Distribution and Concentration of Several Heavy Metals in Snails (Nerita Lineata) from the Intertidal Areas of Peninsular Malaysia

The aim of this study is to determine the background concentrations of heavy metals in the soft and hard tissues of Nerita lineata collected from the west intertidal area of Peninsular Malaysia and to study its potential use as a biomonitor of Cd, Cu, Fe, Ni, Pb and Zn. From this study, the snails N. lineata, and sediments were collected from 15 sites along the west coast of Peninsular Malaysia from December 2005 until April 2006. Snails collected from each sampling site were dissected and pooled into three parts (total soft tissues, operculums and shells) and were analyzed for Cd, Cu, Fe, Ni, Pb and Zn in addition to sediment samples. The mean metal concentrations (µg/g dry weight) in the soft tissues were 1.18 ± 0.17, 15.43 ± 0.86, 546.21 ± 61.98, 6.69 ± 0.45, 94.42 ± 46.81 and 87.07 ± 4.08 for Cd, Cu, Fe, Ni, Pb and Zn, respectively. As for operculums, the mean metals (µg/g dry weight) were 2.99 ± 0.22, 6.38 ± 0.33, 3 5.05 ± 2.49, 23.34 ± 0.92, 48.22 ± 1.99 and 16.59 ± 1.03 for Cd, Cu, Fe, Ni, Pb and Zn, respectively. In the shells, it was found that the mean metal concentrations (µg/g dry weight) were 3.00 ± 0.23, 6.25 ± 0.54, 70.20 ± 14.04, 23.33 ± l.14, 47.17 ± 2.30 and 13.54 ± 3.21 for Cd, Cu, Fe, Ni, Pb and Zn, respectively. The means of heavy metal concentrations (µg/g dry weight) in sediments were 2.86 ± 0.36, 18.95 ± 3.49, 25499.63 ± 1895.43, 12.35 ± 0.95, 47.24 ± 5.87 and 64.61 ± 4.77 for Cd, Cu, Fe, Ni, Pb and Zn, respectively. The snails were good biomonitors for heavy metals as significant correlations were found between sediments and the soft tissues for Cu (P<0.05) and Pb (P<0.01), while operculums and shells were significantly (P<0.01) correlated with sediments for Cd and Pb. Different patterns of heavy metal distribution were found in the different tissues (shell, operculum and soft tissues) of N. lineata as well as spatial differences and distributions. This shows that the distribution of metals in shells and total soft tissues of N. lineata were not similar and this could be due to different rates of metal accumulation, excretion and sequestration. Since N. lineata can be abundantly found in the rocky shores, below jetties and mangrove trees along the intertidal area of the west coast of Peninsular Malaysia and are accumulative of Cd, Cu, Fe, Ni, Pb and Zn, the snail species is therefore a potential biomonitor of heavy metal pollution in the west coast of Peninsular Malaysia

Depuration of gut contents in the intertidal snail Nerita lineata is not necessary for the study of heavy metal contamination and bioavailability: a laboratory study

Some of the scientific papers in the literature regarding heavy metal concentrations in the soft tissues of molluscs are always rejected because there is no depuration of metals before the molluscs samples are analyzed for heavy metal accumulation, although the acceptance of a paper in a journal is assessed based on many other factors. The depuration of gut contents of molluscs has been the initial step before the metal analysis on the soft tissues of molluscs by many researchers. The depuration process in some molluscs involves holding the animals in clean water or clean sediment for a suitable period (8–24 hrs) to purge their guts after exposing them to contaminated conditions, and before they are analyzed for whole-body contaminant burden (Neumann et al., 1999; Gillis et al. , 2004). The depuration ensures that metal-contaminated particles in the animal’s gut do not lead to overestimation of metal bioavailability. Undoubtedly, clearing the gut contents is theoretically a laboratory technique in order to get an accurate estimate of heavy metal concentrations accumulated in the soft tissues of molluscs. In addition, the suggestion on the use of molluscs as biomonitors of metal bioavailability becomes invalid because their soft tissues were not depurated. Consequently, validity on the data of metal concentrations could not be achieved. Therefore, in order to determine if a particular species could be used as biomonitor for metals, depuration of soft tissues of the molluscs is imperative to effectively determine the availability of metal (Riba et al. , 2005; Wang et al. , 2005; Szefer et al. , 1999; Cravo et al. , 2004; Baldwin and Maher, 1997; Nicholson and Szefer, 2003). In standard protocols (ASTM, 2003), although it is not a standard practice to clear the gut of organisms before analyzing their tissues for whole-body metal accumulation, some investigators do transfer animals to clean water conditions in order to purge their guts after they have been collected from the field. In this study, the snail known as Nerita lineata of the Neritidae family, were collected to study if there was any significant difference in the concentrations of Cu and Zn in the soft tissues, before and after four weeks of depuration

Biodiversity of snails: a short review and commentary

This chapter presents a review and commentary of 45 reported publications in the literature on snail biodiversity. Of the 45 papers, it can be concluded that most papers (36 out of 45) fall into three categories: a) Regular checklist of snails is needed, b) New description of snail species would help in the species list documentation, and c) This information is important for future reference and for effective ecosystem management

How elevated levels of Cd, Cu and Pb in the surface sediments collected from the drainage receiving metal industrial effluents? Comparison with metal industrial drainage and intertidal sediments in Selangor, Malaysia

Surface sediments were collected in April 2005 from a drainage receiving metal industrial effluents from Serdang in addition to 6 sampling sites from intertidal area and 4 urban drainage sites. The sediment samples were analysed for Cd, Cu and Pb. The metal concentrations at the Serdang industrial drainage sediments were 15.9 μg/g dw for Cd, 1003.5 μg/ g dw for Cu and 1267 μg/g dw for Pb. These metal levels were significantly higher than those in the sediments collected from intertidal area (6 sites) and other urban drainages (4 sites) [Cd: 1.39-3.41 μg/g dw; Cu: 6.64-122.7 μg/g dw; Pb: 26.0-227.7 μg/g dw]. The total concentrations of Cu, Pb and Cd found at Serdang industrial drainage sediments were 48.76, 23.52 and 8.36 times higher than those in the other sites. Based on the metal concentrations in the four geochemical fractions, for Cu, the EFLE, acid-reducible and oxidisable-organic fractions in the sediment at the Serdang industrial drainage was 59.97, 35.26 and 103.74 times, respectively, higher than those in the other sites. For Pb, the EFLE, acid-reducible and oxidisable-organic fractions in the sediment at the Serdang industrial drainage was 3.60, 2.10 and 25.42 times, respectively, higher than those in the other sites. For Cd, the EFLE, acid-reducible and oxidisable-organic fractions in the sediment at the Serdang industrial drainage was 6.17, 11.8 and 12.39 times, respectively, higher than those in the other sites. Thus, the elevated concentrations of Cu, Cd and Pb in the sediments collected from Serdang industrial drainage sediments were evidently receiving point source industrial effluent from the nearby metal factory. Therefore treatment on the factory effluent based on the present findings is necessary

Tissue distribution of heavy metals (Cd, Cu, Pb and Zn) in the greenlipped mussel perna viridis from Nenasi and Kuala Pontian, East Coast of Peninsular Malaysia

Previous studies reported that the green-lipped mussel Perna viridis were widely found on the west coast of Peninsular Malaysia but not on the east coast of the Peninsula. In this study, surveys and sampling were conducted from Tumpat to Mersing in April 2004, but the mussels were only found at Nenasi and Kuala Pontian in Pahang coastal waters. Therejare, from this study, we confirm that the mussels on the east coast were not as widely found as on the west coast of Peninsular Malaysia. The mussel samples collected were analysed for cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) and the metal concentrations (J.lg/g dry weight) were 1.892.13, 3.84-10.34, 7.95-8.84 and 93.1-119.6 far Cd, Cu, Pb and Zn, respectively. These results indicate that Kuala Pontian samples accumulated higher concentrations of Cu (in remaining soft tissue and mantle) and Zn (in remaining soft tissue, mantle and muscle) compared to those in Nenasi while Cd and Pb showed no significant difference (P> 0.05) between the two sample sites. Since there were no observable anthropogenic inputs ar activities at the two sampling sites, the variation of metal concentrations accumulated in the soft tissues could be mostly attributable to the significant difference in size (shell length, and shell width) and salinity of the two sites. The other environmental factars could also cause differences in the metal bioavailabilities in the coastal waters that were reflected in different concentrations accumulated in the different soft tissues of the mussels

Crystalline style and tissue redistribution in Perna viridis as indicators of Cu and Pb bioavailabilities and contamination in coastal waters

The concentrations of Cu, Pb, and Zn in the crystalline style (CS) and in the remaining soft tissues (ST) of the green-lipped mussel Perna viridis from 10 geographical sites along the coastal waters off peninsular Malaysia were determined. The CS, compared with the remaining ST, accumulated higher levels of Cu in both contaminated and uncontaminated samples, indicating that the style has a higher affinity for the essential Cu to bind with metallothioneins. The similar pattern of Cu accumulation in the different ST of mussels collected from clean and Cu-contaminated sites indicated that the detoxification capacity of the metallothioneins had not been overloaded. For Pb, higher levels of the metal in the CS than in the remaining ST were found only in mussels collected from a contaminated site at Kg. Pasir Puteh. This indicated a tissue redistribution of Pb due to its binding to metallothioneins for Pb detoxification and the potential of the CS as an indicator organ of Pb bioavailability and contamination. For Zn, the above two phenomena were not found since no obvious patterns were observed (lower levels of Zn in the CS than in the remaining ST) in contaminated and uncontaminated samples due to the mechanism of partial regulation. Generally, all the different STs studied (foot, mantle, gonad, CS, gill, muscle, and byssus) are good biomonitoring tissues for Cu and Pb bioavailabilities and contamination. Among these organs, the CS was found to be the best organ for biomonitoring Cu. The present data also suggest the use of the tissue redistribution of Pb in P. viridis as an indicator of Pb bioavailability and contamination in coastal waters

Distribution and concentrations of Ni in tissues of the gastropod Nerita lineata collected from intertidal areas of Peninsular Malaysia

Nickel (Ni) is an essential metal but not a well-studied metal in gastropods. In this study, Nerita lineata snails were collected from 20 sites along the western coast of Peninsular Malaysia from December 2005 to December 2010. The concentrations of Ni were determined in the total soft tissues, opercula and shells of the snails. Different patterns of Ni distribution were found in different tissues (shells, opercula and soft tissues) as well as spatial differences and distributions. This finding showed that the distributions of Ni in the shells and total soft tissues of N. lineata were significantly different, and this could be due to the different rates of Ni accumulation, excretion and sequestration. Since N. lineata can be abundantly found in rocky shores, below jetties and mangrove trees along the intertidal areas of the west coast of Peninsular Malaysia and it can show the ability to accumulate Ni, the snails can therefore act as potential biomonitors of Ni pollution in the western coast of Peninsular Malaysia

Behavioral and sensitivity responses of pomacea insularum to Cd and Cu toxicities

This chapter focuses on the toxicity test of Cd and Cu by using two different sized groups of Pomacea insularum as a test organism, with mortality as an endpoint. The findings indicate the mussel was more sensitive to Cu than Cd although the small size group was more sensitive than the large one since the small group had lower LC50 values than the large one. Results also indicated the ability of P. insularum as a potential bioindicator for acute and subacute exposures to Cu and Cd. This study has provides an important baseline information for Cd and Cu toxicities using P. insularum as a test organism which enables the comparison of the acute sensitivity of P. insularum towards Cd and Cu with other marine invertebrates

Heavy metal contamination and physical barrier are main causal agents for the genetic differentiation of Perna viridis populations in Peninsular Malaysia

A total of 19 polymorphic microsatellite loci were used to analyze the levels of genetic variations for six geographical populations of green-lipped Perna viridis collected from the coastal waters of Peninsular Malaysia. In addition, the total soft tissues of all mussel populations were determined for heavy metals (Cd, Cu, Pb and Zn). FST values revealed that all the six populations of P. viridis in Peninsular Malaysia were categorized as showing 'moderate genetic differentiation' according to the classification of Wright (1978). Cluster analysis revealed that three populations which were located in the western part of the Johor Causeway were clustered differently from the other three populations located in the eastern part. Hierarchical F-statistics and cluster analysis indicated that the Johor Causeway which blocked the free flow of the pelagic larvae swimmers of P. viridis and a distinct effect of heavy metal contamination on the Kg. Pasir Puteh population, were the two main causal agents for the genetic differentiation of the P. viridis populations investigated in this study

Distribution of Ni and Zn in the surface sediments collected from drainages and intertidal areas in Selangor

Surface sediments were collected from 11 sampling sites in selected intertidals and drainages of Selangor. The sediment samples were analysed for Ni and Zn. The metal concentrations ranged from 15.1 to 121 µg/g dry weight for Ni and 50.2 to 336 µg/g dry weight for Zn. The highest total (Ni and Zn) concentrations in sediments were found at an industrial site in Serdang. The Ni and Zn ranges resulting from this study were wider and higher than those reported previously in Malaysia. Generally, the 'oxidisable-organic' fraction contributed the largest percentage of metals among the other three anthropogenic-related fractions. This study shows that the non-resistant fraction dominated the total Zn based on sequential extraction technique. Some sites had higher percentage (>50%) of non-resistant fraction of Ni and Zn, indicating anthropogenic sources of these metals. Therefore, it is suggested that continuous monitoring of the study areas be implemented especially at industrial areas in Serdang. Perhaps, the industrial waste must be treated before draining to the waterways