A Multi-Generation Schmakeria poplesia Culturing System for Use in Ecotoxicological Study

Crustacean zooplankton form the keystone link between primary producers and fish stocks in marine and estuary, ecosystems. We have established a multi-generation cultivation system for zooplankton ruth which future experiments on the biological effects of pollutants in marine and estuary environments can be better performed. A population of calanoid copepod, Sehmakeria poplesia, was collected in December 2003 and maintained in a static system through all stages （eggs to adults）. The population ex- hinted an average developmental time of 13.6 d in conditions corresponding to the natural environment （water temperature 20~C salinity 15）. A series of experiments were performed to examine copepod egg production and hatching success as functions of food type and feeding concentration. Results in our study showed that Isoehrysis galbana was more favored for the reproduction of cope- pods than Phaeodactylum tricornutum, and 10xl0%ellsmL-1 was the most practical algae concentration. We have demonstrated that the Schmakeria poplesia population can be maintained in the laboratory through multiple generations. In addition, methods to control egg production through changes in food concentration have been established, making it feasible to control the start date of exposure experiments or the timing of the collection of oftspring to initiate a new generation.

Tracking Source Variations of Inhalation Cancer Risks and Ozone Formation Potential in Hong Kong over Two Decades(2000−2020)Using Toxic Air Pollutant Monitoring Data

Toxic air pollutants(TAPs)are a class of airborne chemicals known or suspected to cause serious health issues.This study,applying positive matrix factorization and inhalation unit risk estimates of TAPs,quantifies the changes in significant sources contributing to inhalation cancer risks(ICRs)from 2000 to 2020 in Hong Kong,China.Total ICR decreased from 1701 to 451 cases per million between 2000−2004 and 2016−2020,largely attributed to the reduction in diesel particulate matter(DPM),gasoline and solvent use-related volatile organic compounds(VOCs),and coal/biomass combustion-related polycyclic aromatic hydrocarbons and metal(loid)s.The regional contribution of VOCs associated with industrial and halogenated solvent sources increased substantially,representing the largest non-DPM ICR contributor(37%)in 2016−2020,stressing the need for a more comprehensive risk evaluation across the fast-growing and densely populated Greater Bay Area(GBA).ICRs in Hong Kong and the GBA will likely remain over 100 cases per million by 2050.The contributions to ozone formation potential of VOC/carbonyl sources were quantified,which show a notable shift from being solvent/gasoline-dominant in 2000−2004 to being more evenly shared by various sources in 2016−2020.Establishing a similar TAP monitoring network in the GBA is anticipated to provide the monitoring data needed to facilitate the development of more informed air quality management strategies.

城市污水处理厂进出水和中水中优先监测物质的监测方法研究

随着环境恶化的加剧和人类经济和科技发展,人类对已有资源的不满足和对新资源的渴求日益迫切.污水处理厂的二级出水的COD、BOD5、SS等值已达到地表水4级,甚至3级标准;外观清澈透明.……

Heterogeneous degradation of toxic organic pollutants by hydrophobic copper Schiff-base complex under visible irradiation

A hydrophobic complex of Cu2＋[bis-salicylic aldehyde-o-phenylenediamine], Cu-SPA, was prepared and used as a heterogeneous photocatalyst to degrade organic pollutants in water under visible irradiation （λ≥420 nm） at neutral pH. The structure of complex was characterized by using nuclear magnetic resonance （NMR）, elemental analysis, IR and UV-vis spectrometries. Degradation of Rhodamine B （RhB）, Sulforhodamine B （SRB） and Benzoic acid （BA） in water were used as model reactions to evaluate the photocatalytic activities of Cu-SPA. The results indicated that RhB and SRB were easily adsorbed on the hydrophobic surface of Cu-SPA from aqueous solution （the maximum adsorption amount： Qmax = 11.09 and 8.05 μmol/g, respectively）. Under visible irradiation, RhB and SRB were decolorized completely after 210 and 240 min, respectively, and BA was removed completely after 5 h. The efficiency of H202 was 〉 95%, in contrast to that of the reaction without catalyst or light （〈 20%）. In water soluble medium, the hydrophobic Cu-SPA can be used more than 6 cycles. ESR results and the behavior of cy- clic voltammetry showed that, in the reaction process, Cu2＋-SPA was reduced to intermediate state Cu＋-SPA firstly, which was extremely unstable and reacted rapidly with H2O2, leading to high reactive oxygen species （.OH radical ） to degrade the substrate.

EFFECTS OF A TOXICANT ON A SINGLE-SPECIES POPULATION WITH PARTIAL POLLUTION TOLERANCE IN A POLLUTED ENVIRONMENT

We study a model for the long-term behavior of a single-species population with some degree of pollution tolerance in a polluted environment. The model consists of three ordinary differential equations： one for the population density, one for the amount of toxicant inside the living organisms, and one for the amount of toxicant in the environment. We derive sufficient conditions for the persistence and the extinction of the population depending on the exogenous input rate of the toxicant into the environment and the level of pollution tolerance of the organisms. Numerical simulations are carried out to illustrate our main results.

Occurrence of polycyclic aromatic hydrocarbons in the estuarine sediments of the Taihu Lake and their associated toxic effects on aquatic organisms

Polycyclic aromatic hydrocarbons(PAHs)are ubiquitous toxic organic pollutants in the natural environment that are strongly associated with socioeconomic activities.Exploring the distribution,sources,and ecological toxicity of PAHs is essential to abate their pollution and biological risks.The 16 priority PAHs in different lakeside city estuarine sediments in the northern Taihu Lake in China were determined using gas chromatography-mass spectrometry.Results showed that total concentrations of PAHs(ΣPAHs)ranged from 672.07 to 5858.34 ng g^(^(-1)),with a mean value of 2121.37 ng g^(^(-1)).High-molecular-weight PAHs(4-6 rings)were dominant,accounting for 85%of theΣPAHs detected.Due to the barrier of gate/dam in the estuarine area,the concentrations of PAHs in the sediments were significantly different between the river mouth and lake side.Changes in total organic carbon(TOC)content and the spatial distribution of PAHs in the sediments were consistent.Sediment pollution assessment explored using the fuzzy evaluation model indicated 75%of slight PAH pollution.Some estuarine sediments(22%)concentrated in the east of the Wuli Lake in the Meiliang bay of the Taihu Lake were moderately or heavily polluted.The PAHs may lead to occasional detrimental biological consequences in the area.Diagnostic ratios and principal component analysis-multiple linear regression suggested vehicle emission and natural gas combustion as the primary PAH contributors(81%).

Integration of Chemical Methods and Biomarkers for Assessment of Chlorimuron-Ethyl Bioavailability in Soil

Bioavailability is a critical factor for assessing the environmental risk of organic pollutants in soil. In this study, extractions with 3 different solvents, including 2 aqueous solutions, calcium chloride(CaCl_2) and a phosphate buffer solution(PBS), and a mixture of aqueous solution and organic solvent, a PBS-methanol(8:2,volume/volume) mixture(PBS-M), were performed to assess the bioavailability of chlorimuron-ethyl in soil in comparison to a battery of toxicity tests in wheat seedlings. The results indicated that the peroxidase(POD) activity in wheat leaves after 7 d of exposure was one of the sensitive biomarkers of chlorimuron-ethyl in soil.The extractability of chlorimuron-ethyl by all the 3 solvents decreased with exposure time, and the rate of decrease of the PBS-M extraction between 1 and 7 d of exposure was substantially higher than those of the aqueous solution extractions. Chlorimuron-ethyl gradually changed from a water-soluble form into a soil organic matter(SOM)-bound form in the soil. The PBS extraction correlated best with the POD activity in the leaves after 7 d of exposure.