Distribution and accumulation of organotin species in seawater, sediments and organisms collected from a Taiwan mariculture area

The present study was undertaken to evaluate the distribution and accumulation of tributyltin (TBT) and triphenyltin (TPhT) in seawater, sediments and selected organisms from a cage mariculture area in southern Taiwan, Hsiao Liouchiou Island. Our results show that ΣOTs were found in concentrations as high as 196 ng/L in seawater collected from the sites in Pai-Sa harbor, and up 1040 ng/g dry wt. in sediments dredged from sites within Da-Fu harbor. Also, ΣOTs concentrations of 859 ng/g dry wt. were observed in the liver of cobia (Rachycentron canadum) from mariculture cages. As most published studies have focused on the acute toxicity and bioaccumulation of organotins in mussels, the effects of organotins on cobia and other marine fauna are still poorly understood. This study highlights the significance of ΣBTs accumulation in cobia, as well as in the sediments and seawater surrounding their culture facilities.     

Environmental response to sewage treatment strategies: Hong Kong's experience in long term water quality monitoring

In many coastal cities around the world, marine outfalls are used for disposal of partially treated wastewater effluent. The combined use of land-based treatment and marine discharge can be a cost-effective and environmentally acceptable sewage strategy. Before 2001, screened sewage was discharged into Victoria Harbour through many small outfalls. After 2001, the Hong Kong Harbour Area Treatment Scheme (HATS) was implemented to improve the water quality in Victoria Harbour and surrounding waters. Stage I of HATS involved the construction of a 24 km long deep tunnel sewerage system to collect sewage from the densely populated urban areas of Hong Kong to a centralized sewage treatment plant at Stonecutters Island. A sewage flow of 1.4 million m³ d⁻¹ receives Chemically Enhanced Primary Treatment (CEPT) followed by discharge via a 1.2 km long outfall 2 km west of the harbor. The ecosystem recovery in Victoria Harbour and the environmental response to sewage abatement after the implementation of HATS was studied using a 21-year data set from long term monthly water quality monitoring. Overall, the pollution control scheme has achieved the intended objectives. The sewage abatement has resulted in improved water quality in terms of a significant reduction in nutrients and an increase in bottom DO levels. Furthermore, due to the efficient tidal mixing and flushing, the impact of the HATS discharge on water quality in the vicinity of the outfall location is relatively limited. However, Chl a concentrations have not been reduced in Victoria Harbour where algal growth is limited by hydrodynamic mixing and water clarity rather than nutrient concentrations. Phosphorus removal in the summer is suggested to reduce the risk of algal blooms in the more weakly-flushed and stratified southern waters, while nutrient removal is less important in other seasons due to the pronounced role played by hydrodynamic mixing. The need for disinfection of the effluent to reduce bacterial (E. coli) concentrations to acceptable levels is also confirmed and has recently been implemented.     

Seasonal and spatial heterogeneity of recent sea surface temperature trends in the Caribbean Sea and southeast Gulf of Mexico

Recent changes in ocean temperature have impacted marine ecosystem function globally. Nevertheless, the responses have depended upon the rate of change of temperature and the season when the changes occur, which are spatially variable. A rigorous statistical analysis of sea surface temperature observations over 25 years was used to examine spatial variability in overall and seasonal temperature trends within the wider Caribbean. The basin has experienced high spatial variability in rates of change of temperature. Most of the warming has been due to increases in summer rather than winter temperatures. However, warming was faster in winter in the Loop Current area and the south-eastern Caribbean, where the annual temperature ranges have contracted. Waters off Florida, Cuba and the Bahamas had a tendency towards cooling in winter, increasing the amplitude of annual temperature ranges. These detailed patterns can be used to elucidate ecological responses to climatic change in the region.     

西南黄海环流及其对浒苔分布的影响

本文基于高分辨率ROMS(Regional Ocean Modeling System)模式在中国海区域1980—2019年共40 a的模拟结果,研究了西南黄海环流的存在性及成因、季节变化特征等,并初步探究了西南黄海环流与黄海浒苔灾害年际差异之间的关系.结果表明:顺时针方向的西南黄海环流终年存在于山东半岛南部35.0°...     

主要赋铀岩石可见光—短波红外光谱二向性特征初步实验研究

花岗岩和砂岩是我国主要的赋铀岩石,为了提高利用遥感图像识别这两种岩石精度的效果,开展其可见光—短波红外光谱二向性特征实验研究。对其在微光实验室中,用200 W钨灯与平行光管产生平行光,以15°、 30°和45°入射角照射岩石的自然表面,在距离岩石表面20(25)cm、30 cm和40 cm处用ASD光谱仪垂直岩石表面接收可见光—短波红外反射光谱。光谱测试和数据分析发现,岩石的反射光谱二向性特征明显受岩石结构的影响。全晶质的斑状花岗岩,其二向性特征只受岩石结构类型影响;粗粒和细粒花岗岩都是在光线以30°角入射时具有最大的反射率辐射。非全晶质的砂岩,其二向性特征受岩石结构和结晶颗粒大小的双重影响;粗砂岩在照射光45°角入射时具有最大的反射辐射,而细砂岩则在照射光15°角入射时,具有最强的反射辐射。     

广西中东部9县区农田土壤As输入通量研究

对广西中东部9县区农田土壤中的As输入通量进行了初步研究。综合各方面因素,计算获取了大气干湿沉降、施肥和灌溉水输入通量。结果表明,研究区大气干湿沉降和施肥As输入通量基本相当,平均值分别为9.92 g/(hm^2·a)和7.83 g/(hm^2·a),灌溉水通量最高,平均值为14.98 g/(hm^2·a),三者对土壤As污染的贡献率分别为30.31%、23.92%和45.77%。9个不同县区大气干湿沉降、施肥和灌溉水As输入通量占比略有不同,其中6个县区灌溉水和施肥输入通量占主导地位,另外3个县区大气干湿沉降输入通量比例较高。因此,灌溉水是研究区农田土壤As的主要输入途径,应重视灌溉水水质控制。在未考虑农田土壤As输出通量的情况下,以当前的As年平均输入通量估算得到耕层土壤As的质量分数每年升高0.01 mg/kg。与土壤As含量现状相比,As年增量比例很小,因此判断在短期内,外源输入对土壤As分布现状影响不大。该区土壤p H值较低,铁氧化物含量较高,因此外源输入农田土壤的As生物有效性较低。     

广西中东部9县区农田土壤Cd输入通量研究

对广西中东部9县区农田土壤中的Cd输入通量进行了初步研究,确定大气干湿沉降、化肥和灌溉水为Cd的主要输入途径。研究区大气干湿沉降通量平均值为5.01 g/(hm2·a),化肥和灌溉水通量则明显较低,三者对土壤Cd污染的贡献率分别为90.65%、3.02%和6.33%,其中不同县区三者比例略有不同,但大气干湿沉降所占贡献比例均在60%以上,最高达到97.74%。因此,大气干湿沉降是研究区Cd的主要输入途径,大气环境质量监控应该给予足够的重视。如果不考虑农田土壤Cd的输出通量,当前的Cd年平均输入通量可引起土壤Cd质量分数升高0.002×10-6·a。研究区内象州县Cd输入通量最高,并且主要以活动态形式存在于表层土壤中,生物可利用性高。