骆马湖表层水体中32种PPCPs类物质的污染水平、分布特征及风险评估

为评价骆马湖水体中药品和个人护理品(PPCPs)的污染水平、空间分布特征及生态风险,利用高效液相色谱-串联质谱测定了骆马湖水体中22个采样点的32种PPCPs.结果表明,骆马湖表层水体中共检出了23种PPCPs,总浓度范围为892~1 536 ng·L~(-1),其中浓度最高的为诺氟沙星(256~707 ng·L~(-1)),其次是酮洛芬(85~438 ng·L~(-1))、安赛蜜(101~290 ng·L~(-1))及萘普生(1.9~112 ng·L~(-1)).不同采样位点的PPCPs浓度存在一定的空间差异,呈现湖东北部地区较高,西南部地区较低的趋势.房亭河入湖口处PPCPs浓度较高,嶂山闸出湖口处浓度较低.对13种药物类PPCPs生态风险评价结果表明,诺氟沙星RQs为0.26~0.72,对于骆马湖水生生态系统表现为中风险,吉非罗齐在大部分采样点RQs0.01,表现为低风险,其余的化合物RQs0.01未表现出生态环境风险.采用简单叠加模型计算PPCPs的联合毒性风险熵范围为0.29~0.75,整体上看,骆马湖PPCPs对于水生生物表现出中风险.对6种PPCPs的人体健康风险结果表明,RQs均小于1,表明骆马湖PPCPs对人体健康无直接风险.     

Photodegradation of sulfonamide antibiotics in simulated and natural sunlight: Implications for their environmental fate

The photochemical fate of seven sulfonamides was investigated in matrices representative of natural water bodies under various light sources. Fundamental photolysis parameters such as molar absorption coefficient, quantum yield (QY) and first-order rate constants were determined. The photolysis decay rate was dependent on the protonation state of the molecule, pH of the water sample and dissolved organic matter. Natural organic matter was the most significant factor in the indirect photolysis of sulfonamides. Half-lives were in the range of minutes at 254 nm to days under natural sunlight. Under natural sunlight, all sulfonamides showed higher removal rates in natural waters implying that indirect photolysis is the predominant mechanism.     

LEAD AND CADMIUM ASSOCIATED WITH SALTWATER INTRUSION IN A NEW JERSEY AQUIFER SYSTEM1

ABSTRACT: The U.S. Geological Survey collected ground-water samples from the upper and middle aquifers of the Potomac-Raritan-Magothy aquifer system in a 400-square-mile area of New Jersey from 1984 through 1986. Concentrations of lead were greater than the U.S. Environmental Protection Agency maximum contaminant level (MCL) of 50 micrograms per liter in water from 16 of 239 wells. The cencentrations of cadmium were greater than the MCL of 10 micrograms per liter in water from 10 to 241 wells. One-half of the wells that exceeded the lead MCL were in known areas of saltwater intrusion, as were all 10 wells that exceeded the cadmium MCL. The association of elevated concentrations of these metals with elevated concentrations of chloride indicates a mochanism related to saltwater intrusion.     

DISTRIBUTION AND GRAIN-SIZE PARTITIONING OF METALS IN BOVFOM SEDIMENTS OF AN EXPERIMENTALLY ACIDIFIED WISCONSIN LAKE1

ABSTRACT: A study of concentrations and distribution of major and trace elements in surficial bottom sediments of Little Rock Lake in northern Wisconsin included examination of spatial variation and grain-size effects. No significant differences with respect to metal distribution in sediments were observed between the two basins of the lake, despite the experimental acidification of one of the basins from pH 6.1 to 4.6. The concentrations of most elements in the lake sediments were generally similar to soil concentrations in the area and were well below sediment quality criteria. Two exceptions were lead and zinc, whose concentrations in July 1990 exceeded the criteria of 50 μg/g and 100 μg/g, respectively, in both littoral and pelagic sediments. Concentrations of some elements, particularly Cu, Pb, and Zn, increased along transects from nearshore to midlake, following a similar gradient of sedimentary organic carbon. In contrast, Mn, Fe, and alkali/alkaline-earth elements were at maximum concentrations in nearshore sediments. These elements are less likely to partition to organic particles, and their distribution is more dependent on mineralogical composition, grain size, and other factors. Element concentrations varied among different sediment grain-size fractions, although a simple inverse relation to grain size was not observed. Fe, Mn, Pb, and Zn were more concentrated in a grain-size range 20–60 tm than in either the very fine or the coarse fractions, possibly because of the aggregation of smaller particles cemented together by organic and Fe/Mn hydrous-oxide coatings.     

Trace elements in camel tissues from a semi-arid region

Trace and minor element concentrations differ in animal tissues as the result of the surrounding environment (feeding plants, soil contaminated with food and drinking water) and animal absorption of these elements. Concentrations of Ag, Au, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn were determined from different tissues of camel (inter-costal, scapula, sirloin, flank, front knuckle and front limb) from the semi-arid areas of the Aswan desert (Wadi El-Allaqi) and from Aswan city, Egypt. The study included an assessment of these same elements in the desert and city plants used as food by the camels and in soils from the study areas. The results reveal that camel tissues from the desert areas exhibited higher concentrations of Na, Mg, K, Au, Ag, Cu, Co and Zn than in those of the city camels. These higher levels of element are because of the high concentrations of the same elements in the desert plants and soil of the desert area. This, in turn, depends upon the geological formation differences between the desert area and the city area. Camel tissues appear to concentrate high levels of Mn, Ni, Co and Mg in the scapula while flank portions concentrate high levels of Mg and K. The levels of elements in the camel tissues under study were within the recommended safety baseline levels for camel health and human use, as well as within the appropriate limits in the desert and city plants for camel use.     

USE OF X-RAY FLUORESCENCE TO DETERMINE TRACE METALS IN WATER RESOURCES1

ABSTRACT. The X-ray fluorescence method was used to analyze trace metals collected in particulate form on filter papers and from the ionic state by ion exchange filter papers. The samples were prepared by allowing water to pass through these filter papers. The procedures necessary for using the X-ray fluorescence method are described. A number of samples were taken from the Great Miami River in Dayton, Ohio over one year showing the presence of the following metals, Ca, Ti, Cr, Fe, Cu, Zn, Sr, and Cd. Elements in the periodic table between Ti and Cs were detectable to a sensitivity limit of the order of 30 ppb for metals in the particulate form and 0.4 ppm for metals in the ionic form.     

MANGANESE IN LACUSTRINE ECOSYSTEMS: A REVIEW1

This paper serves as a literature review of manganese in fresh water. The major aspects of manganese occurrence discussed are: (1) sources, (2) geochemistry, (3) manganese-iron relationships, (4) effects on the fauna and flora and (5) detection.     

Distribution of Trace Metals in the Surface Sediments of Two Pristine Subalpine Lakes in Taiwan

Sediment cores were collected from two remote subalpine lakes: the rather shallow (1.5 m) Little Ghost Lake at 2040 m elevation and the deeper, Great Ghost Lake (40 m) at 2150 m elevation. Different early diagenesis of metals were observed. the seasonally anoxic hypolimnion drives the annual iron redox cycle and causes the remobilization of metals in the mobile fractions of sediments in the Great Ghost Lake. These result in the redistribution of metals in the mobile fractions of sediment and poor correlation between metal concentrations. in the Little Ghost Lake, the shallow water column is always oxic with less change of metals in the mobile fractions of sediments. As a result, most metals have strong positive correlations with each other.

The distributions of metal/Al ratios, total metal contents and acid-leached metal concentrations in the near-surface sediments of these two lakes suggest that the anthropogenic inputs from the atmospheric fallouts in recent decades are one of the major factors affecting the distributions of metals such as cadmium, lead and, to a lessor extent, zinc. the Pb-206/Pb-207 ratios confirm the anthropogenic lead input in these surface sediments.     

A Quantitative Safety Assessment Model For Transgenic Protein Products Produced In Agricultural Crops

Transgenic plants are now being used to develop pharmaceutical and industrial products in addition to their use in crop improvement. Using confinement requirements, these transgenic plants are grown and processed under conditions that prevent intermixing with commodity crops. Regulatory agencies in the United States have provided guidance of zero tolerance of these new industrial crops with commodity crops. While this is a worthy goal, it is theoretically unattainable. In spite of the best containment practices, there is a potential risk using any system of production due to unforeseen incidences including natural disasters or exposure to workers. The precautionary principle has been used for numerous regulated articles in addressing the potential risks of new products and technology based on a risk assessment in similar situations. We present here a risk assessment model that could be used as a start to develop an accepted model for the industry. The model is based on current risk models used for other regulated articles, but adapted for these types of products. This could be used to determine action levels in the event of an unintended exposure or to ensure that detection or confinement methods are adequate to avoid risks. As an example, aprotinin, a therapeutic protein now being produced in maize, was evaluated for potential risk to humans using this model.     

耐候钢中微量元素的测定

本文分别用化学法和电感耦合等离子体发射光谱法(ICP-AES)测定了Corten-B和Sten3两种耐候钢中Cr、Cu、Mn、Sb、Si、V、P、Ti等8种微量元素的含量,并与传统的化学法进行了对比.试验证明ICP-AES光谱法不但技术简便、快速、易于推广应用,而且ICP-AES光谱法和微波消解技术联用在微量元素测量上有更准确、安全等方面的优点.另外,ICP-AES仅通过对少量样屑的一次溶样即可得到全部元素的分析结果,节省了钢样,这对于难以取样的情况尤为有利.