Pb In Seawater Research Articles

Low-blank method for the offline batch analysis of the low concentration of dissolved lead in natural waters and its application to natural waters, including the tropical Northwest Pacific Ocean

In this study, Presep® PolyChelate resin was utilized for the offline batch extraction process and then combined with the isotope dilution method for the analysis of low concentrations of dissolved lead (Pb) in freshwater and seawater. The application of Presep® PolyChelate resin further lowered the procedural blank by reducing the amount of resin beads and buffer solution that were added with an 8-fold preconcentration. The adsorption and elution times were shortened to 2 d and 30 min, respectively, and > 85% recovery was achieved. The total procedural blank and detection limit were 0.2 ± 0.1 pmol/kg and 0.2 pmol/kg, respectively. The accuracy of this method was also verified using GEOTRACES intercalibration SAFe seawaters, with concentrations of 48.0 ± 0.5 pmol/kg (n = 3) and 27.0 ± 0.7 pmol/kg (n = 3) observed for SAFE S and D2, respectively. Full-depth profiles of dissolved Pb concentrations collected during the 2016 tropical Northwest Pacific Ocean cruise were analyzed. The dissolved Pb concentration increased from 30 pmol/kg at the surface to 50 pmol/kg at the subsurface and it then decreased to 8–9 pmol/kg in the bottom waters.

Occurrence of Heavy Metal in Green Coconut Water and Surface Seawater of the Sea Beach Areas of Bangladesh

Background: Green coconut water is a most popular functional drink in all tropical countries. The presence of toxic heavy metals in surface seawater is a major problem globally, with a large share in developing countries like Bangladesh. The objective of the study was to assess the concentration of heavy metals like Pb, Cr, Ni, Cu, and Cd in green coconut water and surface seawater around sea beach areas of Bangladesh. Methods: Green coconut water and surface seawater samples were collected from six sea beach areas and transferred to the laboratory. Then, they were allowed for digestion, and finally, the concentration of heavy metal was assessed by the atomic absorption spectrophotometer (AAS). Results: In green coconut water, the concentrations of heavy metal exist bellowing the safe limit with the following order: Pb > Cr > Cu > Ni > Cd. But, Pb, and Cr were prevalent in surface seawater and found to decrease in a sequence of Pb > Cr > Ni > Cd, Cu. Besides, Human health risks associated with the intake of these metals were evaluated in terms of metal pollution index (MPI), daily intake of metals (DIM), health risk index (HRI), and hazard index (HI). However, most of the index values were found to be bellowing the reference value. Conclusion: The concentration of green coconut water is almost proportional to surface seawater in sea beach areas. The high prevalence of Pb and Cr in surface seawater is alarming, and this impact is already seen in green coconut water. So, it is necessary to take action on seawater pollution in Bangladesh.

Contamination of Mercury (Hg) and Lead (Pb) in Seawater and Sediments in Coastal waters of Ohoitel Village, Southeast Maluku District

Along with the increasing population in the coastal area of Ohoitel Village, it triggers the level of community settlement with an increase in anthropogenic activities. This study aims to determine the concentration of heavy metal mercury (Hg) and lead (Pb) dissolved in water and accumulated in sediments. Measurement of heavy metal levels using Atomic Absorption Spectrophometer (AAS). The results of the analyis og Hg content obtained in seawater at station I was 0.00100 ± 0.00007 mg/l, station II was 0.00096 ± 0.00026 mg/l and station III was 0.00101 ± 0.000026 mg/l. The results of Hg levels obtained in sediment at station I amounted to 0.08557 ± 0.0003 mg/l, station II amounted to 0.07761 ± 0.0004 mg/l and station III amounted to 0.08733 ± 0.0004 mg/l. The results of the analysis of Pb content in seawater at station I was 0.00050 ± 0.000003 mg/l, station II was 0.000047 ± 0.000003 mg/l and station III was 0.000038 ± 0.000005 mg/l. Based on the results obtained, it shows that it is still below the quality standard threshold that refers to PP RI No 22 0f 2021 for water and ANZECC 2000 for heavy metal Hg in sediment and USEPA for heavy metal Pb in sediment

Vertical and horizontal distribution model of lead (Pb) in Padelegan Waters, Pademawu District, Pamekasan Regency

Seawater quality is importantly used in salt production, but it could be contaminated due to input of anthropogenic wastewater. This study aims to understand the quality of the water and the content of Pb in seawater, which will be used as raw material for salt production. Descriptive research methods and purposive sampling methods were used for the research method and the determination of the sampling respectively. Sampling of seawater was carried out water sampler, followed by analysis of heavy metal Pb based on APHA 1998 using Atomic Absorption Spectrophotometry (AAS). The concentration of Pb on the surface ranged from 0.6332 to 1.0815 mg/L, in the water column from 0.5842 to 1.0516 mg/L, and in the bottom waters from 0.5571 to 0.9375 mg/L, according to the findings. The horizontal distribution of the Pb showed an increasing trend towards the sea with concentrations ranging from 0.6332 to 1.0815 mg/L. Meanwhile, the concentrations of Pb in surface waters increased vertically, ranging from 0.5571 to 1.0815 mg/L. The horizontal distribution is higher towards open sea, while vertical distribution is higher towards the water surface. Seawater in vicinity of study area is still probably used although caution must be observed regarding to the Pb content.

The Atmospheric Input of Dissolvable Pb Based on the Radioactive 210Pb Budget in the Equatorial Western Indian Ocean

To estimate the atmospheric deposition flux of 210Pb in the equatorial western Indian Ocean, we determined the dissolved (<0.45 μm) and particulate 210Pb (>0.45 μm) in the water column. In addition, we calculated the atmosphere-derived dissolvable Pb in seawater using the budget of 210Pb. The dissolved 210Pb and total 210Pb were higher in the surface layer and, overall, showed a decreasing distribution with depth. In particular, radioactive 210Pb activities in the surface-to-upper layer (<1000 m depth) were 1.5 to 2 times higher than those reported in the 1970s (in nearby regions), suggesting that there has been additional 210Pb input in recent years. Based on the mass balance of the total 210Pb budget in the water column, we estimated the atmospheric deposition flux of 210Pb and the residence time of Pb for the first time in this region. The atmospheric deposition flux of 210Pb was estimated to be 0.1–0.5 dpm cm−2 yr−1, and these values agreed with the general global estimations for the major oceans (0.1–0.7 dpm cm−2 yr−1). Considering the residence time of 210Pb (29–41 years) in the water column (estimated from the 210Pb inventory and 234Th-based Pb scavenging rate), the atmospheric input of seawater-dissolvable Pb was quantified to be 0.08–0.1 nmol cm−2 yr−1, which is about eight times higher than the estimated input in the early 1990s in the region. Therefore, these results imply that radioactive 210Pb could be a useful tracer for quantifying Pb flux in seawater.

Plankton diversity and its heavy metal content in Ratai Bay of Pesawaran district, Lampung, Indonesia.

Artisanal and small-scale gold mining (ASGM) activity in Way Ratai River produces heavy metal wastes; therefore, further information regarding heavy metal concentrations in the water was needed, especially in plankton samples. Furthermore, the determination of plankton diversity was also carried out in the waters of Way Ratai to determine the bioconcentration factor (BCF). Eight sampling sites were chosen along the river reaching the coast of Way Ratai. The research was conducted in November 2020 and March 2021. Ten heavy metals, Ag, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn that are commonly found in mining areas, were determined in the water and plankton samples by using ICP-OES. The results indicated that the highest concentration found was Fe in plankton samples (0.725 mg/L in the river and 1.294 mg/L on the coast). Meanwhile, contents of Cd, Cu, Fe, Mn, and Zn in the river exceeded the predetermined water quality standards, while Ag and Pb metals were not detected. The Cd, Cr, Cu, Pb, and Zn content in seawater also exceeded quality standards. The highest BCF value (12.96) was found for Fe at station G, whereas the lowest BCF value (0.13) was found for Ag at stations G and H.

HEAVY METALS CONTENT OF COPPER (CU) AND LEAD (PB) IN CODIUM FRAGILE SEAWEED

This study aims to determine the concentration of copper (Cu) and lead (Pb) inseaweed Codium fragile and is expected to add information about copper (Cu) and lead (Pb) which accumulates inseaweed C. fragile in Puntondo waters. , Takalar Regency. This research was conducted from January to August 2021, located in Puntondo waters, Takalar Regency. This research method collects data in the form of seaweed samples from the field and seaweed obtained from seaweed sales. Data analysis was carried out using the One Way Anova test with a further test of LSD (Least Significant Difference). The results of this study indicate that the metal content of copper (Cu) at each research station in seawater and C. fragile samples has passed the threshold, while the content of lead (Pb) at each station in seawater and C. fragile samples has not passed the threshold based on PP No. 22 of 2021 (<0.008 mg/L) for sea water and BPOM Regulation No. 23 of 2017 (<0.2 mg/kg) for consumption materials. The metal content of copper (Cu) in seawater at each research station was significantly different and the metal content of copper (Cu) in C. fragile at each research station was not significantly different. The metal content of lead (Pb) in C. fragile seaweed at each research station was significantly different and the metal content of lead (Pb) in seawater at each station was below the detection limit of the instrument (<0.01 ppm). The highest content of copper (Cu) in seawater was found at stations near from the ships activity, that is 0.3625 mg/L, followed by stations close to settlements at 0.235 mg/L. The highest content of copper (Cu) in C. fragile was found at stations close to settlements at 6.63 mg/kg followed by stations at PPI Beba at 6.1575 mg/kg and stations close to ships activity at 4,965. mg/kg.

An offline column extraction with Presep® PolyChelate resin and AG1‐X8 resin for the determination of the isotope compositions of low‐concentration lead in natural waters by the multi‐collector inductively coupled plasma mass spectrometry

AbstractA new high‐precision offline method for the determination of seawater lead (Pb) isotope ratios was developed, which simplifies and optimizes previously published protocols for the isotopic analysis of trace elements. The procedure involves initial separation of Pb from 250 to 500 mL of seawater by Presep® PolyChelate cation exchange resin and purification by AG1‐X8 anion exchange resin, and subsequently analyzed by Neptune multi‐collector ICP‐MS. For the extraction of Pb in seawater, the Presep® PolyChelate resin was characterized by a wide pH range and a faster adsorption rate, greatly reducing the volume of buffer solution required and significantly shortening the time required for the whole process. The total procedural Pb blank of this method is < 0.05% of the sample extract and the typical Pb recovery is ~ 100%. The method was evaluated by processing GEOTRACES intercalibration samples surface water (GSI, 206Pb/207Pb = 1.1744, 208Pb/206Pb = 2.0844) and GEOTRACES GP15 sample (14140#, 206Pb/207Pb = 1.1685, 208Pb/206Pb = 2.0960). Finally, this method was applied to riverine samples from the Changjiang and seawater samples from the East China Sea, and the in situ extraction was also applied in the Indian Ocean.

Bioconcentration of Lead at Avicennia Marina in Mangunharjo, Semarang Coastal Area

This study aims to determine the bioconcentration of heavy metal Lead Pb in seawater, sediment, and mangrove plants of Avicennia marina and to determine the bioconcentration factor of heavy metal Lead Pb in mangrove which was conducted in January 2022 in Mangunharjo coastal area. The method used in this research was a survey method with quantitative analysis. The samples of A. marina mangroves were divided into three categories of stem diameter, namely small (3 – 8 cm), medium (6 – 15 cm), and large (11 – 23 cm). Measurement of heavy metal concentrations using AAS (Atomic Absroption Spectrophotometry). Heavy metal bioconsentration in Mangunharjo is classified as high exceeding quality standards.  The study revealed that the concentration of heavy metal Lead Pb in the seawater ranged from 0.672 - 0.867 mg/L, in sediments it ranged from 56.50 – 65.96 mg/kg, and in the roots and leaves of mangroves A. marina ranged from 6.209 – 24,883 mg/kg. The bioconcentration factor of heavy metal Lead Pb ranges from 0.185 to 0.227, so that the mangrove A. marina in Mangunharjo Water Area can be classified as an excluder species.

Seasonal variations of heavy metals in seawater and integrated poly-cultured scallop Chlamys farreri in Ailian Bay, northern China

Seasonal variations of heavy metals in integrated poly-cultured scallops and seawater from Ailian Bay, northern China were analyzed to reveal the potential factor in bioaccumulation of metals in scallop Chlamys farreri. Results showed that heavy metals (Cu, Zn, As, Cd, Cr, Pb and Hg) in seawater were much below the maximum permissible limits and showed no seasonal changes, but were consistent with the growing period of the poly-cultivated kelp. The content of Zn in scallop tissues was highest with an average value of 88.35 ± 11.50 mg/kg, and Hg content was lowest (0.046 ± 0.025 mg/kg). The accumulation of Cu, As, Cd and Hg in scallops presented a significant seasonal change, and they were closely correlated with the physicochemical quality instead of heavy metals in seawater. Cadmium provided 88.9 % of the total hazard index for adults and 72.2 % for children. Arsenic should also be paid more attention in the risk assessment of human health.

Pollution Assessment and SSD-Based Ecological Assessment of Heavy Metals in Multimedia in the Coast of Southeast China

Heavy metals in the ocean exist in various media and assessing heavy metal pollution in the multimedia in seawater is important for proposing effective strategies to protect marine ecosystem health. However, comprehensive coastal pollution assessments and SSD-based assessments of heavy metals have been limited from an international perspective. This study discusses the distribution, sources, interactions, associated environmental factors, and potential ecological risks related to heavy metal pollution. To attain this objective, several tools and models were considered. The partition coefficient between sediment and water was used to understand the ability of heavy metals to be adsorbed from seawater by sediment. The water quality index was applied to evaluate the comprehensive heavy metal pollution at different sampling sites. The species diversity index was calculated by calculating the concentration of chlorophyll a. The geo-accumulation and potential ecological risk indexes were employed for the sediments' general pollution characteristic of heavy metals. Species sensitivity distribution was used for ecological risk evaluation. The results indicated that heavy metal pollution and ecological risk (Cu, Pb, Zn, Cd, As, Cr and Hg) are not serious, and the pollution conditions remain safe. Only Cu, Pb, and Hg concentrations in seawater exceed the Nation Class I Water Quality Standard. The concentrations of heavy metals showed significant spatial characteristics. Fisheries activities and industrial effluent discharges were identified as the main anthropogenic sources. This study provides a comprehensive assessment of heavy metals in multi-media, and the results will provide valuable information for nearshore ecological management and risk avoidance.

Comprehensive Ecological Risk Assessment of Heavy Metals Based on Species Sensitivity Distribution in Aquatic of Coastal Areas in Hong Kong.

In recent decades, the ecological environment of some coastal areas in China has been seriously affected by terrestrial pollutants, and there is an urgent need for ecological risk assessment of China’s coastal environment. The assessment of heavy metal pollution in Hong Kong waters was carried out using different environmental and ecological indicators. The heavy metal contents (Cu, Pb, Zn, Cd, As, Cr, and Hg) in the near coast of Hong Kong were analyzed for two different seasons of the year 2018 (April—spring and September—autumn). We assessed the distribution and enrichment of heavy metals in the near coast of Hong Kong, and the potential biohazardous effects were assessed using the species sensitivity distribution method. The results showed that only Pb, Zn, and Hg in seawater exceeded the Class I standard. Pb, Zn, Cd, and As in organisms exceeded the standard, and no heavy metals exceeded the standard in sediments. The species sensitivity distribution method indicated that the biohazardous factor of heavy metals of the Hong Kong coast is higher in spring than in autumn, and the potential hazard ratio has the characteristics of high northwest and low southeast, which leads to its msPAF also having these characteristics. From the correlational analyses among heavy metals, we found that the pH change in seawater was related to the concentration of heavy metals, the concentration of heavy metals in seawater was proportional to the salinity of seawater, Pb and Cu were likely to have the same source, and Zn and Cd may not have the same emission sources as the other heavy metals. Overall, heavy metal contamination of seawater, sediments, and organisms near the Hong Kong coast was within acceptable limits, but the problem of heavy metal dispersion should be prevented.

A Chelating Resin of EDTA-Type Modified Cross-Linking Polystyrene to Preconcentrate Trace Metals for Seawater Detection.

The determination of trace metals in seawater is an important project of marine environmental monitoring. However, the presence of many alkali metal ions with high concentration, such as sodium ion, seriously interferes with the detection limit and accuracy of atomic absorption spectrometry (AAS, flame/graphite furnace integrated). The conventional chemical methods for the enrichment of trace metals are complex, and low boiling point organic solvents are used. In this paper, a kind of commercial cross-linked polystyrene resin microspheres was chloromethylated and aminated to introduce EDTA-type amino polycarboxylic groups and then loaded in a column as the absorption filler. A set of seawater pretreatment and enrichment devices was designed and assembled. The enriching process and conditions of trace Cu, Zn, Pb, and Cd in standard seawater were studied. 10 g of the modified resin could enrich the equivalent seawater and remove successfully the light metal ions. pH = 5∼9 and 0.2 mL/min of the flow rate were the suitable conditions for preconcentration. The enriched metal ions in the eluent were analyzed on the AAS. Compared with the conventional solvent method, the novel material and enrichment device have high preconcentration efficiency, strong anti-interference ability, and low cost and could be directly applied for routine seawater detection.

Distribution and ecological health risk assessment of dissolved trace metals in surface and bottom seawater of Yantai offshore, China

The biogeochemical cycle of trace metals plays an important role in the coastal zone. The distribution, interaction, and biogeochemical behavior of dissolved trace metals in surface and bottom seawater are still unclear. This study analyzed the distribution and performed an ecological health risk assessment of dissolved trace metals (Zn, Cd, Co, Pb and Cr) in surface and bottom seawater in the summer (August) of 2019 and 2020 in the seawater of the Yantai offshore area, China. Zinc (Zn), cadmium (Cd), cobalt (Co), lead (Pb) and chromium (Cr) ranged from 23.76–117.47 μg/L (42.67 μg/L ± 15.15), 0.21–0.51 μg/L (0.30 μg/L ± 0.05), 0.90–2.94 μg/L (1.09 μg/L ± 0.31), 0.13–1.06 μg/L (0.39 μg/L ± 0.17), and 2.00–9.9 μg/L (5.38 μg/L ± 2.99) in the summer of the two years. The average metal (Zn and Co) concentrations were slightly higher than the other Chinese coastal areas, while the major contamination pressures were from Zn and Pb. The largest contaminants were in the following order: Zn > Pb > Cd > Cr > Co. Correlation analysis, principal component analysis and hierarchical cluster were used to determine the potential origins and cause the spatial distribution of the multiple dissolved trace metals. The major sources of the trace metal contamination in study area were identified as external inputs from natural human and atmospheric settling and the natural release of the trace metals in sediments under external disturbances. Riverine inputs, the Lubei coastal current and aquaculture significantly influenced the multi-parameter horizontal distributions of the dissolved trace metals and dissolved organic carbon. Although the growth of phytoplankton was strong in summer, the uptake of Zn, Cd, Co and Pb was negligible compared with the exogenous input. The concentrations of Zn, Cd, Co and Pb were higher in the surface than those in the bottom. Monsoons, tides and wind waves also influence the migration, transformation and distribution of dissolved trace metals and dissolved organic carbon. This study provides important information on the biogeochemical cycle process (migration and conversion) and distribution of dissolved trace metals at different depths in coastal and marine pasture areas.

Analysis of Heavy Metals in Water and Sediment in Singkep Island Coastal Waters

Analysis of the content of heavy metals Cu, Pb and Zn in seawater, sediment and snails (C. obtusa) in Singkep island was held on June – July 2022. All parameters measured water quality is still within tolerable limits for the survival of the aquatic organism . Samples of sea water, sediment and snails (C. obtusa) were taken from five stations with three replicates at each station. Heavy metals were analyzed in the KLH Pekanbaru laboratory using an Atomic Abortion AA-7000 Shimadzu spectrophotometer. The results showed that the average content of heavy metals in Singkep waters was 0.0724 mg/l (Cu), 0.1285 mg/l (Pb)) and 0.11525 mg/l (Zn), the sediment was 10.7513 ug/g (Cu ), 25.7750 ug/g (Pb) and 34.1493 mg/g (Zn). Simple linear regression analysis indicates negative correlation between metals content in seawater and in sediment with Y = 12.864 –29.178X, r = 0.1616 (Cu), Y = 26.181 – 3.1564X, r = 0.0632(Pb) ; and Y=45.479 - 61.286X, r = 0.2689 (Zn).

Ecological of human health risk of total petroleum hydrocarbons and four metals in seawater of the southeastern Bohai Sea, China.

To obtain systematic knowledge on the waterborne pollution status and ecological and human health risk of total petroleum hydrocarbons (TPHs) and metals in the southeastern Bohai Sea, seawater samples were collected in three seasons from 2014 to 2018. TPHs and mercury (Hg) levels were determined by ultraviolet spectrophotometry and cold atomic absorption spectrometry, respectively, and concentrations of copper (Cu), lead (Pb), and cadmium (Cd) were detected by anodic stripping voltammetry. Spatial distribution patterns indicated that these waterborne pollutants are mainly sourced from terrestrial inputs. Temporal variation showed that Pb contents decreased in the past five years, and summer exhibited higher concentrations of Hg, Cu, and Cd than spring and autumn. Spearman's rank correlation coefficients demonstrated that temperature correlated positively with Cu content, while dissolved oxygen, pH, and suspended particulate material correlated negatively with pollutant concentrations. While hazard quotient values were lower than 1 for TPHs, Hg, Pb, and Cd, the hazard quotient of Cu (4.88) was greater than 1, suggesting potential ecological risks of this element in seawater of the southeastern Bohai Sea. The total target hazard quotients of Hg, Cu, Pb, and Cd in seawater of the southeastern Bohai Sea were all lower than 1, which indicated that there was no noncarcinogenic risk caused by heavy metals in seawater of the southeastern Bohai Sea. However, the carcinogenic risk of Cd (1.54 × 10-5) was in the range of 10-6-10-4, which may lead to the occurrence of cancer. This study sounds an alarm for stricter control of metal emissions into this sea area.

Determination of Fe, Ni, Cu, Zn, Cd and Pb in seawater by isotope dilution automatic solid-phase extraction—ICP-MS

Determination of Fe, Ni, Cu, Zn, Cd and Pb in seawater by isotope dilution automatic solid-phase extraction—ICP-MS

Accumulation of heavy metals Pb and Hg in feather shells (Anadara antiquata) in Lekok Coastal Waters, Pasuruan Regency

This research is a quantitative descriptive study that aims to determine the heavy metal contamination of Pb and Hg. Sampling was carried out exploratively in the waters of Lekok Beach, Pasuruan Regency. The data obtained were analyzed by descriptive analysis by comparing the quality standards of the Minister of Environment Decree No. 51 of 2004. And analyzed by correlation test to determine the relationship between the content of heavy metals Pb and Hg in seawater and sediment with feather shells. The results of this study indicate that shellfish (Anadara antiquata) can accumulate heavy metals Pb and Hg. The average accumulation of heavy metals Pb and Hg in Anadara antiquata was 2,315 ppm and 1,100 ppm. The average heavy metal content of Pb and Hg along the sea waters of the Lekok coast are 0.204 ppm and 0.073 ppm. In the sediment the average metal content of Pb and Hg is 5.318 ppm and 1.215 ppm. The heavy metal content has exceeded the quality standard limit that has been determined by the Decree of the Minister of the Environment No. 51 of 2004 and RNO, so that it can be harmful to human health who consume shellfish. The results of the correlation test showed that there was a positive correlation between the heavy metal content of Pb and Hg in sediment and seawater and the heavy metal content of Pb and Hg in shellfish.

Contaminant Characteristics and Influencing Factors of Heavy Metals in Seawater and Sediments in a Typical Mariculture Bay in South China

Heavy metal pollution in the mariculture areas is of considerable attention due to its potential ecological effects and public concern for seafood safety. A better understanding of the current contamination status and historical trend of heavy metals in the ecosystems of mariculture areas has an important implication for the sustainable development of marine ecosystems and for public health concerns. To assess the impact of human activities on heavy metal pollution in the mariculture area, seven metals (Cu, Pb, Zn, Cd, Hg, As, and Cr) and the environmental parameters were seasonally investigated in the surface seawater and sediments in Qinzhou Bay, a typical mariculture bay in South China. Seasonal variations in the concentration of heavy metals were found in both seawater and sediment, which are mainly influenced by seasonal hydrological change, biological activity, and human influence. The concentration of heavy metals in the seawater was at a relatively higher level than that of other mariculture areas in China, while a lower level was found in the sediment. The concentration of Cu increased in both seawater and sediment for the past decades (by nearly 2 times), which is mainly influenced by the mariculture and shipping activities. The concentration of Hg decreased significantly in the seawater for the past 40 years (decreased by 13 times) due to the decrease in production and usage of Hg. However, the concentrations of Pb, Zn, and Cd in seawater showed an increasing trend in the mariculture bay, while the concentrations of Pb, Zn, As, and Cr decreased in the sediment over the past decades. The decrease in pH value (decreasing by 4.7% for the past 20 years) was responsible for the different trend of those metals between seawater and sediment because the decrease in pH could re-release metals from sediments into the water column. Hg and As are the main ecological risk factors in the mariculture bay. This study suggests that environmental changes, such as ocean acidification, affect the distribution of metals in seawater and sediments, which we should be more vigilant and concerned about under the global climate change.

Environmental Quality and Ecological Risk Assessment of Heavy Metals in the Zhuhai Coast, China

The rapid urbanization and industrialization in the coastal Zhuhai have resulted in severe heavy metal contamination. Heavy metals are extensively used as indicators of coastal contamination, but the comparability among different geographic environments needs to be further explored and scrutinized. In this study, heavy metals (i.e., As, Zn, Cd, Cr, Hg, Cu, and Pb) in surface seawater (20 sites), sediments (10 sites), and organisms (13 sites, shellfish, algae, fish, and crustaceans) were analyzed to assess the distribution, enrichment, and ecological risk in the coastal regions of Zhuhai (2017 and 2018). The results showed that Cu, Zn, and Pb exceeded the standards of seawater, indicating the presence of anthropogenic pollution. Meanwhile, the ecological risk results showed that Cd and Cu indicated moderately high environmental risks. The quantity and quality of heavy metals in organisms showed different trends in the sea, which affected marine organisms in the northeastern area. The main factors contributing to the ecological risk of these two heavy metals are the emissions from chemical companies. Therefore, preserving the high biological diversity in this area is important to ensure the health and productivity of the seawater ecosystem in the coastal area. These results may play a key role in promoting decision makers to manage the sustainability of the Zhuhai coast.