Mitigation options for diffuse phosphorus loss to water

Abstract. Agriculture contributes significant loads of P to surface waters. The reductions in these diffuse P inputs necessary to help prevent eutrophication problems and/or assist in the restoration of water quality will require controls over both nutrient inputs and their subsequent transport in land runoff. Specific mitigation options include nutrient budgeting, input management, soil conservation, land use management and the establishment of riparian, and other buffer zones. The variable nature of diffuse P loss suggests that the best approach to control is through integrated management at a range of scales. Critical control concepts at the farm level include targeting source areas adequately, maintaining P input loading rates within recommended limits and avoiding high-risk management actions. Since eutrophication is a natural phenomenon and with potential conflicts with the need to meet production targets and/or minimize loss of other nutrients (N), some assessment of acceptable levels of P loss, of cost effectiveness of options and some prioritization of goals are necessary to find optimal solutions. As the requirements of individual waterbodies differ, these solutions need to be site specific and their successful adoption requires an appreciation by farmers of the importance of minimizing agricultural P loss both as individuals and collectively within a catchment.     

神府─东胜煤田大柳塔矿区水质及其污染评价

本文在野外考察和水质分析的基础上,对神府煤田大柳塔地区水质进行评价,结果表明,乌兰木伦河两岸支沟泉水水质良好,是生活用水的主要水源.活鸡兔沟矿坑水为强矿化度硬水,水化学性质差,这些矿坑水排入河道,是污染河水的因素之一.目前,乌兰木伦河和活鸡兔沟河水污染尚不严重,但河水水质由上游至下游交差.最后,对河水水质污染趋势作了分析和定性预测,并提出控制污染的建议和措施.     

烟气扩散与环境绿化的探讨

本文以陕西某一火力发电厂为例,通过高斯公式对SO_2扩散着地最大浓度和最大浓度距离的计算及探讨,为工业卫生防护林带绿化位置设计和环境保护提供一定的理论依据。     

PAK-Abnahmen in Bodenproben verschiedener Altlaststandorte bei Aktivierung der autochthonen Mikroflora

PAH decrease in soil samples from different polluted industrial sites by activating the autochthonous microflora In pot experiments under field conditions the PAH decrease in ten different soil samples from former industrial sites with differing PAH load were investigated over a period of 74 and 168 weeks. 15 out of 16 PAH according to US EPA (without acenaphthylene) were determined. Easily degradable organic matter, mineral fertilizers, synthetic surfactants and in some experiments also lime were added to the soil samples in varying amounts. Depending on the nature and quantity of the amendments, the biological activity and (co-)metabolic decomposition of PAH by soil microorganisms could considerably be increased. In the different soil samples a decrease of the initial PAH contents between 12 and 90% was achieved within 74 weeks. Even from 74 up to 168 weeks for some soil samples a remarkable further decrease of the PAH contents could be observed. The decrease of the extractable PAH with time is mainly caused by microbial decomposition and formation of nonextractable residues. This behavior can be fitted by two coupled exponential functions, one for an initial phase of rapid decomposition and the other for a subsequent phase of slow decomposition. Therefore, two different processes (I, II) determine the decrease of PAH. In the first week of the experiment the decomposition rates for process I amount to 4.2–88.3 and for process II to 0.06–5.3 mg PAH ? kg^?1 soil ? week^?1; in the 168th week they are no longer determinable for process I and amount to 0.05–2.3 mg ? kg^?1 ? week' for process II. Higher initial PAH contents often led to higher relative PAH decreases, but also to absolute higher contents of residues. The persistence of PAH is mainly determined by their bioavailability. PAH degradation is increased by the soil treatments. The addition of easily degradable organic matter (C/N ratio < 20) in a quantity of 30g ? kg^?1 (w/w) combined with the addition of nitrate and a surfactant most effectively increased the degradation of PAH. Raising the pH of a very strongly acidic soil sample revealed a maximum PAH decomposition at a pH of 6.     

解析法求湿空气介质的状态点

本文通过分析湿空气的热力过程,提出解析的方法求解过程参数,为热力计算特别是在高温状态下的热力计算提供精确的理论依据     

砖厂含氟废气对农业生态环境污染初探

为了研究含氟废气对农业生态环境的影响,采用环境监测和农业生态学方法进行了全面系统的调查与研究,结果表明,砖厂含氟废气排放点周围的大气,土壤,农作物已受到不同程度的污染,砖厂周围种植的农作物含氟量明显高于对照点,附近的家禽（鸡）死亡率也明显高于建砖厂前,因此,建砖厂时应周围环境污染影响予以重视。     

Cd Pb Cu Zn As复合污染对水稻的影响

应用田间试验和盆栽试验,研究Ｃｄ、Ｐｂ、Ｃｕ、Ｚｎ、Ａｓ复合污染在草甸棕壤上对水稻产量及元素含量的影响。结果表明,在接近土壤环境质量标准低浓度水平下,水稻发育正常,减产幅度＜１０％,但土壤Ｃｄ、Ｐｂ临界值下降,籽实中Ｃｄ、Ｐｂ、Ｚｎ吸收系数提高,Ｃｄ、Ｐｂ含量超标,低剂量时Ｃｄ超标３７．５％,高剂量时超标１００％,增加了对人体健康潜在危险。主要原因在于５元素间存在协同作用,Ｐｂ、Ｃｕ、Ｚｎ、Ａｓ的存在增加了Ｃｄ的活性与解吸率,使其易迁移,为防止土壤污染增加了困难。     

蔬菜铅污染状况及其防治对策

在金属冶炼厂周围和公路两侧200m范围内的蔬菜均受到铅污染,污染源为工业企业排放的烟尘废气和汽车尾气。蔬菜食用部位中的铅含量与菜地距公路的距离成负相关;相同距离点上生长的不同蔬菜中铅含量有明显差别,表明不同种类的蔬菜吸收和积累大气中铅的能力有强弱之分,一般是普通叶菜的铅含量大于结球叶菜、根菜及果菜,且普通叶菜的铅含量超过国家食品卫生标准。减少蔬菜铅污染的措施主要是：1．根治污染源;2．调整菜田布局;3．绿化带间隔;4．食用前多次水洗;5．实行蔬菜售前铅检测。     

崇礼区典型林分空气负离子浓度及影响因素

[目的]对崇礼区3种主要林分类型的空气负离子浓度变化规律以及影响因素进行研究,为该地生态效益评估以及生态旅游规划提供依据。[方法]本研究通过对崇礼区典型林分类型空气负离子浓度进行连续观测,并以开阔无林地为参照对象,采用柱状图、散点图、回归分析等方法研究河北杨(Populus hopeiensis,PHF)、白桦(Betula platyphylla,BF)和油松(Pinus tabulaeformis,PF,)3种纯林以及无林地(NF)空气负离子浓度日变化特征,分析气象因素及植物光合特性对空气负离子的影响,并运用单极系数法以及空气质量系数法对不同林分空气质量进行评价。[结果]表明:(1)空气负离子浓度变化趋势呈双峰型,最低值一般出现在中午,不同林分最高值出现时间不同。不同林分空气负离子浓度具有明显差别,空气负离子浓度从高到底依次为:河北杨(1 101 ion·cm-3)白桦(847 ion·cm-3)油松(755 ion·cm-3)无林地(344 ion·cm-3)。(2)不同林分空气负离子浓度与气温呈负相关,与相对湿度呈正相关;不同林分空气负离子浓度与植物光合特性总体呈正相关。(3)计算空气质量评价参数得出不同林分单极系数从小到大依次为河北杨(0.92)油松(1.01)白桦(1.25)无林地(1.37),各林分空气质量评价指数从大到小依次为河北杨(1.25)白桦(0.85)油松(0.80)无林地(0.27)。[结论]不同林分空气负离子浓度存在差异且阔叶林高于针叶林,空气离子浓度的变化受外界气候因素及自身植物光合特性的影响明显,不同林分空气质量评价指数也存在差异,合理配置林分资源有利于空气质量提升。     

论水土保持在解决中国水问题中的战略地位

洪涝灾害、淡水资源短缺和水污染问题是中国水问题中的三大主要问题,已引起社会各界的高度重视。影响中国三大水问题的因素甚多,但水土保持是解决水问题之根本性、战略性措施。