidence only, our evaluation suggests population- and community-level effects on these organisms due to chronic risks in particular.

Spatial distribution and risk assessment of pyrethroid insecticides in surface waters of East China Sea estuaries

Pyrethroid insecticides are the most commonly used household insecticides and pose substantial risks to marine aquatic organisms. many studies have detected pyrethroid insecticides in the waters and estuaries of the western United States, but their distributions within western Pacific estuaries have not been reported. Accordingly, we used high-throughput organic analyses combined with high volume solid-phase extraction to comprehensively assess 13 pyrethroid insecticides in East China Sea estuaries and the Huangpu River. The results demonstrated the presence of various ∑13pyrethroid insecticides in East China Sea estuaries (mean and median values of 8.45 ± 5.57 and 7.78 ng L-1, respectively), among which cypermethrin was the primary contaminant. The concentrations of ∑12pyrethroid insecticide detected in the surface waters at the Huangpu River (mean 6.7 ng L-1, outlet 16.4 ng L-1) were higher than those in the Shanghai estuary (4.7 ng L-1), suggesting that runoff from inland areas is a notable source of insecticides. Wetlands reduced the amount of runoff containing pyrethroid insecticides that reached the ocean. Several factors influenced pesticide distributions in East China Sea estuaries, and higher proportions were derived from agricultural sources than from urban sources, with a higher proportion of agricultural sources than urban sources, influenced by anthropogenic use in the region. Permethrin and cypermethrin were the main compounds contributing to the high ecological risk in the estuaries. Consequently, to prevent risks to marine aquatic life, policymakers should aim to reduce insecticide contaminants derived from urban and agricultural sources.