深圳市餐饮垃圾收运处置规划研究

文章对深圳市餐饮垃圾单独收运处置进行了规划研究,规划年限2006-2020年.通过对深圳市餐饮垃圾的产生、收运处置现状及存在的问题分析,提出了餐饮垃圾的收运模式以及采用厌氧消化制沼气的处置方式.此外,还提出了深圳市餐饮垃圾的管理建设思路.     

浅谈生物资源平衡与生态平衡

地球是一个具有一定自洁、自我修复功能的大生态系统,它由各种植物、动物、人类、微生物有机的组成,维持着自然界的生态平衡。而大量的人类活动给地球的生态平衡产生了较大影响,特别是明显加快的城市化进程,使得这种平衡逐渐受到不可逆的破坏。论文重点分析了城市化给生态平衡所带来的问题,并由此提出了从生物链的角度建立生物资源平衡,从而实现新的生态平衡。将城市污染物的资源化和生态平衡联系起来,通过建立生物资源补充机制、改变城市垃圾和污水的处理方法等措施,促进生物资源平衡,在相对较大的范围内实现人类发展与自然相协调,实现可持续发展。     

保鲜膜中微塑料和邻苯二甲酸酯浸出行为及斑马鱼胚胎毒性评价

保鲜膜是最常见的一类塑料食品接触材料,在生活中被广泛使用,但对于其在不同食品应用场景中有害物质的浸出情况及对生物可能构成的健康风险尚不明确。选取聚乙烯（PE）和聚氯乙烯（PVC）2种材质保鲜膜,考察3种食品模拟物（水、50%乙醇和正己烷）中微塑料和邻苯二甲酸酯（PAEs）的浸出行为,并探究浸出PAEs对斑马鱼胚胎发育的影响。结果表明,从PE保鲜膜和PVC保鲜膜中浸出的总体微塑料平均丰度分别为（2.67SymbolqB@0.82）个·（100 mL）^-1和（3.78±0.92）个·（100 mL）^-1。PVC保鲜膜浸出微塑料的粒径集中在500～1 000 μm范围（55.9%）,而PE保鲜膜浸出粒径为<500 μm的微塑料占比最大（74.1%）。PVC保鲜膜含醇和油脂环境下的实验组对斑马鱼胚胎发育有显著影响,可诱导胚胎出现心率失常、心包囊肿和脊柱弯曲等症状,PVC保鲜膜在这2种环境下均检测到PAEs的迁移。相比于PE保鲜膜,PVC保鲜膜的浸出毒性需引起重视。     

Residues and dissipation of the pesticide emamectin benzoate under Egyptian field condition: a case study

A simple, rapid analytical procedure for the quantification of emamectin benzoate in tomato was developed using high performance liquid chromatography with fluorescence detector (HPLC-FLD). Emamectin benzoate residues were extracted from tomato samples with n-hexane:ethyl acetate (1:1, v/v). The method involved derivatization using trifluoroacetic anhydride and 1-methylimidazole, prior to analysis by HPLC-FLD. Limit of quantification of this method was found to be 0.01 mg/kg, while limit of detection was 0.005 mg/kg. The dissipation of emamectin benzoate on tomato was studied, and half-life (t_1/2) was estimated in a field study carried out at three different locations. Emamectin benzoate was sprayed on tomato at recommended dosage. Samples of tomato were collected at 0, 1, 3, 7, 10, and 15 days after treatment. The t_1/2 of emamectin benzoate when applied at the recommended doses in tomato was approximately 2.5 days. The residue of emamectin benzoate reached below the maximal residue limit (MRL) 10 days after spraying at the tested dosage. Hence, a safe pre-harvest interval of 10 days is suggested before harvesting of tomato. This study would also be helpful for the Egypt government to establish the MRL of emamectin benzoate in tomatoes and provide guidance on the proper and safe use of this insecticide.     

Inorganic elemental concentrations in birch bolete mushroom (Leccinum scabrum) and top soil: contamination profiles,bioconcentation and annual variations

Abstract

Analysis of inorganic and organic contaminants in foodstuffs aids in understanding the human exposure to these compounds via consumption. In this study, an edible mushroom species (Leccinum scabrum) and top soil samples were analysed for essential and toxic substances including phosphorus and inorganic elements over a period of three fruiting seasons. Analysis of silver (Ag), aluminium (Al), barium (Ba), calcium (Ca), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), mercury (Hg), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), phosphorus (P), lead (Pb), rubidium (Rb), strontium (Sr) and zinc (Zn) in mushrooms and topsoil were performed using inductively coupled plasma optical emission spectroscopy (ICP-OES) with ultrasonic cross flow nebulizer. Total mercury was determined by cold-vapour atomic absorption spectroscopy (CV-AAS). The results exhibited wide variation in concentrations of metals between soil and mushroom (cap and stipes) during three fruiting seasons. Positive bioconcentration factors (BFCs) indicate on bioaccumulation of several metals including, Cd, Cu, Hg, K, Mg, Na, P, Rb and Zn in caps and stipes of fruitbodies of this mushroom, while other metals such as Al, Ba, Ca, Co, Fe, Mn, Ni, Pb and Sr were not exhibiting significant positive BFCs. Over a period studied, the caps were characterised by different (p?<?0.05) concentrations of Al, Co, Cu, Hg, Mn, Ni, P, Pb and Sr. Contamination profiles, temporal fluctuations, BCFs should be taken into consideration when assessing the nutritional value of this mushroom.