Heavy metals in oysters, mussels and clams collected from coastal sites along the Pearl River Delta,South China

Concentrations of 8 heavy metals: cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony (Sb) and tin (Sn) were examined in 3 species of bivalves (Perna viridis, Crassostrea rivularis and Ruditapes philippinarum) collected from 25 sites along the Pearl River Delta coastal waters in the South China Sea from July to August 1996. In general, Cd, Cu, Zn and Sn concentrations in the three bivalve species collected from the Estuarine Zone were significantly higher than those collected from the Western and Eastern Zones of the Pearl River Delta, which are related to the existence of various anthropogenic activities in the catchment of the Pearl River Delta. The Western Estuarine Zone is mainly impacted by Cr, Ni and Cu contamination. In Victoria Harbor, heavy metal contamination is mainly due to Cu and Pb. Cd, Cu and Zn concentrations in oysters were significantly higher than those in mussels and clams. This could be explained by the fact that oysters live mainly in the Estuarine Zone of the Pearl River Delta which receives most of the polluting discharges from the catchment of the Delta. During turbid condition, heavy metals(soluble or adsorbed on suspended particulates) discharged from the Delta are filtered from the water column and subsequently accumulated into the soft body tissues of oysters. Heavy metal concentrations in the three bivalve species were compared with the maximum permissible levels of heavy metals in seafood regulated by the Public Health and Municipal Services Ordinance, Laws of Hong Kong, and it was revealed that Cd and Cr concentrations in the three bivalve species exceeded the upper limits. At certain hotspots in the Delta, the maximum acceptable daily load for Cd was also exceeded.

Evaluation of the Quality for the Egyptian Red Sea Coastal Waters during 2011-2013

To assess the quality of the Egyptian Red Sea coastal waters for the sustainable use and development, due to its importance for the national income, four field campaigns were annually carried out during the period from 2011-2013 to investigate the hydrography, nutrient salts, heavy metals and petroleum hydrocarbons. Except for the area of Bir Shalatein, the results of beach litter cleared out that the shoreline of the studied area is not affected by man-made litter. No sewage could be observed. The results of the present study showed that water temperature followed seasonal changes in air temperature. Red Sea water is more saline than adjacent Arabian Sea. DO revealed high values and presence of well oxygenated waters. Minor changes in the distribution of pH, BOD, DOM and COD, revealed that limited effects of human impacts and depend mainly on the dynamics of its water as well as on the geographical location. Low Chl-a and TSM concentrations and high transparency revealed that also the effect of human impacts is almost negligible. Significantly higher sea water temperatures, TSM, pH, DO, BOD, DOM, and COD were observed in summer season compared to their corresponding values in winter season. Dissolved inorganic nitrogen concentrations were quite low because there is little nutrient input from soil, agriculture and pollution on land. Based on the annual mean values, the pattern concentrations of dissolved inorganic nitrogen forms followed the order: NO3 > NH4 > NO2. The Red Sea coastal waters are classified as oligotrophic to mesotrophic state. A remarkable increase of PO4 concentration was observed in the middle Red Sea stations due to huge amounts of effluents enriched with phosphate from the main shipping and industry of Phosphate Companies. SiO4 displayed a large variability due to the supply of SiO4, which flows in the Red Sea through the strait of Bab El-Mandab, biological consumption, organic matter decomposition and the partial dissolution of quartz particle transported to the sea from the surrounding desert during sand storms. Concentrations of ammonia, phosphorus, total nitrogen, and total phosphorus were significantly higher in summer compared to their corresponding values in winter. In general, the majority of TN and TP in winter were in the form of organic-N (91.3%) and organic P (96.8%). The mean DIN/DIP ratio revealed high nitrogen concentrations in comparison with that of phosphorous and the surface coastal waters of the Red Sea are principally, P-limited for phytoplankton growth with higher values in winter season compared to summer season. Concentrations of heavy metals were quite low most probably due the absence of major local impacts of any land-based sources and/or any major negative impacts of coastal tourism. Regional variations were almost negligible and except for Mn, Cd, and Hg insignificant seasonal variations were observed. The present study revealed concentrations for metals in the acceptable levels. Furthermore, concentrations of petroleum hydrocarbons were significantly higher in winter than in summer which is mainly attributed to the increase in the rate of evaporation for petroleum hydrocarbons in summer. In general, the maximum concentration was much lower than the harmful concentrations reported for seawater. Correlation coefficients as well as principle component analysis (PCA) were applied.

Assessment of the Hydrochemical Characteristics of the Suez Gulf Coastal Waters during 2011-2013

The coastal region of the Suez Gulf, is one of the most densely industrialized zones in Egypt. In order to assess the quality of Suez Gulf coastal waters for the sustainable use and development, and consequently for the national income, 12 field campaigns were carried out in 3 years (2011-2013). The results of beach litter cleared out that the shoreline of the Suez Gulf, especially Ras Gharib area was subjected to many factors which undoubtedly affected the rate of man-made litter accumulation. The most abundant visible items were general litter as they represented 30.64% of the total items encountered. Oil, seaweeds as well as old and new tar constituted 15.41%, 14.85% and 11.84%, respectively. The increase on the levels of water temperature, Chl-a, TSM, DO, BOD, DOM, COD, ammonium ion, nitrite, nitrate, total phosphorus, silicate and total nitrogen developed a eutrophic region. In general, dissolved inorganic nitrogen (DIN) species were almost 9 times higher in the northern parts compared to the south-ern ones revealing that the northern parts of the Gulf were more affected by human impacts compared to the southern area. Moreover, concentrations of most studied metals such as Zn, Mn, Ni, Cu, Cr, Cd, Pb, and Hg were higher in Northern parts com-pared to southern parts of the Gulf. The concentrations of dissolved metals in the northern and southern Suez Gulf followed the following order: Fe ≥ Zn ≥ Cu > Pb > Mn > Ni > Cr > Cd ≥ Hg. Except for Hg, concentrations of metals were in the accepta-ble ranges recommended internationally. Hg concentrations especially in the northern Suez Gulf were slightly higher than the permissible levels. As the northern parts of the Gulf were more suffered from oil pollution, total petroleum hydrocarbons revealed higher concentrations in the northern parts compared to the southern parts of the Gulf. Seasonal variations, on the other hand, indicated higher levels of DO, BOD, DOM and COD, chloropyll-a, TSM, ammonia, nitrate, total nitrogen in winter compared to their corresponding values in summer. In general, the majority of TN and TP in winter were in the form of organic-N (87.2%) and organic P (94.1%). These percentages were 77.8% and 37.3%, respectively in summer. The surface coastal water of the Suez Gulf was principally, P-limited for phytoplankton growth in different investigated regions. Furthermore, the DIN/DIP ratio was higher (94.2:1) in winter season compared to summer season (6.3:1). Concentrations of Fe, Zn, Cd, and Hg in winter exhibited sig-nificantly higher values compared to their corresponding values in summer. On con-trast, Mn, Ni, Cu, Cr, and Pb exhibited significantly higher values in summer compared to their corresponding values in winter. Furthermore, concentrations of petroleum hy-drocarbons were significantly higher in winter than in summer which is mainly at-tributed to the increase in the rate of evaporation for petroleum hydrocarbons in summer due to the increase in water temperature and water salinity. In general, the maximum concentration was much lower than the harmful concentrations reported for seawater. A stepwise multiple linear regression, analysis of variance (ANOVA), and principle component analysis (PCA) were applied.

Environmental Studies on the Aqaba Gulf Coastal Waters during 2011-2013

In order to assess the quality of the Aqaba Gulf coastal waters for the sustainable use and development, and consequently for the national income, four field campaigns were annually carried out during the period from 2011-2013 to monitor hydrographic variables, i.e. temperature, salinity, pH, etc., nutrients, some heavy metals, i.e. iron, lead, copper, cadmium, chromium, etc. in addition to petroleum hydrocarbons. Except for the area of Sharm El-Sheikh Harbor, the results for the density, composition, and distributions of beach litter cleared out that the Egyptian shoreline of the Aqaba Gulf is relatively not affected by man-made litter. The area of Sharm El-Sheikh Harbor was subjected to many factors which undoubtedly affected the rate of man-made litter ac-cumulation, especially, oil contamination (oil and old or new tar) which is a good es-timator of levels of oil contamination and an effective means of evaluating the poten-tial threat of oil on coastal resources. The results of the present study cleared out also that water temperature followed seasonal changes in air temperature. Aqaba Gulf water is characterized by its high salinity and the presence of well oxygenated waters. Minor changes in the distribution of pH, BOD, DOM and COD, revealed limited effects of human impacts. Low levels of Chl-a and TSM concentrations and high transparency revealed also negligible effects for human impacts. Significantly higher sea water temperatures, TSM, DO, BOD, DOM, COD, NH4, NO2, PO4 and TP were observed in summer season compared to their corresponding values in winter season. On contrast, higher values of chlorophyll-a, NO2, TN, and SiO4 were observed in winter compared to summer season. Based on the mean annual values, Aqaba Gulf coastal waters are classified as oligotrophic to mesotrophic state. The concentrations of dissolved inorganic nitrogen forms followed the following order: NH4= NO3>NO2. In general, the majority of TN in winter was in the form of organic-N (96.3%) compared to 91.7% in summer season. On the meantime, TP exhibited more or less comparable organic-P percentage in summer (86.2%) and winter (81.2%) seasons. Moreover, the DIN/DIP ratio showed relatively higher values in winter season (14.2:1) compared to summer season (12.4:1). This indicates high nitrogen concentrations in comparison with that of phosphorous in winter;yet it reflects the generally lower nutrient levels present in the coastal waters of the Aqaba Gulf due to the lack of significant nutrient input or oceanic upwelling. Concentrations of heavy metals were relatively low signifying that Aqaba Gulf Coastal waters are not yet seriously threatened in spite of the rapid recreational and human developments that are considered a challenge to the safety and viability of Aqaba Gulf marine environment. Furthermore, concentrations of petroleum hydrocarbons were significantly higher in summer than in winter that are mainly attributed to the increase in the levels of oil pollution that most probably re-sulted from the increase in accidental, deliberate or operational discharges and spills of oil from ships. In general, the maximum concentration was much lower than the harmful concentrations reported for seawater. A stepwise multiple linear regression, analysis of variance (ANOVA), and principle component analysis (PCA) were applied.

珠海金鼎工业园地下水水质演变及其对水污染防控的提示

以珠海金鼎工业园这一典型的滨海工业园为研究对象,对比分析了工业园建成后不同时期(2005—2007与2015—2022)园区地下水环境监测数据与稳定氢、氧、氮等多种环境同位素数据,探讨了该园区浅层地下水水质时空演变特征,分析了园区地下水水质的超标问题与诱因,并识别了园区地下水、主要离子与无机氮等成分的来源,明确了该浅层含水层特征指标对海水入侵的指示,为滨海工业园区地下水污染的管控提供了科学依据。

福建中、东部沿海主要养殖贝类体重金属的含量与评价

根据2000年11月福建中、东部沿海养殖贝类体重金属的检测资料,分析了牡蛎、菲律宾蛤仔、缢蛏体内重金属的含量水平。结果表明:闽江口附近海域和兴化湾湾顶北部海域养殖的褶牡蛎,体内Zn和Cd的含量明显高于其他养殖区。文中对3种养殖贝类的重金属污染程度进行评价的结果表明:闽中、东沿海的养殖贝类基本未受重金属污染或属微污染水平。

河口近岸水体中颗粒态重金属的潮周期变化

对长江口崇明东滩近岸水体中颗粒态重金属的潮周期变化特征及其影响机制进行了研究．结果表明，受粒度影响，底层水体中颗粒态Cu、Pb、Fe、Mn、Zn、Cr、AI的总量分别高出表层沉积物的184％、99％、56％、62％、147％、50％和45％，其中Cu、Pb、Fe、Mn、Zn、Al可还原态部分在底层水体悬浮颗粒物中的含量也明显高出表层沉积物的2～3倍，但与重金属总量相比，上述元素的可还原态部分所占比例与表层沉积物相差不大．在5次潮汐循环过程中，颗粒态重金属均在涨潮初期、高平潮前后及落潮末期出现较高含量．这种变化主要与水动力条件有关，当水体流速增大时，从底部沉积物再悬浮起来的颗粒态重金属对水体中的永久性悬浮颗粒起了很大的稀释效应．水体中的盐度、130及pH等环境因子对潮周期内颗粒态重金属的变化影响不大．

海洋环境中重金属在贝类体内的蓄积分析

根据2006年5—7月贝类体内重金属含量和海洋环境背景值的调查资料分别分析了海州湾、吕泗、嵊泗和舟山海产贝类重金属与环境中重金属含量之间的关系。结果表明:影响贝类体内重金属Hg,Cd和Pb含量的主要因素是水体中的重金属含量而不是沉积物中的重金属含量;重金属在贝类体内的富集程度由高至低依次为Cd>Hg>Pb;不同贝类对重金属富集效果比较,紫贻贝(Mytiluse dulis)对重金属富集效果最为明显,红螺(Rapana bezoar)对重金属富集效果较其它物种较轻。

广东沿岸牡蛎体内总汞含量变动趋势及其健康风险评价

为保障水产品质量安全和保护广东近岸海洋生态环境,于2004—2010年对广东沿岸17个主要港湾的海水养殖牡蛎进行了采样,运用原子荧光光谱法监测其总汞含量,并结合1989—1993年的历史监测数据分析了广东近岸海域总体及粤东、珠江口和粤西三大主要海区牡蛎体内汞的时空分布规律,应用单因子指数法和人体暴露风险系数法(HQ)评价了牡蛎体汞含量对人体暴露的健康风险。结果表明,1989—2010年广东沿海牡蛎体内汞含量的检出率为100%,变化范围为(0.080±0.114)mg·kg-(1湿重,下同)。单因子指数评价结果与风险系数(HQ)评价结果一致。上世纪80年代末(1989年)广东海域牡蛎体内汞含量处于污染水平,健康风险系数较大(HQ=3.39×10-2);90年代(1991—1993年)牡蛎体内汞含量逐年降低,健康风险显著降低(HQ=2.23×10-2,P<0.05);2004年以来,全海域的牡蛎体内汞含量一直稳定地维持在较低水平([0.012±0.006)mg·kg-1];粤东、珠江口海域牡蛎体内含量稳定下降,粤西海域降幅有所减小。2006—2010年,人均摄取牡蛎软组织20g·d-1,每年食用200d,食用20a后,在人均寿命70岁的时间内,其健康风险系数HQ为0.13×10-2,食用安全,不存在潜在的危害性,食用广东沿海牡蛎对人体日均总汞允许摄入限量的贡献率仅为0.13%。

长江口以南我国沿岸海域经济贝类中的重金属

本文报道了长江口以南我国沿岸海域经济贝类中各重金属的含量及其分布趋势。结果表明，各种贝类体内Zn的含量总是最高，Hg的含量总是最低。各重金属平均含量一般呈Zn＞Cu＞As≈Cd＞Cr≈Pb＞Hg的排列顺序。该海域牡蛎的Hg、Pb、Cr、As的含量低，区域分布较均匀；Cu、Zn、Cd的含量相差悬殊，以珠海海区牡蛎的Cu、Zn、Cd含量最高，分别为431×10-6～474×106，864×10-6～1044×10-6，7．02×10-6～8．25×10-6（m／m），其主要原因可能是工业排污造成的。本调查牡蛎分布较广，对Cu、Zn、Cd有较强的积累能力，推荐它为我国局部海域海洋污染监测Cu、Zn、Cd的指示生物。

南通沿岸经济贝类体内重金属含量分析

对南通沿海滩涂 2 3个贝类样品中的重金属Hg、Cd、Cr、Pb、Cu、总砷、无机砷含量进行了检验分析 ,采用国家标准对检验结果进行评价 ,认为南通沿海经济贝类体内重金属总体含量较低 。

浙江沿岸贝类生物体中Hg、Cd、Pb、As含量的分析

运用冷原子荧光法、无火焰原子吸收分光光度法及分光光度法对 1 998年 5～ 6月所采集的浙江沿岸 1 4个测站 2 3个贝类生物样品中的重金属 Hg、 Cd、 Pb、 As含量进行了分析。结果表明 :贝类生物样品中重金属平均含量 :Hg为 0 .0 2 0× 1 0 - 6、Cd为 1 .5 4× 1 0 - 6、Pb为 0 .49× 1 0 - 6 、 As为 1 .73× 1 0 - 6 。贝类不同科间重金属含量存在明显差异 ,蚶科含 Cd量最高 ,帘蛤科含 As量最高。

近岸海域贝壳与海水重金属含量的相关性研究

近海海域易于受到城市工业等人类活动的污染,重金属污染是其中之一,持续的低度污染也会造成近海生物体内污染物累积,影响海域渔业和生态环境。通过对大连周边6个海区内采集的牡蛎壳体分析测定发现,壳体中重金属的含量与该海区海水中重金属含量线性相关,其中Zn、Cd、Pb和Cu的相关系数分别为0．9430、0．9822、0．9930、0．9815,生物富集系数在1000左右。实验分析手段采用二阶微分阳极溶出伏安极谱,支持电解液为pH4．0～4．5的Hac-NaAc缓冲溶液,标准偏差RSD=0．11～1．16,实验回收率93～105%。研究结果表明,(1)牡蛎壳体可以替代贝类软组织作为监测海域环境的载体,指示海域环境重金属的变化情况; (2)牡蛎壳体层状的生长过程与同时期水质的状况密切相关,层状物理结构便于分层分析,通过本实验相关性的验证,完全有可能建立一种海水水质短期历史追溯的技术方法。

贝类净化技术研究现状与展望

随着养殖水域环境问题日益凸显,贝类食品安全问题越来越受到重视,贝类在进入流通环节前进行净化将成为不可缺少的处理环节。本文从贝类净化工艺类型、净化用水处理技术,以及贝类净化对风味的影响等方面对当前国内外研究进展进行了总结梳理,并提出下一步贝类净化应重点解决的问题,为深入开展贝类净化相关研究提供参考。

中国近海沉积物中重金属的变化特征和生态风险评估

通过对2008-2012年中国近海(南海、东海、黄海、渤海)采集的沉积物样品中重金属含量的测定,结合风险评价的手段,研究了各海域沉积物中重金属含量的空间变化特征、影响因素和潜在生态风险。结果表明,东海沉积物的重金属含量最高,黄海次之,渤海和南海相对较低。沉积物中重金属含量与粒径在不同海域呈现出不同相关性:在南海呈现显著负相关,说明其含量与物源相关,人为影响相对较少;在东海的相关性相对较弱,说明其含量除受物源影响外,很大程度受到外界输入人为影响;在黄海和渤海基本无相关性,说明其含量主要受人为输入影响。重金属污染程度(Cd)和潜在生态危害指数法(ERI)均呈现出相似的结果:东海>南海>黄海、渤海,说明东海是潜在生态风险最高的海域。且Cd和ERI均呈现由近岸向外海降低的趋势,说明近岸潜在生态风险较外海高。

温州近岸海域沉积物中重金属生态风险评价

对2014年温州近岸海域表层沉积物中重金属(Cu、Pb、Zn、Cd、Cr、Hg、As)的含量进行了分析,据其结果分析温州近岸海域表层沉积物中重金属的分布特征,并分别采用地累积指数法和潜在生态风险指数法评价其污染状况。结果表明,温州近岸海域表层沉积物中铜污染情况最为严重,超过第一类沉积物质量标准的站位占64.8%。7种重金属含量均呈现近岸向远岸递减的分布特征,高值区分布在瓯江口、飞云江口、鳌江口海域。地累积指数评价结果显示Pb、Cr、Hg、As未出现污染,Zn表现为轻度污染,Cu、Cd主要表现为轻度污染并有少数测点达到偏中度污染,地累积污染指数大小顺序为Cu>Cd>Zn>Pb>Cr>As>Hg。生态风险指数评价结果显示,温州近岸海域表层沉积物中重金属元素整体表现为低潜在生态风险,Cu、Pb、Zn、Cr、Hg、As表现为低潜在生态风险,而Cd主要表现为中等潜在生态风险并有少数测点达到较高潜在生态风险,各种元素对区域内的潜在生态风险危害的大小顺序为Cd>Cu>Hg>Pb>As>Cr>Zn。

沙埕港多种环境介质中重金属的含量分布及来源分析

通过2013年8月对福建沙埕港海域海水、沉积物及贝类体内重金属进行的调查,结合历史资料对重金属的含量分布及来源进行了讨论和分析.结果表明:沙埕港表层海水中Cu、Cd、Hg和As等溶解态重金属含量整体处于较低水平,但Pb含量在大部分海域略超海水水质一类标准.沉积物中Pb、Cd、Hg和As含量均低于海洋沉积物一类标准,而Cu在上段八尺门海域及中段罗唇溪入海口附近存在超标现象.地积累指数评价表明Pb和Cd处于无污染状态,而Cu、Hg和As 3种重金属在不同区域存在轻微污染.港内八尺门点头镇附近海域采集的2种贝类均存在不同程度的重金属污染.其中缢蛏(Sinonovacula constrzcta)体内重金属污染较轻,而褶牡蛎(Ostrea plicatula)体内重金属污染较重,Cu和Cd污染指数均在10以上.浙闽沿岸流是沙埕港Pb、Cd、Hg和As等重金属的主要来源,而白琳石材加工排放的污水是造成沙埕港上段八尺门浅滩区重金属Cu污染的主要原因.此外,中段罗唇溪入海口附近海域Cu、Pb和Cd含量较高,可能同罗唇港修造船厂的污染排放有关.

厦门海域养殖贝类体内重金属的初步研究

根据2005年4月和10月厦门市贝类生产环境区划调查资料，着重对僧帽牡蛎（Saccostrea cucullata）、菲律宾蛤仔（Rudita pesphilippin adams）、泥蚶（Tegillarca granosa）和缢蛏（Sinonovacula constricta）的软体部、胃含物、外套膜、卵、肌肉和外套腔液中的重金属含量进行探讨和研究。结果表明，厦门4种养殖贝类体内Cu，Pb，Cd和Zn的湿质量比分别为0．88～60．3mg／kg，0．12～0．48mg／kg、0．04～0．72mg／kg和12．4～163．5mg／kg，平均湿质量比分别为16．3，0．24，0．38，63．9mg／kg。在不同养殖水域，同种贝类体内重金属的含量差异较大，在相同养殖水域贝类体内重金属的平均含量种间差异也较大。4种贝类的胃含物中重金属的平均含量最高，外套膜和软体部次之，外套腔液含量最低。根据《无公害食品水产品中有毒有害物质限量》的标准，对4种贝类体重金属的污染程度进行评价，结果表明，僧帽牡蛎、菲律宾蛤仔和缢蛏体中重金属的含量均未超标，但泥蚶体内Cd的含量略微超标。

上川岛沿岸经济贝类体内重金属含量分析

对上川岛沿海滩涂34个贝类样品中的重金属Cr、Cd、Hg、Pb、Cu含量进行了检验分析,采用国家标准对检验结果进行评价,结果表明上川岛沿海经济贝类样品体内Cd总体含量超标,这些贝类不能供人群安全食用.

辽宁沿岸海域重金属和石油污染的生物指示种初步研究

本文根据经济贝类污染物残留量调查结果，对辽宁沿岸海域贻贝、菲律宾蛤仔作为重金属、石油污染的生物指示种的可能性进行了初步研究和评价。应用ＰＯＬＹＤＩＶ统计技术对采自辽宁沿岸海域１４个站点样品中的重金属、石油含量进行了统计分析，结果表明辽宁沿岸海域各站点的贻贝、菲律宾蛤仔受Ｃｕ，Ｚｎ，Ｃｄ，Ｈｇ和石油污染与石油污染程度的分布和沿岸排放工业废水的分布及表层沉积物中的含量相一致。据此，贻贝和菲律宾蛤仔可作为监测Ｃｕ，ｍ，Ｃｄ，Ｈｇ和石油污染的生物指示种；可否作为Ｐｂ的生物指示种尚需进一步研究。