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。     

温度, 光照和盐度对产麻痹性贝类毒素藻类生长及产毒的影响

为探究温度、光照和盐度对产麻痹性贝类毒素（PSP）藻类生长及产毒的影响,本文选取了4株产麻痹性贝毒的藻种（塔玛亚历山大藻（Alexandrium tamarense）香港株（ATHK）、微小亚历山大藻（A.minimum）台湾株（AMSY）、链状亚历山大藻（A.catenella）南海株（ACSY）和链状裸甲藻（Gymnodinium catenatum）防城巷株（GCFC））在不同光照（60、120和200 μmol/（m2·s））、温度（16、22和28℃）和盐度（25、30和35）条件下生长及产毒的变化。结果显示,22℃最适宜4株藻的生长。低温可促进PSP的产生,除GCFC外,其余3株藻的单位细胞产毒量均随温度的升高而降低。ATHK和AMSY的生长与光照正相关。AMSY和GCFC的单位藻细胞产毒量与光照强度正相关,光照为120 μmol/（m2·s）时ATHK和ACSY产毒量最高,弱光均不利于4种藻产毒。盐度30条件下ATHK,AMSY和GCFC长势较好,高盐度（盐度35）促进ACSY的生长。ATHK的单位细胞产毒量均随盐度的升高而增加,AMSY和ACSY在高盐和低盐条件下产毒量均较大,GCFC则在盐度为30条件下产毒量最高。     

1,2,4-三氯苯厌氧还原脱氯过程及荧光增白剂PF对脱氯过程影响研究

南京某化工厂生产荧光增白剂PF(1,2-双(5-甲基-2-苯并唑基)-乙烯,调查发现其地下水中存在多种污染物:1,2,4-三氯苯(TCB)、二氯苯同分异构体(DCB)、一氯苯(MCB)、苯和PF.场地多年监测结果显示很可能存在厌氧条件下氯苯类污染物的自然降解.为了探索污染物降解机制并确定荧光增白剂PF对该脱氯过程的影响,笔者通过室内实验发现1,2,4-TCB被脱氯为1,2-DCB、1,3-DCB和1,4-DCB,摩尔比率约为10%、35%、55%.随着1,2,4-TCB投喂次数的增加,降解菌的脱氯速度越来越快,最高可达到7μmol·d~(-1).1,2-DCB和1,3-DCB先脱氯产生MCB,1,4-DCB滞后约两周开始降解,脱氯速度从第14周的0.19μmol·d~(-1)增加到第17周的0.88μmol·d~(-1),并在第108 d左右消耗完全.虽然1,2-DCB和1,3-DCB比1,4-DCB先开始脱氯,但脱氯速度相对缓慢,1,2-DCB的脱氯速度从第12周的0.001μmol·d~(-1)增加到第15周的0.21μmol·d~(-1),1,3-DCB的脱氯速度从第12周的0.06μmol·d~(-1)增加到第17周的0.14μmol·d~(-1).DCBs降解产生的MCB在第160 d左右开始脱氯生成苯,脱氯速度从第23周的0.296μmol·d~(-1)到第25周的1.94μmol·d~(-1)再到第28周的0.007μmol·d~(-1).同时,实验结果表明荧光增白剂PF不会改变1,2,4-TCB的脱氯过程,但在MCB脱氯到苯的过程中具有一定的抑制作用.     

近25年洞庭湖水质演变趋势及下降风险

利用1991~2015年水质数据研究了洞庭湖水质演变特征,识别了主要驱动因子,并探讨了水质下降对其生态风险影响.结果表明,1991~2015年间,洞庭湖水质总体呈下降趋势,TN和TP是影响水质变化的主要指标,其浓度年均值分别介于1.060~2.072mg/L和0.026~0.146mg/L;其中,1991~2002年间,TN和TP浓度均显著上升,多元回归分析显示水位和泥沙淤积是导致洞庭湖TN和TP浓度升高的主要因素;2003~2015年间,TN浓度进一步明显上升,而TP浓度维持高位,波动变化,氮、磷负荷输入量和水位是影响TN和TP浓度变化的主要因素.洞庭湖生态风险等级则由轻微风险转变为中等风险,TP是影响生态风险的主要水质指标;受洪水、农业面源污染和城市化等影响,洞庭湖磷风险时空差异较大,1991~2008年间,各湖区磷风险均有所升高,其中西洞庭湖磷风险增长幅度最大;2009~2015年,各湖区磷风险均有所降低,其中西洞庭湖下降幅度最大,而东洞庭湖下降幅度较小.因此,进一步控制入湖氮磷负荷、优化水位及重点关注磷风险是保护洞庭湖水生态的重要举措.     

陕西省成品油供应链现状及优化建议

介绍了陕西省成品油生产、消费、流通等环节的现状,针对各环节潜在问题提出了优化建议:加强采炼销环节管理,实现采炼销动态平衡;加强配送中心建设,高效链接一次物流和二次物流环节;加强信息网络建设,高度集成各环节管理系统和油品信息资源;加强全链条环节的油气回收,建立污染排放清单。     

“十二五”期间黑龙江省城市饮用水水源地环境问题与对策研究

黑龙江省从2006年开始部署和落实全省饮用水水源地环境保护调查、评估和规划工作。截止至2015年,全省参与调查评估的地级城市集中式饮用水水源地共计36个,涉及取水量86 262.2万吨/年,服务人口1 034.4万人。"十二五"期间,全省水源地水质达标率有所下降,水量达标率呈上升趋势,水质连续五年未能达到Ⅲ类的水源地合计4个,主要超标因子为铁、锰、氨氮。我省水源地监测能力建设、规范化管理、风险防范和应急能力等方面仍存在问题。需从多方面入手加强水源地保护。