Polycyclic aromatic hydrocarbons in surface sediments held in experimental mesocosms

Sediment was collected from three locations along a pollution gradient in Narragansett Bay and transplanted to controlled mesocosms. Total hydrocarbons and eleven individual polycyclic aromatic hydrocarbons (PAHs) were measured in these sediments over a period of 394 days. Total hydrocarbon concentrations increased in the “relatively uncontaminated”; (Rhode Island Sound) sediment that was held in the mesocosms, but did not change in the two other sediments. The concentrations of four PAHs: naphthalene, 2‐methyl naphthalene, 1‐methyl naphthalene and biphenyl, decreased in the “contaminated”; (Providence River) sediment during the experiment and the calculated half‐lives for these compounds were 287, 353, 321 and 333 days, respectively.     

The interethnic differences of the human serum paraoxonase polymorphism analysed by a quantitative and a qualitative method †

The polymorphism of the human serum paraoxonase¹ was analyzed by two distinguished methods in six different ethnic groups (Caucasians, Mongoloids, Negroids), using (1) the Computer Method² and (2) the Carro‐Ciampi Method³‘⁴. Analysis of the response of the enzyme activities to salts resulting in low and high activity ratios.

Comparison of the results:

In Caucasians we distinguished three phenotypes by the Computer method. The polymorphism was governed by two alleles. The Hardy‐Weinberg rule for a two‐allele model was valid. Individuals belonging to the homozygotic group with low activity had a low activity ratio (Carro‐Ciampi method). With both methods a frequency between 57% and 61% was observed for this group. Individuals with medium and high activity had a high activity ratio.

In Negroids and Mongoloids samples we found (by the Computer method) a low activity group (Ghanaians 9.6%, Jamaicans 13.6%, Indonesians 6.7%, Koreans 19.6%). The Hardy‐Weinberg rule for a two‐ or three‐allele model was not valid. Individuals belonging to the low activity group had a low activity ratio, all individuals with higher activity a high activity ratio (Carro‐Ciampi method).

Our results suggest that the members of the low activity group in the three races are homozygote for an identical allele.     

Aliphatic and aromatic halocarbons as potential mutagens in drinking water

Chlorinated phenols are either products of industrial chemical processes or the result of chlorination of drinking water. Often, the formation of chlorinated phenols is based upon naturally occurring phenol. The following chlorinated phenols have been selected for testing in the Ames‐test for their mutagenic activity: 3‐chlorophenol, 4‐chlorophenol, 2,3,6‐, 2,4,5‐, 2,4,6‐trichlorophenol, 4‐chloro‐2‐methylphenol and 4‐chloro‐3‐methylchlorophenol. The tester strains TA97, TA98, TA100 and TA104 were employed. All tested compounds produced mutagenic activity at least in one tester strain. The highest numbers of revertants were detected for 2,3,6‐ and 2,4,6‐trichlorophenol. But in contrast to the other substances, these two induced only frameshift mutations in presence of a metabolizing system. The evidence of their presence in drinking water and of their mutagenic activity makes them to a potential health hazard.     

Speciation and carcinogenic classification—some limits of assessment and prevention procedures—the case of “nickel”

The speciation of nickel is of the highest importance for the definition of lists of substances for regulatory activity in terms of prevention, regarding possible cancer risk. A review is made of the different attitudes of outstanding administrations in front of nickel speciation. Some of them show a maximum of care in chemical definition, others reflect a lack of scientific rigor leading to generic classifications, more or less abusive. The great complexity of the chemistry and physicochemistry of nickel imposes the “two‐level speciation concept” (chemical and physicochemical), at least for compliance with the “Good Laboratory Practice” as far as experimental toxicology is concerned. Recommendations are exposed for the attention of toxicologists and regulators who have been for some years now extremely solicited for prevention aims.     

Regression models for octanol‐water partition coefficients,and for bioconcentration in fish

Octanol‐water partition coefficients (P) of a number of organochlorine insecticides (OCs) are presented. The merits of log‐log regressions between experimental ? values and calculated estimates of P, solute activity coefficients in water, solute molecular surface area data, and reversed‐phase liquid‐chromatographic net retention data, are critically evaluated for several classes of pollutants: polycyclic aromatic hydrocarbons (PAHs), chlorinated benzenes, chlorinated biphenyls and OCs. Special attention is paid to the predictive accuracy of such semi‐empirical regressions in connection with possible effects of solute molecular shape and polarity.

Finally, bioconcentration and ‐accumulation of hydrophobic pollutants in fish are briefly discussed.     

秸秆污泥堆肥产纤维素酶细菌的筛选及产酶条件优化

从添加秸秆进行堆肥处理的污泥中采集样品,通过富集培养和刚果红平板染色法筛选分离出具有纤维素降解能力的细菌,再通过酶活力测定从中分离筛选出1株相对高活性的产纤维素酶细菌CI;通过基于16S rRNA基因序列的系统发育分析,初步确定该菌株为Devosia sp..利用单因素试验对目的菌株C1进行产纤维素酶发酵条件优化,结果表明菌株C1产纤维素酶的最佳发酵时间、培养温度、摇床转速以及最适初始pH值分别为60 h、30℃、130 r·min^-1和7.2～7.5,且在该条件下其滤纸酶（FPase）和羧甲基纤维素酶（CMCase）活力分别达23.10和54.97 U·mL^-1.     

氨基脲的毒性效应研究进展

环境及食品中的氨基脲主要来源于硝基呋喃类药物及偶氮二甲酰胺的分解;同时,次氯酸盐与氨基酸的作用也能产生氨基脲. 氨基脲曾在食品动物、玻璃包装食品等多种食品中被检出,近期在我国东营潮河入海口邻近海域也有检出. 早期的研究表明,氨基脲具有致诱变性和潜在的致癌性;而近期的研究表明,氨基脲不仅能够在组织形态学水平上导致多种组织器官的形态改变,而且还可对神经系统、内分泌系统的功能产生影响. 50~150mg/L氨基脲可导致大鼠胎儿肺和肝脏器官内核酸水平显著降低,增加幼年小鼠肺肿瘤发生率;此外,能够显著增加鼠骨髓嗜多染红细胞的微核率,表现出弱遗传毒性. 氨基脲是GABA合成酶GAD(谷氨酸脱羧酶)的抑制剂,并且对NMDAR(N-甲基-D-天氡氨酸受体)具有拮抗作用,从而产生神经毒性. 氨基脲可致大鼠多个靶组织器官形态结构的改变且具有一定的性别差异,其中,对胸腺及肾上腺的组织学改变仅在雌性中表现出来,而对甲状腺组织结构的改变仅在雄性中表现明显,对生殖器官的毒性表现为其能够改变雌性卵巢和雄性睾丸显微结构. 雌性大鼠口服40、75、140mg/kg氨基脲28d能够降低其血浆内E₂(雌二醇)水平,并且呈剂量-效应关系,表现出抗雌激素效应. 未来应继续补充氨基脲的毒性数据,以揭示其毒性作用机制;同时,应从其衍生物降解规律、环境风险评价等角度进行深入研究.      

Efficacy of rapeseed residue and eggshell waste on enzyme activity and soil quality in rice paddy

Addition of plant residue into soils improves soil physiochemical properties and its fertility. Rapeseed residue is an emerging N source to paddy soils via rice-rape double-cropping practice. The objective of this study was to evaluate the effects of rapeseed residue and eggshell waste on chemical changes and enzyme activity in the rice paddy soil. The powdered eggshells at 0, 1, 3, and 5% were applied once to 7.0 kg paddy repacked soils in each pot treated with the rapeseed residue or the conventional N, P, and K fertilisers. Eight rice seedlings (Oriza sativa L. cv. Ilmibyeo) (40 days after sowing) were transplanted to the treated each pot. The contents of total C (TC) and N (TN), and organic matter (OM) were significantly increased in soils treated with the rapeseed residue compared to the N, P, and K fertilisers. With the addition of eggshell containing ～92% CaCO₃, a considerable increase of soil pH was observed in soils treated with the rapeseed residue and the N, P, and K fertilisers, compared to the untreated soil. Activities of β-glucosidase, urease, and arylsulfatase enzymes were higher in soils treated with the rapeseed residue than soils treated with the N, P, and K fertilisers. The eggshell additions at 1, 3, and 5% into soils treated with the rapeseed residue increased enzyme activity mainly resulting from N mineralisation, whereas no change in enzyme activity was observed in the soils treated with the NPK fertiliser. The combined use of the rapeseed residue and the eggshells can be beneficial to improve soil environment.     

庐山植物园11种植物的根际土壤氮磷有效性和酶活性

通过比较不同种源植物的土壤理化性质与生物学活性的差异及根际效应,探讨不同种源植物对庐山酸性山地土壤的环境适应性。在庐山植物园内选择引种多年的11种不同种源的常绿树种,在生长季节中采集根际土和非根际土,测定有机碳含量、碱解氮及有效磷含量、脲酶和酸性磷酸酶活性,并分析各树种根际土壤氮磷养分及酶活性的根际效应。结果表明,（1）不同树种之间的根际土壤酸性磷酸酶（P〈0.01）、有效磷（P〈0.05）和碱解氮（P〈0.01）存在明显差异,而脲酶没有差异。（2）根际与非根际土壤氮磷有效性和酶活性表现出不同的特征,大部分树种根际土壤有效磷及酸性磷酸酶存在一定的根际效应（R/S〉1）,例如红花木莲Manglietia insignis、桂南木莲Manglietia chingii及云南拟单性木兰Parakmeria yunnanensis的根际与非根际土壤有效磷含量存在显著差异（P〈0.05）,红花木莲、桂南木莲、巴东木莲Manglietia patungensis、红茴香Illicium henryi及红皮糙果茶Camellia crapnelliana与乡土树种云锦杜鹃Rhododendron fortunei根际与非根际土壤酸性磷酸酶存在显著差异（P〈0.05）。但是,根际与非根际土壤碱解氮和脲酶差异不明显,有的甚至出现脲酶的根际负效应（R/S〈1）,如巴东木莲和红花木莲等树种根际土壤低于非根际土壤（P〈0.05）。（3）不同种源树种影响下的土壤有效磷和酸性磷酸酶的根际效应（R/S比值）明显,原产西南地区的树种如桂南木莲、云南拟单性木兰和巴东木莲与华南地区的红花木莲、红茴香等土壤有效磷的根际效应（R/S〉1.5）比原产华东亚热带地区的深山含笑Michelia maudiae和云锦杜鹃更明显,相应的酸性磷酸酶的根际效应也较高。土壤脲酶和碱解氮的根际效应却不明显。（4）土壤有机碳与碱解氮、有效磷和酸性磷酸酶存在显著正相关关系（P〈0.01）,土壤碱解氮与有效磷（P〈0.01）和酸性磷酸酶（P〈0.05）具显著正相关关系,酸性磷酸酶与pH值（P〈0.05）显著负相关,说明根际土壤有机物质的积累对根际微区的理化环境及根际土壤养分活性具有重要影响。     

水位对小叶章湿地CO2、CH4排放及土壤微生物活性的影响

湿地生态系统对全球碳平衡和气候变化起着极其重要的作用,而水位波动将影响湿地生物地球化学过程,导致温室气体通量变化,为了明确湿地生态系统温室气体通量以及土壤微生物活性对水位梯度的生态响应,通过野外盆栽培养试验,设T1:-5 cm,T2:0 cm,T3:5 cm,T4:10 cm 4种水位梯度,T1和T2模拟湿地非淹水的水分状况,T3和T4模拟淹水状况,研究了不同水位梯度下小叶章(Calamagrostis angustifolia)湿地CO2、CH4通量、土壤微生物量碳、氮及土壤酶活性的变化规律.结果表明:不同水位条件下,小叶章湿地系统CO2和CH4通量差异较大,-5 cm水位时小叶章湿地CO2通量为(643.35±61.89) mg·m-2·h -1,随着水位增加,CO2通量依次降低6.9%、12.1%、40.0%,且水位升高到10 cm时,小叶章湿地CO2排放量显著降低(P<0.05);而CH4通量则随水位增加呈显著增加趋势,通量变化为(1.52±0.12)~(5.34±0.61) mg·m-2·h-1;水位对微生物活性影响显著,非淹水条件下小叶章湿地土壤微生物量碳、氮含量以及土壤蔗糖酶、淀粉酶活性高于淹水土壤,且随着淹水位增加,微生物活性显著降低.