Dissolution and spatial distribution of resin acids and retene in sediments contaminated by pulp and paper industry

Purpose

Wood extractives in sediments originating from the wood industry may interfere with benthic biota in aquatic environments. The research area was the Äänekoski watercourse in Central Finland, which has been affected by the chemical wood industry for over a century. The goal was to determine the dissolution potency of resin acids (RAs) and their derivative, retene, in the sediment, and their current vertical and spatial stratification to assess the load due to potential erosion.

Materials and methods

Sediments were collected from two upstream reference sites and three lake-like basins, located as far as 33 km downstream from the mills. The dissolution potency was studied by two different agitation times and temperatures from sediment-water (1+4 v/v) elutriates. The vertical distribution of extractives was determined from the uppermost 20 cm of sediment. Using spatial interpolation, the distribution of extractives was estimated from two upper sediment layers (0–2 and 2–5 cm) downstream from the source. According to the interpolation, the total amount of dehydroabietic (DHAA) and isopimaric acids (IPA) were calculated as kg/ha in the whole sediment area.

Results and discussion

The total concentration of RAs in the surface sediment reached up to 168 µg/g dw, and they were found to desorb to water up to 77 µg/l. The concentrations of retene were low both in the sediment (<51 µg/g dw) and elutriate (<0.53 µg/l). Spatial interpolation showed that the highest calculated amounts of the most abundant RAs were in Kuhnamo basin, in the sediment layer 2–5 cm; the estimated amount of DHAA and IPA were approximately 440 and 85 kg/ha, respectively.

Conclusions

Disturbances may change the exposure situation, causing desorption of sediment-associated compounds in levels that may be harmful to aquatic animals. The amount of desorption varies depending on the concentration of contaminants in sediment, the nature of disturbance, and the sediment organic carbon content. Low retene concentrations can be explained by oxic conditions and low abundance of RAs in the sediments.

     

灰枣、骏枣不同枝条叶片净光合速率的对比研究

以直播建立果园的灰枣、骏枣为试材,研究其不同枝条叶片净光合速率日变化规律,结果表明:灰枣、骏枣不同枝条叶片净光合速率日变化趋势相似,均呈单峰曲线.灰枣不同枝条叶片最高峰均出现在13:00左右.骏枣枣头叶片峰值在13:00,其余枝条叶片在15:00.灰枣枣头枝叶片始终大于骏枣枣头枝叶片,13:00-17:00灰枣枣拐叶片净光合速率高于骏枣,上部枣吊叶片净光合速率变化基本相同,基部枣吊叶片净光合速率变化较大.不同叶片净光合速率大小依次为上部枣吊叶片＞枣拐叶＞枣头叶＞基部枣吊叶片.枣吊叶序叶片净光合速率呈现高-低-高-低的变化,中部叶序叶片净光合速率较高,顶部叶片最小.     

不同水培方式对草莓生长发育影响的初步研究

以3种浓度的营养液,采用桶式水培、管式水培对草莓新明星品种进行栽培试验。结果表明：草莓新明星的株高、新根数、新根长度、单叶叶面积、叶绿素相对含量等,管式栽培均优于桶式栽培。管式栽培选用0.5倍剂量浓度的营养液其生长发育除单叶面积外均优于1.5倍剂量和1.0倍剂量处理。桶式栽培选用0.5倍剂量浓度的营养液其生长发育除新根长度外均优于1.5倍剂量和1.0倍剂量处理。     

海南‘金煌’芒干物质及养分年积累量研究

研究海南‘金煌’芒果干物质及养分年积累量,为平衡施肥提供参考。通过采集‘金煌’芒不同器官干物质并进行养分分析,结果表明：（1）‘金煌’树体不同器官干物质年积累量顺序为：采收果>修剪叶>花及梗>修剪枝>落果;其中花及梗占17.17%、落果1.26%、修剪叶22.23%、修剪枝8.64%、采收果50.70%。（2）‘金煌’树体11种营养元素年积累量大小顺序为：N>K>Ca>P>Mg>S>Mn>Fe>Zn>B>Cu。（3）以生产1000 kg‘金煌’芒计,树体养分需求为：干物质464.68 kg、N 5.46 kg、P 0.57 kg、K 4.62 kg、Ca 2.69 kg、Mg 0.40 kg、S 0.33 kg、Fe 51.62 g、Mn 158.84 g、Cu 2.90 g、Zn 9.43 g、B 7.26 g。     

水分胁迫对巴西香蕉幼苗生长量及营养元素含量的影响

采用设置7个土壤相对含水量水平和8次重复大棚盆栽试验方法.研究不同土壤水分条件下水分胁迫对巴西香蕉(Musa AAA Cavendish subgroup cv.Brazil)幼苗的生长及营养吸收的影响.结果表明:(1)土壤水分胁迫明显影响香蕉幼苗的生长及对营养的吸收.其中土壤相对含水量为田间持水量的71%～80%处理明显优于其它处理.(2)随着土壤水分含量的减少,香蕉幼苗根、茎中的全N、K、Ca、Mg、Fe、Zn量,根中的全P、Cu、Mn量和叶中的全N、P、Fe、Zn量均呈先上升后下降的趋势,其它矿质元素总的均呈下降的趋势.(3)各种土壤水分处理下,全Fe、Cu等元素量分配比例在根中最多,叶中次之,茎中最少;全Zn量分配比例在根中最多,茎中次之,叶中最少;全P、K、Mg等元素量分配比例在茎中最多,叶中次之,根中最少;全N、Ca、Mn等元素量在叶中最多,茎中次之,根中最少.(4)综合各项指标,香蕉幼苗生长最适宜的土壤相对含水量为田间持水量的71%～80%.     

多辊下压式拉形柔性浮动夹持数值模拟与实验

采用ANSYS/LS-DYNA对使用柔性浮动夹持方式的多辊下压式拉形过程进行了数值模拟,验证了柔性浮动夹持的效果,分析了所得成形件在拉形过程中的应力、应变分布。结果表明:柔性浮动夹持方式适用于多辊下压式拉形,能够实现柔性、浮动夹持的效果;使用柔性浮动夹持时所得成形件应力、应变分布均匀,成形效果较好。完成了相关实验验证,对数值模拟结果和实验结果进行了对比,结果表明:数值模拟结果与实验结果吻合较好。     

The effects of fragmentation on the susceptibility of a boreal forest ecosystem to wind damage

The clear cuts and seedling stands can speed up winds and may trigger blowdown at the edges of neighbour stands. Therefore, the height contrast of the neighbour stands and fragmentation at landscape level could be used to indicate the susceptibility of windthrow. In this study, we studied how forest fragmentation affects the susceptibility of a boreal forest ecosystem to wind damage, both at patch and landscape level based on theoretical computations. For this purpose we generated, based on real stand inventory data of a Finnish forest ecosystem, different landscape configurations of Scots pine and Norway spruce forests using Monte Carlo simulation. Thereafter, we applied a mechanistic wind damage model to predict the wind speeds needed for wind damage at forest edges. The fragmentation metrics of Contrast-Weighted Edge Density with three different height dissimilarity calculation methods were used to analyze the fragmentation at the landscape level.     

Efficacy and safety of food fortification with calcium among adults in Finland

OBJECTIVE: To examine the efficacy and safety of foods fortified with calcium in the adult population in Finland. DESIGN: A simulation study based on the FINDIET 2002 Survey, which estimated habitual food consumption, dietary supplement use and nutrient intakes using 48-hour recall and two 3-day food records, and an Internet survey of the consumption of fortified foods and dietary supplements. SETTING/PARTICIPANTS: Participants of FINDIET 2002 were 25-64 years old from five areas (n = 2007). Participants of the Internet-based survey (n = 1537) were over 15 years of age from all over the country. RESULTS: If all potentially fortifiable foods were to be fortified with calcium, the proportion of participants with calcium intake below the recommended level (< 800 mg day(-1)) would decrease from 20.3% to 3.0% in men and from 27.8% to 5.6% in women compared with the situation where no foods were fortified. At the same time, the proportion of participants with calcium intake above the tolerable upper intake level (UL, > 2500 mg day(-1)) would increase from 0.6% to 12.7% in men and from 0.1% to 3.8% in women. However, in a probability-based model (11% of all fortifiable foods to be fortified with calcium) the proportion of participants with calcium intake below the recommended level would be 15.7% in men and 23.2% in women. The proportion with intake above the UL in this model would be 1.2% in men and 0.7% in women. CONCLUSIONS: Food fortification would be a relatively effective and safe way to increase the calcium intake of the Finnish adult population.     

Effects of post-fire management practices and slope-aspect on medium-term Spanish black pine regeneration: implications of using a direct seeding strategy in burnt areas

The natural regeneration of non-serotinous Spanish black pine (Pinus nigra Arn. ssp. salzmannii) is known to be null or limited after severe wildfires. However, it remains challenging to define efficient management strategies within the burnt area, which can help to increase the post-fire resilience of this species. We conducted a direct seeding experiment during 2011–2015 to assess the effect of different post-fire management treatments (control, soil ripping, woodchips, and soil ripping?+?woodchips) performed in opposite slope-aspects (north- and south-facing) on pine emergence, seed predation, survival, growth, and biomass allocation during the early stages of seedling development (1–5 years) after a severe wildfire. Our results showed that the slope-aspect did not have an important effect in both the seedling emergence and seed predation rates. In contrast, the influence of slope-aspect was significant as both survival and growth of pine seedlings were reduced at the south-facing slope-aspect compared to the north-facing slope-aspect due to harsher environmental conditions. A variable and reduced impact on seedling emergence and seed predation rates was induced by both soil ripping and woodchips treatments. Overall, post-fire management treatments helped to enhance survival rates during early growth stages, although this effect was short-lasting. This knowledge can be used to define post-fire seeding management strategies oriented to enhance the resilience of severely burnt pine forest stands; therefore, while both the soil ripping and woodchips treatments might not be practices leading to increase their post-fire regeneration, direct seeding at north-facing slope-aspects could be a more appropriate management strategy.