Pollution status and potential ecological risk assessment in the surface sediments of the Yellow River estuary

Based on the ＂Project 908＂ survey data in 2006--2007 on surface sediments of the sea area adjacent to the Yellow River estuary, the research was conducted on the concentration distribution characteristics of heavy metals in surface sediments of the estuary, which show that the mean contents of seven heavy metals （Cu, Pb, Zn, Cd, Cr, Hg, As） in the Yellow River estuary and its surrounding areas all comply with the Level-I of National Marine Sediments Quality Standard of China. Statistically significant correlation between the elements Cu-Cd, Pb-Cr and Cr-As in sediments indicates that the two heavy metals in each group may respectively have similar geochemical properties and sources. By using the Potential Ecological Risk Index （PERI） proposed by Hakanson, the assessment shows that the potential ecological risks in the estuary surface sediments are mainly attributed to Cd and Hg. The biological toxicity effects are assessed with the biological effects of concentration method, resulting in a conclusion that the adverse effects of As on organisms in the estuary marine environment occasionally occur, in contrast, Cu, Pb, Zn, Cd, Cr and Hg will not generate adverse biological effects on a short and medium time scale.

Dynamic assessment of pollution risk of groundwater source area in Northern China

Based on the dynamic analysis and research of pollution risk of groundwater sources, this paper creates the dynamic assessment method of pollution risk of groundwater source area under the theory of "source-pathway-receptor", and applies this method to one typical fissure karst groundwater source area in northern China. Following the 30-year petroleum pollutant migration simulation and pollution risk assessment of groundwater source area, this study finds that the very high risk zone is mainly located in Q Petrochemical Company and the surrounding area and the area adjacent to River Z. Within this period of thirty years, the pollution risk of groundwater source area has showed a dynamic trend that features an inverted "V" shape. The ratio of very high risk zone to the total area will be 18.1%, 17.47% and 16.62% during the tenth year, the twentieth year and the thirtieth year separately, and will reach the highest level of 19.45% during the fifteenth year. Meanwhile, the vertical migration distance of pollutant centre concentration changed from the surface soil at the outset to the deepest point of about 250 meters underground during the tenth year. The results of this risk assessment indicate the dynamic feature of pollution risk. The dilution, degradation and migration of petroleum pollutants in groundwater system contribute to an ultimate decline in pollution risk.

The Pollution Character Analysis and Risk Assessment for Metals in Dust and PM_(10) around Road from China

INTRODUCTION In recent years, with the gradual improvement of road construction, the rapid increase of the number of motor vehicles, vehicle emissions and the current poor vehicle performance, poor vehicle maintenance, higher emission factor and so on, air pollution caused by the traffic issues becomes the focus of people attention. The harmful substances are gradually accumulated to atmosphere particles surrounding roads due to dust particles （soil dusts, road dusts, construction dusts）, coal emissions, industrial emissions, vehicle emissions, biomass burning, secondary particles, which has a certain harmful influence to the atmosphere, soil and plants surrounding roads.

Distribution,enrichment mechanism and risk assessment for fluoride in groundwater:a case study of Mihe-Weihe River Basin,China

Due to the unclear distribution characteristics and causes of fluoride in groundwater of Mihe-Weihe River Basin(China),there is a higher risk for the future development and utilization of groundwater.Therefore,based on the systematic sampling and analysis,the distribution features and enrichment mechanism for fluoride in groundwater were studied by the graphic method,hydrogeochemical modeling,the proportionality factor between conventional ions and factor analysis.The results show that the fluorine content in groundwater is generally on the high side,with a large area of medium-fluorine water(0.5–1.0 mg/L),and high-fluorine water is chiefly in the interfluvial lowlands and alluvial-marine plain,which mainly contains HCO_(3)·Cl-Na-and HCO_(3)^(-)Na-type water.The vertical zonation characteristics of the fluorine content decrease with increasing depth to the water table.The high flouride groundwater during the wet season is chiefly controlled by the weathering and dissolution of fluorine-containing minerals,as well as the influence of rock weathering,evaporation and concentration.The weak alkaline environment that is rich in sodium and poor in calcium during the dry season is the main reason for the enrichment of fluorine.Finally,an integrated assessment model is established using rough set theory and an improved matter element extension model,and the level of groundwater pollution caused by fluoride in the Mihe-Weihe River Basin during the wet and dry seasons in the Shandong Peninsula is defined to show the necessity for local management measures to reduce the potential risks caused by groundwater quality.

Excretion of manure-borne estrogens and androgens and their potential risk estimation in the Yangtze River Basin

The Yangtze River is the longest river in China, and the river basin spans one fifth of the area of the whole country. Based on statistical data, the excretion of manure-borne steroid hormones, including steroid estrogens（SEs） and steroid androgens（SAs）, in 10 provinces of China within the region has been estimated. The potential environmental and ecological risk of manure-borne steroid estrogens to the surface water in this region was also assessed. The manure-borne SE and SA excretions in the 10 provinces and municipalities vary in the order： Sichuan 〉 Hunan 〉 Hubei 〉 Yunnan 〉 Jiangsu 〉 Anhui 〉 Jiangxi 〉Chongqing 〉 Qinghai 〉 Shanghai. The highest increase of manure-borne SEs（1434.3 kg）and SAs（408.5 kg） was found in Hunan and Hubei provinces, respectively, and the total excretion in 2013 was 65% more than 15 years earlier in these two provinces. However, the emissions in Anhui and Shanghai decreased in this 15 year period of time. Swine urine,chicken feces, cattle urine, and laying hen feces were considered the dominant sources of manure-borne E1, βE2, αE2, and SAs, respectively. Although Jiangsu province did not have the largest excretion of manure-borne SEs, it had the highest level of predicted17β-estradiol equivalency（EEQs） value of 16.65 ng/L in surface water because of the limited surface water resources. According to the lowest observable effect level of 10 ng/L for17β-estradiol, the manure-borne SEs in Jiangsu province might potentially pose ecological risk to its wild aquatic organisms.

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%).