Trace metals in sediments and in blood cockle from a coastal area in Thailand and Malaysia

Prince of Songkla Universit

Levels of non-essential (Cd, Pb and Hg) elements in muscle tissues of Anguilla bicolor bicolor, McClelland 1844 from Kedah and Anguilla bengalensis bengalensis, Gray 1831 from Perak and human consumption risks

A study on heavy metals accumulation and human health risk assessment in the consumption of two tropical freshwater eel species (Anguilla bengalensis bengalensis) from the Sungai Perak at Kuala Kangsar, Perak and (Anguilla bicolor bicolor) from the Air Hitam irrigation canal, Kampung Kuala Sanglang, Kedah was carried out. Specimens were examined and analyzed for Pb and Cd concentrations using ICP-MS while the total Hg concentration was measured using a direct mercury analyzer (MA-3000). The range for the total concentrations (μg/g wet wt.) in Anguilla bicolor bicolor were 0.01-0.4 (Cd), 0.03-0.77 (Pb) and 0.36-0.94 (Hg) while for Anguilla bengalensis bengalensis, they were 0.76-1.23 (Cd), 0.01-0.10 (Pb) and 0.27-1.5 (Hg). Anguilla bengalensis bengalensis (Sungai Perak) showed a significant strong relationship between Hg/Pb (r = .771, P < 0.05) and Anguilla bicolor bicolor (Air Hitam irrigation canal) with Cd/Pb (r = -.895, P < 0.05) in muscle tissues and the results indicated Hg and Pb were introduced from point and non-point sources, therefore it is of concern. Interspatial comparison with the findings of previous local and international studies showed both species of freshwater eels accumulated Hg to high levels, exceeding the safe limits stipulated in the Malaysian Food Act of 1984, Food Regulations (1985) and USEPA (1997). However, the Target Hazard Quotient (THQ) and Hazard Index (HI) indicated that both freshwater eels from the studied sites are safe to consume as there is no risk posed from consumption based on the health risk assessment results as Pb, Cd and Hg concentrations were under the permissible limits of nutrient intake

Distribution of trace metals in tropical surface sediment during pre-monsoon and post-monsoon

Surface sediment samples were collected in the Gulf of Thailand and South China Sea during pre-monsoon and post-monsoon periods. Eighty-one stations were sampled for trace metal analyses i. e., lead (Pb), iron (Fe), chromium (Cr) and manganese (Mn). Results during the pre-monsoon shows that, metals concentration ranges between 7.02-27.8 μgg-l, 0.71-2.82%, 20.5-122 μgg-1 and 209-720 μgg-1 for Pb, Fe, Cr and Mn respectively. During the post-monsoon cruise, however, the metal concentration ranges between 5.24-91 μgg-l, 0.70-2.38 %, 21.1-101 μgg-1 and 117-797 μgg-1 for Pb, Fe, Cr and Mn respectively. In general, the concentrations of Fe, Cr and Mn were higher in the pre-monsoon period except for Pb. This is related to the influence of the monsoon season on sediment

Heavy metal distribution of the South China Sea continental shelf sediments off Sabah and Sarawak coastlines

Fifty-one surface sediment samples from offshore Sabah and Sarawak were collected from the two cruises of the Marine Vessel Southeast Asian Fisheries Development Centre (MV SEAFDEC) before and after the northeast monsoon. The sediments were analyzed for heavy metal contents to determine the effects of monsoon seasons and spatial patterns of distribution. The contents of heavy metals were measured from the 63 μm fraction of the dried sediments and analyzed using an Atomic Absorption Spectrophotometer. The heavy metals studied were Al, Fe, Cr, Cu, Zn, Pb and Mn. Results showed that some metals were in concentrations lower than the average Earth's crust. The lower or higher-than-normal values of some of the heavy metals studied can be attributed to the intensive weathering in the study area, mineralogy, effect of the monsoon and the Rajang River. Furthermore, normalization was done using Al as normalizer to determine whether the high levels of Pb were due to anthropogenic input or not. It was found that the values were higher but not necessarily an indication of inputs from human activities as high levels were also found far from the coast. This may be attributed to input of particulates from the Rajang River and possibly movement of bottom sediments

Distribution of trace metals in tropical surface sediment during pre-monsoon and post-monsoon

Surface sediment samples were collected in the Gulf of Thailand and South China Sea during pre-monsoon and post-monsoon periods. Eighty-one stations were sampled for trace metal analyses i. e., lead (Pb), iron (Fe), chromium (Cr) and manganese (Mn). Results during the pre-monsoon shows that, metals concentration ranges between 7.02-27.8 μgg-l, 0.71-2.82%, 20.5-122 μgg-1 and 209-720 μgg-1 for Pb, Fe, Cr and Mn respectively. During the post-monsoon cruise, however, the metal concentration ranges between 5.24-91 μgg-l, 0.70-2.38 %, 21.1-101 μgg-1 and 117-797 μgg-1 for Pb, Fe, Cr and Mn respectively. In general, the concentrations of Fe, Cr and Mn were higher in the pre-monsoon period except for Pb. This is related to the influence of the monsoon season on sediment

Efficiency and feasibility of Acacia mangium in extracting heavy metals from contaminated soil

Contamination of soil by heavy metals commonly occurs and remediation is required before the soil is suitable for normal use. Phytoremediation is a low cost and reliable technique to remediate contaminated soil but this technique is not yet commonly used in Malaysia. In addition, phytoremediation using timber species are rarely reported. This study aims to evaluate the efficiency and feasibility of Acacia mangium, a renowned timber species in Malaysia to remediate heavy metals namely Zn, Cu and Cd contaminated soil. A pilot study was conducted in which over 200 saplings of A. mangium were planted in rows on a sewage sludge disposal site with distance of 2m apart. The growth of the trees planted was recorded for 12 months and total aboveground biomass was determined at the end of the experiment period. Results show that A. mangium accumulates 200mg/kg of Zn, 40mg/kg of Cu and 2.0mg/kg of Cd in their aboveground biomass. Thus it can be estimated that 339t/ha of biomass would be required to remove 79.8kg/ha of Zn; 1173t/ha and 1165t/ha of biomass to remove 46.9kg/ha and 2.33kg/ha for Cu and Cd, respectively. This study shows that a hectare of A. mangium plantation could generate aboveground biomass over 2,044t/ha within just 3 years, which is above the requirement needed to remove Zn, Cu and Cd of the amount stated above. Furthermore, if the biomass estimation was set to a 10-year period, over 31,000t/ha could be produced with over 25,300m3 of timber which could generate a substantial income for the remediation project and have high potential for this soil remediation technique to be commercialized

Growth performance, biomass and phytoextraction efficiency of Acacia mangium and Melaleuca cajuputi in remediating heavy metal contaminated soil

Heavy metals are very toxic and soil contaminated with sewage sludge urgently need remediation in order to avoid related health hazards. Phytoremediation is a low cost and reliable technique to remediate heavy metal contamination. However phytoremediation using timber species was rarely reported and its efficiency was questionable. A field study was conducted to examine the efficiency of two timber species namely Acacia mangium and Melaleuca cajuputi in phytoextraction of Zn, Cu and Cd from contaminated soil. Two hundred of A. mangium and M. cajuputi were planted on sewage sludge disposal site and the growth was recorded for 12 months before at the end total biomass of each species was determined. Results show in 12 months, about 72 and 4 t ha−1 of aboveground biomass can be produced by A. mangium and M. cajuputi, respectively. Both species show potential for phytoremediation, however A. mangium is more efficient compared to M. cajuputi where efficiency of A. mangium to remove Zn was 24.4, 6.2 for Cu and 9.5% for Cd. As for M. cajuputi the efficiency was 1.3, 0.3 and 0.14% for Zn, Cu and Cd, respectively. It is projected that A. mangium require 5, 17 and 20 years to remove 79.82 kg ha−1 of Zn, 46.94 kg ha−1 of Cu and 2.33 kg ha−1 of Cd, respectively