Fuzzy Based Health Risk Assessment of Heavy Metals Introduced into the Marine Environment

Abstract

There are concerns among scientists about the significant amount of heavy metals introduced into the marine environment by the petroleum industry during exploration and production phases. The toxicity of heavy metals such as arsenic (As), cadmium (Cd), chromium (Cr), and mercury (Hg) are of particular concern, because they may pose major human health risks through consumption of contaminated food. This study conducts a conservative human health risk assessment study for the selected heavy metals discharged into the marine environment through petroleum operations. Probabilistic risk assessment technique, together with fuzzy set theory, is used to incorporate uncertainties into the risk assessment model. Random and fuzzy variables were integrated to develop the membership functions to individuals’ risk at different fractiles, and corresponding cumulative distribution functions (CDF) of risks were developed. The α-cut concept was used to handle fuzzy arithmetic and Monte Carlo simulation (MCS) was used to carry out the statistical calculations. Using human ingestion pathway, the 90th percentile membership function of cumulative cancer risk due to various heavy metals was calculated, and the support of this fuzzy cancer risk is from 1.0E–08 to 2.50E–05. Non-cancer risk was evaluated as well and found to be within the acceptable limits.