Evidence of mid-Holocene climate instability from variations in carbon burial in Seneca Lake, New York

The amounts and types of carbon delivered to the sediments Seneca Lake, New York, have varied since the middle Holocene. Concentrations of CaCO₃ first fluctuate between 14 and 6% around 7 ka before decreasing erratically until about 5 ka and then remain 2% in younger sediments. Because the amount of calcite that precipitates in hard-water lakes is related to summertime thermal stratification, the carbonate fluctuations suggest that cyclic strengthening and weakening of seasonality at intervals of about three centuries accompanied the end of the Holocene Hypsithermal in northeast North America. Organic C/total N values record short, decade-long intervals of enhanced delivery of land-plant material during episodes of wetter climate that are independent of the temperature variations. Higher organic ¹³C values indicate that recent fertilization of lake waters from soil disturbance and land-derived runoff has increased aquatic productivity.     

Calcium levels in <Emphasis Type="Italic">Daphnia</Emphasis> ephippia cannot provide a useful paleolimnological indicator of historical lakewater Ca concentrations

Despite reductions in atmospheric sulphur emissions and the resulting decline in acidic deposition, many lakes on the Canadian Shield that have experienced acidification are either recovering at a rate slower than expected or not recovering at all. This lack of recovery is believed to be partly the consequence of the depletion of exchangeable base cations (principally calcium, Ca) from watershed soils. Although the implications of reduced Ca availability for biological communities remain poorly understood, the effects on crustacean zooplankton populations may be severe, as Ca is the primary structural component of the crustacean zooplankton exoskeleton. Because the daphniid resting egg is protected by a modified portion of the exoskeleton (ephippia) and because these ephippia are well preserved in lake sediments, we investigated whether inter-specific differences in Ca content are recoverable from Daphnia ephippia. However, using two methods, we did not find a recoverable Ca signal in the ephippia, indicating that future efforts should be focused upon sedimentary taxonomic assemblage differences, not differences in ephippial Ca levels.     

溶液中钙镁含量准确测定的方法研究

经典测定钙、镁含量的方法是用EDTA标准溶液滴定钙镁总量后再滴定钙,此方法对于含钙、镁离子盐水体系溶解度的测定,尤其在镁含量较高的情况下,其分析精度和准确度远远迭不到要求。针对硝酸钙、硝酸镁混合样品,采用EDTA质量滴定法测定钙镁总量,用草酸钙沉淀法从镁中定量分离钙,然后运用羔减法计算出镁的含量。实验结果表明,当混合溶液中镁钙的质量比不超过10：1时,钙、镁离子分析结果的相对误差在±0．3％之内,但镁钙的质量比超过10：1时,相对误差达到1％。因此,在一定的镁钙质量比范围内,此方法可用于盐水体系中钙、镁含量的准确测定。     

山东地区三类典型制药企业的VOCs源成分谱及排放特征研究

制药行业因在提取等过程中使用有机溶剂排放大量挥发性有机物（VOCs）而备受关注.本研究在山东省选择化学合成、生物发酵、中药共三家制药企业开展了107种VOCs组分的监测和分析,并建立制药企业的VOCs源成分谱.研究结果表明：化学合成类和生物发酵类制药企业排放总质量浓度均超过20 mg/m³,中药制药企业的样品的平均质量浓度相对较小,为902.66 μg/m³.本研究所分析的107种组分中,以含氧挥发性有机物（OVOCs）为主,三家企业均超过75%,其中,化学合成制药类卤代烃物种的占比较高.企业类型、生产环节、收集排放措施等是影响VOCs成分的重要因素.     

Preparation and Structural Investigation of CuCl2 Graphite Intercalation Compounds

Superfine graphite powder was prepared by ball-milling exfoliated graphite containing anhydrous CuCl2 in planetary ball milling systems. Nano-scale CuCl2 graphite intercalation compounds were synthesized by heating a mixture of anhydrous CuCl2 and graphite nanosheets. Scanning electron microscopy, energy-dispersive X-ray spectroscopy and high-resolution transmission electron microscopy were performed to characterize the microstructures of stage-1 nano-scale CuCl2 graphite intercalation compounds. The structure and components of the domain wall and core in the nano-scale CuCl2 graphite intercalation compounds are described. The results show that the content of CuCl2 in the mixture plays a crucial role in the size of the nano-scale CuCl2 graphite intercalation compound.     

Using chemical and microbiological indicators to track the impacts from the land application of treated municipal wastewater and other sources on groundwater quality in a karstic springs basin

Multiple chemical constituents (nutrients; N, O, H, C stable isotopes; 64 organic wastewater compounds, 16 pharmaceutical compounds) and microbiological indicators were used to assess the impact on groundwater quality from the land application of approximately 9.5 million liters per day of treated municipal sewage effluent to a sprayfield in the 960-km² Ichetucknee Springs basin, northern Florida. Enriched stable isotope signatures (δ¹⁸O and δ²H) were found in water from the effluent reservoir and a sprayfield monitoring well (MW-7) due to evaporation; however, groundwater samples downgradient from the sprayfield have δ¹⁸O and δ²H concentrations that represented recharge of meteoric water. Boron and chloride concentrations also were elevated in water from the sprayfield effluent reservoir and MW-7, but concentrations in groundwater decreased substantially with distance downgradient to background levels in the springs (about 12 km) and indicated at least a tenfold dilution factor. Nitrate-nitrogen isotope (δ¹⁵N–NO₃) values above 10 ‰ in most water samples were indicative of organic nitrogen sources except Blue Hole Spring (δ¹⁵N–NO₃ = 4.6–4.9 ‰), which indicated an inorganic source of nitrogen (fertilizers). The detection of low concentrations the insect repellent N,N-diethyl-metatoluamide (DEET), and other organic compounds associated with domestic wastewater in Devil’s Eye Spring indicated that leakage from a nearby septic tank drainfield likely has occurred. Elevated levels of fecal coliforms and enterococci were found in Blue Hole Spring during higher flow conditions, which likely resulted from hydraulic connections to upgradient sinkholes and are consistent with previoius dye-trace studies. Enteroviruses were not detected in the sprayfield effluent reservoir, but were found in low concentrations in water samples from a downgradient well and Blue Hole Spring during high-flow conditions indicating a human wastewater source. The Upper Floridan aquifer in the Ichetucknee Springs basin is highly vulnerable to contamination from multiple anthropogenic sources throughout the springs basin.     

Influence Factors on the In-situ Remediation of Halogenated Organic Compounds by Nanoscale Zerovalent Iron

The pollution of soil and groundwater by halogenated organic compounds (HOCs) is more and more severe. HOCs are of strong toxicity and difficult to be biodegraded. Due to its unique advantages, nanoscale zerovalent iron (NZVI) has become a hot research topic in the field of in situ remediation around the world. In this paper, basic reaction theories and kinetics of HOCs degradation by NZVI are briefly summarized. The influence factors on the in situ remediation of HOCs by NZVI are comprehensively discussed. The influence factors include the intrinsic properties of NZVI due to its different preparation and modification methods, and environment factors, such as pH, dissolved oxygen, ionic species, metals, nonreactive hydrophobic and natural organic compounds, concentrations and components of HOCs, microorganisms and subsurface heterogeneity. The effects of all these factors on NZVI stability, deliverability, targeting ability, and reactivity during in situ remediation are emphasized. Finally, the practical application of this technology are summarized and prospected.     

天津地区典型土壤剖面多环芳烃的垂向分布特征

天津地区不同环境功能区表层土中均检出萘、苊、苊烯、联苯、菲、惹烯、芴、二苯并呋喃、二苯并噻吩、荧蒽、芘、屈、苯并芴、苯并蒽、苯并荧蒽、苯并芘、、二苯并[a,h]蒽、茚并[1,2,3-cd]芘、苯并[g,h,i]等多环芳烃化合物,但含量差别显著,南、北排污河污灌区多环芳烃含量明显高于非污染区及北部山区。不同剖面表土中多环芳烃的组成特征也存在明显差别,与非污灌耕地及北部山地相比,污灌耕地和滨海盐土耕地四环以上芳烃相对含量明显较高,而烷基取代物含量明显较低。剖面表层至40cm土壤中多环芳烃含量相对较高,深处含量明显降低,但不同剖面变化幅度存在明显差别,污灌耕地和滨海盐土耕地降低幅度最大,其它剖面变化较小,但剖面深部(>40cm)芳烃化合物组成特征基本趋于一致。     

Characterization of Estonian Kukersite by spectroscopy and pyrolysis: Evidence for abundant alkyl phenolic moieties in an Ordovician, marine, type II/I kerogen

The kerogen of a sample of Estonian Kukersite (Ordovician) was examined by spectroscopic (solid state ¹³C NMR, FTIR) and pyrolytic (“off-line”, flash) methods. This revealed an important contribution of long, linear alkyl chains in Kukersite kerogen. The hydrocarbons formed upon pyrolysis are dominated by n-alkanes and n-alk-1-enes and probably reflect a major contribution of selectivity preserved, highly aliphatic, resistant biomacromolecules from the outer cell walls of Gloeocapsomorpha prisca. This is consistent with the abundant presence of this fossilized organism in Kukersite kerogen. In addition high amounts of phenolic compounds were identified in the pyrolysates. Series of non-methylated, mono-, di- and trimethylated 3-n-alkylphenols, 5-n-alkyl-1,3-benzenediols and n-alkylhydroxybenzofurans were identified. All series of phenolic compounds contain long (up to C₁₉), linear alkyl side-chains. Kukersite kerogen is, therefore, an aliphatic type II/I kerogen, despite the abundance of free phenolic moieties. This study shows that phenol-derived moieties are not necessarily associated with higher plant-derived organic matter.The flash pyrolysate of Kukersite kerogen was also compared with that of the kerogen of the Guttenberg Oil Rock (Ordovician) which is also composed of accumulations of fossilized G. prisca. Similarities in the distributions of hydrocarbons and sulphur compounds were noted, especially for the C₁–C₆ alkylbenzene and alkylthiophene distributions. However, no phenolic compounds were detected in the flash pyrolysate of the Guttenberg kerogen. Possible explanations for the observed similarities and differences are discussed.     

Distribution and Significance of Carbazole Compounds in Palaeozoic Oils from the Tazhong Uplift, Tarim

Carbazole compounds in crude oils from the Tazhong uplift of the Tarim basin have been fractionated and detected and successfully used to study petroleum migration and trace source rocks in the study area. Alkylcarbazoles have been found in large amounts in the oil samples analyzed and alkylbenzocarbazoles detected in a small concentration only in part of the samples, but alkyldibenzocarbazoles have not been found in oils. Based on the distribution of G1, G2 and G3 of C2-alkylcarbazoles, the ratio of C3-carbazoles to C2-carbazoles and the relative amounts of alkylcarbazoles and alkylbenzocarbazoles, one can know that the vertical oil migration in the Tazhong uplift is generally from below upward, i.e. from the Ordovician through the Silurian to the Carboniferous. Evidently, source rocks in the uplift should be lower Palaeozoic strata (Ordovician and Cambrian). This study shows that carbazoles are of great importance in the study of petroleum migration and source rocks.