Heavy Metal Content Analysis and Toxicity Assessment of Oil-Based Drilling Mud using Zebrafish Embryos

Aim: Used oil-based drilling muds (OBDMs) are toxic to marine organisms due to the fluid’s complex chemical nature. The illegal dumping of used OBDMs is still rampant in many parts of the world despite of the stringent laws and regulations pertaining to its disposal. To date, study of the assessment of heavy metal content in used OBDMs from the Malaysian oil and gas industry has been limited. Furthermore, the study of the toxic effect of OBDMs using a zebrafish embryo model has never been reported before. Therefore, in this research, the used oil-based drilling muds (OBDMs) were analyzed for their heavy metal content and toxicity against Zebrafish embryos. Methods: Used OBDMs were collected from an Anchor Handling Tug Supply (AHTS) vessel mud tank from Kemaman, Terengganu. The heavy metal content in the mud was analyzed using ICP-AES. Zebrafish embryos were exposed to OBDMs of varying concentrations (i.e., 0.25 mg/ml, 0.125 mg/ml, 0.06 mg/ml, 0.03 mg/ml, 0.015 mg/ml, 0.0076 mg/ml, 0.0034 mg/ml and 0.0019 mg/ml). The toxicity and teratogenicity of the mud on zebrafish embryos were assessed every 24 hours, for 96 hours, using endpoints like embryo mortality, heart rate and hatching rate. Results: The heavy metal content of used OBDMs had the highest concentration of barium (Ba) 2360 ppm, followed by lead (Pb) 120 ppm, zinc (Zn) 104 ppm, arsenic (As) 9 ppm, and chromium (Cr) 16 ppm, with cadmium (Cd) concentration of less than 1 ppm being the lowest. The Ba (2360 mg/L) concentration in the OBDM sample exceeded the concentration of Ba in normal marine sediment reported to be around 2000 mg/L. The 96 h LC50 of the OBDM in zebrafish embryos was reported to be 0.005 mg/mL (5 ppm). Zebrafish embryos that were exposed to high concentrations of OBDMs exhibited a lower hatching rate and reduced heart rate than the control group. Conclusion: The findings of this study are indicative of the highly toxic nature of used OBDMs and its dosage-dependent teratogenicity effects on zebrafish embryo. Knowledge of the potential environmental impacts of OBDMs released into the marine environment can be the basis for prudent decision-making that will help minimize environmental damage.

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Study of The Pharmacological Activity and Heavy Metal Content of Eichhornia Crassipes Extract

ICONIET PROCEEDING ◽

10.33555/iconiet.v2i2.17 ◽

2019 ◽

Vol 2 (2) ◽

pp. 91-95 ◽

Cited By ~ 1

Author(s):

Jimmy Jimmy ◽

Diah Indriani Widiputri ◽

Paulus Gunawan

Keyword(s):

Heavy Metal ◽

Pharmacological Activity ◽

Water Hyacinth ◽

Metal Content ◽

Eichhornia Crassipes ◽

High Light Intensity ◽

Milling Process ◽

Heavy Metal Content ◽

Solvent Ratio ◽

Negative Impacts

Eichhornia crassipes is well-known as water hyacinth. Water hyacinth grows rapidly in the nutrient-rich water and high light intensity places. The uncontrollable growth of water hyacinth has caused many negative impacts to the environment. For instance, interrupted water transport and decreased population of aquatic lives. The capacity of utilising water hyacinth is slower than water hyacinth growth and water hyacinth is still considered as a threat to theecosystem. This work was focused on the study of the pharmacological activity and heavy metal content of water hyacinth in Lake Cipondoh, Tangerang. Fresh water hyacinth was pre-treated through oven-drying and milling process. After that, each part of the plant was macerated by using multiple extraction method with 96% ethanol/water and three variations of sample-to-solvent ratios (1:30, 1:50, and 1:75 w/v). The result of the experiment showed thatwater hyacinth leaves produced an extract with lowest IC 50 (55.76 ± 6.73 ppm) compared toother parts. The most optimum solvent used to achieve this result was 96% ethanol/water (1:1 v/v). In order to obtain the lowest antioxidant activity, the sample to solvent ratio used was 1:50 and the heavy metal in the extract was very low. With this result, it was concluded that there is a promising opportunity to apply the water hyacinth growing in Lake Cipondoh, Tangerang as herbal medicine ingredient. Through this utilization, the overall number of water hyacinth in Indonesia can be reduced or at the least be controlled, so that the environmental problem caused by this plant can be minimized.

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