Sediment quality guidelines for copper and zinc for filter-feeding estuarine oysters?

Sediment quality guidelines (SQGs) assess the ability of bottom sediment to sustain healthy infauna and water quality guidelines (WQGs) provide protection for a designated percentage of aquatic species. Filter-feeding marine species, e.g. oysters and mussels, acquire food from particles in the water column and protection of these animals is not provided by SQGs or WQGs. The current work investigated the relationship between metal (Cu, Zn) concentrations in total and fine-fraction (<62.5 μm) surficial sediment digested in a range of acids and chelating agents and oyster tissue metal concentrations. A strong correlation between oyster tissue Cu and Zn concentrations and fine-fraction surficial sediment digested in 1 M HCl provided a sedimentary guideline which predicted tissue metal concentrations in oysters and established a level (<45 μg g⁻¹ and <1000 μg g⁻¹, respectively) for protecting oysters from exceeding human consumption levels (70 μg g⁻¹ and 1000 μg g⁻¹, respectively).     

Inputs of antifouling paint-derived dichlorodiphenyltrichloroethanes (DDTs) to a typical mariculture zone (South China): potential impact on aquafarming environment

Existing evidence indicated that dichlorodiphenyltrichloroethane (DDT)-containing antifouling paints were an important source of DDT residues to mariculture zones. However, the magnitude of the impact on aquafarming environment has remained largely unknown. In the present study, the concentrations of DDT and its metabolites (designated as DDXs) were determined in harbor sediment and antifouling paint samples collected from a typical mariculture zone in South China. Compositional and concentration correlation analyses implicated the DDT-containing antifouling paints for fishing boat maintenance as an important source of DDT in the mariculture zone. The annual emission of DDXs to the study region was estimated at 0.58 tons/yr. Furthermore, a comparison of the expected DDT loadings in pelagic fish and field measurements indicated that fish feed especially trash fish was a major source of DDTs in the fish body. Nevertheless, the use of DDT-containing antifouling paints should be limited to prevent further deterioration in aquafarming environment.     

Organochlorine pesticide residues in sediments from the Uganda side of Lake Victoria

Organochlorine (OC) residues were analysed in 117 sediment samples collected from four bays of the Uganda side of Lake Victoria. The sediments were collected with a corer at a depth of 0-20 cm, and extracted for OC residues using a solid dispersion method. The extracts were cleaned using gel permeation chromatography and analysed for pesticide residues using a gas chromatograph (GC) equipped with an electron capture detector. The results were confirmed using a GC equipped with a mass spectrometer (MS). A total of 16 OC residues, most of them persistent organic pollutants (POPs) were identified and quantified. The OC residue levels were expressed on an oven dry weight (d.w.) basis. Endosulphan sulphate, in the range of 0.82-5.62 μg kg⁻¹d.w., was the most frequently detected residue. Aldrin and dieldrin were in the ranges of 0.22-15.96 and 0.94-7.18 μg kg⁻¹d.w., respectively. DDT and its metabolites lay between 0.11-3.59 for p,p′-DDE, 0.38-4.02 for p,p′-DDD, 0.04-1.46 for p,p′-DDT, 0.07-2.72 for o,p′-DDE and 0.01-1.63 μg kg⁻¹d.w. for o,p′-DDT. The levels of γ-HCH varied from 0.05 to 5.48 μg kg⁻¹d.w. Heptachlor was detected only once at a level of 0.81 μg kg⁻¹d.w., while its photo-oxidation product, heptachlor epoxide, ranged between non-detectable (ND) to 3.19 μg kg⁻¹d.w. Chlordane ranged from ND to 0.76 μg kg⁻¹d.w. Based on the threshold effect concentration (TEC) for fresh water ecosystems, aldrin and dieldrin were the only OCs that seemed to be a threat to the lake environment.     

Runoff effect on eutrophic lake water quality and heavy metal distribution in recent littoral sediment

Multivariate statistical methods (hierarchical clustering analysis: HCA, and principal component analysis: PCA) were used to study the influence of runoff and other diffuse pollution sources on lake water chemistry of Hough Park lake in Central Missouri. In addition, heavy metal concentrations in lake littoral sediment were evaluated for enrichment and probable ecological risk. The abundance of macronutrients in the lake water column followed the order: Ca > Mg > TIC > K > Na > S > NO₃ - N > Fe > NH₃ - N > TP. Heavy metal concentrations in the lake water column were below acute and chronic level ecological guidelines. TN:TP ratios (range: 4.1-6.8) revealed nitrogen limitation of algal and other photosynthetic plant growth. The HCA showed two major clusters of similarity between the sampling points suggesting different pollution levels for the clusters. PCA 1, 2 and 3 reflected the influence of natural biochemical processes, atmospheric deposition and runoff respectively on lake water chemistry. The abundance of heavy metals and the normalizing element (Li) in littoral sediment (<63 μm fraction) samples analyzed in decreasing order were: Mn > Zn > Cr > Ni > Li > Cu > Pb > Cd > Hg. The average concentration of Cr, Mn and Ni in littoral sediment fraction exceeded the respective lowest effects level (LEL) threshold limit. Metal bioavailability in sediment fraction was low since the most labile metal species contained between 0% and 11% of the total metal content. Using the risk assessment code (RAC) criteria, only Mn posed a medium risk to the lake system.     

Limitations of reverse polyethylene samplers (RePES) for evaluating toxicity of field contaminated sediments

Passive samplers are used to measure dissolved nonionic organic contaminants (NOCs) in environmental media. More recently, reverse polyethylene samplers (RePES) have been used with spiked sediments to recreate interstitial water exposure concentrations and observed toxicity. In the present study, RePES were used with field contaminated sediments. The RePES was not capable of recreating the pattern of toxicity with the amphipod and mysid observed with intact field sediments. Decreased survival in the RePES exposures as compared to the whole sediment exposures was most likely caused by an overexposure to NOCs due to a lack of surrogate black carbon in the RePES system. As an alternative, aqueous phase studies were performed in which polyethylene was allowed to equilibrate with slurries of intact sediments for 3 weeks. Three weeks was found to be an insufficient amount of time for the polyethylene to equilibrate with the sediment. An additional study demonstrated 3 months was sufficient for lower contaminant concentrations, but might not be an adequate amount of time for more highly contaminated sediments. The aqueous phase transfer approach may be useful if equilibration is sufficiently long, although this length of time may be impractical for use in certain applications, such as toxicity identification evaluations (TIEs).     

Polychlorinated biphenyls in surface sediments of Yueqing Bay, Xiangshan Bay, and Sanmen Bay in East China Sea

The spatial distribution and source of polychlorinated biphenyls (PCBs) in 30 surface sediments of Yueqing Bay, Xiangshan Bay, and Sanmen Bay in Eastern China were analysed. Total concentrations of PCBs ranged from 9.33 to 19.60 ng g⁻¹ dry weight for all the sampling stations. The observed PCB levels were lower than those in areas of high urbanisation or contamination in the bay. Low-chlorinated PCBs, dominated by tri-PCB, were identified as the prevalent contaminate of surface sediments, and the top three PCB congeners were lighter chlorinated congeners (PCB 8, PCB 18 and PCB 28). These results were in agreement with the fact that tri-PCB compounds are the dominant contaminants in China. The result of the principal component analysis revealed that all samples were similar in composition to Aroclor 1242, suggesting they might originate from electrical capacitors and transformers. The levels of PCBs were significantly correlated with the total organic carbon in the sediments.     

珠江(广州河段)表层沉积物中的重金属污染调查与评价

应用地累积指数法对珠江(广州河段)表层沉积物中重金属污染程度进行了调查与评价.结果表明,其表层沉积物中重金属的地累积指数大小顺序为:Cu＞Cd＞Zn＞Pb＞As＞Cr＞Hg,其中Cu是主要污染物,Cd、Zn和Pb的地累积指数较高.在所有监测断面中,地累积级别达到4级(强污染)的有5个断面,即4#(雅瑶大桥)、5#(黄歧)、6#(黄沙)、7#(横滘)和16#(花地涌北出口).     

多种聚氧乙烯牛脂胺混合物MON 0818的水生环境危害评估：脉冲暴露后沉积物、温度和恢复能力的影响

我们对一种商业表面活性剂混合物(多种聚氧乙烯牛脂胺)MON 0818进行了一系列毒性测试：1. 测定底栖无脊椎动物和鱼类在沉积物存在的情况下受到的毒性;2.测定大型蚤(Daphnia magna)和4种初级生产者经过24 h的脉冲暴露之后的恢复能力;3.鉴定水体温度上升对于2种冷水鱼类所受到MON 0818毒性的潜在影响。在沉积物存在的情况下,5种生物中有3种在最高10 mg/L的浓度下短期(24 h)死亡率为零。其余2种物种的中位有效浓度则显著高于仅对水体进行测试的结果。15 ℃下北极红点鲑(Salvelinus alpinus)的半数有效浓度统计上低于10 ℃下。绿藻(Rhabdocelis subcapitata)和普通小球藻(Chlorella vulgaris)在经过24 h 1 mg/L的暴露后的恢复期中显示出生长延迟的状况,表明该暴露可能存在潜在影响。尽管如此,2个物种的最大绝对生长速率并未改变,表明其均可恢复。1.5 mg/L下的蝾螈共生藻(Oophila sp.)和100 mg/L下的浮萍(Lemna minor)经过24 h的暴露并未显示显著反应。24 h 5 mg/L暴露之后的恢复期中,大型蚤显示出潜在的死亡率。然而存活个体的生殖终端指标并未受到影响。结果表明在沉积物的存在下MON 0818的快速损耗可以减轻对于被暴露生物的效果,在不小于环境中可能出现的MON 0818浓度情况下,24 h暴露以后的生物的完全恢复是可能的。
精选自Jose L. Rodriguez-Gil, Ryan Prosser, Gregory Hanta, David Poirier, Linda Lissemore, Mark Hanson, Keith R. Solomon. Aquatic hazard assessment of MON 0818, a commercial mixture of alkylamine ethoxylates commonly used in glyphosate-containing herbicide formulations. Part 2: Roles of sediment, temperature, and capacity for recovery following a pulsed exposure. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 512–521, July 2017. DOI: 10.1002/etc.3558
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3558/full
     

Behaviour of pharmaceuticals in spiked lake sediments - effects and interactions with benthic invertebrates

The behaviour and effects of atorvastatin (ATO), carbamazepine (CBZ), and 17α-ethinylestradiol (EE2) were investigated in spiked lake sediments, at concentrations up to 56.5 mg kg⁻¹ dry weight (dw), with the benthic invertebrates Chironomus dilutus and Hyalella azteca. Desorption constants were calculated in the presence and absence of animals, using linear isotherms, yielding K_d values of 28.2, 189.0 and 125.1 L kg⁻¹ (ATO), 73.7, 201.7 and 263.2 L kg⁻¹ (CBZ), and 114.9, 114.2 and 519.2 L kg⁻¹ (EE2) for C. dilutus, H. azteca, and without animals, respectively. For ATO and CBZ, K_d values were smaller in the presence of C. dilutus, indicating greater desorption to the overlying water from bioturbation, which is consistent with the predominantly benthic occurrence of C. dilutus compared to H. azteca. In contrast, due to its greater hydrophobicity, bioturbation did not significantly affect desorption of EE2. No significant toxicity was observed, indicating decreased bioavailability of the chemicals sorbed to sediments compared with water-only toxicity assays.     

Release of pentachlorophenol from black carbon-inclusive sediments under different environmental conditions

To investigate the feasibility of using black carbon (BC) in the control of hydrophobic organic contaminants (HOCs) in sediment, we added BCs from various sources (rice straw charcoal (RC), fly ash (FC) and soot (SC)) to sediment to create different BC-inclusive sediments and studied the release of pentachlorophenol (PCP) in the sediments under different condition. Different pH values had no obvious effect on the release of PCP in BC-inclusive sediment, but solid/liquid ratio, temperature, salinity and dissolved organic matter (DOM) content had significant influences on the release of PCP in all sediments except the RC-inclusive sediment. Adding 2% RC to sediment resulted in a 90% decrease in PCP release, which was a greater decrease than observed with FC- and SC-inclusive sediments. Therefore, from the standpoint of HOC release, the application of RC is feasible for organic pollution control in the water environment.