碩士 / 國立屏東科技大學 / 環境工程與科學系所 / 105 / Estuaries receive nutrients and contaminants from the upper reaches of rivers, leading to higher levels of contamination in estuarine sediments. The degree of pollution is usually assessed with chemical analyses, but estuarine toxicity tests to evaluate the actual degree of risk are still insufficient, and therefore there is a lack of data on bioavailability. The development of estuarine sediment toxicity tests using the native Taiwanese species Ptilohyale barbicornis (Hyalidae) as a test species was conducted in the present research. The biological exposure to water toxicity test conditions (salinity, size, and temperature) and sediment toxicity test conditions (formulated sediment, salinity, age, and temperature) on reference toxicants were first evaluated.
Field sediments were collected from ten locations, including the Keya River Estuary (KY), Dacheng Wetlands (DW), Long Gong River Estuary (LG), Jiangjyun Harbour (JJ), Cigu Lagoon (CL), Cigu Tidal Marsh (CT), A-gong-dian River Estuary (AGD), Houjing River Estuary (HJ), Cijin Harbour (CJ), and Linpien River Estuary (LP), along the coastline in Taiwan in order to assess the accumulation of metals and polycyclic aromatic hydrocarbons. The correlations of chemical analyses in sediments with survival in an acute toxicity test and growth in a chronic toxicity test were performed. Other methods to assess the degree of metals contamination used the Enrichment Factor (EF) and Source Analysis, and the Equilibrium Partitioning Sediment Benchmark Toxic Unit (ESBTU) for PAHs.
Our results indicated that the most suitable test conditions for Ptilohyale barbicornis in the water toxicity test were 19‰ salinity, a size passing through a 0.6 ~ 0.355 mm screen, and 25 ± 2 ℃for temperature. The 96 hr toxicant exposure showed that the LC50 2.012 to 2.597 mg/L for copper, 1.931 to 2.154 mg/L for cadmium, and 6.477 to 10.16 mg/L for Ptilohyale barbicornis indicating capability serving as a toxicity test species.
The analysis of metals and PAHs in sediments at ten sites to assess their levels of pollution revealed that a high proportion of trace metals at site KY exceeded Sediment Quality Guideline (SQGs). However, metals were highest in site CL sediment according to the Enrichment Factor (EF). Among these sediment samples, 4- and 5,6-ring PAHs were the predominant PAH congeners, exceeding the SQGs and producing the maximum value for the total toxic equivalent (ESBTU) for PAHs that was calculated in the DC sample (3.99).
A 10-day acute toxicity test showed the highest survival rate of 72% at the KY site, followed by the site JJ (69%), indicating that the bioavailability of trace metals was not high. Although the survival rate was also high in the chronic toxicity test, growth in terms of body weight and length was suppressed when compared with controls. Overall, the correlation between the concentrations of trace metals and PAHs with survival in toxicity tests was not obvious, with the exception of BaP. Various estuarine sediment pollutants in the quality guidelines can be further evaluated using Ptilohyale barbicornis to understand their comprehensive biological effects and ecological risks.
Keywords: estuary sediment, amphipoda, Ptilohyale barbicornis, toxicity test
| Identifer | oai:union.ndltd.org:TW/105NPUS5615033 |
| Date | January 2017 |
| Creators | Wang, Chen-CI, 王莀㥓 |
| Contributors | Hsieh, Chi-Ying, 謝季吟 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 126 |
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