The annual cycle of abundance and distribution of the scyphozoan medusae Aurelia aurita, Cyanea lamarckii, C. capillata and Chrysaora hysoscella were studied in the southern North Sea in 2004 and 2005. Three different patterns of seasonal occurrence of medusae were
distinguished: (1) the early occurring C. lamarckii (February–August), (2) C. capillata and A. aurita (April–August) and (3) the late appearing C. hysoscella (July/August–September). Cyanea lamarckii was the most frequently encountered species in this study; its highest mean abundance was 1.8 ± 2.7 ind. 100 m−3. The prey spectra of C. lamarckii, C. capillata and C. hysoscella contained several copepod and other crustacean species and thus make them potential competitors with fish larvae. Medusae
in this study also consumed fish eggs and larvae, including clupeids, in all months analysed. Although peak spawning of sprat
(Sprattus sprattus) coincides with the maximum abundance of medusae (May–June) the relative low abundance of all medusae species in this study
makes jellyfish predation unlikely to be a factor controlling sprat recruitment in the time frame investigated. 相似文献
When microalgae are simultaneously applied for wastewater treatment and lipid production, soluble algal products (SAP) should be paid much attention, as they are important precursors for formation of disinfection byproducts (DBPs), which have potential risks for human health. Chlorella sp. HQ is an oleaginous microalga that can generate SAP during growth, especially in the exponential phase. This study investigated the contribution of SAP from Chlorella sp. HQ to DBP formation after chlorination. The predominant DBP precursors from SAP were identified with the 3D excitation-emission matrix fluorescence. After chlorination, a significant reduction was observed in the fluorescence intensity of five specific fluorescence regions, particularly aromatic proteins and soluble microbial by-product-like regions, accompanied with slight shifting of the peak. The produced DBPs were demonstrated to include trihalomethanes and haloacetic acids. As the algal cultivation time was extended in wastewater, the accumulated SAP strengthened the formation of DBPs. The trend for DBP formation was as follows: chloroform>dichloroacetic acid>trichloroacetic acid.
• Hg bioaccumulation by phytoplankton varies among aquatic ecosystems.• Active Hg uptake may exist for the phytoplankton in aquatic ecosystems.• Impacts of nutrient imbalance on food chain Hg transfer should be addressed. The bioaccumulation of mercury (Hg) in aquatic ecosystem poses a potential health risk to human being and aquatic organism. Bioaccumulations by plankton represent a crucial process of Hg transfer from water to aquatic food chain. However, the current understanding of major factors affecting Hg accumulation by plankton is inadequate. In this study, a data set of 89 aquatic ecosystems worldwide, including inland water, nearshore water and open sea, was established. Key factors influencing plankton Hg bioaccumulation (i.e., plankton species, cell sizes and biomasses) were discussed. The results indicated that total Hg (THg) and methylmercury (MeHg) concentrations in plankton in inland waters were significantly higher than those in nearshore waters and open seas. Bioaccumulation factors for the logarithm of THg and MeHg of phytoplankton were 2.4–6.0 and 2.6–6.7 L/kg, respectively, in all aquatic ecosystems. They could be further biomagnified by a factor of 2.1–15.1 and 5.3–28.2 from phytoplankton to zooplankton. Higher MeHg concentrations were observed with the increases of cell size for both phyto- and zooplankton. A contrasting trend was observed between the plankton biomasses and BAFMeHg, with a positive relationship for zooplankton and a negative relationship for phytoplankton. Plankton physiologic traits impose constraints on the rates of nutrients and contaminants obtaining process from water. Nowadays, many aquatic ecosystems are facing rapid shifts in nutrient compositions. We suggested that these potential influences on the growth and composition of plankton should be incorporated in future aquatic Hg modeling and ecological risk assessments. 相似文献
● Reduce the quantifying MPs time by using Nile red staining.● The removal rate of MPs and PAEs in wastewater and sludge were investigated.● MPs and PAEs were firstly analyzed during thermal hydrolysis treatment.● The removal of PAEs from wastewater and sludge was mainly biodegradation. Microplastics (MPs) and plasticizers, such as phthalate esters (PAEs), were frequently detected in municipal wastewater treatment plants (MWTP). Previous research mainly studied the removal of MPs and PAEs in wastewater. However, the occurrence of MPs and PAEs in the sludge was generally ignored. To comprehensively investigate the occurrence and the migration behaviors of MPs and PAEs in MWTP, a series of representative parameters including the number, size, color, shape of MPs, and the concentrations of PAEs in wastewater and sludge were systematically investigated. In this study, the concentrations of MPs in the influent and effluent were 15.46±0.37 and 0.30±0.14 particles/L. The MP removal efficiency of 98.1% was achieved and about 73.8% of MPs were accumulated in the sludge in the MWTP. The numbers of MPs in the sludge before and after digestion were 4.40±0.14 and 0.31±0.01 particles/g (dry sludge), respectively. Fourier Transform Infrared Spectroscopy (ATR FT-IR) analysis showed that the main types of MPs were polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), and polystyrene (PS). Six PAEs, including phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), ortho dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), and bis(2-ethyl) hexyl phthalate (DEHP), were detected in the MWTP. The concentrations of total PAEs (ΣPAEs) in the influent and effluent were 76.66 and 6.28 µg/L, respectively. The concentrations of ΣPAEs in the sludge before and after digestion were 152.64 and 31.70 µg/g, respectively. In the process of thermal hydrolysis, the number and size of MPs decreased accompanied by the increase of the plasticizer concentration. 相似文献
● This study systematically examined the relationship between groundwater Cd and UCL.● The study covered 211 UCL and sociological characteristic from nine groundwater samples.● We found a significant positive correlation between groundwater Cd and UCL.● Smoking status and education level also significantly affected UCL. Cadmium (Cd) has received widespread attention owing to its persistent toxicity and non-degradability. Cd in the human body is mainly absorbed from the external environment and is usually assessed using urinary Cd. Hunan Province is the heartland of the Chinese non-ferrous mining area, where several serious Cd pollution events have occurred, including high levels of Cd in the urine of residents. However, the environmental factors influencing high urinary Cd levels (UCLs) in nearby residents remain unclear. Therefore, 211 nearby residents’ UCLs and the corresponding sociological characteristics from nine groundwater samples in this area were analyzed using statistical analysis models. Groundwater Cd concentration ranged from 0.02 to 1.15 μg/L, aligning with class III of the national standard; the range of UCL of nearby residents was 0.37–36.60 μg/L, exceeding the national guideline of 0–2.5 μg/L. Groundwater Cd levels were positively correlated with the UCL (P < 0.001, correlation coefficient 95 % CI = 9.68, R2 = 0.06). In addition, sociological characteristics, such as smoking status and education level, also affect UCL. All results indicate that local governments should strengthen the prevention and abatement of groundwater Cd pollution. This study is the first to systematically evaluate the relationship between groundwater Cd and UCL using internal and external environmental exposure data. These findings provide essential bases for relevant departments to reduce Cd exposure in regions where the heavy metal industry is globally prevalent. 相似文献
• A novel and multi-functional clay-based oil spill remediation system was constructed.• TiO2@PAL functions as a particulate dispersant to break oil slick into tiny droplets.• Effective dispersion leads to the direct contact of TiO2 with oil pollutes directly.• TiO2 loaded on PAL exhibits efficient photodegradation for oil pollutants.• TiO2@PAL shows a typical dispersion-photocatalysis synergistic remediation. Removing spilled oil from the water surface is critically important given that oil spill accidents are a common occurrence. In this study, TiO2@Palygorskite composite prepared by a simple coprecipitation method was used for oil spill remediation via a dispersion-photodegradation synergy. Diesel could be efficiently dispersed into small oil droplets by TiO2@Palygorskite. These dispersed droplets had an average diameter of 20–30 mm and exhibited good time stability. The tight adsorption of TiO2@Palygorskite on the surface of the droplets was observed in fluorescence and SEM images. As a particulate dispersant, the direct contact of TiO2@Palygorskite with oil pollutants effectively enhanced the photodegradation efficiency of TiO2 for oil. During the photodegradation process, •O2−and •OH were detected by ESR and radical trapping experiments. The photodegradation efficiency of diesel by TiO2@Palygorskite was enhanced by about 5 times compared with pure TiO2 under simulated sunlight irradiation. The establishment of this new dispersion-photodegradation synergistic remediation system provides a new direction for the development of marine oil spill remediation. 相似文献