The inventories of anthropogenic Ph,Zn, As,Cd, and the radionuclides 137Cs and excess 210Pb in lake sediments of the Adirondack region,USA

We determined the inventories of four anthropogenic trace elements, Pb, Zn, As, and Cd, and two radionuclides, ¹³⁷Cs and excess ²¹⁰Pb, in sediment cores collected from eight remote lakes in the Adirondack region of the northeastern United States. The inventories of all six substances vary considerably among the sediment cores, although the lakes and their associated catchments must have received similar cumulative per unit area atmospheric inputs of these substances. These variations are highly correlated, indicating that the trace elements and radionuclides are affected in a coherent way by the processes controlling their deposition to the sediments of these lakes. Assuming that the anthropogenic trace element inventories in each sediment core are enhanced or depleted relative to cumulative atmospheric deposition to the extent indicated by the sediment core inventories of either ¹³⁷Cs or excess ²¹⁰Pb, we produced estimates of the cumulative atmospheric inputs of the four anthropogenic trace elements to this region. Comparison of the excess ²¹⁰Pb normalized anthropogenic Pb, Zn, Cd inventories of the Adirondack sediment cores with excess ²¹⁰Pb normalized inventories of the same substances in a group of South Central Ontario lakes suggests that the Adirondack region has received greater cumulative anthropogenic inputs of Pb, Zn and Cd by a factor of 1.6, 4.5, and 2.9, respectively.     

Decomposition nitrogen is better retained than simulated deposition from mineral amendments in a temperate forest

Nitrogen (N) deposition (N_DEP) drives forest carbon (C) sequestration but the size of this effect is still uncertain. In the field, an estimate of these effects can be obtained by applying mineral N fertilizers over the soil or forest canopy. A ¹⁵N label in the fertilizer can be then used to trace the movement of the added N into ecosystem pools and deduce a C effect. However, N recycling via litter decomposition provides most of the nutrition for trees, even under heavy N_DEP inputs. If this recycled litter nitrogen is retained in ecosystem pools differently to added mineral N, then estimates of the effects of N_DEP on the relative change in C (?C/?N) based on short‐term isotope‐labelled mineral fertilizer additions should be questioned. We used ¹⁵N labelled litter to track decomposed N in the soil system (litter, soils, microbes, and roots) over 18 months in a Sitka spruce plantation and directly compared the fate of this ¹⁵N to an equivalent amount in simulated N_DEP treatments. By the end of the experiment, three times as much ¹⁵N was retained in the O and A soil layers when N was derived from litter decomposition than from mineral N additions (60% and 20%, respectively), primarily because of increased recovery in the O layer. Roots expressed slightly more ¹⁵N tracer from litter decomposition than from simulated mineral N_DEP (7.5% and 4.5%) and compared to soil recovery, expressed proportionally more ¹⁵N in the A layer than the O layer, potentially indicating uptake of organic N from decomposition. These results suggest effects of N_DEP on forest ?C/?N may not be apparent from mineral ¹⁵N tracer experiments alone. Given the importance of N recycling, an important but underestimated effect of N_DEP is its influence on the rate of N release from litter.     

Copper and zinc concentrations in human hair and popular foodstuffs in China

Concentrations of copper (Cu) and zinc (Zn) were determined in 383 human hair samples and in 445 food samples purchased in 11 Chinese cities. The concentrations of Cu were 7.91, 5.39, 2.27 and 2.20 mg kg^?1 and those of Zn were 47.2, 24.8, 52.8 and 30.2 mg kg^?1 in vegetables, cereals, meat and fish, respectively. The overall mean concentrations of hair Cu and Zn were 8.97 and 128 mg kg^?1, respectively. Hair Cu and Zn concentrations were higher in females than in males, especially in the 13–19 and 20–50 year age groups. Hair Cu concentration increased with increasing age and these changes occurred mainly in males. In contrast, 51–65 years old females had the lowest hair Zn concentrations. Residents of rural areas had similar hair Cu or Zn concentrations to people in urban areas. There were no significant correlations between hair concentration and food intake in terms of Cu and Zn among the cities. The results indicate that hair Cu and Zn concentrations and their changes with biological and environmental factors cannot be explained satisfactorily by the estimated food intakes in the cities sampled.     

湖南新化下石炭统遗迹化石及其沉积环境

鉴定了产自湖南新化地区早石炭世碳酸岩沉积中的遗迹化石6属(Zoophycus, Chondrites, Phycodes, Planolites, Palaeophycus, Skolithos)16种.并根据岩性实体与遗迹化石以及沉积构造等特征,划分为2个沉积亚相、21个微相、19个遗迹相.     

Probing the effects of dietary selenised glucose on the selenium concentration,quality, and antioxidant activity of eggs and production performances of laying hens

Selenised glucose (SeGlu) is a newly invented organic selenium compound being synthesised through the selenisation reaction of glucose with NaHSe. We hypothesised that glucose could be used as a carrier for the stable low-valent organoselenium to enhance the selenium concentrations of eggs. To probe the effects of SeGlu on production performances of laying hens, egg selenium concentration, egg quality, and antioxidant indexes, 360 Hy-Line Brown laying hens were randomly assigned to three treatment groups fed with a basal diet alone or the diet supplemented with 5 or 10 mg/kg of Se from SeGlu. The results showed that SeGlu treatment not only enhanced (P < 0.001) the Se concentration in albumen and yolks, glutathione peroxidase activity, and total antioxidant capacity of eggs but also increased (P = 0.032) the Haugh unit of eggs being stored for 2 weeks, while the production performances and egg qualities of fresh eggs were not affected. Moreover, SeGlu supplementation linearly (P < 0.001) increased the scavenging ability of superoxide radicals in eggs. Briefly, SeGlu can enhance the selenium deposition and antioxidant activity of eggs, thereby meeting the nutritional requirement for Se-deficient humans.     

Trace element composition of Ural licorice Glycyrrhiza uralensis Fisch. (Fabaceae Family)

The trace element composition of the subsurface (roots and rhizomes), overground (leaves and stems), and reproductive (bean valves) organs of Glycyrrhiza uralensis Fisch. was determined by synchrotron radiation X-ray fluorescence analysis (SRXFA). Concentrations of Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Hg, Pb, Bi, Th, and U were measured. The data obtained were used to estimate the distribution of some elements in samples of various organs of licorice. Glycyrrhiza uralensis is an accumulator of Fe, Mn, Cu, and Co.     

水分对林地和草地土壤氮初级转化速率的影响

水分含量是与土壤氮转化相关微生物活性的重要影响因素。本研究以黑龙江省北安市的草地和林地土壤为对象,通过室内培养试验,利用¹⁵N同位素标记技术和FLUAZ数值优化模型研究60%和100%田间持水量(WHC)条件下土壤氮初级矿化速率、初级固定速率、初级硝化速率和初级反硝化速率,以探讨土壤氮初级转化速率对水分含量变化的响应,阐明不同水分条件下土壤中氮的产生、消耗、保存机制及其生态环境效应。结果表明: 土壤水分变化不影响草地和林地土壤氮初级矿化速率和铵态氮固定速率,水分含量由60% WHC增加至100% WHC后显著增加了林地土壤的初级硝化速率,但对草地土壤的初级硝化速率没有显著影响。60% WHC条件下草地和林地土壤的初级反硝化速率可以忽略不计,水分含量增加至100% WHC后土壤初级反硝化速率显著提高,且草地土壤的初级反硝化速率显著低于林地土壤。100% WHC条件下林地土壤初级硝化速率与铵态氮固定速率比值(gn/ia)和N₂O排放量均显著高于60% WHC;100% WHC条件下草地土壤的N₂O排放量显著高于60% WHC,但两个水分条件下的gn/ia值无显著差异。表明短期内水分含量的增加可能会增加草地和林地土壤氮转化的负面环境效应,且对林地土壤的影响尤为显著。     

Human Health Risk Assessment of Non-Regulated Xenobiotics in Recycled Water: A Review

Water suppliers face increased pressure to explain the relative health risks from non-regulated xenobiotics that may be present in recycled water, including pharmaceuticals and personal care products (PPCPs) and endocrine disrupting compounds. This report reviews their occurrence, fate, and recent human health risk assessments for potable and non-potable water reuse. The most effective advanced treatment for PPCPs is reverse osmosis (RO) followed by advanced oxidation. During soil aquifer treatment, the majority of PPCPs are attenuated relatively quickly (within 100 days), yet some are persistent and can migrate to the underlying groundwater at low concentrations. Recently, several investigations have assessed the potential human health risks associated with xenobiotics in recycled water, focusing on exposure from drinking water (e.g., planned and unplanned indirect potable reuse) and non-potable reuse (e.g., exposure via recreational, occupational, and irrigation-related activities at sites utilizing recycled water). Risk assessments conducted over the last 10 years have found no adverse human health effects or significant risks. Though advanced treatment of wastewater that is discharged or recycled may not be required to protect public health, it may be necessary to prevent potential effects on exposed biota and to address, to some degree, the public's perception of water reuse.     

Magnesium,calcium, copper,and zinc in meals

Meals of 12 diets were prepared from conventional foods with precautions against contamination by metallic elements because of epidemiologic associations between ischemic heart disease and the metabolism of magnesium, calcium, copper, and zinc. Magnesium, calcium, copper, and zinc were measured by atomic absorption spectrometry with satisfactory accuracy and precision. The mean daily amount of copper in the diets was less than the apparent adult requirement. Mean amounts of magnesium and zinc were close to apparent requirements; however, adults consuming amounts less than one standard deviation below these means may be depleting body stores and be at risk of pathology. Magnesium and copper were highly correlated (r=0.849,P=0.0001) in meals. This and other significant correlations probably will prevent the relationships of these elements to ischemic heart disease from being elucidated by epidemiology. Metabolic experiments will be necessary to differentiate among several hypotheses.     

Serum zinc in highly trained adolescent gymnasts

Serum zinc was measured in 20 adolescent gymnasts (9 boys, 11 girls, age 12–15 yr) explored for detecting possible adverse effects of intense training on pubertal maturation and growth. They had low serum zinc (0.599±0.026 mg/L) when compared to matched control sedentary children (n=118 mean 0.81±0.014p<0.001). Girls had lower zinc than boys (0.557±0.023 vs 0.651±0.044p<0.001). Zinc was correlated to isometric adductor strength (r=0.468p<0.05). Children with serum zinc <0.6 mg/L had lower insulin-like growth factor binding protein 3 than others (2.326±0.264 vs 2.699±0.12p<0.01). Thus, zinc is lowered in trained adolescent gymnasts and even lower in females. This reduction could play some role in abnormalities of puberty, growth, or muscular performance.