苏北沿海互花米草入侵盐沼自然移除外源苯乙烯的特征研究

Nature removal to exogenous styrene gas of Spartina alterniflora salt marsh in the coastal area of Northern Jiangsu

恶臭气体苯乙烯在环境中的长期暴露可致人体产生黏膜与眼睛刺激以及肠胃功能紊乱,甚至产生疼痛、疲劳、乏力、抑郁和神经病变,严重地危害着人体的健康.分别于生长季(2004年7月)和非生长季(2005年1月)在苏北海岸带盐沼沿环境梯度采用静态箱技术原位测定苯乙烯通量.结果表明:研究区大气中苯乙烯的浓度接近于国家规定的厂界污染源排放的最大允许值,在由海向陆的梯度上,大气中苯乙烯的浓度变化表现为近陆海点高而远陆海点低,由此推断,本区大气中苯乙烯主要源自沿海化学和石化工业排放以及外海苯乙烯的大气、潮水和潮流的横向输送;海岸带盐沼生态系统中,盐沼植物和土壤对外源苯乙烯的自然移除是苯乙烯的重要汇,盐沼对苯乙烯的自然移除能力具有显著的季节和空间变化性,并具有显著的物种依赖性.高等植物对苯乙烯的自然移除能力可能与高等植物生物量、叶面蜡质含量以及气孔丰度有关.而土壤对苯乙烯的自然移除能力可能取决于土壤温度、孔隙度、有机质含量、全氮含量以及可溶性盐总量.互花米草的入侵并没有增加海岸带盐沼对苯乙烯气体的自然移除能力,没有显著的增汇效应.

Acute exposure to styrene in humans results in mucous membrane and eye irritations as well as gastroin-testinal disorders .Chronic contact causes a variety of discomforts including headache ,fatigue ,weakness ,depres-sion ,and peripheral neuropathy ,and has a serious threat to human health .The fluxes of styrene were measured seasonally using static flux chambers along an elevational gradient of a salt marsh in the coastal area of Northern Jiangsu ,China .The results show that atmospheric concentration of styrene gas is closed to the maximum allowable concentration of anthropogenic sources in study area ,and the concentration of points close to land and sea is high and away from that is low .It is inferred that styrene of the atmosphere may be from external input of seawater , coastal chemical and petrochemical industries emissions .The plant and soil of coastal salt marsh ecosystem is impor-tant sink of styrene ,seasonal and spatial variation of natural absorption flux of styrene are significant ,and its strength has significant species dependent .The natural removal ability of higher plants to styrene may be related to biomass ,content of foliar wax and abundance of stomata ,and the ability of soil may depend on soil temperature ,po-rosity ,organic matter content ,nitrogen content ,and total soluble salts .Spartina alternif lora invasion did not in-crease removal capacity of styrene of coastal salt marsh ,and the effect of increasing carbon sink is not significant .