Ecological and Human Health Risk Assessment of Heavy Metal in Sediment and

Overview

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species were below the regulation range of 1.0 × 10−6 to 1.0 × 10−4 set by the USEPA. The cluster analysis revealed two clusters. Cluster
Table 1. Sediment Quality Guidelines (SQG) of Heavy Metals and Metalloid (Unit: mg/kg)
deionized water. The solution was filtered through Whatman with 21% probability of being toxic, mPEL Q = 1.51 ~ 2.3 in-
were performed for initial and periodic verification of calibra- contamination with 73% probability of being toxic respectively
terized compared the effects range low (ERL), effects range me- guideline of threshold effects level (Long et al., 2006; Paul et al.,
(MET) (Table 1). Equation (2) shows the formulae used to calcu- < 10 indicates moderate hazards; HQ > 10 indicates high hazards
late the mean PEL quotient: (Feng et al., 2011; Benson et al., 2018).
The newly mHQ was computed to ascertain the degree of ate severity; 1.0 < mHQ < 1.5 means low severity, and 0.5 < mHQ
3.5 means extreme severity; 3.0 < mHQ < 3.5 indicates very high (7) of USEPA Region III Risk-Based Concentration (USEPA,
severity; 2.5 < mHQ < 3.0 means high severity; 2.0 < mHQ < 2.5 2011) which estimates non-carcinogenic health risk associated
(Mc  FIR  10−3  EF  ED) 3). The mean PCI for As (0.01), Hg (0.10), and Pb (0.06) were
slope, oral (mg/kg bw-1 day-1) for Pb, and Cd are 0.009 and 0.6
ing SPSS v.25 and PAST 4.10 (Hammer et al., 2001). ArcGIS 3.3. Ecotoxicological Assessment and Mean Effect Level
heavy metals/metalloid in sediment. Levels of Cd were higher than TEL by 100%, As by 3%,
Hg by 24%, and Pb in 3.6% in sediment across all stations. For
1. Results and Discussion PEL, As was higher by 1.04%, Hg by 8.4%, Cd by 18.2%, and
Pb by 1.4% in sediment. The estimated mean probable effects
The heavy metals concentrations geospatial distribution as presented in Figure 4. Generally, the mean probable effects
(green) and Hg (white) showed significant increase in concentra- 0.1) notably with 8% minimal probability of being toxic, except
significant increase in concentrations at station 3. Generally, tion (0.11 ~ 1.5) with 21% probability of being toxic which cor-
Figure 5. Mean variations of heavy metals/metalloids in muscle of fish species. Note: (*) indicates significant differences (p <
priority indicating low degree of contamination across all sta- Hg values ranged from 0.021 to 0.74, Cd values ranged from
tions with 9% probability of being toxic in the sediment 0.66 to 1.51, Pb values ranged from 0.02 to 0.05 (Table 2). As
Quotient for Sediment As, Hg, and Pb was generally below 0.5, while Cd ranged from
The estimated HQ of As values ranged from 0.002 to 0.067, 0.56 to 1.30 across all stations off western Nigeria coast (Table
Table 3. Estimated THQ, HI And TCR of Metals in Demersal Fish Species
and 4 respectively fell within the range of 1 < HQ < 10 which once it is, it is slowly eliminated, much like other metals, and
of contamination, while Cd ranged between 0.5 and 1.0 which
The EDI values for As ranged from 0.19 × 10 -9 (Rhizopri-
onodon acutus) to 8 × 10-9 (Sardinella maderensis), Hg ranged
maderensis), Cd ranged from 0.12 × 10-9 (Pagellus ehrenbergi)
to 1.45 × 10 -8 (Galeoides decadactylus) and Pb ranged from
The heavy metal levels in the muscle tissues of demersal loid in demersal marine fish species are shown in Table 3. The
marine fish species are presented in Figure 5. Mean levels of THQ values in demersal marine fish species from the western
As, Hg, Cd, and Pb in muscles of the demersal fish species fell off Nigeria coast ranged from 0.01 × 10-5 to 8.99 × 10-5. The
Clarias anguillaris, had As ranged from 0.05 ± 0.01 ~ 0.15 ± cation to consumers over a period time. These findings also cor-
Studies in Marine Science, 18, 44-56. https://doi.org/10.1016/j.rsm and uses of mean sediment quality guideline quotients: A critical re-
Santos, J.L., Malvar, J.L., Martín, J., Aparicio, I. and Alonso, E. (2020). Table: November (2011). http://www.epa.gov/regshwmd/risk/hum

Methods (brief)

with fish consumption from western Nigeria offshore in the Gulf of Guinea. Triplicate samples of demersal marine fish species and
sediments were collected from five stations (fishing ground) and analysed for heavy metals (mercury (Hg), cadmium (Cd), and lead (Pb))
and metalloid (arsenic (As)) using ICP-OES (inductively coupled plasma optical emission spectrometry) adopted USEPA 200.7 standard
grounds of the Western Offshore Nigeria, Gulf of Guinea. 2.2. Sample Collection
and 04°35′ E, and latitudes of 06°00′ and 06°15′ N, which is and surface sediments were collected. Demersal fishes were
fish stock assessments were carried out on five sampling hotspots was collected using 0.1 m2 van Veen grab sediment sampler. Trip-
(fishing grounds) along western offshore Nigeria, Gulf of Guinea licates of each fish species were collected in Ziploc bags, and
the Delta flank consists of three main subsurface lithostrati- Sample (surface sediments and fish muscle) preparation
and analyses of As, Hg, Cd, and Pb in samples were performed
with USEPA. 200.7 standard method using ICP-OE spectrom- mPELQ = i =1
cle size < 2 mm) of sediment and fish muscle samples, were tion, and PEL is probable effect level value of the individual
placed into a digestion vessel. Then 2 mL (1:1) HNO3 and 5 mL metal (Darwish et al., 2021).The mPELQ is categorized (Paches
in Cd, Pb, and As of the fish species across sampled stations 0.43 × 10-5 which fell within the recommended threshold dose
sessment of heavy metals in fish species collected from catchments Palaeontologia Electronica, 4(1), 1-9. https://palaeoelectronica.org

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The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised