Assessment of chlorinated hydrocarbons and trace metal contamination of Moroccan marine species

مرکز و کتابخانه مطالعات اسلامی به زبان های اروپایی

منو

" Assessment of chlorinated hydrocarbons and trace metal contamination of Moroccan marine species "
A. El Hraiki

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1113015
Doc. No	:	TLpq304064592
Main Entry	:	A. El Hraiki
Title & Author	:	Assessment of chlorinated hydrocarbons and trace metal contamination of Moroccan marine species\ A. El Hraiki
College	:	Oregon State University
Date	:	1993
student score	:	1993
Degree	:	Ph.D.
Page No	:	175
Abstract	:	The major aims of this study are to: (1) Assess the relative degree of heavy metal and chlorinated hydrocarbons contamination of fish products collected from several different locations and times from the Mediterranean Sea and Atlantic Ocean; (2) Conduct health risk analysis of high fish consumers; (3) Assess the extent of heavy metal contamination of mussels along the Atlantic Coast of Morocco; and (4) Examine the feasibility of using hepatic mixed function oxidase as a bioindicator of fish exposure to pollutants. Contamination results of fishery products by metals revealed relatively high levels but they remain within acceptable limits for most of the species. The mean concentration detected in the most consumed fish species are 0.195 0.103 for Pb, 0.186 0.118 for Cr, 0.504 0.138 for total Hg and 0.030 0.006 mg/kg fresh weight (f.w.) for Cd. The use of mussels (Mytilus edulis) to assess metal contamination in a coastal area shows considerable promise since these invertebrates are sedentary and thus accurately reflect the degree of local contamination. Despite some variations due to size of mussels and seasonal effects, this assay can be optimized by using the whole soft tissue of a composite mussel sample of similar size organisms (5-6 cm). Contamination of fish by chlorinated hydrocarbon pesticides showed moderate levels of DDTs (ppDDE, ppDDD, ppDDT) and lindane as the predominant compounds in most species with mean concentrations for DDTs varying from 5.6-18 mug/kg f.w. from the Atlantic Ocean and from 3-19.2 mug/kg f.w. from the Mediterranean Sea. PCB contamination yielded a mean concentration of 10.8 mug/kg f.w. for Mediterranean fishes and 17.9 mug/kg for Atlantic species. Chlorinated hydrocarbons, cadmium, lead, and total mercury were selected for human health risk assessment. The risk was evaluated by measuring contaminant concentration in the most consumed fish species by a population of fishermen with heavy fish consumption; and by calculation of intake based on fish consumption. Risk evaluation was based on the Acceptable Daily Intake (ADI) set by FAO/WHO regulatory policy. This assessment revealed that chlorinated hydrocarbons and PCBs are not likely to cause toxicity problems for the study population. However, lead, cadmium, and mercury intake were respectively 10%, 14%, and 145% of the ADI which is alarming, especially regarding mercury. The use of mixed function oxidase as an index of exposure of fish to contaminants was difficult to establish in environmental samples. Fish are exposed to a mixture of pollutants and a correlation between chlorinated hydrocarbon or polyaromatic hydrocarbon exposure and the induction of mfo systems becomes rather uncertain.
Subject	:	Aquaculture
	:	Biological sciences
	:	Environmental science
	:	Fish production
	:	Health and environmental sciences
	:	Toxicology