[Speciation and Risk Characteristics of Heavy Metals in the Sediments of the Yangtze Estuary].

Based on the investigation on the distribution of total contents and speciation of 8 heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) in the surface sediments at 14 typical sites of the Yangtze Estuary during three hydrological seasons ( wet, normal, and dry seasons) , this study applied equilibrium partitioning approach to build the sediment quality guidelines (SQGs) of the Yangtze Estuary, and assessed ecological risks of the heavy metals. The relationship between ecological risk and speciation of heavy metals was also revealed. The results showed that, except for Cd, the residual fraction was the main speciation of heavy metals, especially for As, Cr and Hg, their residual fraction proportions were all over 90%. The sediment quality guidelines of the Yangtze Estuary for As, Cd, Cr, Cu, Hg, Ni, Pb, Zn were 43.29, 0.672, 79.65, 19.08, 0.569, 339.09, 30.87, 411.36 µg · g⁻¹, respectively. Cu had the highest ecological risk to aquatic organisms. The upstream of Yangtze Estuary was mainly affected by Yangtze River runoff, where the risks were relatively high in wet season and relatively low in normal and dry seasons. However, the downstream of the estuary was mainly affected by municipal sewage of cities like Shanghai, where the risks were relatively high, especially in normal and dry seasons. There were three different relationships between the ecological risks and speciation of the eight heavy metals.

Investigation of the interaction between As and Sb species and dissolved organic matter in the Yangtze Estuary, China, using excitation-emission matrices with parallel factor analysis.

The interactions between trivalent or pentavalent As/Sb and dissolved organic matter (DOM) in four regions (the river channel, the adjacent coastal area, and the northern and southern nearshore areas) of the Yangtze Estuary, China, were studied using fluorescence quenching titration combined with excitation-emission matrix spectroscopy and parallel factor analysis (PARAFAC). The As/Sb-DOM complexation characteristics were investigated using FTIR and UV absorbance spectroscopy and zeta potential analysis. Four protein-like components and one humic-like component were identified in the DOM from the Yangtze Estuary, China, by PARAFAC analysis. The tryptophan-like substance represented by component 2 was the dominant component and played an important role in the complexation between DOM and As/Sb. The results of complexation modeling demonstrated that the binding capacity of trivalent As/Sb with DOM was higher than that of pentavalent As/Sb with DOM. The DOM from the north nearshore area with the most acidic functional groups and greatest aromaticity possessed the highest binding capacity for trivalent and pentavalent As/Sb. The increase in the UV absorbance and the charge neutralization further indicated the interaction between As/Sb and DOM. The higher binding capacity of Sb(III) with DOM was mainly due to the hydroxyl and carboxyl groups. Our study demonstrates that the use of the advanced EEM-PARAFAC method in fluorescence quenching studies is very useful for evaluating the properties of DOM-pollutant interactions.

[Excretion of manure-borne steroid hormones and their potential risk in the three northeast provinces of China].

The excretion of manure-borne steroid hormones, including estrogens and androgens in Liaoning, Jilin and Heilongjiang province was estimated in this study on the basis of statistical data and by using the referenced estimation method in developed countries. In addition, the potential ecological risk of manure-borne steroid estrogens to local surface water systems from applying animal manure was preliminarily assessed. As a result of the rapid development of animal production, the excretions of manure-borne steroid hormones increased in all the three northeast provinces. In 2008, the emissions of total manure-borne estrogens and androgens increased by 2 272.7, 1 951.1 and 1 634.8 kg compared to those in 1998 in Liaoning, Jilin and Heilongjiang provinces, respectively. Especially, the growth rates in the three capital cities of Shenyang, Changchun and Harbin were the fastest among their own provinces. The largest emissions of manure-borne steroid hormones, as well as the highest concentration of predicted estradiol equivalency (EEQs) in the surface water system were found in Liaoning province. According to the lowest observable effect concentration for 17beta-estradiol (10 ng x L(-1)) recommended by the Environmental Agency of United Kingdom, 17.1 ng x L(-1) of EEQs level in Liaoning province might have become a potential risk to local surface water systems.

Migration of natural estrogens around a concentrated dairy-feeding operation.

Concentrated animal feeding operations have been recognized as one of the most important contributors of natural estrogens which show significant endocrine-disrupting properties in aquatic environments. In this study, the concentrations of 17α-estradiol (17α-E2), 17ß-estradiol (17ß-E2), estrone (E1), and estriol (E3) in several matrices, including soils (surface and deep), sediments (surface and deep), and groundwaters, around a typical dairy farm were surveyed using gas chromatography/mass spectrometry. Of the two farmlands, surface and subsurface sediments in waste lagoon and along effluent drainage drench, the concentrations of 17α-E2, 17ß-E2, and E1 ranged from below detection limit to the highest level of 6.60 µg/kg, except that E3 was not detectable. Three estrogens of 17α-E2, 17ß-E2, and E1 with the concentrations of 3.18-31.61 ng/L were observed in two groundwater samples. The results clearly demonstrated the vertical migration and horizontal transport of estrogens in the investigated area. Within 750-m distance, it was observed the attenuation of 17α-E2, 17ß-E2, and E1 along the effluent route and the horizontal migration of estrogens was less than 1,350 m in this survey.

Seasonal variations of chemical and physical characteristics of dissolved organic matter and trihalomethane precursors in a reservoir: a case study.

Dissolved organic matter (DOM) and its potential to form disinfection by-products (DBPs) during water treatment are of great public health concern. Understanding the seasonal changes in DOM composition and their reactivity in DBP formation could lead to a better treatment of drinking water and a more consistent water quality. DOM from the East-Lake, a reservoir in the south-China, was fractionated and characterized by XAD resin adsorption (RA) and ultrafiltration (UF) techniques during different seasons within a year. The properties of chemical fractions (isolated by RA) appeared more stable than those of physical fractions (separated by UF) throughout the sampling period. The relative contribution of each chemical fraction to the total dissolved organic carbon (DOC), UV(254) absorbance and trihalomethane formation potential (THMFP) remained relatively constant across the sampling period. However, the physical (molecular weight) fractions of the DOM exhibited large seasonal changes in UV(254) and THMFP. Compared to the parameter of DOC, the THMFP and specific THMFP (STHMFP) of either chemical or physical fractions were more variable. In terms of DOC concentration, the hydrophobic acids (HoA) and hydrophilic matter (HiM) dominated in the DOM in most of the seasons; while the components with molecular weight of 10-30 kDa and less than 1 kDa were the predominant physical fractions.