双酚A和典型类固醇环境激素迁移转化研究进展

近年来有关环境激素污染的认知、研究与防治已经开始受到全球的重视,其中双酚A(BPA)和类固醇是环境中检出频率较高的几种环境激素.国外有关BPA和类固醇环境激素的调查和其迁移转化的研究已经广泛展开,但我国仍处于起步阶段.综述了国内外BPA和两种典型类固醇激素17β-雌二醇(E2)和17α-乙炔基雌二醇(EE2)的研究进展,介绍了其基本性质、用途、危害、环境中浓度和其迁移转化规律;指出为了阐明BPA、E2和EE2在环境中危害,有关其吸附、生物降解和光降解等迁移转化规律,及各迁移转化过程之间协同作用与相互影响的研究还有待于进一步深入.     

人工神经网络在强化一级处理系统过程模拟与优化中的应用

针对化学强化一级处理系统(CEPT)处理废水时影响因素多,难以进行适当的控制和处理效果的预测等问题,建立起基于BP人工神经网络的CEPT法处理猪场稳定塘废水预测模型,并应用该模型对烧杯试验进行了模拟.结果表明,预测值和实测值吻合较好,模型对COD、总磷、浊度去除率预测的平均相对误差分别为7.5%、4.8%和4.9%.通过对pH值和絮凝剂投药量等可控参数进行优化计算,得到CEPT系统的最佳操作条件和最合理操作条件.该模型的建立为CEPT法处理废水工艺系统实现自动化控制提供了一条简便实用的途径.     

Modification of chemical oxygen demand monitoring in the Yellow River, China, with a high content of sediments.

This paper presents a modification of chemical oxygen demand (COD) monitoring giving a better indication of the pollution level compared with the conventional COD method for rivers with a high content of sediments. The correlation between the sediment organic carbon and COD was investigated using sediments sampled in the middle Yellow River, China. Partitioning of the sediment organic carbon between the water and sediment phases was also investigated using batch experiments, with the sediment concentration varying from 20 to 400 g/L. As a result, the COD modification equations are proposed for both turbid water (mixture of water and sediment) and supematant water (filtrate using a 0.45-microm membrane). The modified COD in turbid water and supernatant water could be 40 and 10% less than the monitored COD values, respectively. These results may have a significant influence on the assessment of water quality class in the Yellow River.     

Tissue distributions and seasonal dynamics of the hepatotoxic microcystins-LR and -RR in a freshwater snail (Bellamya aeruginosa) from a large shallow, eutrophic lake of the subtropical China

Tissue distributions and seasonal dynamics of the hepatotoxic microcystins-LR and -RR in a freshwater snail (Bellamya aeruginosa) were studied monthly in a large shallow, eutrophic lake of the subtropical China during June-November, 2003. Microcystins (MCs) were quantitatively determined by High-Performance Liquid Chromatography (HPLC) with a qualitative analysis by a Finnigan LC-MS system. On the average of the study period, hepatopancreas was the highest in MC contents (mean 4.14 and range 1.06-7.42 microg g(-1)DW), followed by digestive tracts (mean 1.69 and range 0.8-4.54 microg g(-1)DW) and gonad (mean 0.715 and range 0-2.62 microg g(-1)DW), whereas foot was the least (mean 0.01 and range 0-0.06 microg g(-1)DW). There was a positive correlation in MC contents between digestive tracts and hepatopancreas. A constantly higher MC content in hepatopancreas than in digestive tracts indicates a substantial bioaccumulation of MCs in the hepatopancreas of the snail. The average ratio of MC-LR/MC-RR showed a steady increase from digestive tracts (0.44) to hepatopancreas (0.63) and to gonad (0.96), suggesting that MC-LR was more resistant to degradation in the snail. Since most MCs were present in the hepatopancreas, digestive tracts and gonad with only a very small amount in the edible foot, the risk to human health may not be significant if these toxic parts are removed prior to snail consumption. However, the possible transference of toxins along food chains should not be a negligible concern.     

Assessing copper thresholds for phytotoxicity and potential dietary toxicity in selected vegetable crops

Copper pollution in soils is widespread, and its accumulation in crop products could pose a risk on human health. In this paper, bioavailability of added copper (Cu) and critical Cu concentrations in a vegetable garden soil was evaluated for Chinese cabbage (Brassica chinensis L.), pakchoi (Brassica chinensis L.), and celery (Apiumg graveolens L. var. dulce DC) based on human dietary toxicity. The availability of added Cu in the soil decreased with incubation time, and had minimal change after 10-12 weeks. After incubated for 12 weeks, about 60% of added Cu was not extractable by DTPA. The same crops were also grown in sand culture to determine their responses to solution Cu. Shoot growth was significantly inhibited at Cu concentrations above 10 mg kg(-1) in the solution or above 150 mg kg(-1) (DTPA-Cu) in the soil. The sensitivity of the crops to Cu toxicity differed among the three vegetable crops. Copper concentration in shoots and edible parts varied with Cu supply levels and type of the vegetables. Negative correlations (r=-0.90-0.99**) were noted between Cu concentration in shoots and fresh matter yields, but Cu concentrations in the edible parts were positively correlated with available and total Cu in the soil (r=0.91-0.99**). The critical tissue Cu concentrations at 10% shoot DM reduction were 19.4, 5.5, 30.9 mg kg(-1) for Chinese cabbage, pakchoi, and celery, respectively. Based on the threshold of human dietary toxicity for Cu (10 mg kg(-1)), the critical concentrations of total and available Cu in the soil were 430 and 269 mg kg(-1) for pakchoi, 608 and 313 mg kg(-1) for celery, and 835 and 339 mg kg(-1) for Chinese cabbage, respectively.     

流化床垃圾焚烧炉产生的有毒二噁英同类物分布研究

测定了流化床垃圾焚烧炉焚烧产生的飞灰、烟尘和烟气中的2，3，7，8位氯取代二噁英同类物的含量及其毒性当量。结果表明，产生的二噁英主要存在于飞灰中，烟气中的含量很少。飞灰中二噁英总浓度和毒性当量分别为8.44ng／g和0．80ng／g，经过布袋除尘器后的烟尘和烟气中二噁英的浓度之和与毒性当量之和分别为0．34ng／m^3和0．02ng／m^3，而布袋除尘器前的烟尘和烟气中二噁英的浓度之和与毒性当量之和分别为40．78ng／m^3和3．0ng／m^3。飞灰和烟尘中2，3，7，8位氯取代二噁英同类物的分布相似，但是与烟气中2，3，7，8位氯取代二噁英同类物的分布差别较大。通过了解有毒二噁英同类物的分布，可以进一步优化流化床垃圾焚烧炉的焚烧条件，降低二噁英的排放量，减少垃圾焚烧对环境的污染。     

鱼外渔场海洋生物体内重金属和多环芳烃含量水平与食用风险评价

本文对2018年2月采自东海鱼外渔场的海洋生物(包括鱼类、头足类和甲壳类)体内的5种重金属(Cu、Pb、Cr、As、Cd)和16种多环芳烃(PAHs)的残留水平进行了测定,分析了污染物在生物体内的累积特性并计算了潜在的食用风险,并结合氮稳定同位素技术,初步探讨了生物体内重金属和PAHs的营养级传递特性。结果表明:5种重金属在生物中的平均浓度表现为CuPbCrAsCd;参照我国《食品中污染物限量》和《无公害食品水产品中有毒有害物质限量》,重金属Cu、Cd和Cr均未超过食用标准,但Pb和As的超标现象较为严重。与世界其他范围海域生物体内重金属浓度相比,该渔场生物体内Cu和Pb浓度较高。∑PAHs的平均浓度为283 ng·g~(-1)dw,以低环PAHs(2～3环)占比较大,且主要贡献单体为萘(NAP),总体处于较低污染水平。海洋生物对重金属的富集能力较PAHs高,尤其对Cu的富集最为明显。但风险计算结果表明,重金属和PAHs都不会对消费者的人体健康产生明显风险。重金属Cu和Cd浓度随营养级的升高出现了稀释现象,但重金属Pb、Cr、As和PAHs的营养传递特性不明显,覆盖完整食物链的污染物营养传递特性有待进一步深入研究。     

山东省的灌丛资源及其保护利用

山东省的灌丛资源十分丰富，有３０多个类型，主要的类型有山茶，大叶胡颓子，盐肤木、白檀，胡枝子，绣线菊，黄栌，鹅耳枥，柽柳，白腊，映山红，榛灌丛等１３个。本文对这些灌丛类型的群落学特点，种类组成，地理分布及其它方面进行了论述，并对各灌丛类型提出一定的保护利用措施。     

毁林与汉代居延垦区的衰落

本文根据历史史料，阐明了汉代居延垦区由兴旺发达到衰落的历史原因。进一步说明了乱破滥伐森林带来的恶果。开发大自然必须遵循自然规律，切不可盲目蛮干，毫无克制。     

我国沙漠化灾害的发展及其危害

沙漠化灾害是在特定自然环境背景下产生的,严重危及人类生产和生存。文章着重阐述沙漠化发展对农、牧业、工矿交通及环境等方面造成的经济损失。据初步统计,全国每年因沙漠化遭受的直接经济损失达36～45亿元,间接经济损失高达292亿元以上。同时,指出沙漠化的实质是从根本上毁损土壤肥力,丧失人类赖以生存的土地。因此,从沙漠化发生时间的频繁性、经常性,空间分布的广泛性,致害的多样性及造成的经济损失严重性看,沙漠化灾害是我国严重自然灾害之一。